Document 7RavjorYvwJr41X8QRdO7KoXo

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PRELIMINARY DRAFT CHAPTER 7 ENVIRONMENTAL CENCENTRATIONS AND POTENTIAL HUMAN EXPOSURE TABLE OF CONTENTS 7.1 --7 . 2 7.4 INTRODUCTION......... .................................................................................. 7-1 AMBIENT CONCENTRATIONS................................................... ........................... 7.2.1 Ambient Air--......................... .......... ............................. *---------- 7.2.1.1 Total Airborne Lead Concentration------- ...... 7,2.. 1.2 Airborne Particle Size Distribution............... 7.2.1,3 Vertical Gradients of Lead in the Atmosphere.................................................. .............. 7.2.2 Soil.................................. ......................................................... .......... 7.2.3 Dusts......................... ................ ..................................................... 7.2.4 Vegetation......................... ........ ......................................... 7-1 7-1 7-2 7-27 7-38 7-41 7-4.3 7-45 POTENTIAL HUMAN EXPOSURES. . ................................... ................................ 7-46 7.3.1 Mobile Source Exposures................................................. 7-46 7.3.2 Point Source Exposures....... ................ -------------------------------- 7-52 7.3.3 Dietary Exposures..,,...,............. ,,............ ............. 7-55 7.3.3.1 Food.................. ........................................................... .. 7-55 7.3.3.2 Water.................... .............. ............ ....................... 7-64 7.3.4 Exposures Resulting from Manmade Materials...................... 7-71 7.3.5 $oi 1 and Dust Exposures...................... .............. ............ 7-73 7.3.6 Occupational Exposures............................... ............................... 7-73 7.3.6.1 Exposures in Lead Mining, Smelting, and Refining........... ................................................. .. 7-74 7.3.6.2 Exposures in Welding and Cutting of Metals Contai ni ng Lead........................................... 7-77 7.3.6.3 Exposures in the Electric Storage Battery I ndustry .................................................................... 7-78 7.3.6.4 Exposures in the Printing Industry.7-78 7.3.6.5 Exposures in Alkyl Lead Manufacture.................. 7-78 7.3.6.6 Exposures in Other Occupations...................... 7-79 SUMMARY...................................... ............. ............................................. .......... 7-80 N33758 PB7/A 1 12-15-82 TEH 0530383 PRELIMINARY DRAFT Table No. 7-1 7-2 7-3 7-4 7-5 7-6 7-7 7-8 7-9 7-10 7-11 7-12 7-13 7-14 7-15 LIST OF TABLES Page Atmospheric Lead in Urban, Rural, and Remote Areas of the World........................... .......................... ........... ....................... 7-3 Comparison of(Indoor and Outdoor rborne Lead Concen trati airs . '.T."........... ............ .......... ........... .................. 7-5 Number of NASN Urban Stations Whose Data Fall Within Selected Annual Average Lead Concentration Intervals, 1966-1980................................................... ......... .............................. .. 7-8 Number of NASN Nonurban Stations Whose Data Fall Within Selected Annual Average Lead Concentration Intervals, 1966-1980................. ................. ......... ................ ........... ............................ 7-10 Cumulative Frequency Distributions of Quarterly Lead Measurements at Urban Stations by Year, 1970-1980......... 7-12 Cumulative Frequency Distributions of Quarterly Lead Measurements at Nonurban Stations by Year, 1970-1980...... 7-13 Trends in Quarterly Lead Values for Selected Urban Sites, 1975-1980............. ......... ............................................... .............. .. 7-16 Locations Reporting Valld^uarterly Lead ConcentFaHSftS5****^^ Greater than 1.0 pg/nr (The Current Ambient Air StandardT^\ 1 n 1979 and 1980..,............. ..................... ....................... 7-17 Maximum Quarter Lead Concentrations Reported for SMSA's > 1 Million Population, 1979-1981................... ................................ 7-22 Summary of Maximum Quarterly Lead Average by Selected Concentrations According to Site-Type, 1979-81--.................. 7-25 Summary of Lead Concentrations Near a Roadway in Cincinnati, Ohio.................. ............... ........ ........................... .. 7-26 Information Associated with the Airborne Lead Size Distributions of Figure 7-2............................................................... 7-29 Fraction of Inhaled Airborne Lead Deposited in Each Compartment of the Human Respiratory System.......------ .... 7-39 Airborne Lead Concentrations at 5- and 20-ft Elevations Above Street Level................. ............ ............................... ......... 7-40 Four-Hour and 24-Hour Airborne Lead Concentrations at Two Roadside Sites in the Los Angeles Catalyst Study, 1974-1977..................... .......... ....................... .......................... 7-47 PB7/A 12-15-82 TEH 0530384 DUP050031297 PRELIMINARY DRAFT Table No, 7-16 7-17 7-18 7-19 7-20 7-21 7-22a 7-22b 7-23 List of Tables (continued) Lead Concentrations in Street Dust in Lancaster, England.... Lead Dust on and Near Heavily Traveled Roadways.,.............. ........ Lead Content in or on Roadside Soils and Grass as a Function of Distance from Traffic and Grass Depth in Profi 1 e. *..................... ........................................................................... Lead Dust in Residential Areas,.,--............................. Lead Concentrations in Various Samples as Measured by the Caltech and NMFS Laboratories,........................................................... Airborne Lead Concentrations Based on Personal Samplers, Worn by Employees at a Lead Mining and Grinding Operation in the Missouri Lead Belt..,,.................. .............. Two Hypothetical Estimates of Contributions of Specific Routes of Exposure to the Total Absorption of Lead by Populations of Urban Children.............................................. Two Hypothetical Examples of Estimates of Contributions of Specific Sources of Exposure to Total Absorption of Lead For Subsets of the General Adult Population................. .. Comparison of Estimated Natural Levels of Lead in the Environment with Typical Present-Day Levels........... ................... Page 7-49 7-50 7-51 7-53 7-62 7-75 7-84 7-85 7-87 PB7/A 1 1 12-15-82 TEH 0530385 DUP050031298 PRELIMINARY DRAFT Figure No, 7-1 7-2 7-3 7-4 7-5 7-6 7-7 7-8 7-9 LIST OF FIGURES Seasonal patterns and trends in quarterly average urban lead concentrations................................................. Airborne mass size distributions for lead taken from the 1 i terature................ ........................................ ............. ................... Deposition of monodisperse aerosols in the pulmonary region for mouth breathing as a function of aerodynamic di ameter......... ............................. --_________--.......... .............. .. Deposition of monodisperse aerosols in the tracheobronchial region for mouth breathing in percent of the aerosols entering the trachea as a function of aerodynamic di ameter------- ----------------------- Deposition of monodisperse aerosols in extrathoracic region for mouth breathing as a function of D2Q.................... Solubility of lead in street dust as a function of pH, using hydrochloric acid at 20C, .......................... Annual ambient air lead concentration near a smelter, by area, before the August 1974 and August 1975 surveys... Change in drinking water lead concentration in a house with lead plumbing for the first use of water in the morning... Theoretical distribution of drinking water lead concentrations based on the model of Bailey and Russell (1981)............... .. Page 7-15 7-28 7-35 7-36 7-37 7-54 7-56 7-67 7-70 PB7/A 17 12-15-82 TEH 0530386 DUP050031299 PRELIMINARY DRAFT 7.1 INTRODUCTION Lead-bearing aerosol particles emitted from the sources described in Chapter 5, arrive at their point of deposition by mechanisms described in Chapter 6. Even though the distance traveled may be a few meters or several thousand kilometers, the important point is that until the particle deposits on a surface, it will have no effect on plants, animals, or humans. If this surface is alveolar lung tissue, the lead may be incorporated directly. For other surfaces, the lead must be ingested (animals) or absorbed (plants) before any effect is possible. Therefore, it is necessary to understand the ambient concentrations of lead in air normally breathed by humans, and in other environmental components such as soil, dust, and vegetation likely to be directly or indirectly ingested by adults and children. This chapter is divided into two parts. In the first part, the range of ambient concentrations normally encountered by humans in typical working, living, and playing environments are emphasized. Air concentrations represent the bulk of this discussion because the most information is available on this topic. Lead in soil, dust, and vegetation are one step closer to ingestion but data are limited since there are no organized sampling networks for these media. In the second part of the chapter, ambient concentrations are discussed in the context of potential human exposure. It is at this point that the effects of atmospheric lead are combined with lead from other sources, such as paint, industrial milling processes, and plasticizers to produce a composite picture of human exposure based on diet, the living and recreational environment, and a few sensitive occupational situations, 7.2 AMBIENT CONCENTRATIONS Quantifying human exposure to lead requires an understanding of ambient lead levels in environmental media. Of particular importance are lead concen trations in air, soil, dust, and vegetation. The sections which follow discuss environmental lead concentrations in each of these media in the context of how these concentration increase or decrease human exposure. 7,2.1 Ambient Air Ambient airborne lead concentrations may influence human exposure through direct inhalation of lead-containing particles, and through ingestion of lead which has been deposited from the air onto surfaces. Although a plethora of data on airborne lead is now available, our understanding of human exposure is far from complete: most ambient measurements were not taken in conjunction PB7/A 7-1 12-15-82 TEH 0530387 DUP050031300 PRELIMINARY DRAFT with epidemiological studies of the effects of lead on man or other organisms. Yet that is the context in which these studies must now be interpreted to shed the most light possible on the concentrations likely to be encountered in various environmental settings. Three categories of studies are included in this section. First, data on total airborne lead concentrations are summarized. Included in this category are data from government sampling networks as well as the results of independent investigators. The second category involves airborne lead size distribution measurements. Finally, vertical gradients of lead in the atmosphere, particularly near roadways, are discussed, 7,2.1,1 Total Airborne lead Concentratlons--A thorough understanding of human exposure to airborne lead requires detailed knowledge of spatial and temporal variations in ambient concentrations. The wide range of concentrations is apparent from Table 7-1, which summarizes data obtained from numerous independent measurements. Concentrations vary from less than 0.001 pg/m in remote areas to over 10 pg/m near sources. Many of the remote areas are far from human habitation and therefore do not reflect human exposure. However, a few of the regions characterized by small lead concentrations are populated by individuals with primitive lifestyles; these data provide baseline airborne lead data to which modern American lead exposures can be compared. Examples include some of the data from South America and the data for Nepal. Comparing urban, rural, and remote airborne lead concentrations in Table 7-1 suggests that human exposure to lead has increased over time, as the use of lead in inhabited areas has increased. This is consistent with published results of retrospective human exposure studies. For example, Ericson et al. (1979) have analyzed the teeth and bones of Peruvians buried 1600 years ago. Based on their data, they estimate that the skeletons of present-day American and British adults contain roughly 500 times the amount of lead which would occur naturally, in the absence of widespread anthropogenic lead emissions. Grandjean et al. (1979) and Shapiro et al. (1980) report lead levels in teeth and bones of contemporary populations to be elevated 100-fold over levels in ancient Nubians buried before 750 A.D. On the other hand, Barry and Connolly (1981) report excessive lead concentrations in buried medieval English skeletons; the lead is attributed mainly to absorption from the surrounding soil. It is important to note that the remote area concentrations reported in Table 7-1 do not necessarily reflect natural, preindustrial lead. Murozumi et PB7/A 7-2 12-15-82 TEH 0530388 DUP050031301 PRELIMINARY DRAFT TABLE 7-1. ATMOSPHERIC LEAD IN URBAN, RURAL, AND REMOTE AREAS OF THE WORLD. Adapted from Nriagu (1978). ___ ^ Location o Sampling Period Lead cone, (pg/m ) Reference Urban Berlin Vienna Zurich Liege Turin Rome Pari s Mi ami New York Boston St. Louis Ci ncinnati Chicago Salt Lake City Denver Los Angeles Rio de Janeiro Ottowa Toronto Montreal 1966-67 1970 1970 1972 1974 1972-73 1964 1974 1974 1972 1973 1970 1970 1974 1970 1968-69 1972-73 1975 1975 1975 Rural United Kingdom New York Bight Framingham, MA Chadron, NE 1972 1974 1972 1973-74 Remote White Mtn., CA Antarctica South Pole Thule, Greenland Thule, Greenland Prins Christian- sund, Greenland Dye 3, Greenland High Sierra, CA Olympic Nat. Park, WA Enewetak, Pacific Ocean Kumjung, Nepal Bermuda Spitsbergen 1969-70 1971 1970 1965 1978-79 1978-79 1979 1976-77 1980 1979 1979 1973-75 1973-74 3.8 2.9 3.8 2.7 5.0 4.5 4.6 1.3 1.1 4.5 1.1 1.8 1.1 0.89 0.8 3.6 0.8 1.3 1.3 2.0 0.13 0.13 0.9 0.045 .008 .0004 .00063 .0005 .008 .018 .00015 .021 .0022 .00017 .00086 .0041 .0058 Blokker, 1972 Hartl and Resch, 1973 HSgger, 1973 Rondia and DeGraeve, 1973 Magi et al., 1975 Colacino and Lavagnini, 1974 Blokker, 1972 HASL, 1975 HASL, 1975 O'Brien et al., 1975 Tanner et al., 1974 Lee et al., 1972 Lee et al., 1972 HASL, 1975 Lee et al., 1972 Chow, 1973 Branquinho and Robinson, 1976 NAPS, 1975 NAPS, 1975 NAPS, 1975 Cawse, 1974 Duce et al., 1975 O'Brien et al., 1975 Struempier, 1975 Chow et al., 1972 DuCe, 1972 Zoller et al., 1974 Murozumi et al., 1969 Heidam, 1971 Heidam, 1981 Davidson et al., 1981c Elias and Davidson, 1980 Davidson et al., 1982 Settle and Patterson, 1982 Davidson et al., 1981b Duce et al., 1976 Larssen, 1977 PB7/A 7-3 12-15-82 TEH 0530389 DUP050031302 PRELIMINARY DRAFT a"). (1969) and Ng and Patterson (1981) have measured a 200-fold increase in the lead content of Greenland snow over the past 3000 years. The authors state that this lead originates in populated mid latitude regions, and is transported over thousands of kilometers through the atmosphere to the Arctic. It is apparent that most of the concentrations in Table 7-1, including values for remote areas, may be influenced by anthropogenic lead emissions. All of the data in Table 7-1 refer to the ambient atmosphere. Because people spend much of their time indoors, these data cannot be used to obtain an accurate indication of exposure to airborne lead. Table 7-2 summarizes the results of several indoor/outdoor airborne lead studies. In nearly all cases, the Indoor concentration is substantially smaller than the corresponding value outdoors; the only indoor/outdoor ratio exceeding unity is for a high-rise apartment building, where air taken in near street level is rapidly distributed through the building air circulation system. Some of the studies of Table 7-2 include published data showing smaller indoor/outdoor ratios during the winter, when windows and doors are tightly closed. Overall, it has been suggested that indoor/outdoor ratios of 0.6 to 0.8 are typical for airborne lead in non-air conditioned houses. Ratios in air conditioned houses are expected to be closer to 0.3 to 0.5 (Yocum, 1982). The avaliable data imply that virtually all airborne lead found indoors is associated with material transported in from the outside. Because of the complexity of factors affecting infiltration of air into buildings, however, it is difficult to accurately predict indoor lead concentrations based on outdoor levels. Detailed knowledge of indoor and outdoor airborne lead concentrations may still be insufficient to assess human exposure to airborne lead. The study of Tosteson et al. (1981) in Table 7-2 included measurement of airborne lead concentrations using personal exposure monitors, carried by individuals going about their day-to-day activities. In contrast to the lead concentrations of 0.092 and 0.12 pg/m3 given in the table, the average personal exposure was 0.16 pg/m . The authors suggest the inadequacy of using fixed monitors at either indoor or outdoor locations to assess exposure. A problem with the studies referenced in Tables 7-1 and 7-2 is that quality control and interlaboratory comparability are generally unspecified. In contrast, there are two principal airborne lead data bases which include PB7/A 7-4 12-15-82 TEH 0530390 DUP050031303 c tH Ics*n u e t- *0+1- o.c +> a.: 3 O & 003 CTl SrH--4 -uUf- CPcrMN> ,+UJ wpH >* r"N 03 r<HT> C xz 0 0 UJ e r- O. = s 5 <0 E w c 5s s- -J c0 : Scr OO CD r00-). C JC 0 </) z <c o IX c so r~ h- 4-5 z tu <0 u O: o z o 44-5 >z n 3s* Y II It II II II > z x: O) Sr O i. 3 43 >- s = 5 4V-5) o Jo S- o ,3e z z3a6> O4P5u- aO <c X> UJ UJ z >O+S3-v5- *Q4.Of---C5 G o o U50HHifl.0 mo CM l>> n rH CO 00 00 rH r>. CO C XcJ sf r** to in tn qqgdo'd mo OH 1111 i111 OP 00 VO 00 VO CM CM CO CM d dd d ddddd cc o 0 1 o C oo o c Q O iOf) -V1O- 0rH3 t0o t. O o 4-05 *j* ai co ** t* 00 Cp O CO CO CCOO CJ CM I^ OCr1HO pOfr1H. rCCH1OO OCH1O0 CM rH rH iH CM rH CM iH I O do 0 tliifltl >or- <c zo CHO O rH V 00 tD N- > Ui a: a. CMHfOlON^-QC Ca. 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CQ MC C > 0> CM > O O < > oco u<u H- .3: ao a: o =E re 7-6 , 12-15-82 TEH 0530392 DUP050031305 PRELIMINARY DRAFT measurements subjected to quality assurance procedures. The first is EPA's National Air Sampling Network (NASN), providing comprehensive nationwide data on long-term trends. The second data base contains information contributed to EPA's National Aerometric Data Bank by state and local agencies, whose stations are sited to monitor compliance with, or progress toward compliance with the current ambient airborne standard for lead (1.5 pg/m averaged over a calendar quarter) promulgated in 1978, EPA Nationwide Sampling Network. Tables 7-3 and 7-4, categorize respec tively the urban and nonurban NASN sites with valid annual averages (4 valid quarters) into several annual average concentration ranges (Akland, 1976; Shearer et al.; 1972, U.S. Environmental Protection Agency, 1978, 1979; Quar terly Averages.... from the National Filter Analysis Network, 1982). Nearly all 3 of the urban sites reported annual averages below 2.0 pg/m and the majority of the nonurban sites reported annual averages below 0.2 pg/m . Although the decreasing number of stations in service in recent years could account for some of the shift in averages toward lower concentrations, trends at indivi dual urban stations, discussed below, confirm the indicated general trend. Tables 7-5 and 7-6 provide cumulative frequency distributions of all quarterly lead concentrations for urban and nonurban NASN stations, respec tively (1st quarter = Jan-Mar, etc). Samples collected by the NASN from 1970 through 1976 were combined for analysis into quarterly composites. Since 1977, the 24-hour samples have been analyzed individually. These data have been arithmetically averaged for comparison with the quarterly composite data. (Note, also, that the EPA data base has been renamed the National Filter Analysis Network, or NFAN.) Each of the summary percentiles and means for urban stations (Table 7-5) has decreased over the period from 1970 to 1980; the 1980 levels are in the range of one-third to one-fourth of the values in 1970. The data from non urban locations (Table 7-6) represent far fewer sites than the urban data and many concentrations are below the measurement method's detection limit, there fore, summary statistics are more susceptible to the presence or absence of individual sites from year to year, and if more than half the samples contain less than detectable amounts of lead, the means are not reported. The upper percentiles are fairly stable, however, and while the composite nonurban concentrations are approximately one-seventh of the urban concentrations, they exhibit a relative decrease over the 1979-1980 period similar to that seen in the data from the urban sites. PB7/A 7-7 12-15-82 TEH 0530393 DUP050031306 PRELIMINARY DRAFT TABLE 7-3. NUMBER OF NASN URBAN STATIONS WHOSE DATA FALL WITHIN SELECTED ANNUAL AVERAGE LEAD CONCENTRATION INTERVALS, 1966-1980 (AKLAND, 1976; SHEARER et al., 1972; U.S. EPA 1978, 1979; Annual averages...from NFAN, 1982) Year <0,5 3 ......... Concentration Interval, pg/m 0.5-0.9 1.0-1.9 2.0-3.9 4.0 Total 1966: No. stations Percent 9 9 1967: No. stations Percent 4 3 1968: No. stations Percent 14 9 1969: No. stations Percent 5 2 1970: No. stations Percent 9 5 1971: No. stations Percent :--------- 1972: No. stations Percent 16 9 1973: No. stations Percent 20 15 1974; No. stations Percent 19 15 1975: No. stations Percent 28 17 40 42 37 32 67 45 46 25 54 33 23 21 67 37 76 55 69 53 94 56 40 42 63 55 54 36 103 57 80 50 64 58 84 47 36 26 38 29 38 22 6 6 -- 9-- 7 -- 10 1 61 23 1 12 1 15 1 91 21 1 19 1 12 1 70 41 31 40 30 71 41 95 100 113 100 146 100 178 100 159 100 109 100 180 100 137 100 130 100 168 100 PB7/A 7-8 12-15-82 TEH 0530394 DUP050031307 PRELIMINARY DRAFT Year TABLE 7-3 (continued). <0.5 ... Concentration interval, (jg/m 0.5-0.9 1.0-1.9 2,0-3.9 4.0-5.3 1976: No. stations Percent 23 14 1977: No. stations Percent 21 16 1978: No. stations Percent 21 29 1979: No. stations Percent 23 54 1980: No. stations Percent 51 89 99 62 73 54 42 58 15 35 6 11 36 22 35 26 8 11 4 9 0 0 40 20 50 40 10 20 10 20 00 00 Total 162 100 134 100 72 100 43 100 57 100 PB7/A 7-9 12-15-82 TEH 0530395 DUP050031308 PRELIMINARY DRAFT TABLE 7-4. NUMBER OF NASN NONURBAN STATIONS WHOSE DATA FALL WITHIN SELECTED ANNUAL AVERAGE LEAD CONCENTRATION INTERVALS, 1966-1980 (AKLAND, 1976; SHEARER et al., 1972; U.S. EPA 1978, 1979; Annual averages...from NFAN, 1982) Year 1966: No. stations Percent 1967: No. stations Percent 1968: No. stations Percent 1969: No. stations Percent 1970-1971: No. stations Percent 1972: No. stations Percent 1973:' No. stations Percent 1974: No. stations Percent 1975: No. stations Percent 1976: No. stations Percent 3 Concentration interval, ytg/m <0.03 0.03-0.096 0.10-0.19 0.20-0.45 Total 10 52 17 5 35 1 15 5 75 11 -- 52 -- 10 4 29 12 97 39 31 35 19 31 00 00 00 00 6 32 10 50 4 20 9 43 7 70 9 26 6 26 6 38 1 20 3 50 3 19 16 100 2 20 10 100 20 -- 100 1 21 5 100 3 10 30 100 11 34 33 100 1 23 4 100 2 16 12 100 45 80 100 36 50 100 PB7/A 7-10 12-15-82 TEH 0530396 DUP050031309 PRELIMINARY DRAFT TABLE 7-4 (continued). Year 1977: No. stations Percent 1978: No. stations Percent 1979: No. stations Percent 1980: No. stations Percent Concentration interval , M3/m3 <0.03 0,03-0.096 0,10-0. 19 0.20-0.45 Total 58 24 38 13 20 60 11 25 25 12 33 67 7 33 1 20 1 25 0 0 1 21 5 100 05 0 100 14 25 100 03 0 100 PB7/A 7-11 12-15-82 TEH 0530397 DUP050031310 </> CM 00 LQUC CD 3 S z SC Q<z Bo LU S- t3 > u +-> QJ LO TO s4> 0 e oc a> nj zo L> + > 0 r < > "O +> a; s JZ 44 e * <0 0 <z o 05 rs fs o CvJ o 05 fs 05 CO CO CD 0D CD0 CD > 00 00 s.0 00 00 CO rH rH rH rH r--1 rH rH rH rH rH rH 05 O CO VO U1 CM CO O 05 or o.* is rs P". n- VO in CO CM o rH o o d d d o 00 4 o rs CD* o CD rs o to o TV to o O LO 0 o IO IO4 o o CO d VO d 00 to d is CM d 01 rl CO CSJ CO H CM CD 01 CO o 00 in CO rH 05 CO V0 VO to CSJ co rH rH rH o' d o d d d d >- 00 -J CTl . OCH U) HLnUo Xoo <0O0)) =eCr>azXsS00S>w- U. t-- o >> r-- v/> rs u Z 0> >OH H*+*0J45/ CO rH <0 CO 05 'ch VO to 05 VO X CO CO CD CO o <T> in 05 00 in o z if) vp VO LO ** 0 CO co co rH rH CO co to CO o VO to rs o CM O * M00 ** coCO CO CO CO CM c m co to VO CD rs to CD o s 01 CM O CfsM CO co LLOP in CSJ CM CM CM CM CM co < ey e r- rH H CO CM rH rH rv 05 05 in t-H UJ N OH >- - OJ 4-> Co O CM 05 V> 4 VO > U> M" VD rH4 O in 4 h - cn a. 0 05 CM CM rH iH rH rH iH rH rH H O LO >- IS. V o t-H co <r> - a rH O r-* CM to Lf> O VO VO in M* CO CO H" LU LO >- z O O CO a. o co iH *3r-3 CM4 rH O H o rH 054 O 05 O 05 o IS. o VP 9 o CO4 o <C z t-H r- QS l u h- cn O rH m rH S. r> in oo in cO >DC cyi-- LU LO OS < o in o0 rH O rH 05 o 4 o r*. * o .4 o rs.4 O N. O in4 o d CO .4 o <C u. z a. z < LU HH z HH -J LU 00 > os . t--t S3 L0 t-- o CO in r> iH CM 1^4. CO m r>. m4 00 m 00 m4 r-. in4 co *$ CO CD4 rH <N ooQooooodo LU '* h- X) QC ~u c Qu x> .*> Z LO CM LO in VO r>. r-. Sh CM X> P>o 01 i--i o rH c0t 4 <o CO co co co CM CM rH4 oO o o oo oo d in a 1z ^3 UJ > -J < CD CO 00 VO r> o CO fC r-- a -4 a o--J a o d o -U o _J o o O, o rH4 o o <9 OTrr r*H CO 05 5^ m O CO CM o o rH o LO CO VO CM z r r>. rs u> m VD %n CS1 rH CM s- rH CM M- LO 00 O 0 r^* S- r^. r>. is. 0 >- rH rH rH rH rH rH rH rH rH rH rH PB7/.A 7-12 12-15-82 TEH 0530398 DUP050031311 PB7/A TABLE 7 -6 . CUMULATIVE FREQUENCY DISTRIBUTIONS OF QUARTERLY LEAD MEASUREMENTS . .AT NONURBAN STATIONS BY YEAR, 1970 THROUGH 1980 (AKLAND, 1976; U.S. EPA 1978, 1979; Q u a rte rly averages. from NAFN, 1982) 7-13 12-15-82 TEH 0530399 DUP050031312 PRELIMINARY DRAFT Long-term trends and seasonal variations in airborne lead levels at urban sites can be seen in Figure 7-1. The 10th, 50th, and 90th percentile concen trations are graphed, using quarterly composite and quarterly average data from an original group of 92 urban stations (1965-1974) updated with data for 1975 through 1980., Note that maximum lead concentrations typically occur in the winter, while minima occur in the summer. In contrast, automotive emis sions of lead would be expected to be greater in the summer for two reasons: (1) gasoline usage is higher in the summer, and (2) lead content is raised in summer gasolines to replace some of the more volatile high-octane components that cannot be used in summertime gasolines. The controlling influence, apparently, is the seasonal pattern of lower meteorological ventilation capacity in winter, higher capacity in summer. Figure 7-1 also clearly portrays the significant decrease in airborne lead levels over the past decade. This trend is attributed to the decreasing lead content of regular and premium gasoline, and to the increasing usage of unleaded gasoline. The close parallel between these two parameters is dis cussed in detail in Chapter 5, (See Figure 5-4 and Table 5-6.) The decrease in lead concentrations, particularly in 1979 and 1980, were not caused by the disappearance from the network of sites with characteristi cally high concentrations; the quarterly values for sites in six cities repre senting the east coast, the central, and the western sections of the country (Table 7-7) indicate that the decrease is a real and pervasive phenomenon. State and Local Agency Data, Table 7-8 lists stations operated by state and local agencies where one or more quarterly averages exceeded the current standard of 1,5 pg/ro^ in 1979 and/or 1980. A portion of each agency's com pliance monitoring network consists of monitors sited in areas expected to yield high concentrations associated with identifiable sources. In the case of lead, these locations are most likely to be near stationary point sources such as smelters or refineries, and near routes of high traffic density. Both situations are represented in Table 7-8, e.g,, the Idaho data reflect predomi nantly stationary source emissions, the Washington, D.C. data reflect predomi nantly vehicular emissions. Table 7-9 shows the maximum quarter lead concentrations for Standard Metropolitan Statistical Areas greater than 1 million. Table 7-10 summarizes the maximum quarter lead values for those stations reporting 4 valid quarters in 1979, 1989, and 1981, grouped according to principal exposure orientation or influence--population, stationary source, or PB7/A 7-14 12-15-82 TEH 0530400 DUP050031313 PB7/A 7-15 12-15-82 I 0530401 DUP050031314 PRELIMINARY DRAFT TABLE 7-7. TRENDS IN QUARTERLY LEAD VALUES FOR SELECTED URBAN SITES, 1975-1980 Q 1975 Tucson, Arizona Des Moines Iowa Worchester, Massachusetts Reno, Nevada Newark, New Jersey Akron, Ohio 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 0.78 0.49 0.42 1.27 0.71 0.66 0.86 1.18 <0.12 <0.12 0.78 0.89 1.48 0.50 0.60 2.15 0.91 <0.12 1.18 1.25 0.61 0.50 0.78 0.79 1976 0.68 0.63 0.38 0.94 0.44 1.18 -* 1.04 0.75 0.78 0.60 -- -- 0.96 3.00 1.09 1.37 1.08 0.37 1.02 0.77 0.77 1977 1978 0.87 0.33 0.30 0.91 -. -- -- 0.58 0.71 0.94 1.03 0.40 0.50 1.98 -- 0.99 1.11 1,16 0.59 0.59 0.63 0.44 0.74 0.42 0.37 0.67 -- 0.72 0.79 0.42 0.54 0.76 1.30 0.74 0,37 0.45 2,05 0.67 0.54 1.06 1.72 0.36 0.62 0.55 0.58 1979 0.52 0.39 0.22 0.22 0.68 0.56 -- 0.38 0.57 0.34 0.45 0.76 0.54 0.32 0.23 0.61 1.17 0.63 0.54 0,79 0.42 0.37 0.46 0,29 1980 0.35 0.19 0.21 0.34 0.37 0.34 0.34 0.28 0.56 0,37 0.50 0-45 0.53 0.19 0.27 0.79 0.54 0.27 0.36 0.42 0,29 0.24 0.38 0.26 PB7/A 7-16 12-15-82 TEH 0530402 DUP050031315 PRELIMINARY DRAFT Table STATE A1abama Arizona California Colorado Connecticut Delaware PB7/A ris Reporting Valid Quarterly Lead Concentrations Greater (The Current Ambient Air Standard) in 1979 and 1980,* (OAQPS, 1982) CITY OR COUNTY YEAR MAX. QIR. pg/m .UkU NO. OF QUARTERS >1.0 pg/nr TroyII (003) 1979 1980 Glendale (001) 1979 Phoenix (002A) II 1979 1980 Phoenix (Q02G) II 1979 1980 Phoenix (004) 1979 Pho(1enix (013) 1979 1980 Scottsdale (003) II 1979 1980 Tucson (009) 1979 Nogales (004) 1980 Los Angeles (001) 1979 Anaheim (001) 1979 Adams Co, (001) 1979 Arapahoe Co. (001) 1979 Arvada (003) 1979 Brighton (001) 1979 Colorado Springs (004) 1979 Denver (001) 1979 Denver (002) II 1979 1980 Denver (003) II 1979 1980 Denver (009) 41 1979 1980 Denver (010) 1979 Denver (012) 11 1979 1980 Englewood (001) 1979 Garfield Co. (001) 1979 Grand Junction (010) 1979 II 1980 Longmont (001) 1979 Pueblo (001) 1979 Pueblo (003) 1979 Routt Co. (003) 1979 New Haven (123) 1979 Waterbury (123) 1979 Wilmington (002) 1979 2.78 1.13 1.06 1.54 1.29 2.59 1.49 1.48 1.55 1.06 1.41 1.13 1.18 1.10 1.51 1.11 1.77 1.10 1.60 1.17 1.37 1.70 3.47 1.53 2.13 1.03 1.57 1.23 1.67 1.67 1.10 1.80 1,20 1.53 1.27 1.07 1,03 1.03 1.33 1.57 1.41 1.21 2 2 1 1 2 2 2 2 2 1 2 1 1 1 1 1 2 1 1 ,1 1 2 4 2 3 1 1 2 2 2 1 1 1 2 1 2 1 1 1 3 3 2 7-17 12-15-82 TEH 0530403 DUP050031316 PRELIMINARY DRAFT Table 7-8 (continued) STATE CITY OR COUNTY YEAR Dist. of Col. Florida Idaho Illinois Washington (005) 1979 Washington (007) 1979 Washington (008). 1979 Washington (Oil) 1979 Washington (015) 1979 Washington (017) 1979 Dade Co. (020) 1979 Miami (016) 11 1979 1980 Perrine (002) 1979 Hillsborough Co. (082) 1979 11 1980 Tam1p1 a (043) 1979 1980 Boise City (003) 1980 Kellogg (004) It 1979 1980 Kell11ogg (006) 1979 1980 Shoshone Co. (015) 1979 Shoshone Co. (016) 1979 it 1980 Shoshone Co. (017) 1979 II 1980 Shoshone Co. (020) 1979 ft 1980 Shoshone Co. (021) 1979 11 1980 Shoshone Co, (027) 1979 11 1980 Chicago (022) 1980 Chicago (030) 1980 Chicago (005) 1979 Chicago (036) 1979 Chicago (037) 1979 Cicero (001) 1979 Elgin (004) 1980 Granite City (007) 1979 Granite City (009) 1979 Granite City (010) 1979 n 1980 II 1981 Grani1t1e City (Oil) 1979 1980 11 1981 MAX. QIR. gg/nr 1.49 1.89 1.90 1.44 1.06 1,45 1,16 1.46 1.10 1,01 1.31 1.09 1.60 1.07 1.01 9.02 6.88 8.25 8.72 1.21 2.27 1.02 4.57 3.33 4.11 2.15 13.54 13.67 10.81 7.18 1.02 1.06 1.05 1.02 1.14 1.00 1.95 1.04 1.15 3.17 2.97 7.27 1.33 1.43 1.13 JOU NO. OF QUARTERS >1.0 pg/nT 1 4 1 2 2 1 1 3 2 1 2 1 3 1 1 4 2 4 4 2 1 1 4 3 2 2 4 4 4 3 1 1 1 1 1 1 1 1 4 4 3 4 4 1 1 PB7/A 7- 18 12-15-82 TEH 0530404 DUP050031317 STATE Indiana Iowa Kentucky Louisiana Maine Mary1 and PRELIMINARY DRAFT Table 7-8 (continued) CITY OR COUNTY YEAR Jeffersonville (001) 1979 East Chicago (001) 1979 East Chicago (003) 1979 East Chicago (004) 1979 East Chicago (006) 1979 IS 1980 Hammond (004) 1979 Hammond (006) 1979 Indianapolis (030) 1979 Des Moines (051) 1979 Buechel (001) 1980 Covington (001) 1979 Covington (008) 1979 Greenup Co. (003) 1979 Jefferson Co. (029) 1979 II 1980 Louisville (004) II 1979 1980 Louisville (009) 1980 Louisville (019) 1980 Louisville (020) 1980 Louis11ville (021) 1979 1980 Louisville (028) 1979 Newport (002) 1979 Okolon.11a (001) 1979 1980 Paducha (004) 1979 Paducha (020) 1979 St. Matthews (004) 1979 11 1980 Shively (002) 1979 Baton Rouge (002) 1979 Portland (009) 1979 Anne Arundel Co. (001) 1979 Anne Arundel Co. (003) 1979 Baltimore (001) 1979 Baltimore (006) 1979 Baltimore (008) 1979 Baltimore (009) 1979 Baltimore (018) 1979 Cheverly (004) 1979 Essex (001) 1979 Hyattsville 1979 MAX. QIR. pg/m 1.38 2.19 1.42 1.67 1.34 1.04 1.18 1.46 1.16 1.30 1.41 1.12 1.16 1.42 1,05 1.78 1.01 2.41 1.75 1.59 2.52 1.29 1.42 1.06 1.06 1,51 2.31 1.41 1.22 1.20 1.83 1.56 1.57 1.02 1.27 1.45 1.06 1.09 1.24 1,08 1.12 1.51 1.15 1.18 NO, OF >1.0 3 2 2 1 2 1 2 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 2 1 2 2 1 1 1 2 4 2 2 JUU) PB7/A 7-19 12-15-82 TEH 0530405 DUP050031318 PRELIMINARY DRAFT Table 7-8 (continued) STATE CITY OR COUNTY YEAR Massachusetts Minnesota Montana Nebraska Nevada New Jersey New York Ohi o Pennsylvania Puerto Rico Rhode Island South Carolina Springfield (002) 1979 II 1980 Boston (012) 1979 Minneapolis (027) 1979 Minneapolis (055) 1980 RicIIhfield (004) 1979 1980 St. Louis Park (007) II 1979 1980 St. Paul (031) 1979 St. 11 Paul (038) 1979 1980 Lewis &11Clark Co. (002) 1979 1980 Lewis & Clark Co. (008) 1980 Omaha (034) 1979 Las Vegas (001) 1979 Newark (001). 1979 Perth Amboy (001) 1979 Paterson (005) 1979 Elizabeth (002) 1979 Yonkers (001) 1979 Cincinnati (001) 1979 LauIIrel dale (717) 1979 1980 Reading (712) 1979 E. Conemaugh (804) 1979 Throop (019) 1979 Lancaster City (315) 1979 New Castle (015) 1979 Montgomery Co. (103) 1979 Pottstown (101) 1979 Philadelphia (026) 1979 Phi1ade1phia (028) 1979 II 1980 Philadelphia (031) 1979 Philadelphia (038) 1979 Guaynabo Co. (001) 1979 fl 1980 Ponce (002) 1979 San Juan Co. (003) 1979 E. Providence (008) 1979 Providence (007) II 1979 1980 Providence (015) 1979 Greenville (001) 1979 PB7/A 7-20 MAX. QIR. pg/nir 1.68 1.04 1.01 2.44 2.41 1.95 1.18 2.87 3.04 1.04 1.36 1.82 4.19 2.75 1.19 1.08 1.15 1.17 1.08 1.42 1.16 1.08 1.15 3.30 1.86 1.11 1.28 1.13 1.18 1.01 1.23 1.16 1.21 2.71 1.26 1.29 1.06 1.60 1.06 1.08 3.59 1.10 1.92 1.16 1.34 1.38 NO. OF QUARTERS >1.0 pg/nr 1 1 1 1 3 4 2 2 4 1 1 3 4 4 1 1 1 1 1 1 1 1 1 4 2 1 3 1 1 1 1 2 3 4 3 2 1 2 1 1 4 2 4 2 1 2 12-15-82 TEH 0530406 DUP050031319 PRELIMINARY DRAFT Table 7-8 (continued) STATE CITY OR COUNTY YEAR Tennessee Texas Washington West Virginia Nashville-Davidson (006) 1979 San Antonio (034) 1979 Dallas (018) 1979 Dallas (029) 1979 Dallas (035) 1979 Dallas (046) 1979 Dallas (049) 1979 Dallas (050) 1979 El Paso (D02A) II 1980 1980 El Paso (002F) 1979 El Paso (002G) 1979 El Paso (018) 1979 El Paso (021) 1979 El Paso (022) 1979 El Paso (023) 1979 El Paso (027) It 1979 1980 El Paso (028) 1980 El Paso (030) 1979 El Paso (031) 1979 El Paso (033) 1979 Houston (001) 1979 Houston (002) 1979 Houston (037) 1979 Houston (049) 1979 Ft. Worth (003) 1979 Seattle (057) 1979 Tacoma (004) 1979 Charleston (001) 1979 MAX. QIR. pg/nr 1.05 1.23 1.59 1.07 1.12 1.22 1.01 1,13 1.90 2.12 1.90 2.60 1.91 1.02 1.84 2.12 2.15 1.74 1.16 1.02 2.47 1.97 1,35 1.39 1.26 1.13 1.14 1.36 1.06 1.09 *As of November 1982 jm NO. OF QUARTERS >1.0 pg/nr 1 1 1 1 3 1 1 2 1 1 1 4 2 1 2 2 2 2 1 1 1 1 2 2 1 3 2 1 1 1 PB7/A 7-21 12-15-82 TEH 0530407 DUP050031320 'PRELIMINARY DRAFT TABLE 7-9. MAXIMUM QUARTER LEAD CONCENTRATIONS REPORTED FOR SMSA's > 1 MILLION POPULATION, 1979-1981 Anaheim-Santa Ana-Garden Grove, CA Atlanta, GA Baltimore, MD Boston, MA Buffalo, NY Chicago, IL Cincinnati, OH-KY-IN Cleveland, OH Columbus, OH Dallas-Fort Worth, TX Denver-Boulder, CO Fort Lauderdale-Hollywood, FL Houston, TX Indianapolis, IN Kansas City, MO-KS Lps Angeles-Long Beach, CA Miami, FL 1979 1980 1981 1980 1981 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 1.11 0.47 0.93 0.51 0.39 3.41 1.11 0.61 1.01 0.57 0.47 0.41 0.38 0.89 1.16 0.85 0.37 0.38 0.34 0.43 0.35 0.34 1.59 0.67 3.47 1.53 0.97 0.33 0.36 0.23 1.39 0.64 1.16 0.63 0.42 0.82 0.38 0.19 1.51 0.68 1.43 1.46 1.10 0.75 PB7/A 7-22 12-15-82 TEH 0530408 DUP050031321 PRELIMINARY DRAFT Table 7-9 (continued) Milwaukee, WI MinneapoTis-St. Paul, MN-WI Newark, NJ New Orleans, LA New York, NY-NJ Philadelphia, PA-NJ Phoenix, AZ Pittsburgh, PA Portland, OR-WA Riverside-San Bernardino-Ontario, CA Sacramento, CA San Antonio, TX San Diego, CA San Francisco-Oakland, CA San Jose, CA San Juan, PR Seattle-Everett, VA 1979 1980 1981 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 1979 1980 1981 PB7/A 7-23 0.72 0.49 0.31 2.87 3.04 3.11 1.17 0.53 0.70 0.35 0.25 1.08 0.47 2.71 1.26 1,30 2.59 1.49 1.39 0.82 0.44 0.41 0.60 0.41 0,29 0.91 0.54 0.57 0.69 0.18 0.62 1.23 0.79 0.91 0.83 0.60 0.42 0.13 0,28 0.92 0.86 0.61 3.59 1,06 1.02 1.36 0.86 0.52 12-15-82 TEH 0530409 DUP050031322 PRELIMINARY DRAFT Table 7-9 (continued) St. Louis, MO-IL Tampa-St. Petersburg, FL Washington, DC-MD-VA 1979 1980 1981 1979 1980 1981 1979 1980 1981 3,17 2,97 7.27 1.60 1.09 0.68 1.90 0.69 0.48 Source: OAQPS (1982) PB7/A 7-24 1Z-IS-BZ TEH 0530410 DUP050031323 PRELIMINARY DRAFT TABLE 7r-10. SUMMARY OF MAXIMUM QUARTERLY LEAD AVERAGE BY SELECTED CONCENTRATIONS ACCORDING TO SITE-TYPE, 1979-81,* CONCENTRATION RANGES (pg/m3) Site-Type Population >.5 >1.0 >1.5 Total No, of <.5 1.0 <1.5 2.0 >2.0 Site-Years 300 173 46 7 5 531 Stationary Source 50 12 10 2 21 104 Background 21 0 0 0 0 21 Total (site-years) 380 185 56 9 26 656 Percent of Sites in Concentration 58 28 9 1 4 Range *Any site-year which had all four quarters valid was included in the summary. Source: background. The stationary source-oriented sites clearly dominate the concentrations over 2.0 pg/m ; however, new siting guidelines, discussed below, will probably effect some increase in the upper end of the distribution of values from population-oriented sites by adding sites closer to traffic emissions. New guidelines for siting ambient air lead monitors went into effect in July, 1981 (Federal Register, 1981). "Microscale" sites, placed between 5 and 15 meters from thoroughfares and 2 to 7 meters above the ground, are prescribed, but until now few monitors have been located that close to heavily travelled roadways. Many of these microscale sites might be expected to show higher lead concentrations than those historically measured at urban sites. One study (Pedco, 1981) does give limited insight into the relationship between a microscale location and locations further from a roadway. The data in Table 7-11 summarize TSP and particulate lead concentrations in samples collected in Cincinnati, Ohio, on 21 consecutive days in April and May, 1980, adjacent to a PB7/A 7-25 12-15-82 TEH 0530411 DUP050031324 PRELIMINARY DRAFT TABLE 7-11, SUMMARY OF LEAD CONCENTRATIONS NEAR A ROADWAY* IN CINCINNATI, OHIO (Pedco, 1981) 3 a: Total Suspended Particulate Concentrations**, pg/m Elevation Distance from Roadway 2.8 m 7.1 m 21.4 m 10.5 m; 95 6,3 m: 103 1.1 m: 133 3 Lead Concentrations**, pg/m 104 119t 126 106 109 112 Elevation Distance from Roadway 2.8 m 7.1 m 21.4 m 10.5 m: 6.3 m: 1.1 m: 0.81 0.96 1.33 0.93 1.07 1.16 0.90 0.97 1.01 *58,500 vehicles per day, **Averages of 21 samples between 4/17/80 and 5/7/80. tThis site would qualify as a "microscale'' site. 58,500 vehicles-per-day expressway connector. Simple interpolation indicates that a microscale monitor as close as 5 meters from the roadway and 2 meters above the ground would record concentrations some 20 percent higher than those at a "middle scale" site 21.4 meters from the roadway. On the other hand, these PEDCO data also indicate that although lead concentrations very close to the roadway (2,8m setback) are quite dependent on the height of the sampler, the averages at the three selected heights converge rapidly with increasing distance from the roadway. In fact, the average lead for the one monitor (6.3m height, 7,1m setback) that satisfies the microscale site definition proves to be not significantly different from the averages for its two com panions at 7. lm,, or from the averages for any of the three monitors at the 21,4m setback. Other urban locations around the country with their Own characteristic wind flow patterns and complex Settings, such as multiple roadways, may pro duce situations where the microscale site does not record the highest concen trations. Collectively, however, the addition of these microscale sites to PB7/A 7-26 12-15-82 TEH 0530412 DUP050031325 PRELIMINARY DRAFT the nation's networks can be expected to shift the distribution of reported quarterly averages toward higher values. This shift will result from the change in composition of the networks and is a separate phenomenon from downward trend at long established sites described above, reflecting the decrease in lead additives used in gasoline, 7.2.1.2 Airborne Particle Size Distributions--The effects of airborne lead on human health and welfare depend upon the sizes of the lead-containing particles. As discussed in Chapter 6, large particles are removed relatively quickly from the atmosphere by dry and wet deposition processes. Such particles are also unlikely to reach the lower human repiratory system when inhaled, because of entrapment by the cilia and walls of the upper respiratory tract. Particles with diameter smaller than a few micrometers tend to remain airborne for long time periods, and penetrate into the lower Tung. Figure 7-2 summarizes airborne lead size data from the literature. Minimum and maximum aerodynamic particle diameters of 0.05 pm and 25 pm, respectively, have been assumed unless otherwise specified in the original reference. Note that roost of the airborne lead mass is associated with small particles. There is also a distinct peak in the upper end of many of the distributions. Two separate categories of sources are responsible: the small particles result from nucleation of vapor phase lead emissions (predominantly automotive), while the larger particles represent primary aerosol emitted from combustion or from mechanical processes (such as soil erosion, abrasion of metal products, resuspension of automobile tailpipe deposits, and flaking paint). Table 7-13 presents information associated with each of the distributions of Figure 7-2. The first six distributions were obtained by an EPA cascade impactor network established in several cities during the calendar year 1970 (Lee et al., 1972). These distributions represent the most extensive size distribution data base available. However, the impactors were operated at excessive air flow rates most likely resulting in particle bounceoff, biasing the data toward smaller particles (Dzubay et al., 1976). Many of the later distributions, although obtained by independent investigators with unknown quality control, were collected using techniques which minimize particle bounceoff and hence may be more reliable. It is important to note that a few of the distributions were obtained without backup filters to capture the smallest particles. These distributions PB7/A 7-27 12-15-82 TEH 0530413 DUP050031326 n i t r "i i r i i 1.00 1 CHICAGO, IL 0.75 0.60 03S 0 1.00 2 CINCINNATI, OH ;_ it10.75 0.60 0.25 0 1.00 JENVER, CO i " I'l 1 "1 1 1 T ALTON. It 10 CENTWVILU.IL rs 11 COL rlNSVILLE, It fifL i 7 n ""i 1 1 1 1 1 1 1 17 S.E. MISS O.UR1. NEAR 8MEL1 IFSTTwiss >URI. FAR FROM SMELTER 10 NEW BRUNSWICK. NJ HIGHWAY 26 GREAT SMOKIES NAT L PARK, TN 2 PITTSBURGH, PA 1-->-JL 27 NEPAL m HIMALAYAS n h a r Ro r . mi ' ' [U,i 24 ANN ARBOR. Ml rU : 36 CHICAGO. lt 0.75 0.50 I-1-1-. 0.25 f-------- ' 0 1.00 4 PHILADELPHIA, PA | :rx- 0.75 0-50 f 035 0 g i.oo 6T. LOUIS. MO 0.75 0.50 033 ; 12 KM< RADIO 20 SAN FRANCISCO. CA TRANSMITTER. r^uIL 17 PERE I MARQUETTE rPAfiK.lt 21 tOS ANGELES, CA r--m 1* EXPORT, M Ml N.CO.U , NE r^V 2S PACKWOOD. WA 37TAUAKIA&SEE..FL r-JL JV50S* : . 0 1.00 WASHINGTON, O.C, LrV0,75 0.50 035 14 WOOD 4 ^ 1.496 RIVER, it 22 tDS ANDELES.CA FRE EWAY ^-rna, 00 OLYMPIC NAT'L .30 CHILTON. ENGLAND PARK. WA _ ..r^L r'V; 0 Lu,1.00 0.76 0.50 0.25 7 CINCINNATI, OH --, 16 CINCINNATI, OH RJXFREEWAY 0 U-j --i1.00 0.7S 0.60 035 0 FAIRFAX, OH 16 GLASGOW, SCOTLAND 0 -1- 1 1 1 1 1 IJ.lll. i | i i i i iT^li i i 23 PASADENA CA 01 BERMUDA ----------------------k . IT7TJ l?r^i, rV_24PASADENA.CA 02 BERMUDA -I. 1-X.J__ . . 1 39 TRE6ANOS. ENGLAND ,-A-vi 40 NEW YORK. NY rx! l i.i i..11 i tT n x. 0.01 0.1 1 10 0.01 0.1 1 10 0.01 0.1 1 10 0.01 0.1 1 10 0.01 0.1 1 10 dp, pm Figure 7-2. Airborne mass size distributions for lead taken from the literature. AC represents the airborne lead concentration in each size range, Cj is the total airborne lead concentra tion in ail size ranges, and dp is the aerodynamic particle diameter. A density of 6 g/cm* for lead-containing particles has been used to convert aerodynamic to physical diameter when applying the lower end of the lung deposition curves of Figures 7-3 through 7-5. PB7/A 7-28 12-15-82 TEH 0530414 DUP050031327 XB 9 3. .( O- Q asc l ss: sc 00 tf> C> ..... .. . .. >. ......... CO re.- ouo en CM l> a- ooo o o TABLE 7 -1 2 . INFORMATION ASSOCIATED WITH THE AIRBORNE LEAD SIZE DISTRIBUTIONS OF FIGURE 7-2. aop CO co CO <43 CO CO O. 3 .X eu s01. <v ys 4re $ x: Q. tl 4-> tEO C *r- CO -D .*- 9O .-+>*- * - U 9 05 r- re Q. O Q.I-- .>> O E-r- :e Q. 3 .x cy 9 re IA X5 &9 x: TJ +> C >rCJ O tr 9O *i-- +n SH- O 9 t-- tO 4-1 O 0.1-- Ogir E *i- 4- o. co om t/3 43 s05 -G XJ P C r< 5: TJ tr05 O *r-- P SP U 05 *-- id P TJ O.*-. O *rset - p Q_ 3 44 co 05 fO V) 43 S S~ P O ft) *- <0 P Us: *- p - X 9c yre .re rt *. 9 x: y +j C r- <c je -9o *o. <i"t- +y> j. 9 i-- re 4-> 13 Q-r-- O B *i- E-r- 1^ 05 C r--r- to CL r* BO to C V) r- P rfM-*I O c <* oo l-- 05 44 (0 mu L> 1-- O jz -J o o. *rx: o r? + > 10 c c r-- U c *f-- o o *o cu t. o r-- o o > s<D > c a> o reL re x: c Q. <0 r--' > 01 -- O >> rd to r^ C *r" C -C C) c l a. rS3 O 05 V> p* #> 05 r-- 3 O P V) ' o. o A c o p o> C p O) 2c O) c r-- r-" o. E ro V) P o 05 05 P td o P i-->> 9 Ot- S. 9 - i~re re 4-> W -P "D 1-900 o re i-- +J !- N cr> 3 cr Q. E re t. 9 rH re ax re- v> o> y . core U <49O "a 9 +>- C -r- 9 CS -P 9 -r- C 9 1-- CL *<A- 1 Dim in 3 . rse- oa. 91- rtAe 4o3 C 9 E a. re > o 9 r-4 re- l~3 <t y *- CM CM CO rH o in ipre O (A r- HD cn Dll-- 9 rH c re *r- r+J 05 O * 9 u o0) r*e-- 4J c l 9 D) 1 > rH C re -r- * u to XZ t-- 9 CL O. ero r*e- sre SV50 W </) 13 if) P o o td o p s- cn 05-- 0> rH c to a *i- p 05 O 03 aU> m. p c *r- a (U up- i >h a td s -c m QJ O. U5 cem (0 fO S- rH O LO c? CM o CM tn p O 10 O (A fs *o 03 Or- O rH C Ifl'r r- p L 05 O O U fO P Q. o<y 0) * 05 >HC i id r-- s- a) Ja= fa-- B (0 B atsd. <d <S> u m <o IA CM CM if) P o fO o to X? O 03 r-- O rH c <d r- ri-- P t- U ow 05 O fl> (s0. P o. <L) - 05 >HC 1 <d p c -C r-- 0)0id.0s. (d to U Cd O V5 O W co CM </) P o id o v> *o o 03r-- O rH c to <-- . r-- P 30 *0) UHC re _ i- 9 a. o. & e re e (0 re *. re O V)0 > 05 <J C 05 a> p 05 Qd CM r>. 05 rH w r-- m p 0> 05 05 -J J= to o 6z PB7/A CM CM CM CM CM r>. r-. rv CT5 05 CT5 0*5 cr> rH rH pH rH H a L .* r-- r-- r-- td id <d td id p PPPp 05 05 05 05 05 05 05 05 05 05 at 0) 05 05 05 pPPP P CM CO un LQ iT'nS*' owin 7-29 12-15-82 H DUP050031328 Xe o 3. ' s- cn CM rH rH <c 2CL Q CL *pj CM >=* M CM CO : o O CM Q O o r-4 tn 00 o rH CO 1E 00N 1-- CO cn o CO <3* CM ^. CO CM VO CO o - * o o 3. cM Ooo 14) r*. l--1 CM oo 4C 4C pP >e 36 E CM CM P S- . J- u O rl "O pc O rH -O + G o xP 03 u *2 O 3 UP &. o ns t- o ,f* dL Q. 0) 5- a. os i- O.T- 11 e p O) E -*-> o s p r r-- r-- p-- f- CO i-- Q3 r* CL c p je C4- C -3 03 ^p 03 P P o to Cl VO D. CO U U 2 Cl *- 2 5- (0 > 03 > 03 .43 CL XJ u o -o u o no >> c ns i C f0 4 Co <C 43 os <XJ 0 < c c. t- 0) O 4-> 4^ l--" O i* 4Q. E a. r* 3 o2 u vo 43 03 -2 o 4-> c*r <C 5 tU 0) o +> +j r" U 4" a. E CL <i- 3 cu 03 VO jQ <D ." o P C *r* <c ^ tX- .03 OP P rO *rmp Q. E Q*r- 3 023 JOS VO 43 03 . 2 P CP C ^ si~ as o-*- +> r(J *r (0 4D. E a. r* 3 CU 03 CO 43 S03 43 "O P Cp <% .A p op P 03 UP ra.rP a. 22 03 VO u s- 03 43 *o co <C C TABLE 7-12 (c o n tin u e d ). 05 c `ff*-r a. o e<0 l-- 4= CO O p #> o i-- P c <TJ oC r- ,C P n" <0 u o -O c r> po r P10 c c *r* ^U oc i-- r- 43 O O P * o X to 43 P fcS- 2 r- 43 f0 2 Ll . 0) (t0- 03 .c 0t V) CT) r* 03 o s. cm i-- r~ r* f0 C3> 1--1 *r-- !-- S-. 2 ^P o CV1J O3 P Tt r- C P <31 </> V) i-- o cu r~ C .r-- r- N P <0 * 03 P .r- O .r"* >C 03 P 03 X- P P C r-- C ^ 03 03 o e 0*0 V) co rO SC fO r- o j Pc l-H 0 03 ^ 503 (0 r-- r-- r-- P C0 U) > *<-- *r-- Vi i. 3 CP o 1-- (/) --J I-- 3 r- -a . o c + O VJ k * V5 CO C P C0 m o 03 to U c S-P pp 2 r-- O O -- p P p l -i to "O p (0 JL. p S- S-Pto 03 CO X P 3 S- Q P *0 <0 2S p C 03 ep c XJ c 03 *r* P co o. P3 CO w> 03 CO Pp P O V) 0) CP 2 *r* 2 CTr- O S. r-- P CO HH s: --p 03 44 V) J- J03 CO <*- d* c- o #> CO &. r~ nJ O 03 cc *.p r-- CO p 03 PI f(c0- X- p 03 fO V0 >P P P S- 3 QP O CO P "O 3 0*0 O CP 3s to U. QC O >- CC <C 05 v> c r-- c2 r-- X- CL CO CO 2c S- * 4= 0 CO to c2 u (0 u #* u> c2 in S- >> JC # u CO c2 u v> i+ JZ V CO c2 s- CO 41 <0# U c2 x. VO 4= u (O 2c s- VO CO 4Z >> 5> >> >i fd iH U CO ro fd ro T3 CM CM cn - ozUJ C/5 iH m cn x: to XJ CM CO "O ro u CM o CO *o P tH P u r-^ p ,r>. p O r-> P P pp CL p s~ o CO O 5? >> O) S- 05 CD U CJ) CD X- 05 CD S- O) O) 03 P CO CO O p S- 4= Q. 2 >> X- w *Q p u*? S- c to s- S- B S- t- g s X- X E XE x. X. o > -<5*- > 2 >> 2>> 2> > 2>> 2> > 2>> CO < CM M- < co < to CO < CO <c CO <c CO <c to c u c X p cc JC CL o U TZ. o PB7/A co co cr> r-H * r P P 00 to a> rH r* P CO CO to co Ps. r> Q) cn CO rH rH rH AA c2C "O -a *o CL a. OL go o rH H rH 7-30 CO O) rH A c *o a. CM rH co CO r>- ov o> rH rH .C 2A *o -a d. Cl CO rH rH 12-15-82 TCM 0330416 DUP050031329 XE O 3. 0.0 CCMO rtHn 00 mco o> re- Lof> cCoM oo CO CM o' d o' o cr> u OI 3. CO f- rH r** rH rH CuOi d to CM lO *jr CM rH r0e0o a* uo o o 4 5 f- ua* oP rse_ P rOp r-- <0 P t m0 Q. e a. p3 CO tre x a. TJ P .>> <C P3 o l_- c 3 a> o S- P t- r-- CB Pp UP re x CL CLP E3 p re -orise >o -i--rexJO: r-eg oirne p3<- ocEo a c 3 O S. > to (- cn P re rue i--px: CLP p EP r re a. > e3o rwe orxe t- re re x E o r- co . < C rH 0) O) p O c *0 fl-r r C-P 10 to o o a. f- c ETO o a> * O P *P" m to ep p *H (0 o s- o c u o rH E C oo O *f" c * U u ** o in h - c 3C r <D *r- o P P EO cn to i-- O V) u if) o A (0 o -J CO 1ft ro co r*. S i-- u 3 -O o re in re in r-- -rz re PE U) o re s- t p re XP P E i-- 3 o re OO E m oo w o *o i. - fc. o t- o> p re u p re re p x r O CL > C3O 0) ^ JD U> U <0 (- id 0J j Q e X> f** C < CH -T3 rr- f0 rH u re 3 r- X oa in re re MX L i-P(J Z EP POO in Sre p f~ re re X EP p iZ -- 3 re om e i/i w x 3 IL o p Ore Lre- CLP E *( p P re o a. re s o .* Vre) ure O X) m, rH 0) "O P C3 <0 o ec <J0 r-. i/i .x u Oi _ T3 >- E in re o C in in C 3 tre p t- re p ,core pE^_ in O 3 3 co re re ro in z z sU Q) OP P r* U *" 10 Ha. sr- a3 eo a> co v) .a re x oP e -i<3 p re 3 re o tx re O) 3O OU L- in Xp Pu c <n re re tP u. -- in c re oi m k o P U <0 a 6r C OJ u O) o c 3 --J r C So r- U * o r V> jL 0) > r cc 1. c t. re 3 OP o P <-- u U -1- oi re p a. re E &X p 3P X cure re re > </> x> o s- X re x re TJ P c -f- E < 3<N rreSF re 3 tcoo repp XJ Cp 3 >in o re re "o o Cl . ^* p re in o re re C r(- re re >, a> r1-3 S3 5 3 re o re w x t- o in p p TABLE 7-12 (c o n tin u e d ). c Q a >o<cs- CL. ccr-n wu, a> >> T1O0 as. C<O9 <4o- >aV*) <e CO 1cn0 pO o o10 cn rH mr** Po to rH c0n) o> c rH 3 a> p rc O r**r- A) (. >i 10 t. c; "o CL < >H5 co U oc 3 ca> *-o o A U> o> c S3- rct>- CM CO fU o.r-~ in * oiHi pt0c.) rte- E e r3c 3in p o rcreen t- re > re re ir>ne) -o r-* cm in c OI t3- pc oi x t- CM U o_r-^ p in or-ii o re re ure i. re rcen re >> re re p s t. -a pce3re> 4- 3 ><H p3c re L. pc r>e -o oo p o icn pot- re 0 3t_ 0. 0O1l^C XP co re s- re re co is re ) Ol > 1 in >roe, p r-l O Ol c rH 3 U p>> 3 cre oo icn 35- 00 O X ID r-l U cr-nl c- Po re re in Xre rOeI t- 3 E re ure xo >O re > ID_ Z < r-l <tA- 3 -OC 00 p CO o rc-n* c3 rH S- > 10 c0J Xo k CD ID WK , 4> 10 uQct-J p 0) Opa0>f) r(O-0 Uj z CCcr*OnOH *co o> <0 f*Mo crHn H oiOoCt c c(u0 3 s: o crHn * r4 re p re c ao N OI r-l 0t 4 r-- (0 PQ> Csoo m, r-- <0 Po *0ct--) }os O(0 cHn r-- <0 P0) PVca) co rg a> aS rH O l-~ OrHl 44 c xCQUc>>O P3 rre pre ur* M pC in X3 orHn are. o aS- z PB7/A in ID > 7-31 l <M CM CM CM 12-15-82 TEH 0530417 DUP050031330 XE oi. 3. Cl Q Cl <* eg o r- CO TO- O 05 o u> cn CM * o rH o o' rH o B < H- 05 CJ ZL tn CO TO" CO rH rH rH r o O rH O i--1 CO O rH C\l o , . O oo O rH o o. a. Q. 3 O. TO a. 3 o. 3 < C -X 0) 3 JC 3 ex o 3 (. >> to u > X 4J JX TO TO U > 0 *- o t- C U 4- 01 TO O cu cu> cn TO O cu> 0 4-C O (0 o (- j O j Q TO TO TO TO TO O t- z z TO TO O U 4-> r- 4-> to jQ TO TO U) Z > in Z Z TO TO v> z z 4J U`I" w S- 4- 05 Z z. t- O S- TO T3 Z _ t- TO 10 4- 4) O C C +J E TO Z Z TO Z c +> E TO Z CL CL ^ e B CL to r 3<t. t/> ^ o Tl+i O'r C *r- t. "O C ? 1-- c *r C'C c m > Z rH -a TOM C T3 + TO C !- <>E TO- 6 C T- CM i o rH C < *r- M 3- O rH -O TO CO C Z 4J E C *r- Z < > "O rH C CU 05 a s- o 3 i- t- *>3 T3 C- a t- 3 i- S- 3 Z (- 3 +o 0) <0 4- C UiiJ O'r C- 0*0 05 O JQ +5 1- 4- U O >* 4- O in O r- i- i~ Z CJ TO D> TO O r- *J t- -a H- U TO c TOO - O r- 4J U U <f- O TO O) 4- O U) O ,r-- C- CZ U TO CD TOO r O r *5 t- l> 4- U TO O) cl S) ti- r4JW O TO + r- TO +J 3 'r- TO +J O TO Z r- TO s C - C 3 a a.*-- o O *r- p Cl <-- TO E >- z o a>-- O O E*<- t. O ar- TO O E !- Z X Q.r-- TO E -r- Z Z &(- TO O E -r- Z < joa X *r- 4- V> CM '1" 4- + ZE V- 1*- 05 x *-> CM >- 4- +> X *r> 4- 4H 05 c rr- c r-- U a. o 4(0 to <0 4- o o ** c ITS Oc r-- 0) -o to <0 u V5 o <0 J a. 4-> in TO Z TO <0 C TO e t- t- r~ O r o o o C I-- CZ *> 4- U- u 4-> E TO D> D)4- o TO TO > E J- C *r- r* 41- WS CM r- E O TO5 r-S 3 rt3 O >5 Z ^C r"* O MM >, MOM meo <0 O TO TO TO _ c TO- -P fO *r *r* U *r * -- *r- i- E C +J 3* 44 V) -X > ZC TO CM TO TO <- r- 05 r Z *1" c TO V) TO 3 r-- Z CO *> 0 4- O M+J 0) XJ E Ol+J Z> Vi m /-- . +> O t* r 2Jt r-- Z2 (0 C TO Jtf *- c TO > O 10 4-5 JX TO U VI r- TO L. Zc a. t o Q. (- V5 U t- C to r-- i- TO i-- TO TO <-- X 3 (0 TO 3 *r- o. UC3 0. Cl . Cl . Z TO l u *- a> O. fc. O. TABLE 7-12 (c o n tin u e d ). Lu <. Q a U> *- in u> in Iac cn c 3 t- s- tin to O in 3 3 3 >> e- c z c O O O Jo 05 3 3ZZ CL XJ E rH <JZ o CM o> sz cn c m eg TO fd to >vCVJ o Ol rH TO CM U r cn r- CO to 05 f-- <0 Pn rH TO 05 rH 4- 3 4-'# O 4-- 'C- TO rH 4- 4 4- a. 4-- O o rH O O o oo OO O >i <rt ex CO t- CO 00 UC X? 07 i. t- C TO TO S- TO C 05 C 05 C Lfl (0 3 C 35 3 TO 3 V) 013 Z3 rH 3 rH 3 a> 3 S4-> iro o o o oc u- o to <0 O S- -C >5 05 tO > rH ^ C tD Z i_ o +> TO OC OO 1 TO O >, 5- Z i-- TO 3 >O '-s cn E tTO O TO TO C OO ta> C 0J 3C OO 5^ r# 3C no a u c4J to- 4C-J a: x; Q. ro o S- Z CD * P<D ua o r pN U) c r^. 3 05 3: i-i ro eg PB7/A rv 05 rH A c o xt1>o> to o 04 TO P TO C o0) o 1>- o CO t o cr> O rH to -p o c o U5 X3 10 r- rH > 00 to a> Q rH m to CM eg 7-32 I-- to p 0) c o X3 JQ r rH > CO to 05 Q rH eg eg 00 05 rH X? ce to o U) XJ X3 r- *r O> O to CD O eg 00 95 rH X * ce m oto rX3 *Xr> O> O to oo CO eg 05 eg 12-15- TEH 0530418 DUP050031331 X o ZL u r> ro to CL O Cl C 1 CO in d O rH o 00 CD CM CM *M CD 3- to oO do 3- ur> csi 00 T--1 CO o o H O) o o o o o CO o ZL o pH CM 00 o o>,* H CM* o rH o X a> d) 0 + > Ql &.X a.x= o.x: 3 3 +J 3+> 3P % JxC Q) CU> EU EU GO u a) >9 o 3 (0 > 3 CO > to > o S- un -O -Q 5- r- 1 O O X) X) O O JO (AO o &- 3 p o og >X > JO CO G f!J u O. D+i E B <Cc V* UD. - i x *+rJ- E O) * O 1 +J x: - e 05 O XJ P C-rr < >o CL !-. rP-- t/3 rH C *p- CM r- CM CM r-* X S~ 3 x s- X t- TO S* CP P o a>>. a> o * o *r +J L L 4-. *f-- U 4-} 05 XJ D-r-- O 4r-- G o flj +J s_ x> s- u a> c Sfl)- (C0L 4-> r-- 3 O r- E *f- S_ I0 PO t.~ "O uu e J- r-- to P a.r- *p- 3 P 0O - p" P S- X3 Pu c rXJ tO P Q.r- 3 O r- U u) U 03l ^ TcO U p- Z r- 4- p </>(- <*- o> CD *r- 4- D> Z 05 <C JO G P r- .36 So p u sa. P rp r-- r-- CP tn o. t- 3 *o Mo G <G G P r~ s t- o p u c. CL P r-- r-- GP tn a. t- 3 ^ XJ c u < -Q a. a. U) >>3 C 4) 1 O XJ r-- r- G *r- j-- '' O G3 PG PG *O CO (0 * C O i- P O C r~ i--. Q, r-- g <3)03 0 OCO to *0 o to *r *r rH P D P O . c C Z 0>) o <0 o r- r~ o *- P *r- CL U tt-. >>.JJ*- o 3 i-- 10 --J 3= O O- M-- O + > tn <5 o U P tn <0 T3 x3 + E 3 S- lO/l 0V3 4O P (D m o u p </3 <o m a> x j J= 3 P3 O tn CO G <0 05 G a i-- i t. o X fc. < c c < c in 09 G r r-- G O in o r- G r* z r-- r* *k M SG Z r~ P C fp r~ X O G W ! O) r*j* X C O p *r- U C r- a G *r-- S tn 0 C G r* r-- cO CM U. < C O tn >Q <C z <n Oc t3 r- o 53xO &.3 O g x: r> tf) G3 S- * ipt to V) k tn g c3 G 3 t/1 c C3 u s_ S- 3 &- CL o CM S- CD CO CM CD 0> in i-i r-' i--i CD rH CM G in g rH O t0o0 o rH G G CO u M S05 rH G Ui 4/) rl o O CD O rH Oa.f P P O o 03 .3 C o c <J\ u rH P Q 3. u> p ao o to tn CD U PO >,0 1/3 3 tn < 3 33 ri 3 O) fc. H 0)3 03 t- rH 03 3 X 03 05 1 SP <0 0) O 3C o *3 fc >(0> <Cs> so t- >> r- o3 a,C p-- 3 Ur- 5, O G a.> <C <C CM O . i- G P <J > <* O <C CM t/> 3 1 s- o >> G > Z< CO O S- G P OU <> <C3M- <1U S- ic a) q> 0 < (0 0) uc s<D P ga S- z o PB7/A CM CO CD rH Xc c* o to TO *3 r* *r* > O oo o CO <0 p to u 3 <7% Q rH rH CO to p to u .3 CD Q rH l-w p G O V) *-- S- rH s o> ZC rH CM CD CO CD 7--33 CM or rH XJ C* u p p </) p G .r- U i~- C l-- |-- OS CD CM <T> rH XJ ,G * . S- P P u> P G r- U r- C r- *r- in CD cm or rH G* $- p P V5 P G r- u r- C r- *i-- ozt - r-- P G O t<nn c to GP O 05 X rH to P CD CD 12 -15-82 CJ> rr 0 eo u, 0 X Ui 1- DUP050031332 TABLE 7-12 (c o n tin u e d ). TEH 0530420 XE o s. io. o NLO- <> CL s < s: .. o o O CO .0) .a. u CL 0) Q. .> CD PC (0 V) c o *rP U O. HCD o -C A P o? ?- .* s- tEo rH PU * S- Q. iE-- rP-!- v^ r- C 0P 3 O V) Q. S- ~So- c ^3uro0r> CO CSJ o JC >oQ p r t. . U >-* P r- **/--- XC3 C P 3O VJ-) Q . 0S-) IcD Uror C X5 P CSJ O.P 3 0 0) 0>4 C C U P *r*r (0 Q0 r>-- O O r- tS- *r* je a PC -Q 0) *r- c *e ,t- o O SU tt> *> r-- +J +J in UW >> >><- in U in 1- H - o c C <0 r- r-- CD C UJ O) C LU Of- oc p V) cO >ou- rr- J3 *r- ox: L- g z & Pc u T3 tJ) Crt. *3o P 3 JO fc- o po CL J= P tn m P c o V) > pcc < LU CD Cf f= (0 cfo>o V) 0c> 'S3~ rC*O* - x: os, u (c3A fc. " sz rJC J3 P P *r > C 3 Q. (ft 0o 1 p >> rl<i- (0 d> j c 3 D)p <c I s- o LD PO u i |H C(0D-* - t- S- Po 0) c L 0) PC r- O o r3*" O X<H O) 3> <C M 'r *r PP $- (. P PC c(A Oc u0c) 10 5. P 4000-) .to > r*. co c "cO pp.ro*s.- eo <0 ci-- Oro>sS iH P ct/> c * 5- -C Po oo L- +c3 3u U Q. CE O *-h U CJ r-i CL t--( 00 QC C 0) 5- *0 OO O<0. O 5- 2 00 co O O CO CO jsQ- *Cs"- tf- < Q. K PB7/A 7-34 12-15-82 DUP050031333 PB7/A 7-35 3O E c .o *5 t tcoo 3a moo km a km a *ooc5 E c *3 *o5a5 O R aD3.) iz 12-15-82 TEH 0530421 DUP050031334 breathing as a function of aerodynamic diameter* except below 0.5 pm where deposi tion is plotted vs. physical diameter. The eye-fit band envelops deposition data cited by the different investigators. The dashed line is the theoretical deposition model of Yu (1978) and the broken line is the estimate o f pulmonary deposition for nose breathing derived by Lippmann (1977). s-- % E c > =5 fe ot *e ^ 0 >J5 C JQ 0^ C 2 8> 9 tu 25 o <5 I ?P 1i 5 *"5 | SI! zi CO ffl !9 O SS -c i i| !& . jl w *c u ;o P-B7A 7-36 12-15-82 TEH 0530422 DUP050031335 PB7/A AERODYNAMIC DIAMETER (at 30 liters/min). jum 7-37 xcc 3o a, "o c 22$a 5 *3 e-2-o - g 5 8 | .sS'gg o as . gg Sg pas o> > * x o-S -II 0 g | * o | SO - 2 2Ss S *5 x s > .2 9 c m !<? 1d 3 E h _ 2 *. ,Oco.v2Sr*SB1so0 V3 O V) ^ Oft X jO- XL. Ow M CO ft- S' 2 c' " .S' g I m x .E c 12-15-82 H 0530423 DUP050031336 PRELIMINARY DRAFT are likely to be inaccurate, since an appreciable fraction of the airborne lead mass was probably not sampled. The distributions of Figure 7-2 have been used with published lung deposition data to estimate the fraction of inhaled airborne lead deposited in the human respiratory system,, Figures 7-3 through 7-5, showing lung deposition as a function of particle site, have been taken from the ERA document Air Quality Criteria for Particulate Matter and Sulfur Oxides. Results of this calculation are shown in Table 7-13. Note that a significant fraction of lead can reach the pulmonary region where transfer to the bloodstream occurs. The observed deposition fractions are consistent with the results of lead isotope studies, showing appreciable transfer of inhaled lead into the blood (Chapter 10). 7.2.1.3 Vertical Gradients of Lead in the Atmosphere--Few studies have been conducted to determine the variation of lead concentration with height above the ground. Of those that were found, all contain the premise, either explicitly or implicitly, that the concentrations being studied derive principally from automotive emissions. Of the studies found in the literature, none were adequately designed to establish the lead concentration versus height relationship. Such a study would require simultaneous measurement (preferably continuous) at given height intervals over a long period of time (a minimum of one year). Even then, the results would be valid only for a location having the same character istics and experiencing the same atmospheric conditions. A single set of concentration values obtained over short and variable time intervals is not sufficient to draw conclusions regarding general exposure conditions. Edwards (1975) has reported measurements made in downtown Ft, Collins, Colorado. Measurements were made in a street canyon formed by two and three story buildings (average height 9 m). With a 2.3 m/sec wind from the northeast (street running north-south), lead concentrations along the east side of the street canyon ranged from 11.3 pg/m at street level to 4.0 pg/m at roof 3 level. On the west side of the street, concentrations ranged from 0,9 pg/m at street level to 1.3 pg/m3 at roof level. Values for two additional sampling points above the rooftops on each side of the street were 0.4 (east side) and O 0.9 pg/m (west side). Lead concentrations 2 to 5 blocks away ranged from 0.1 to 0.3 pg/m . These data reflect the wide variability that can be expected in urban traffic environments. Under moderate cross-wind conditions, concentrations within the canyon were stringly anisotropic, and street-level concentrations along the upwind building faces were substantially higher than those along the PB7/A 7-38 12-15-82 TEH 0530424 DUP050031337 PRELIMINARY DRAFT TABLE 7-13, FRACTION OF INHALED AIRBORNE LEAD DEPOSITED IN EACH COMPARTMENT OF THE HUMAN RE5PIRAT0RY SYSTEM* Range Arithmetic Average and Standard Deviation Pulmonary Min. 0,08 - 0.16 Max. 0.21 - 0.35 Tracheobronchial 0.05 - 0.40 Extrathoracic 0.03 - 0.23 Total (based on max. pulmonary deposition 0.30 - 0.94 0.11 0.016 0.26 0.031 0.16 0.075 0.09 0,048 0.51 0.13 *Based on the size distributions of Figure 7-2 and the deposition curves of Figures 7-3 through 7-5. downwind faces. With different wind regimes, building configurations, and stability conditions, the distribution of concentrations would also be different. Barltrop and Strehlow (1976) conducted an air sampling program at a proposed nursery site under an elevated motorway. The height of the motorway was 9.3 meters. Air samplers were operated at five to seven sites during the period from Monday to Friday, 8 AM to 6 PM, for one year. The maximum individual value observed was 18 pg/m . The 12 month mean ranged from 1.51 pg/m to 1.35 pg/m , with standard deviations of 0.91 and 0.66, respectively. The authors reported that the airborne concentrations were independent of height from ground level up to 7 meters. Pedco-Environmental (1977) measured lead concentrations at heights of 5 and 20 feet at sites in Kansas City, Missouri and Cincinnati, Ohio. The sampling sites in Kansas City were described as unsheltered, unbiased by local pollution influences, and not immediately surrounded by large buildings. The Cincinnati study area was located in a primarily residential area with one commercial street. Samplers were operated for 24-hour periods from 8 AM to 8 AM, but a few 12-hour samples were collected from 8 AM to 8 PM. Data were obtained in Kansas City on 35 days and in Cincinnati on 33 days. The range and average PB7/A 7-39 12-15-82 TEH 0530425 DUP050031338 PRELIMINARY DRAFT values reported are shown in Table 7-14, In all cases except two, the measured concentrations were greater at 5 feet than at 20 feet. Note that the difference between the east side and west side of the street was approximately the same as the difference between 5 feet and 20 feet in height. Ter Haar (1979) measured airborne lead at several heights above the ground, using samplers positioned 6 m from a heavily traveled road in Detroit. A total of nine 8-hour daytime samples were collected. The overall average airborne lead concentrations at heights of 0,3, 0.9, 1.5, and 3,0 m were 4.2, 4.8, 4.7, and 4.6 gg/m , respectively, indicating a uniform concentration over this range of heights at the measurement site. It should be noted that at any one height, the concentration varied by as much as a factor of 10 from one day to the next; the importance of simultaneous sampling when attempting to measure gradients is clearly demonstrated. Sinn (1980) investigated airborne lead concentrations at heights of 3 and 20 m above a road in Frankfurt, Germany. Measurements conducted in December 1975, Decembe3r 1976, and January 1978 gave monthly mean values of 3,18, 1.04, and 0.66 gg/m , respectively, at 3 m. The corresponding values at 20 m were 3 0.59, 0.38, and 0.31 pg/ro , showing a substantial reduction at this height. The decrease in concentration over the 2-year period was attributed to a decrease in the permissible lead content of gasoline from 0.4 to 0,15 g/liter beginning in January 1976. TABLE 7-14. AIRBORNE LEAD CONCENTRATIONS AT 5- AND 20-FT ELEVATIONS ABOVE STREET LEVEL (PEDC0 ENVIRONMENTAL, 1977) (gg/m3) Location Kansas City Cincinnati Range 0.8 - 4,0 0.1 - 4. 6 Averages East side of street West side of street 20 ft. 5 ft. Diff. 20 ft. 5 ft. Diff. 1.7 2.0 0.3 1.5 1.7 0.2 0.9 1.4 0.5 0,6 0.8 0,2 a5ide of street. ^Height above street level. PB7/A 7-40 12-15-82 TEH 0530426 DUP050031339 PRELIMINARY DRAFT These data reflect the strong influence of the geometry of the boundary layer, wind, and atmospheric stability conditions on the vertical gradient of lead resulting from automobile emissions. The variability of concentration with height is further complicated by elevated emissions (i.e., from stacks). Concentrations measured from sampling stations on the roofs of buildings several stories high may not reflect actual human exposure conditions, but neither would a single sampling station located at ground level in a building complex. The height variation in concentration resulting from vertical diffusion of automobile emissions is likely to be small compared to temporal and spatial variations resulting from surface geometry, wind, and atmospheric conditions. Our understanding of the complex factors affecting the vertical distribution of airborne lead is extremely limited. 7.2.2 Soil Lead concentrations in soil at a depth of 20 cm range from less than 10 to greater than 70 jjg/g (Shack!ett et al., 1971). The arithmetic mean of 20 and geometric mean of 16 pg/g reflects the fact that most of the 863 samples were below 30 pg/g at this depth. The study was designed to determine the elemental composition of soil materials derived from the earth's crust, not the atomosphere. The range of values probably represent natural levels of lead in soil, although there may have been some contamination with anthro pogenic lead during collection and handling. McKeague and Wolyneta (1980) found the same arithmetic(we^r/(2Q pg/g) for 53 uncultivated Canadian soils. The range was 5 to 50 pg/g and there was no differences with depth between the A, B and C horizons in the soil profile. Studies discussed in Chapter 6 have determined that atmospheric lead is retained in the upper two centimeters of undisturbed soil, especially soils with at least 5% organic matter and a pH of 5 or above. There has been no general survey of this upper 2 cm of the soil surface in the United States, but several studies of soil lead near roadsides and smelters and a few studies of soil lead near old houses with leadbased paint can provide the backgound information for determining potential human exposures to lead from soil. Because lead is immobilized by the organic component of soil (Chapter 6), the concentration of anthropogenic leac in the upper 2 cm is determined by the flux of atmospheric lead to the soil surface. Near roadsides and smelters, this flux is largely by dry deposition and the rate depends on particle size and concentration. These factors vary with traffic density and average vehicle speed. (Chapter 6). In general, deposition flux drops off abruptly with PB7/A 7-41 12-15-82 TEH 0530427 DUP050031340 PRELIMINARY DRAFT increasing distance from the roadway. This effect is demonstrated in studies which show surfacesoil lead decreases exponentially up to 25 m from the edge of the road. The original work of Quarles et al (1974) showed decreases in soil lead from 550 pg/g within 25 m along side a highway with 12,500 vehicles/ day in Virginia. Their findings were confirmed by Wheeler and Rolfe (1979), who observed an exponential decrease linearly correlated with traffic volume. Agrawal et al (1981) found similar correlations between traffic density and roadside proximity in Baroda City, as did Garcia-Miragaya et al (1980) in Venzuela and Wong and Tam (1978) in Hong Kong. The extensive study of Little and Wiffen (1978) is discussed in Chapter 6; these authors found additional relationships between particle size and roadside proximity and decreases with depth in the soild profile. The general conclusion from these studies is that roadside soils may contain atmospheric lead from 30 to 2000 pg/g in excess of natural levels within 25 meters of the roadbed, all in the upper layer of the soil profile. Near primary and secondary smelters, lead in soil decreases exponentially within a 5 to 10 km zone ground the smelter complex. Soil lead contamination varies with the smelter emission rate, length of time the smelter has been in operation, prevailing windspeed and direction, regional climatic conditions and local topography (Roberts, 1976). Little and Martin (1972) observed decreases from 125 to 10 pg/g in a 6 km zone around a smelting complex in Great Britain, and all of the excess lead in the upper 6 cm of the soil profile. Roberts (1976) reported soil lead between 15.000 and 20,000 near a smelter in Toronto. Kerin (1976) found 5,000 to 9.000 pg/g adjacent to a Yugoslavian smelter; the contamination zone was 7 km in radius. Ragaini et al. (1977) observed 7900 pg/g near a smelter in Kellogg, Idaho; they also observed a 100-fold decrease with depth doax to 20 cm in the soil profile. Palmer and Lucera (1980) observed soil lead in excess of 60,000 pg/g near two smelters in Missouri, decreasing to 10 pg/g at 10 km. Urban soils may be contaminated from a variety of atmospheric and nonatmospheric sources. The major sources of soil lead seem to be paint chips from older houses and deposition from nearby highways. Lead in soil adjacent to a house decreased with distance; this may be due to paint chips or to dust of atmospheric origin washing from the rooftop (Wheeler and Rolfe, 1979). Davies (1978) and Davies et al. (1979) have described the effect of soil lead contaminations in urban gardens in London. Soils ranged from 10 to 2600 pg/g; lead in radishes was 50-fold higher in the contaminated soil. This relation- PB7/A 7-42 12-15-82 TEH 0530428 DUP050031341 PRELIMINARY DRAFT ship between soil and plant lead is discussed further in Section 7.2,4 and in Chapter 8. Andresen et a I (1980) reported lead in the litter layer of 51 forest soils in the northeastern United States. They found values from 20 to 700 pg/g, which can be compared only qualitatively to the soil lead concentration cited above. This study clearly shows that the major pathway of lead to the soil is by the decomposition of plant material containing high concentrations of atmospheric lead. Finally, a definitive study which describes the source of soil lead was reported by Gulson et al (1981) for soils in the vicinity of Adelaide, South Australia. In an urban to rural transect, stable lead isotopes were measured in the top 10 cm of soils over a 50 km distance. By their isotopic composi tions, three sources of lead were identified: natural, non-automotive industrial lead from Australia, and tetraethyl lead manufactured in the United States. The results indicated most of the soil surface lead originated from leaded gasoline. Similar studies have not been conducted in the United States. 7.2.3, Dusts Dusts are solid aerosol particles which are usually produced by the disintegration of larger particles (FriedTander, 1977). They should be dis tinguished from soil, which is complex mixture of organic and inorganic substances of varied origin. Exposed surface soil may become airborne during wind erosion, at which time it becomes dust. Other sources of dust may be auto motive exhausts, industrial stack emissions and fugitive dust from manufac turing processes. Dusts of importance to potential human exposure are roadway dusts which may wash or settle into adjacent play areas, manufacturing dusts which may be carried home on the clothing of workers, and household dusts which accummulate on windowsills and other flat surfaces likely to contact the hands and mouths of small children. Nriagu (1978) reviewed several studies of lead in street dust, including a report by Kaye and Reznikoff (1947) that lead in New York City street dust was 1200 pg/g in 1924 before the use of lead additives in gasoline. The source of lead was probably flue dust from burning coal. Warren et al. (1971) reported lead in street dust of 20,000 pg/g in a heavily traffiked area. In the review by Nriagu (1978), street dust lead concentrations ranged from 300 to 18,000 pg/g in several cities in the United States. In Hong Kong, lead in street dust ranged from 960 to 7400 pg/g with no direct relationship to traffic volume (Ho, 1979), In other reports from Hong Kong, Lau and Wong (1982) found PB7/A 7-43 12-15-82 TEH 0530429 DUP050031342 PRELIMINARY DRAFT values from 130 pg/g at 20 vehicles/day to 3900 pg/g at 37,000 vehicles/day. Fourteen sites In this study showed close correlation with traffic density. In the United Kingdom, lead in urban and rural street dusts was determined to be 970 and 85 pg/g, respectively, by Day et al. (1975). A later report by this group (Day et al., 1979) discusses the persistency of lead dusts in rainwashed areas of Great Britain and New Zealand and the potential health hazard due to ingestion by children. They concluded that, whereas the acidity of rain was insufficient to dissolve and transport lead particles, the potential ' ealth hazard lies with the ingestion of these particles during the normal play activities of children residing near these areas. A child playing at a playground near a roadside might consume 20 to 200 pg Pb while eating a single piece of candy with unwashed hands. Lead in manufacturing dusts varies greatly with the type of industry. There are two types, stack emissions which are dispersed locally or regionally, and fugitive dusts which are usually confined at or near the working environ ment. Occupational exposure to manufacturing dusts are discussed in Section 7.3.6. Of interest here is the contribution of industrial dusts on workers' clothing to the household environment. Dust is a normal component of the home environment. It accumulates on all upfacing surfaces, especially furniture, rugs and windowsills. For reasons of hygiene and respiratory health, most homemakers devote much time and money toward removing this dust from the household. Because there are at least two circumstances where these measures are inadequate, it is important to consider the possible concentration of lead in these dusts in order to determine potential exposure to young children. First, some households do not practice regular dust removal, and secondly, in some households, of workers exposed occupationally to lead dusts, the worker may carry dust home. In Omaha, Nebraska, Angle and Mclntire (1979) found lead in household dust ranged from 18 to 5600 pg/g. In Lancaster, England, a region of low industrial lead emissions, Harrison (1979) found household dust ranged from 510 to 970 with a mean of 720 pg/g. They observed soil particles (10200 pm), carpet and clothing fibers, animal and human hairs, food particles, and an occasional chip of paint. The previous Air Quality Criteria for Lead document (U.S. Environmental Protection Agency, 1977) summarized earlier reports of lead in household dust showing residential surburban areas range from 280 to 1500 pg Pb/g, urban residential from 600 to 2000 pg/g, urban industrial from 900 to 16,000. In El Paso, Texas, household dust ranged from 2800 to 100,000 pg/g within 2 km of a smelter (Landrigan et al. 1975). PB7/A 7-44 12-15-82 TEH 0530430 DUP050031343 PRELIMINARY DRAFT 7.2.4 Vegetation Lead in vegetation may be atmospheric on the surface or a combination of atmospheric and soil in the internal tissues. The mechanisms for the dry deposition of aerosol particles directly to vegetation surfaces are discussed in Chapter 6 and the mechanisms for the transfer of lead from soil to roots are discussed in Chapter 8. Of interest here are lead concentrations in roadside and urban vegetation which may affect potential human exposures. As with soils, lead on vegetation surfaces decreases exponentially with distance away from roadsides and smelters (Cannon and Bowles, 1962; see also Chapter 8), This lead is persistent. It is neither washed off by rain nor taken up through the leaf surface. For many years, plant surfaces have been used as as indcators of lead pollution (Garty and Fuchs, 1982; Pilegaard, 1978; Ratcliffe, 1975; Ruhling and Tyler, 1969; Tanaka and Ichikuni, 1982) and in some cases for the exploration of lead (Brooks et al., 1979). These data all show that lead on the surface of leaves and park is proportional to traffic density and distance from the highway, which are the primary determinants of air lead concentrations and particle size, distrubutions. Other factors such as surface roughness, wind direction and speed are discussed in Chapter 6. The data also show that lead in internal plant tissues is directly related to lead in soil. Lead in forage was found to exceed 950 pg/g within 25 m of roadsides by Graham and Kalman (1974), with 25,000 or more vehicles per day. At lesser volumes, 200 pg/g were found. These authors review other reports of 20 to 660 pg/g with the same same relationship to traffic volume and distance from the road. A more recent study of Crump and Barlow (1982) showed the accumulation of lead on forage is directly related to the deposition rate, which varied seasonally according to traffic density. The deposition rate was measured using the moss bag technique. Rain was not effective in removing lead from the surface. The effect of lead on edible crops was measured by Ter Haar (1970), who showed that edible plant parts not exposed to air (potatoes, cron, carrots, etc.) are not affected by atmospheric concentrations of lead. Leafy vegetables are. In edible parts, such as corn husks, wheat and oat chaff and soybean hulls were also contaminated. These results were confirmed by McLean and Shields (1977), who found most of the lead on leaves and husks. The general conclusion from these studies is that lead in food crops varies according to exposure to the atmosphere and in proportion to the effort taken to separate PB7/A 7-45 12-15-82 TEH 0530431 DUP050031344 PRELIMINARY DRAFT husks, chaff and hulls from edible parts during processing for human or animal consumption. Near Smelters, Merry et al., (1981) found a pattern different from road side studies cited above. They observed that wheat crops contained lead in proportion to the amount of soil lead, not surface contamination. A similar effect was reported by Harris (1981). 7.3 POTENTIAL HUMAN EXPOSURES The preceding section discussed ambient concentrations of lead in the environment, focusing on levels in the air, soil, and vegetation. The available data showed that lead levels in environmental media vary greatly, because of natural variations as well as anthropogenic activities. In this section, environmental lead concentrations are examined from the perspective of potential exposures. Six categories of sources of exposure are considered: emissions from mobile sources, emissions from stationary sources, dietary lead (food and water), lead in manmade materials, lead in soil and dust, and occupational exposures. 7.3.1 Mobile Source Exposures Several major studies have been undertaken to determine the lead levels in the air and in settled dust near busy highways that are far from any stationary lead source. Among the most intensive of these studies is the Los Angeles Catalyst Study of 1974-1977, undertaken by EPA to measure the impact of the catalytic converter on air quality, near a major traffic lead source (USEPA, 1979). Table 7-15 summarizes the average 4-hour and 24-hour airborne lead concen trations during the summer months (May-October). Note that concentrations measured at sites upwind of the freeway are considerably smaller than levels at downwind locations. The data show a progressive decrease in airborne lead through 1974-1976, followed by a substantial increase in 1977. The decrease is attributed to the growing fraction of Catalytic converter-equipped vehicles, which use unleaded gasoline. The increase in 1977 is due to the opening of a new northbound lane; this resulted in an increase in traffic speed. Hirschler et a]. (1957) have shown that lead emissions increase with traffic speed. Ledolter et al. (1979) have used 1976-1977 data from the Los Angeles catalyst study to develop a simple model for roadside airborne lead concentrations. The model shows that concentrations are functions of traffic density, vehicle speed, atmospheric stability, windspeed, and wind direction. The influence of PB7/A 7-46 12-15-82 TEH 0530432 DUP050031345 PRELIMINARY DRAFT Site C 0 TABLE 7-15. FOUR-HOUR AND 24-HOUR AIRBORNE LEAD CONCENTRATIONS AT TWO ROADSIDE SITES IN THE LOS ANGELES CATALYST STUDY, 1974-1977 Year(s) 1975 1976 1977 1974 1975 1976 1977 4-Hr Pb Concentrations (3 p.m. to 7 p.m.) Mean Standard Deviation Number of Observations 8.16 6.77 11.41 5.64 4.90 4.40 6.18 2.78 2.25 2.14 1.29 1.00 0.96 1.18 174 166 92 151 176 166 20 Site C D Year(s) 1974 1975 1976 1977 1974 1975 1976 1977 Mean 8.19 7.98 7.00 7.43 5.00 4.19 3.75 4.16 24-Hr Pb Concentrations Standard Deviation Number of Observations 1.83 1.48 1.60 1.19 1.02 1.01 0.73 0.70 143 173 166 74 46 57 57 63 Source: Ledolter et al. (1979) the road on ambient airborne concentrations can be observed only for a short downwind distance, due to rapid settling of large lead-containing particles as well as dilution. In a study conducted in London, England, Harrison et al. (1975) measured ambient air levels of organic lead at urban sites. Concentrations of organic lead ranging from 0,04 to 0.11 pg/m were found on streets of varying widths and traffic flow. These values were 0.3 to 2.65 percent of the total airborne lead. The level of organic lead inside a busy tunnel was 0.02 pg/m or 0.1 percent of the total airborne lead. Not surprisingly, organic lead concentrations measured at a busy service station ranged from 0.21 to 0.59 pg/m3, or 3.9 to PB7/A 7-47 12-15-82 TEH 0530433 DUP050031346 PRELIMINARY DRAFT 9.7 percent of total airborne lead at that site. At a less busy service station, the concentration of organic lead was 0.07 pg/m , or 4.2 percent of the total airborne lead. Jansen et al, (1978) studied the influence of automotive lead emissions on child lead exposure in Morton Grove, Illinois, a Chicago suburb. Annual average airborne lead levels between November 1974 and October 1975 ranged 3 from 0.73 to 3.04 pg/m , with the greatest values measured near a heavily traveled road. Soil lead levels were generally greater within 200 feet of the road, compared with samples collected at greater distances. Similarly, children aged 1 to 12 years living within 200 feet of the road had greater blood lead levels than children living farther away. The greatest blood lead levels were found in the youngest children, aged 1 to 3 years, who had lived all of their lives close to the road. The authors concluded that child blood lead levels may have been influenced by ingestion of deposited automobile-emitted lead as a result of hand-to-mouth activities. Chamberlain et al, (1978) summarized the results of several studies conducted at Harwell Laboratories, England over the past decade, the overall objective being to assess human exposure to lead emitted from mobile sources. Many of the measurements were conducted near a highway carrying 90,000 vehicles per day in London. Size distributions measured with an inertial impactor, a diffusion battery, a thermal precipitator, and a cascade centripeter showed that most of the mass of automobile-emitted particles was submicron; nearly all of the lead mass was also submicron. Airborne lead concentration measurements and atmospheric dispersion calculations suggested that roadside lead levels 3 were about 2 pg/m for each 1000 vehicles/hour. For a traffic flow of 1000 yehicles/hour, an airborne lead concentration exceeding 1 pg/m extended from the curb to 15 m on either side of the road; the zone increased to 100 m on either side for 4000 vehicles/hour. Deposition data for trays of washed grass set beside the highway were used to calculate that about 10 percent of the lead emitted during steady cruise operations on a level highway was deposited within 100 m of the road. However, accounting for the lead content of soil and vegetation near the highway since its opening in 1965, the authors concluded that 40 percent of the lead emitted during 1965-1976 had deposited within 100 m. Even greater fractions of deposited lead could be expected in the vicinity of stop-and-go traffic, rapid accelerations, or uphill grades. Additional data from this study, covering intake and absorption of automobile-emitted lead by the human body, are discussed in Chapter 12. PB7/A 7-48 12-15-82 TEH 0530434 DUP050031347 PRELIMINARY DRAFT Harrison (1979) measured the lead content of street dust in Lancaster, England. Results are shown in Table 7-16. Note that the lead content of the dust is greatest in areas of high traffic density. In contrast, Day et al. (1975) measured relatively uniform lead concentrations in dust throughout the city of Manchester, England. Harrison (1979) hypothesized that because Manchester is heavily industrialized, stationary source emissions may be more important than vehicular emissions in determining lead levels there; the influence of mobile sources may be more pronounced In a nonindustrial city such as Lancaster. TABLE 7-16. LEAD CONCENTRATIONS IN STREET DUST IN LANCASTER, ENGLAND Site No. of samples Car parks Garage forecourts Town centre streets Main roads Residential areas Rural roads 4 16 2 7 13 19 7 4 Range of concentrations 39,700-51,900 950-15,000 44,100-48,900 1,370-4,480 840-4,530 740-4,880 620-1,240 410-870 Mean 46,300 4,560 46,500 2,310 2,130 1,890 850 570 Standard deviation 5,900 3,700 1,150 960 1,030 230 210 Source: Harrison (1979) Duggan and Williams (1977) found a similar trend in the lead content pf street dust as a function of traffic density. Seventy-nine street dust samples collected in several residential areas of London yielded an average of 1460 pg Pb/g for main roads and 900 pg Pb/g for side roads. An additional seven samples collected from a footpath in a rural area near London contained an average of 35 pg Pb/g. Data obtained in a number of other studies on lead in dust near roadways are summarized in Tables 7-17 and 7-18. These data demonstrate that abnormally high concentrations of lead are found in the air and dust near major roadways, and that people who live or work in such areas (e.g., traffic policemen, service station and garage attendants) are exposed to high lead concentrations. PB7/A 7-49 12-15-82 TEH 0530435 DUP050031348 PRELIMINARY DRAFT TABLE 7-17. LEAD DUST ON AND NEAR HEAVILY TRAVELED ROADWAYS Sampling site Washington, D.C.: Busy intersection Many sites Chicago: Near expressway Philadelphia: Near expressway Brooklyn: Near expressway New York City: Near expressway Detroit: Street dust Philadelphia: Gutter (low pressure) Gutter (high pressure) Miscellaneous U.S. Cities: Highways and tunnels Netherlands: Heavily traveled roads Concentration, pg Pb/g 12820 (4000-8000) (Fritsch and Prival, 1972) 6600 (3000-8000) (Kennedy, 1973) (900-4900) (Lombardo, 1973) 2000 (Pinkerton et al., 1973) (966-1213) (Ter Haar and Aronow, 1974) 1507 (270-2626) (Shapiro et al., 1973) 3262 (280-8201) (Shapiro et al., 1973) (10000-20000) (Buckley et al., 1973) 5000 (Rameau, 1973) PB7/A 7-50 12-15-82 TEH 0530436 DUP050031349 PRELIMINARY DRAFT TABLE 7-18. LEAD CONTENT IN OR ON ROADSIDE SOILS AND GRASS AS A FUNCTION OF DISTANCE FROM TRAFFIC AND GRASS DEPTH IN PROFILE* Site and distance from road Grass Lead content, pg/g dry weight 0-5 cm 5-10 cm 10-15 cm Soil depth Soil depth Soil depth West of U.S. 1, near Plant Industry Station, Beltsville, MD: 8 16 32 68.2 522 460 416 47.5 378 260 104 26.3 164 108 69 West of southbound lanes, Washington-Baltimore Parkway, Bladensburg, MD: 8 51.3 540 300 98 16 30.0 202 105 60 32 18.5 140 60 38 West of Interstate 29, Platte City, MO: 8 16 32 21.3 12.5 7.5 242 140 61 112 104 55 95 66 60 North of Seymour Road Cincinnati, OH: 8 16 32 31.3 150 29 11 26.0 101 14 8.2 7.6 55 10 6.1 ^Adapted from Lagerwerff and Specht (cited in National Academy of Sciences, 1972). PB7/A 7-51 12-15-82 TEH 0530437 DUP050031350 PRELIMINARY DRAFT For comparison. Table 7-19 summarizes lead in dusts from nominally residential urban areas. These concentrations have a wider range and are in general smaller than those in traffic-oriented dust samples. It is of interest to determine the fraction of lead in street dust which is soluble in hydrochloric acid at the concentration existing in the stomach. This allows calculation of the amount of lead readily available for absorption into the bloodstream. Day et al. 1979) analyzed samples from Manchester, England and Christchurch, New Zealand for lead using hydrochloric acid at concentrations of 10 M to 1.0 M (pH 5 to 0). The maximum extractable lead was determined using boiling 2 M nitric acid. Results are presented in Figure 7-6, and show that the solubility is a strong function of pH; most of the lead is soluble at a pH of 1, characteristic of the stomach acid concentration. Similarly, Harrison (1979) found that 48-77 percent of the lead in Lancaster street dust is soluble at stomach acid concentration, while Duggan and Williams (1977) report an average of 60 percent soluble lead in London street dust. A large fraction of the lead in street dust which is ingested is apparently available for absorption into the bloodstream. ^ Overall, these data suggest that environmental lead levels in the vicinity of heavily traveled roads are elevated above background levels, and that these levels may result in significant increases in lead exposure. Such exposure may be due to direct inhalation of airorne lead, ingestion of food or water containing deposited lead-containing aerosol, or direct ingestion of leaded dust. 7.3.2 Point Source Exposures Several studies have been undertaken to investigate lead levels in the vicinity of various point sources of lead emission such as smelters or battery plants. By far the most complete and informative studies are those carried out by Yankel et al. (1977) and by Landrigan et al. (1976) in the neighborhood of a smelter in Silver Valley, Idaho. Consequently, the data from these studies will be descibed in some detail. Other studies carried out in the United States, Canada, and Europe are summarized in Appendix C. Their findings are in substantive agreement with those of the Idaho study. Yankel et al, (1977) defined five study areas arranged concentrically around the smelter and two control areas. Area I consisted of homes within 1 mile of the smelter; area II, 1 to 2-1/2 miles from the smelter; area III, PB7/A 7-52 12-15-82 TEH 0530438 DUP050031351 PRELIMINARY DRAFT TABLE 7-19. LEAD DUST IN RESIDENTIAL AREAS Sampling site Philadelphia: Classroom Playground Window frames Boston and New York: House dust Brattleboro, Vt.: In home Birmingham, England: In home New York City: Middle class Residential Philadelphia: Urban industrial Residential Suburban Concentration, pg Pb/g 2000 3000 1750 (Shapiro et. a!., 1973) (1000-2000) (Needleman and Scanlon, 1973) (500-900) (Darrow and Schroeder, 1973) (608-742) (Pinkerton et. al., 1973) 3855 (929-15680) (Needleman et. al., 1974) 614 (293-1030) (Needleman et. al., 1974) 830 (277-1517) (Needleman et al., Derbyshire, England: Low soil lead area High soil lead area 518 (130-3000) (Barltrop et al., 1975) 4881 (1050-28000) (Barltrop et al., 1975) PB7/A 7-53 12-15-82 TEH 0530439 DUP050031352 T> 3 49 0 1o X 0O k. 1>3 9 % Xa *5 co 3oc33 Xa . mm .9 I C a sm = PB7/A 7-54 12-15-82 TEH 0530440 DUP050031353 PRELIMINARY DRAFT 2-1/2 to 6 miles; area IV, 6 to 15 miles; and area V, 15 to 20 miles. Environmental samples, including surface soil, house dust, paint, grass, and garden vegetables were collected at the homes in each area, as were blood samples from the resident children aged 1 to 9 years. The mean lead levels found in the ambient air, soil, and house dust all decreased with increasing distance from the smelter. As mentioned in Chapter 12, the blood lead levels of the resident children followed a similar pattern. Ambient air lead levels were measured by high-volume samplers stationed throughout Silver Valley, A highly significant relationship between distance from the smelter and ambient lead concentration was found, and relationship was used to estimate the ambient air lead level lead for any location in the study area. The mean annual ambient air levels near the smelter for two different years (1974, 1975) are shown graphically in Figure 7-7. Similar results were obtained for the lead content of soil and house dust. As noted in Chapter 12, the childrens' blood lead levels correlated quite closely with ambient air lead levels, although this result should not be interpreted as suggesting direct inhalation of lead is the principal exposure mechanism. One result of this study was that some specific emergency measures were taken in 1974 (including covering contaminated soil with clean soil and reducing smelter emissions), and these measures brought about a decrease in blood lead levels that were determined a year later. The details of the blood lead levels and their significance presented in Chapter 12, The conclusion to be drawn from this study (and from the similar studies referred to above) is that people who live in the vicinity of a major industrial source of lead (e.g., a smelter) are exposed to abnormally high lead concentrations. 7.3.3 Dietary Exposures 7.3.3.1 Food--The route by which most people receive the largest portion of their daily lead intake is through foods. Several studies have reported average dietary lead intakes in the range 10D to 500 pg/day for adults, with individual diets covering a much greater range (Schroeder and Tipton, 1968; Tepper, 1971; Mahaffey, 1978; Nutrition Foundation Expert Advisory Committee, 1982). Gross (1981) analyzed results of the extensive lead mass balance experiments of Kehoe 1961), which were conducted from 1937 to 1972; according to these data, total dietary lead intake decreased from approximately 300 pg/day in 1937 to 100 pg/day in 1970, although there is considerable Variability in the data. Only a fraction of this lead is absorbed, as discussed in Chapter ,10 PB7/A 7-55 12-15-82 TEH 0530441 DUP050031354 BY AREA...............,....... ........... Figure 7-7. Annual ambient air lead concentration near a smelter, by area, before the August 1874 and August 1975 surveys. Area 1 is within 1 mile of smelter; Area 2 is 1 to 1% miles from smelter; Area 3,2V to 6 miles; Area 4,6 to 15 miles; and Area 5,15 to 20 miles. Source: Yankel et al. (1977). PB7/A 7-56 12-15-82 TEH 0530442 DUP050031355 PRELIMINARY DRAFT The sources of the lead content of unprocessed vegetable foods have been noted earlier (Section 6.4,3). Studies of the lead associated with crops (near highways) have shown that both lead taken up from soil and aerosol lead delivered by deposition are found with the edible portions of common vegetable crops. However, there is enormous variability in the amount of lead associated with such crops and in the relative amounts of lead in the plants versus on the plants. This depends upon several factors, the most prominent of which are the plant species, the traffic density, the meteorological conditions, and the local soil Conditions (Welch and Dick, 1975; Rabinowitz, 1974; Arvik, 1973; Dedolph et al., 1970; Motto et a]., 1970; Schuck and Locke, 1970; Ter Haar, 1970), The variability induced by differences in the above factors, coupled with the fact that many studies have neglected differentiation between lead on plants versus lead in plants, makes it difficult to generalize. Data of Schuck and Locke (1970) suggest that in some cases (e.g,, tomatoes and oranges) much of the surface lead is readily removed by washing. But as noted in Section 6.4.3., this is not universally true; in some cases, much more vigorous washing procedures are necessary. In view of the wide variability of soil conditions (pH, organic matter, cation exchange capacity, phosphorus content, etc.), of meteorology (especially wind conditions and rainfall), and of the effects of species diversity on the routes of lead accumulation, only crude general correlations between air lead levels and food crop levels are possible. Furthermore, the lead associated with plants may be derived from natural sources, from automotive sources, and from other sources such as manufacturing or combustion. One study in Southern California reported that 60 to 70 percent of the lead associated with oat tops was directly attributable to automobile (aerosol) emissions, but did not distinguish between lead in the edible portion (grain) and lead on the hulls or chaff (Rabinowitz, 1974). This same study reported that lettuce grown in the Salinas Valley had 3 to 25 pg/g lead (dry weight) associated with it, whereas the soil content was only 10 pg/g. The lead content in the lettuce was reported to be 0.15 to 1.5 pg/g on a fresh weight basis. The limited data accumulated were used to deduce that the excess lead was delivered to the lettuce by atmospheric transport of automobile-emitted material, and that removal of lead from automobile exhaust would reduce the lead content of the lettuce by as much as 80 percent (Rabinowitz, 1974). Other studies have similarly reported the importance of deposited airborne lead in influencing lead levels in leafy vegetables (Motto et al., 1970; Schuck and Locke, 1970). PB7/A 7-57 12-15-82 TEH 0530443 DUP050031356 PRELIMINARY DRAFT In contrast, food grains may be somewhat less influenced by airborne lead. Ter Haar (1970) found that inedible portions of several plants (bean leaves, corn husks, soybean husks, and chaff from oats, wheat, and rice) had two to three times the lead concentration when grown near, a busy highway compared with similar plants grown in a greenhouse supplied with filtered air. The edible portions of these and other plants showed Tittle or no difference in lead content between those grown in ambient air and those grown in the filtered air. Dedolph et al. (1970) found that while ryegrass and radish leaves grown near a busy highway contained deposited airborne lead, the edible portion of the radish was unaffected by variations in either soil lead or air lead. An overall analysis of the data available supports the contention that plants grown near busy highways consistently have more lead in them and on them than those in other areas. This difference is typically very hard to detect at distances greater than about 100 to 200 m from the highway, due to dilution and deposition of the emitted lead. The available data are not sufficient to permit the quantitative estimate of the contribution of automotive lead to foodstuffs on a national or even a regional scale. The concentrations of lead in various food items are highly variable, and t as much variation is found within specific food items as between different food categories. Schroeder and Balassa (1961), in a study of American foods conducted during 19??, have found maximum concentrations of 1.5 pg/g for condiments, 2.5 pg/g for fish and other seafood, 3.7 pg/g for meats and eggs, 1.4 pg/g for grains, and 1.3 pg/g for vegetables. All of these values refer to unprocessed foods. A British report (United Kingdom Ministry of Agriculture, Fisheries, and Food, 1982) in a study conducted in 1979-80 on lead in foods describes similar maximum values for meat and eggs, grain products (flour and bread), and vegetables, but concentrations up to 14 pg/g in condiments, and up to 18 pg/g in shellfish. More recently, the Nutrition Foundation Expert Advisory Committee (1982) has used data from a 1975 Canadian survey to estimate lead levels in several categories of infant food. Strained meats, vegetables, and fruits typically contained 0.03 to 0,05 pg/g, while cereals contained 0.09 pg/g. Ziegler et al. (1978) reported in a study in 1974-75, a wide range of 0.013 to 0.327 pg/g for lead in infant fruit juices, fruits, and vegetables. The lead content of milk is of special interest because it is a major component of the diets of infants and young children. Brandt and Bentz (1971) PB7/A 7-58 12-15-82 TEH 0530444 DUP050031357 PRELIMINARY DRAFT report that levels in fresh milk are typically less than than 5 pg/liter, The survey by USFDA (1975) found lead concentrations in whole milk ranging from 10 to 70 pg/liter, and averaging about 20 pg/liter. In a recent survey by Ziegler et al. (1978), seven samples of baby formula and three samples of whole cow's milk were analyzed in duplicate. Mean concentrations of lead were 18 pg/liter (range 15 to 20 pg/liter) in formula and 10 pg/liter in milk. Tolan and Elton (1973) reported lead levels of 30 pg/liter in fresh milk in Great Britain and 50 pg/liter in canned (evaporated) milk. Michel! and Aldous (1974) reported a comparable average of 40 g/liter for fresh whole milk purchased in New York State, but their results for evaporated milk averaged 202 pg/liter and ranged as high as 820 pg/liter. The amount of lead taken in with food varies from person to person. It depends upon (a) the types of food in the diet, (b) the total amount of food eaten, (c) the history of the food during growth, (d) its opportunity to acquire intrinsic lead (absorbed from soil or water), and (e) the manner in which the food is prepared. As an example of the last category, it has been shown that vegetables prepared in water containing lead can absorb a considerable fraction of this lead during boiling. Moore et al. (1979) estimate that water containing 200 pg Pb/liter can contribute up to 396 pg Pb/day through consumption of vegetables. Little et al. (1981) report ranges of 18-46 pg/day and 72-182 pg/day for vegetables boiled in water containing 50 and 200 pg Pb/liter, respectively. The latter study also reports wide variations in lead absorption from the human GI tract for different lead compounds associated with vegetables. Using the United Kingdom Total Diet Study (Buss and Lidsay, 1978) to estimate food consumption, Smart et al. (1981) estimate a lead intake as small as 23 pg/day for vegetables prepared in soft water containing 55 pg Pb/liter; hard water containing 520 pg Pb/liter provides a vegetable lead intake as great as 130 pg/day. These authors estimate a total dietary lead intake of 87 to 440 pg/day. On a per-weight basis, the dietary intake of children has been shown to be two to three times that of adults. This additional dietary intake is especially significant when the lead added to food by processing and to water by plumbing (vide infra) is considered. The Glasgow Duplicate Diet Study (United Kingdom Department of the Environment, 1982) reports that children approximately 13 weeks old living in lead-plumbed houses consume 6 to 480 pg Pb/day. Water lead levels in the 131 homes studied ranged from less than 50 PB7/A 7-59 12-15-82 TEH 0530445 DUP050031358 PRELIMINARY DRAFT to over 500 pg/liter. Those children and mothers living in the homes containing high water lead levels generally had greater total lead consumption and higher blood lead levels, according to the study. Breast-fed infants were exposed to much less lead than bottle-fed infants. Because the project was designed to investigate child and mother blood lead levels over a wide range of water lead concentrations, the individuals studied do not represent a typical cross-section of the population. However, results of the study suggest that infants living in lead-plumbed homes may have exposure to considerable amounts of lead. This conclusion was also demonstrated by Sherlock et al. (1982) in a duplicate diet study in Ayr, Scotland. For typical North American lead exposures, generally in the absense of lead plumbing, the Nutrition Foundation Expert Advisory Committee (1982) used 1975 Canadian food data to estimate lead intakes of 61-73 pg/day for children aged 1-4 years, and intakes of 77-132 pg/day for older children and adults. In a survey of heavy metals in foods, the USFDA (1975) found relatively high lead concentrations in metal-canned foods. In the adult food category, canned foods averaged 0.376 pg Pb/g, and non-canned foods averaged 0.156 pg Pb/g. In the baby food category, canned foods (juices) averaged 0.329 pg Pb/g, and foods in jars averaged 0.090 pg/g. The report concluded that from the age of about 1 year on, canned foods comprise 11 to 12 percent of a person's diet, but they contribute about 30 percent of the average dietary lead intake. In a more recent survey, Beloian (1982) estimates that canned foods contribute 51 percent, 30 percent, and 33 percent of the total dietary lead intake for I children aged 0-5 months, 6-23 months, and 2-5 years, respectively. In a comparison made in the United Kingdom (To!an and Elton, 1973), lead concentrations in canned foods were found to vary widely with the precise nature of the food but they averaged about ten times greater than those in fresh foods. The soldered seam of tin cans is evidently the major source of the additional lead in canned foods, and increasing lead concentrations in samples of a can's contents taken progressively nearer the seam have been found (Michel! and Aldous, 1974). Similarly, there is a correlation between increasing lead concentrations in canned products and the increasing ratio of the cans' seam length to volume. Of 256 metal-canned foods examined, 37 percent contained 200 pg Pb/liter or more; 12 percent contained 400 pg Pb/liter or more. These levels are markedly above the potable water standard of 50 pg Pb/liter (0.05 mg/kg) established by the U.S. Public Health Service. However, recent data PB7/A 7-60 12-15-82 TEH 0530446 DUP050031359 PRELIMINARY DRAFT show that lead levels in canned foods have decreased somewhat through the 1970's (Schaffner, 1981). Canned pet foods have been found to contain from 0.9 to 7.0 pg Pb/g (900 to 7000 pg/liter), and 18 products averaged 2.7 pg/g (Hankin et al., 1975). Apart from the possible toxic effects on pets, the products pose a hazard to people who may include themq in their own diet. The contribution of the canning process to overall lead levels in albacore tuna has been reported by Settle and Patterson (1980). Using rigorous clean laboratory procedures, these investigators analyzed lead in fresh tuna, as well as in processed tuna packaged in soldered and unsoldered cans. The data, presented in Table 7-20, show that lead concentrations in canned tuna are elevated above levels in fresh tuna by a factor of 4000. This factor becomes 40,000 if one compares the canned tuna levels with estimated concentrations assumed to exist prior to the widespread use of lead. Nearly all of the increase results from leaching of the lead from the soldered seam of the can; tuna from an unsoldered can is elevated by a factor of only 20 compared with tuna fresh from the sea. Note that when the tuna is dried and pulverized, as in the NBS reference material, lead levels are seen to increase by a factor of 400 over fresh sea tuna. Table 7-20 also shows the results of analyses conducted by the National Marine Fisheries Service- The lead concentrations reported by NMFS in fresh tuna are considerably greater than the Caltech laboratory data. Settle and Patterson (1980) explain this difference as due to poor contamination control by NMFS during Sample handling and analysis; they also state that most other lead analysis laboratories have similar problems which preclude obtaining accurate lead data at levels commonly encountered in food and in the environment. Hankin et al. (1974) suggest an additional food-related source of potential lead exposure, again predominantly affecting children. The colored portions of wrappers from bakery confections, candies, gums, and frozen confections have lead concentrations ranging from 8 to 10,000 pg/g. The higher concentrations are attributed to lead-containing inks. No related illnesses were identified, nor was contamination of the food implied; but the eating of foods from such wrappers and the licking or chewing of the wrappers were postulated as one more avenue for an additional increment of lead exposure. The presence of high-lead concentrations in illicit whiskey (moonshine), which is still popular in some parts of the United States, occasionally causes lead poisoning in adults. The apparent source of the lead is the soldered joints in the distilling apparatus. PB7/A 7-61 12-15-82 TEH 0530447 DUP050031360 PRELIMINARY DRAFT / TABLE 7-20. LEAD CONCENTRATIONS IN VARIOUS SAMPLES AS MEASURED BY THE CALTECH AND NMFS LABORATORIES Sample Lead Concentration* Analysis by Caltech laboratory Surface seawater, prehistoric (estimated) 0.005 Surface seawater, modern 0.005 Albacore muscle, prehistoric (estimated) 0.03 Albacore muscle, fresh (dissected in Caltech laboratory) 0.3 Albacore muscle from die-punched unsoldered can 7 Albacore muscle, NBS reference material 120 Albacore muscle from lead-soldered can 1,400 Entire albacore 6 Entire anchovy from albacore stomach 21 Part of anchovy from lead-soldered can 4,200 Analysis by NMFS laboratory Albacore muscle, fresh (dissected by NMFS Laboratory) 400 Albacore muscle, fresh (dissected in Caltech Laboratory) 20 Albacore muscle from lead-soldered can 700 *A11 values are expressed as ppb wet weight. Source: Settle and Patterson (1980). PB7/A 7-02 12-15-82 TEH 0530448 DUP050031361 PRELIMINARY DRAFT Another potential source of dietary lead poisoning is the use of inadequately glazed earthenware vessels for food storage and cooking. An impressive example of this danger involved the severe poisoning of a physician's family in Idaho which resulted from drinking orange juice that had been stored in an earthenware pitcher (Block, 1969). Similar cases, sometimes including fatalities, have involved other relatively acidic beverages such as fruit juices and soft drinks, and have been documented by other workers (Klein et al., 1970; Harris and El sen, 1967). Because of these incidents, the USFDA (1979) has established a maximum permissible concentration of 7 pg Pb/g in solution after leaching with 4 percent acetic acid in the earthenware vessel for 24 hours. Inadequately glazed pottery manufactured in other countries continues to pose a significant health hazard. For example. Spiel hoitz and Kaplan (1980) report 24 hour acetic acid-leached lead concentrations as great as 4400 pg/g in Mexican pottery. The leached lead decreases with exposure time, and after several days appears to asymptotically oach a value which may be as great as 600 pg/g. These investigators have also measured excessive lead concentrations leached into acidic foods cooked for two hours in the same pottery. Similarly, Acra et al. (1981) report that 85 percent of 275 earthenware vessels produced in primitive Lebanese potteries had lead levels above the 7 pg/g USFDA limit. However, only 9 percent of 75 vessels produced in a modern Beirut pottery exceeded the limit. Cubbon et al. (1981) have examined properly glazed ceramic plates in the United Kingdom, and have found a decrease in leached lead with exposure time down to very low levels. The authors state that earthenware satisfying the 7 pg/g limit will contribute about 3 pg/day to the dietary intake of the average consumer. Reports on lead in European wines (Olsen et al., 1981; Boudene et al., 1975 Zurlo and Graffini, 1973) show concentrations averaging 100-200 pg/liter and ranging as high as 300 pg/liter. Measurements of lead in domestic wines have not been undertaken; if the European data ndicative, domestic wines could contain lead concentrations comparable to processed foods previously discussed. Lead levels in beer are generally smaller than those in wine: Thalacker (1980) reports a maximum concentration of 80 pg/Titer several brands of German beer. Lead in also present in tobacco. WHO (1977) estimates a lead content of 2.5-12.2 pg per cigarette; roughly two to six percent of this lead may be inhaled by the smoker. The Committee on Lead in the Human Environment, National Research Council (1980) has used these data to conclude that a typical urban PB7/A 7-63 12-15-82 TEH 0530449 DUP050031362 PRELIMINARY DRAFT resident who smokes 30 cigarettes per day may inhale roughly equal amounts of lead from smoking and from breathing urban air. 7.3.3.2 Water---The U.S. Public Health Service standards specify that lead levels in drinking water should not exceed 50 gg/liter. The average adult drinks about 1 liter of water per day. The presence of detectable amounts of lead in untreated public water supplies was shown by Durum (1971) to be widespread, but only a few samples contained amounts above the 50 pg/liter standard. Durfor and Becker (1964) analyzed untreated and treated water for the largest U.S. cities, and almost all pairs of samples showed a substantial decrease in lead that was ascribable to treatment provided. A maximum lead concentration of 62 pg/liter was detected in finished water from one of several wells used in Salt Lake City to supplement their surface water supply. Some 95% of the water supplies sampled, however, had lead concentrations below 10 pg/liter in the treated water before entering the distribution system. Eight of the water supplies distributed water with a pH of less than 7, which could be corrosive to the distribution piping*, most of these were in the Northwest, A chemical analysis of interstate carrier water supplies in 1975 showed that only 0.3 percent exceeded the 50 pg/liter standard (USEPA, 1975). These samples were collected after treatment but before distribution, and they represent both suspended and dissolved lead. Interstate carrier water supplies serve planes, trains, buses, and vessels in interstate commerce, and they include almost all of the largest U.S. water supplies. The presence of lead in drinking water may result from contamination of the water source or from the use of lead materials in the water distribution system. Although lead is a relatively minor constituent of the earth's crust, it is widely distributed in low concentrations in sedimentary rock and soils (as discussed in Chapter 3), and naturally occurring deposits may be an important source of contamination in isolated instances. Industrial waste may also contribute to the lead content of water sources, but this appears to be a local and not a widespread problem. The extensive use of lead compounds as gasoline additives has greatly increased the availability of lead for solution in ground and surface waters. For example, in a study in east-central Illinois (Rolfe and Haney, 1975), the urban portion of an 86 square mile watershed (constituting 14 percent of the area) contributed about 75 percent of the lead in drainage waters. The principal source of this lead was identified as automotive emissions. Detailed data reported for 1 month (June 1972) showed PB7/A 7-64 12-15-82 TEH 0530450 DUP050031363 PRELIMINARY DRAFT that drainage waters from this urban portion contained an average total lead concentration of 69.5 pg/liter, including 6.3 pg/liter of soluble lead. The rural portion yielded an average lead concentration of 7.4 pg/liter in drainage water, including 2.1 pg/liter of soluble lead. Hem and Durum (1973) discussed the solubilty of those species of lead that may be present in drinking water and suggested that the solution of lead from environmental sources may be an important contribution in certain areas, depending upon the chemical composition of the runoff water. Above pH 8.0, the solubility of lead is below 10 pg/liter, regardless of the alkalinity of the water. In waters near pH 6.5 with low alkalinity, however, the solubility of lead could approach or exceed 100 pg/liter, Lazrus et al. (1970) determined the lead content of precipitation at 32 points in the United States for a period of 6 months in 1966 and 1967. They reported an average lead concentration of 34 pg/liter after filtering the samples. Samples of rainfall at.Menlo Park, California during 1971 showed a wide range of lead concentrations, from a few pg/liter to more than 100 pg/liter (Hem and Durum, 1973). These authors hypothesized that higher lead concentrations should occur in runoff water and impounded raw water supplies in the Northeast, certain urban areas of the South, and along the Pacific Coast because of low pH and alkalinity in waters. However, in much of the rest of the United States, lead fallout rates and chemical composition of the runoff (pH >8, alkalinity >100 pg/liter) would minimize the problem. Information to test their hypothesis is limited at present. Of the few surveys of surface waters that have been conducted, most were not done after periods of heavy rainfall, and most have measured dissolved rather than total lead. Durum (1971) measured lead at 700 lake and river sites in the United States. These measurements were primarily single samples, taken at times of relatively low stream flows in October and November 1970. Detectable concentrations of dissolved lead (>1 pg/liter) were found in 63 percent of the samples, but only three samples contained more than 50 pg/liter. A Targe proportion of the samples for the northeastern and southeastern states contained lead above the detection limit, and quite a few of the samples showed levels above 10 pg/liter. This regional distribution of lead in stream water is in accord with the idea that water composition in the eastern states is more commonly favorable for solution of lead. A substantial number of samples from southern California were high in lead, and these influenced the data from the southwestern PB7/A 7-65 12-15-82 TEH 0530451 DUP050031364 PRELIMINARY DRAFT states. Kopp and Kroner (1967) presented data on dissolved lead in rivers and lakes of the United States. The data were gathered over a 5-year period (1962 to 1967) and represent more than 1500 samples. A detectable concentration of dissolved lead was found in 305, or 19.3 percent, of the samples; the observed values ranged from 2 to 140 pg/liter. The highest concentration was detected in the Ohio River at Evansville, Indiana. Twenty-seven of their samples exceeded 50 pg/liter. Observed mean observations of >30 pg/liter dissolved lead were found 'in the following river basins: Ohio, Lake Erie, Upper Mississippi, Missouri, Lower Mississippi, and Colorado. The major source of lead contamination in drinking water is the water supply system itself. Water that is corrosive can leach considerable amounts of lead from lead plumbing and lead compounds used to join pipe. Several widely adopted cedes, such as the ASA-A40 Code, Uniform Plumbing Code, and BOCA Code, allow the use of lead pipe and list lead as an acceptable soldering material for joining pipes that convey water. Lead pipe is currently in use in many parts of the United States for water service lines and interior plumbing, particularly in older urban areas. In a community water supply survey of 969 water systems conducted in nine geographically distributed areas of the United States in 1969 and 1970, it was found that 1.4 percent of all tap water samples exceeded the 50 pg/liter standard (McCabe et al., 1970). The maximum concentration found was 640 pg/liter total lead. The occurrence of samples exceeding the standard was more prevalent in waters with a relatively low pH and low specific conductance. It was estimated that 2 percent of the survey population of 18.2 million was exposed to high lead levels at the tap. Considerable research related to lead in home tap water has been conducted in the United Kingdom, where lead plumbing is prevalent. Moore (1977) reported lead concentrations in Glasgow drinking water to be considerably greater than 50 pg/liter in many homes using lead pipes, due to leaching caused by the soft water. The lead levels decreased if the water was allowed to run for several minutes. Highest lead concentrations were found in the early morning after the water had been standing in the pipes all night (Figure 7-8). This study also measured blood lead concentrations in residents of western Scotland, found a significant correlation between blood lead and water lead. It was concluded that the use of lead plumbing in soft water areas may pose a more severe hazard than atmospheric lead, PB7/A 7-66 12-15-82 TEH 0530452 DUP050031365 TEH 0530453 Figure 7-8. Change in drinking water lead concentration in a house with lead plumbing for the first use of water in the morning. Flushing rate was 10 liters/minute. Source: Moore 11977). PB7/A 7-67 12-15-82 DUP050031366 PRELIMINARY DRAFT In another study by Moore et al. (1977), blood lead levels in mentally retarded children were found to be greater than in control children. A significant correlation was also found between blood lead and water lead levels in the childrens1 homes. Water lead concentrations as great as 1850 pg/liter were measured in these homes. April 1978, the pH of the water supply to 920,000 Glasgow residents was increased from 6.3 to 7.8 using lime-dosing. Prior to this treatment, over 50 percent of the random daytime water samples collected in the city had lead levels above 100 pg/1iter. This figure was reduced to 20 percent following treatment (Moore et al., 1981). In August 1980, the pH of the water supply was increased to 9, resulting in an estimated further reduction to 5 percent of the water samples in excess of 100 pg/1iter. The reduction in water lead content caused a significant decrease in blood lead levels of mothers in the postnatal ward of a Glasgow hospital, demonstrating the positive effect of the 1ime-dosing treatment. A series of studies has been conducted in northern Wales involving lead levels in home tap water. In one study, mean lead concentrations in first draw water samples from 14 dwellings with lead plumbing was 370 pg/liter. This level dropped to 85 pg/liter after the water was allowed to run for ten minutes (Thomas and Elwood, 1978). In a related set of studies (Badawy, 1978; Thomas et al., 1979; Thomas, 1980) water lead levels were measured in 60 lead-plumbed houses and in 75 copper-plumbed houses: first flush samples averaged 1075 pg/liter in the former, but only 4 pg/liter in the latter. Blood lead concentrations in mothers and their children living in the leadplumbed homes were significantly greater than concentrations in residents of the houses which used copper plumbing. Within the homes containing lead plumbing, lead levels were greatest in those individuals who regularly consumed first draw water. A survey of water lead concentrations in over 2000 households throughout Great Britain has been conducted by Pocock (1980). The effects of water stagnation time in the pipes, pH, alkalinity, position/extent of lead plumbing, age of dwelling, and number of occupants were investigated. Results were in agreement with previous studies, showing that soft, acidic water in homes with considerable lead plumbing has the greatest lead concentration. On the average, the daytime concentration of lead was about 57 percent of the first draw concentration, PB7/A 7-68 12-15-82 TEH 0530454 DUP050031367 PRELIMINARY DRAFT Bailey and Russell (1981) have developed a model for population exposure to lead in home drinking water. The model incorporates data for lead concentration as a function of stagnation time in the pipes, as well as probability distributions for times of water use throughout the day. Population surveys conducted as part of the United Kingdom Regional Heart Survey provided these water use distributions. The final probability density function for water lead levels is given in Figure 7-9. The effect of instructing all individuals to refrain from drinking first draw water is evident; median, mean, and 95th percentile lead levels decrease measurably. Other recent studies have.been conducted in Canada and Belgium. Lead levels in water boiled in electric kettles were measured in 574 households in Ottawa (Wigle and Chariebois, 1978). Concentrations greater than 50 pg/liter were observed in 42.5 percent of the households, and excessive lead levels were associated with kettles more than five years old. Blood lead concentrations were not significantly correlated with lead levels in water boiled in electric kettles. However, age, and smoking habits were correlated with blood lead. The authors concluded that lead exposure from such kettles does not pose a significant health hazard to adults, but may present a hazard to infants. Hubermont et al. (1978) examined the influence of water lead concentration on the transplacental transfer of lead in 70 pregnant women in rural Belgium. Water lead levels ranged from 0.2 to 43.4 pg/liter in 41 households (group A), and from 61.5 to 1228.5 pg/liter in an additional 29 households (group B). Blood lead levels in the mothers, umbilical cords, and placentas were significantly greater in group B than in group A. Sartor and Rondia (1980) studied the relation between water lead level and blood lead concentration in two Belgian urban areas: Liege population 426,777, serviced by hard water) and Verviers (population approximately 50,000* serviced by soft water). The subjects included males over a wide range of ages who were not occupationally exposed. A total of 390 Liege residents and 320 Verviers residents were sampled. Water lead levels in Verviers were considerably greater than those in Liege, with some concentrations as great as 1500 pg/liter. The blood lead levels in Verviers residents were considerably greater than levels in Liege residents, presumably due to the higher water lead concentrations. Blood lead levels in Liege increased with age until approximately 25 years, then achieved a constant value. In Verviers, blood lead levels continued to increase past age 60. The authors concluded that the PB7/A 7-69 12-15-82. TEH 0530455 DUP050031368 Figure 7-9. Theoretical distribution of drinking water lead concentrations based on the model of Bailey and Russell {1981). Shown on the graph are the reductions in median, mean, and 95 percentile lead levels if first draw water consumption is removed. PB7/A 7-70 12-15-82 TEH 0530456 DUP050031369 PRELIMINARY DRAFT excessive lead exposure in Verviers lengthened the exposure time required to reach equilibrium between blood lead and environmental lead levels; equilibrium was not achieved in a normal lifetime. Numerous studies regarding the lead content of drinking water, and the relationship to blood lead levels, were conducted in Europe in the early and mid 1970's. A thorough literature review of these studies has been conducted by Berlin et al. (1977). On the basis of these studies, it was concluded that lead in drinking water at even modest concentrations may have a significant effect on blood lead level, both from direct ingestion and from cooking with the water, 7.3.4 Exposures Resulting from Manmade Materials At least two manmade materials in widespread use are known to contain lead, namely paint and plastics. In 1974, the Consumer Product Safety Commission collected several household paint samples and analyzed them for lead content (Committee on Toxicology, National Research Council, 1976). Analysis of 489 samples showed that 8 percent of the oil-based paints and 1 percent of the water-based paints contained greater than 0.5 percent lead (5000 pg Pb/g paint, based on dried solids), which was the statutory limit at the time of the study. The current statutory limit for Federal construction is 0.06 percent. Several studies have shown that children living in homes containing accessible leaded paint may have a greater tendency to develop elevated blood lead levels. For example, Guinee (1972) found loose leaded paint 76 percent of the houses of lead-poisohed children, compared with 38 percent of the houses of non-poisoned children (controls), Gilbert et a). (1979) reported loose leaded paint in 100 percent of the houses of children with elevated blood lead levels, compared with 50 percent for controls, A significant correlation was found between child fecal lead content and the presence of leaded paint, and between blood lead content and the presence of leaded paint (Hammond et al,, 1980). The greatest amounts of leaded paint are typically found in the kitchens, bathrooms, and bedrooms (Tyler, 1970; Laurer et al., 1973; Gilbert et al., 1979). However, Stark et al. (1982) found a better correlation between exterior paint lead content and blood lead than between interior paint lead and blood lead. Some .investigators have shown that flaking paint can cause elevated lead concentrations in nearby soil. For example, Hardy et al. (1971) measured soil PB7/A 7-71 12-15-82 TEH 0530457 DUP050031370 PRELIMINARY DRAFT lead levels of 2000 fjg/g next to a barn in rural Massachusetts. A steady decrease in lead level with increasing distance from the barn was shown, reaching 60 pg/g at fifty feet from the barn. Ter Haar (1974) reported elevated soil lead levels in Detroit near eighteen old wood frame houses painted with lead-based paint. The average soil lead level within two feet of a house was just over 2000 pg/g; the average concentration at ten feet was slightly more than 400 pg/g- The same author reported smaller soil lead elevations in the vicinity of eighteen brick veneer houses in Detroit. Soil lead levels near painted barns located in rural areas were similar to urban soil lead concentrations near painted houses, suggesting the importance of leaded paint at both urban and rural locations. Mouthing of non-food items is prevalent in most youngsters, and hence ingestion of leaded paint is a major problem for small children in general. An especially severe health problem is posed for children with pica, who may habitually ingest 1 to 3 g (or more) of paint per week (Committee on Toxicology, National Research Council, 1976). Plastics contain a number of heavy metals that are constituents of organometallic stabilizers added during the manufacturing process. The most commonly used lead-containing stabilizer is dibasic lead stearate, in amounts ranging from 0.5 to 2.0 parts per 100 parts of resin (Piver, 1977). The stabilizer is normally used in rigid PVC products. Diffusion, or leaching by solvents, is estimated to be quite slow--on the order of 10 to 10 cm /sec at room temperature--but no definitive information is available. Incineration of lead-containing plastics may become an increasingly significant source of localized lead pollution. It has been estimaQted that in the year 2000, for example, there could be approximately 2.54 x 10 Qkg of PVC plastic waste to be disposed of annually, of which about 0.59 x 10 would probably be incinerated (Vaughn et a!., 1975). Assuming that lead will be emitted from the uncontrolled incineration of PVC's at the rate of 0.2 g lead/kg waste (a figure applied to all solid waste, according to the U.S. 5 Environmental Protection Agency, 1976), about 1.2 x 10 kg lead could be released each year. This would be an increase of more than fourteenfold over the estimate for 1975. Since the greater part of the lead in these incinerated plastic wastes will remain in the ash, electrostatic precipitators can sub stantially decrease the emitted fraction (to an estimated 0.03 g/kg). This process only aggravates the difficulties of residual solid waste disposal with PB7/A 7-72 12-15-82 TEH 0530458 DUP050031371 PRELIMINARY DRAFT its attendant problems of fugitive dust and the potential contamination of soil, surface waters, and ground waters through leaching from landfill operations Lead is present in other products which may constitute sources of lead exposure when used or disposed of. Lead may be found in newsprint, craft and hobby materials, toothpaste tubes, cosmetic products, candle wicks, pewter and silver hollowware, painted utensils, and decals on glassware. For example, colored newsprint may contain up to 2800 pg Pb/g (Hankin et a!., 1973), while colored gift wrapping may contain up to 14,300 pg Pb/g (Bertagnolli and Katz, 1979). Some cosmetic hair-darkening preparations contain lead acetate, although the absorption of this lead through the skin is small (Moore et a!., 1980). Lead in the paint on handles of kitchen utensils has been found by Hankin et al, (1976) to contain as much as 97,000 pg Pb/g (9.7 percent); more than half of the samples exceeded the allowable limit for painted toys, which is 0.06 percent, 7.3.5 Soil and Dust Exposures In each of the previous subsections on potential exposures, the role of lead in soil and dust may have been important. The discussion of mobile sources illustrated that the lead content of road dust and of surface soil near roads increases as traffic density increases. Household dust and surface soil in the vicinity of lead-emitting stationary sources may also have elevated lead content. Dietary intake can be influenced by deposited lead-containing dust, particularly if the diet includes crops grown near sources of lead. Regarding manmade materials, flaking paint can increase the lead content of housedust and surface soil near painted surfaces. It is clear that even in the absence of anthropogenic lead emissions, there would be some human exposure to lead through inadvertent ingestion of natural lead in soil. In the case of small children, deliberate ingestion of lead-containing soil is possible- The extent to which current human exposure to lead exceeds that expected from natural sources is discussed in the final section of this chapter. 7.3.6 Occupational Exposures The highest and most prolonged exposures to lead are found among workers in the lead smelting, refining, and manufacturing industries (WHO, 1977). In the work areas, the major route of lead exposure is by inhalation and ingestion of lead-bearing dusts and fumes. Airborne dusts settle out of the air onto food, water, the workers' clothing, and other objects, and may be subsequently PB7/A 7-73 12-15-82 TEH 0530459 DUP050031372 PRELIMINARY DRAFT transferred to the mouth. Therefore, good housekeeping and good ventilation have a major impact on exposure. It has been found that exposure levels might be quite high in one factory and low in another solely because of differences in ventilation, or differences in housekeeping practices and worker education. 7,3.6.1 Exposures in Lead Mining, Smelting, and Refining--Exposures for workers involved in lead mining depend to some extent upon the solubility of the lead from the ores. The lead sulfide (PbS) composing galena is insoluble, and absorption through the lung may be slight. In the stomach, however, some of the lead sulfide may be converted to slightly soluble lead chloride, which may then be absorbed in moderate amounts. Roy (1977) studied exposures during mining and grinding of lead sulfide at a mill in the Missouri lead belt. Primary smelting operations were 2.5 miles from the mill, hence the influence of the smelter was believed to be negligible. Personal samplers worn by mill employees gave results shown in Table 7-21. Note that the total airborne lead levels are much greater than the concentrations of respirable lead, indicating a predominance of coarse material. Solubility tests conducted as part of this study showed that only 0.77 to 1.4 percent (mean 0.94 percent) of the lead sulfide dissolved in 0.1 N hydrochloric acid, representative of the human stomach. The author also reported generally poor correlation between overall air lead and blood lead levels. It was concluded that because of the large particle sizes and low solubility, a health standard based on total airborne lead concentration would not be appropriate for lead sulfide workers. The greatest potential for high-level exposure exists in the process of lead smelting and refining (WHO, 1977). The most hazardous operations are those in which molten lead and lead alloys are brought to high temperatures, resulting in the vaporization of lead. This is because condensed lead vapor or fume has, to a substantial degree, a small (respirable) particle size range. Although the total air lead concentration may be greater in the vicinity of ore-proportioning bins than it is in the vicinity of a blast furnace in a smelter, the amount of particle mass in the respirable size range may be much greater near the furnace, A measure of the potential lead exposure in smelters was obtained in a study of three typical installations in Utah (WHO, 1977). Air lead concentrations near all major operations, as determined using personal monitors worn by workers, were found to vary from about 100 to more than 4000 pg/m . Obviously, PB7/A 7-74 12-15-82 TEH 0530460 DUP050031373 PRELIMINARY DRAFT TABLE 7-21. AIRBORNE LEAD CONCENTRATIONS BASED ON PERSONAL SAMPLERS, WORN BY EMPLOYEES AT A LEAD MINING AND GRINDING OPERATION IN THE MISSOURI LEAD BELT (mg/m3) Occupation N* Mill operator Flotation operator Filter operator Crusher operator Sample finisher Crusher utility Shift boss Equipment operator 6 6 4 4 4 4 4 4 2 2 1 1 5 6 1 2 T R T R T R T R T R T R T R T R N denotes number of air samples. * T - total lead on air ?? R - Respirable lead on air Source: Roy (1977). High 0.30 0.06 0.75 0.04 2.45 0.24 0.59 0.01 10.00 0.19 --" 0.56 0.08 -- 0.14 Low 0.05 0.01 0.10 0,03 0.38 0.05 0.02 0.01 7.07 0.16 -- 0.11 0.01 0,03 Mean 0.18 0.03 0.32 0,04 1.33 0.11 0.19 0.01 8.53 0,17 0.07 0.07 0.29 0.05 0.43 0.08 PB7/A 7-75 12-15-82 TEH 0530461 DUP050031374 PRELIMINARY DRAFT the hazard to these workers would be extremely serious if it were not for the fact that the use of respirators is mandatory in theseOparticular smelters. Maximum airborne lead concentrations of about 300 pg/m were measured in a primary lead-zinc smelter in the United Kingdom (King et al., 1979). These authors found poor correlations between airborne lead and blood lead in the smelter workers, and concluded that a program designed to protect these workers should focus on monitoring of biological parameters rather than environmental levels. Spivey et al. (1979) studied a secondary smelter in southern California which recovers lead mainly from automotive storage batteries. Airborne lead concentrations of 10 to 4800 g/m were measured. The project also involved measurement of biological parameters as well as a survey of symptoms commonly associated with lead exposure; a poor correlation was found between indices of lead absorption and symptom reporting. The authors suggested that such factors as educational level, knowledge of possible symptoms, and biological susceptibility may be as important as lead absorption in influencing symptom reporting. In a second article covering this same study, Brown et al. (1980) reported that smokers working at a smelter had greater blood lead levels than nonsmokers. Furthermore, smokers Who brought their cigarettes into the workplace had greater blood lead levels than those who left their cigarettes elsewhere. It was concluded that direct environmental contamination of the cigarettes by lead-containing dust may be a major exposure pathway for these individuals. Winegar et al. (1977) examined environmental concentrations as well as biological indicators and symptom reporting in workers in a secondary lead smelter near St. Raul, Minnesota. The smelter recovers approximately 9000 metric tons of lead per year from automotive batteries. The lead concentrations in cuff dust from trousers worn by two workers were 60,000 and 600,000 pg/g. The amount of lead contained in pieces of cloth 1 in cut from the bottoms of trousers worn by the workers ranged from 700 to 19,000 pg, with a median of 2640 pg. In all cases, the trousers were worn under coveralls. Dust samples from 25 households of smelter workers ranged from 120 to 26,000 pg/g, with a median of 2400 pg/g. No significant correlations were found between dust lead concentrations and biological indicators, or between symptom reporting and biological indicators. However, there was an increased frequency of certain objective physical signs, possibly due to lead toxicity, with increased blood lead level. The authors also concluded that the high dust lead levels in the workers' homes are most likely due to lead originating in the smelter. PB7/A 7-76 12-15-82 TEH 0530402 DUP050031375 PRELIMINARY DRAFT Secondary lead smelters in Memphis, Tennessee and Salt Lake City, Utah were studied by Baker et al. (1979), The former plant extracted lead principally from automotive batteries, producing 11,500 metric tons of lead in the eleven months preceding the measurements. The latter plant used scrap to recover 258 metric tons of lead in the six months preceding the measurements. Airborne concentrations of lead in Tennessee exceeded 2003 pg/m in some instances, with personal air sampler data ranging from 120 pg/m for a battery wrecker to 350 3 pg/m for two yard workers. At the Utah plant, airborne lead levels in the office, lunchroom, and furnace room (furnace not operating) were 60, 90, and 100 pg/m , respectively. When charging the furnace, the last value increased to 2650 pg/m3, Personal samplers yielded concentrations of 17 pg/m3 for an office worker, 700 pg/m3 for two welders, and 2660 pg/m3 for two furnace workers. Some workers in both plants showed clinical manifestations of lead poisoning; a significant correlation was found between blood lead levels and symptom reporting. High levels of atmospheric lead are also found in foundries in which molten lead is alloyed with other metals. Berg, and Zenz (1967) found in one such operation that average concentrations of lead in various work areas were 280 to 600 pg/m . These levels were subsequently reduced to 30 to 40 pg/m with the installation of forced ventilation systems to exhaust the work area atmosphere to the outside. 7.3.6.2 Exposures in Welding and Cutting of Metals Containing Lead--When metals that contain lead or are protected with a lead-containing coating are heated in the process of welding or cutting, copious quantises of lead in the respirable size range may be emitted. Under conditions of poor ventilation, electric arc welding of zinc silicate-coated steel (containing 29 mg Pb/tn2 of 3 coating) produced breathing-zone concentrations of lead reaching 15,000 pg/m , far in excess of 450 pg/m , the Current occupational short-term exposure limit (STEL) in the United States (Pegues, 1960). Under good ventilation conditions, 3 a concentration of 140 pg/m was measured (Tabershaw et al., 1943). In a study of salvage workers using oxy-acetylene cutting torches on lead-painted structural steel under conditions of good ventilation, breathingzone concentrations of lead averaged 1200 pg/m and ranged as high as 2400 pg/m (Rieke, 1969). Lead poisoning in workers dismantling a painted bridge has been reported by Graben et al. (1978). Fishbein et al, (1978) discuss the exposure of workers dismantling an elevated subway line in New York City, PB7/A 7-77 12-15-82 TEH 0530463 DUP050031376 PRELIMINARY DRAFT where the lead content of the paint is as great as 40 percent. The authors report that one cubic millimeter of air can contain 0.05 g lead at the source of emission. Similarly, Grandjean and Kon (1981) report elevated lead exposures of welders and other employees in a Baltimore, Maryland shipyard. 7.3.6.3 Exposures in the Electric Storage Battery Industry--At all stages in battery manufacture except for final assembly and finishing, workers are exposed to high air lead concentrations, particularly lead oxide dust. For 3 example, Boscolo et al. (1978) report air lead concentrations of 16-100 pg/m in a battery factory in Italy, while values up to 1315 pg/m3 have been measured by Richter et al. (1979) in an Israeli battery factory. Excessive concentrations, as great as 5400 pg/m , have been quoted by WHO (1977). The hazard in plate casting, which is a molten-metal operation, is from the spillage of dross, resulting in dusty floors. During oxide mixing, which is probably the most hazardous occupation, ventilation is needed when the mix is loaded with the lead oxide powder, and frequently cleanup is necessary to prevent the accumulation of dust. In the pasting of the plates, either by hand or by machine, the danger is again from dust which accumulates as the paste dries. The forming and stacking processes are also dusty, and ventilation is needed there. The data cited are sufficiently alarming to suggest that respirators must be worn in most of these operations. 7.3.6.4 Exposures in the Printing Industry--In a printing establishment, the exposure to lead is probably in direct proportion to the dispersion of lead oxide dust, secondary to a remelt operation, Brandt and Reichenbach (1943) have reported on a study in which melting pots were located in a variety of places where used type was discarded, The pots were maintained at temperatures ranging from 268 to 446C. The highest air lead concentration recorded was 570 Mg/m . In I960, Tsuchiya and Harashima (1965) found airborne lead levels 3 of 30-360 pg/m in several print shops in Japan. More recently, Parikb et al. (1979) reported concentrations approximately 10-30 pg/m3 in five type foundries in India; these investigators also reported much greater levels, up to 140 pg/m , in seven battery reconditioning plants. Greene et al. (1979) discuss the increased risk of cancer to employees in the Government Printing Office. Excess deaths from myeloma were reported for workers who spent considerable amounts of time in the composing room, where lead is the principal contaminant. 7.3.6.5 Exposures In Alkyl Lead Manufacture--Workers involved in the manufacture of both tetraethyl lead and tetramethyl lead, two alkyl lead compounds, are PB7/A 7-78 12-15-82 TEH 0530464 DUP050031377 PRELIMINARY DRAFT exposed to both inorganic and alkyl lead. Some exposure also occurs at the petroleum refineries where the two compounds are blended into gasoline, but no sure data are available on these blenders. The major potential hazard in the manufacture of tetraethyl lead and tetramethyl lead is from skin absorption, but this is guarded against by the use of protective clothing. Linch et al. (1970) found a correlation between an index of organic plus inorganic lead concentrations in a plant and the rate of lead excretion in the urine of workers. Significant concentrations of organic lead in the urine were found in workers involved with tetramethyl lead and those involved with tetraethyl lead; lead levels in the tetramethyl lead workers were slightly higher because the reaction between the organic reagent and lead alloy takes place at a somewhat higher temperature and pressure than that employed in tetraethyl lead production, Cope et al, (1979) used personal air samplers to assess exposures of five alkyl lead workers exposed primarily to tetraethyl lead. Blood and urine levels were measured over a six-week period. Alkyl lead levels ranged from 1.3 to 1249 pg/rn , while inorganic lead varied from 1.3 to 62.6 pg/m . There was no significant correlation between airborne lead (either alkyl or inorganic) and blood or urine levels. The authors concluded that biological monitoring, rather than airborne lead monitoring, is a more reliable indicator of potential exposure problems. 7,3.6.6 Exposures in Other Occupations--In both the rubber products industry and the plastics industry there are potentially high exposures to lead. The potential hazard of the use of lead stearate as a stabilizer in the manufacture of polyvinyl chloride was noted in the 1971 Annual Report of the British Chief Inspector of Factories (1972). The inspector stated that the number of reported cases of lead poisoning in the plastics industry was second only to that in the lead smelting industry. Scarlato et al. (1969) and Maljkovic (1971) have reported on other individual cases of exposure. The source of this problem is the dust that is generated when the lead stearate is milled and mixed with the polyvinyl chloride and the plasticizer. An encapsulated stabilizer which greatly reduces the occupational hazard is reported by Fischbein et al. (1982). Sakurai et al. (1974), in a study of bioindicators of lead exposure, found ambient air concentrations averaging 58 pg/m in the lead covering department of a rubber hose manufacturing plant. Unfortunately, no ambient air measurements were taken for other departments or the control group. P87/A 7-79 12-15-82 TEH 0530465 DUP050031378 PRELIMINARY DRAFT The manufacture of cans with leaded seams may expose workers to elevated environmental lead levels. Bishop (1980) reports airborne lead concentrations 3 of 25-800 pg/m in several can manufacturing plants in the United Kingdom. Between 23 percent and 54 percent of the airborne lead was associated with respirable particles, based on cyclone sampler data. Firing ranges may be characterized by high airborne lead concentrations, hence instructors who spend considerable amounts of time in such areas may be exposed to lead. For example, Smith (1976) reports airborne lead concentrations of 30-160 pg/m at a firing range in the United Kingdom. Anderson et al. (1977) discuss plumb ism in a 17 year old male employee of a New York City firing range, where airborne lead concentrations as great as 1,000 pg/m were measured during sweeping operations. Another report from the same research3 group presents time-weighted average exposures of instructors of 45-900 pg/m in three New York City firing ranges (Fishbein et al., 1979). Removal of leaded paint from walls and other surfaces in old houses may pose a health hazard. Feldman (1978) reports an airborne lead concentration of 510 pg/m, after 22 minutes of sanding an outdoor post coated with paint containing 2.5 mg Pb/cmo. After only five minutes of sanding an indoor window sill containing 0.8-0.9 trig Pb/cm2 , the air contained 550 pg/m3 . Homeowners who attempt to remove leaded paint themselves may constitute a relatively large group at risk of excessive lead exposure. Garage mechanics may be exposed to excessive lead concentrations. Clausen and Rastogi (1977) report airborne lead levels of 0.2-35.5 pg/m in ten garages in Denmark; the greatest concentration was measured in a paint workshop. Used motor oils were found to contain 1500-3500 pg Pb/g, while one brand of gear oil, unused, contained 9280 pg Pb/g. The authors state that absorption through damaged skin could be an important exposure pathway. Other occupations involving risk of lead exposure include stained glass manufacturing and repair, arts and crafts, and soldering and splicing. 7.4 SUMMARY This chapter has reviewed the available information on lead concentrations in various environmental media which may result in lead exposure in populations. The first half of the chapter discusses ambient lead levels in air, soil, and vegetation. These data have generally not been obtained in conjunction with uman exposure or epidemiologic information, and serve only to provide estimates of environmental lead levels. The second half of the chapter presents information 7-8D 12-15-82 TEH 0530466 DUP050031379 PRELIMINARY DRAFT on several categories of sources of potential lead exposure in humans. Included are mobile source emissions, stationary source emissions, dietary intake, lead in manmade materials, lead in soil and dust, and occupational exposures. . Each section of the chapter will now be briefly summarized. Ambient airborne lead concentrations have shown no marked trend from 1965 to 1977. Over the past five years, however, distinct decreases have occurred. These decreases reflect the smaller lead emissions from mobile sources in recent years. Airborne size distribution data indicate that most of the airborne lead mass is found in submicron particles. Application of respiratory deposition curves to these distributions suggests that a significant fraction of airborne lead mass can reach the lower lungs. Our understanding of vertical gradients of airborne lead is poor: data in the literature are inconsistent with respect to changes in airborne lead concentration with height. Mobile source studies have shown elevated lead concentrations in air, soil, and vegetation near heavily traveled roads. The amounts of lead in these environmental media are functions of distance from the road, traffic density, vehicle speed, atmospheric stability, windspeed, and wind direction. Persons spending con siderable time in the vicinity of heavily traveled roads may experience increased lead exposure compared to the general population. Point source studies have shown that environmental lead concentrations increase as one approaches a smelter, battery plant, or other lead emission source. Persons living in the vicinity of such a source may experience sig nificant lead exposure. Families having at least one individual employed at or near this type of source may receive additional exposure, due primarily to lead-bearing dust carried home air, skin, and clothing. Most people receive the largest portion of their lead intake through foods. Unprocessed foods such as fresh fruits and vegetables receive lead by atmospheric deposition as well as uptake from soil; crops grown near heavily traveled roads generally have greater lead levels than those grown at greater distances from traffic. For many crops, the edible internal portions of the plant (e.g, kernals of corn and wheat) have considerably less lead than the outer more exposed parts such as stems, leaves, and husks. Processed foods have greater lead concentrations than unprocessed foods, due to lead inadvertantly added during processing. Foods packaged in soldered cans have much greater lead levels than foods packaged in other types of containers. Lead in inadequately glazed pottery may also be leached into foods, occasionally causing high exposures. PB7/A 7-81 12-15-82 TEH 0530467 DUP050031380 PRELIMINARY DRAFT Significant amounts of lead in drinking water can result from contamination at the water source and from the use of lead plumbing in the water distribution system. Atmospheric deposition has been shown to increase lead levels in rivers, reservoirs, and other sources of drinking water; in many areas, however, lead pipes pose a more serious problem. Soft, acidic water in homes with lead plumbing may have excessive lead concentrations. Besides direct consumption of the water, exposure may occur when vegetables and other foods are cooked in water containing lead. A number of manmade materials are known to contain lead, the most important being paint and plastics. Lead-based paints, although no longer used, are a major problem in older homes. Small children who ingest paint flakes can receive excessive lead exposure. Incineration of plastics may emit large amounts of lead into the atmosphere. Because of the increasing use of plastics, this source is likely to become more important. Other manmade materials containing lead include colored dyes, cosmetic products, candle wicks, and products made of pewter and silver. All of the categories of potential lead exposure discussed above may influence or be influenced by dust and soil. For example, lead in street dust is derived primarily from vehicular emissions, while leaded house dust may originate from nearby stationary or mobile sources. Food and water may include lead adsorbed from soil as well as deposited atmospheric material. Flaking lead-based paint has been shown to increase soil lead levels. Natural concen trations of lead in soil average approximately 15 pg/g; this natural lead, in addition to authropogenic lead emissions, influences human exposure. The final section of the chapter concerns occupational exposure to lead. The greatest exposures are found in the lead smelting and refining industries. Excessive airborne lead concentrations and dust lead levels are occasionally found in primary and secondary smelters; smaller exposures are associated with mining and processing of the lead ores. Welding and cutting of metal surfaces coated with lead-based paint may also result in excessive exposure. Other occupations with potentially high exposures to lead include the manufacture of lead storage batteries, printing equipment, alkyl lead, rubber products, plastics, and cans; individuals removing lead paint from walls and those who work in indoor firing ranges may also be exposed to lead. On the basis of the published studies summarized in this chapter, it is apparent that the total exposure to lead for the general population depends PB7/A 7-82 12-15-82 TEH 0530468 DUP050031381 PRELIMINARY DRAFT upon the contributions from several pathways. The amount of airborne lead inhaled, the amount of lead ingested from food, water, dust, and manmade materials, and the absorption of this lead into the body are important factors. Drill et al, (1979) used typical lead concentrations in various media, with estimates of human intake and absorption factors, to determine the contribution to total lead absorbed in urban children from each of several exposure pathways. The technique was applied by the Committee on Lead in the Human Environment, National Research Council (1980) to estimate lead absorption for four subsets of the general population: children with pica and an accessible source of lead-based paint, children without pica, urban adults who smoke cigarettes, and rural nonsmoking adults. The results of these calculations are shown in Table 7-22. Note that ingestion of leaded paint is by far the most important exposure pathway for children in the first category; ingestion of food dominates for the other three populations. It is important to recognize that a certain fraction of the lead in food may result from lead-containing particles which have settled from the atmosphere, hence airborne lead may have a significant effect on total lead exposure. Of course, the values in Table 7-22 are only rough estimates. Environmental lead concentrations, amounts consumed, and absorption factors can vary markedly from individual to individual. (For example, note that the dietary contributions in the table are somewhat smaller than the estimates given in Section 7.3.3.) Because the emissions of lead from motor vehicles have decreased over the past several years, it is likely that the exposures in some categories of Table 7-22 may be greater than typical current exposures. It is apparent that lead exposures of children can be considerably greater than those of adults. The second national Health and Nutrition Examination Survey (HANES II) shows that blood lead levels generally decline during pre-school years. This may be due to decreased mouthing of non-food objects and decreased hand-to-mouth activity, as well as physiological changes. The latter include a decrease in basal metabolism rate with age (resulting in smaller amounts of air, food, and water consumed per unit body weight) and reduced gastrointestinal tract absorption (Mahaffey et al., 1979). The fact that children are exposed to greater amounts of lead than adults, combined with the greater sensitivity of children to the effects of lead (Needleman and Landrigan, 1981), suggest that child exposures via all major pathways merit considerable attention. PB7/A 7-83 12-15-82 TEH 0530469 DUP050031382 TABLE 7-22a. TWO HYPOTHETICAL ESTIMATES OF CONTRIBUTIONS OF SPECIFIC ROUTES OF EXPOSURE TO THE TOTAL ABSORPTION OF LEAD BY POPULATIONS OF URBAN CHILDREN <*- tJ O O) T03> +>r-X C *-- Oi- O to in t- 4-> JO CU O ID Qu -P <ou M- +CO3O-> J(o1ro/-J1 TS>td3o3>-> e g a: rao> in CO rH co 00 o rA a? fv i-5 SM l r>* o o o o in a*> ro- to rH ro lO ^ Ol N O IP CM M N O to 1 VO 1--1 1 40 r- % po a+J *- o OP V) P .Q c "O 0*0 r- PP -C CD >, C CP nj r- 03*0 .C C M-- c o o a> o p .a o s. :3 4) CD pO 32 o os LXLI p co fN G. to 40 o rH * "O O o o o O 4> 41) P JO I *o A3 4) U u p c CO o> V PE jQ CO \ o> 05 3. XJ CD r- \ s c a N 03 03 o P O) .2. ZL o in n o P r> rH O o o op r* o rH O to rH (X x: p *r- * C 4) *o r-* i-- JZ o -p CD o r-- I--1 o <d . N P P 4> a> T3 r-- C o ID P tp - p p O O o K <d a <c U- v> (X to in ro 4 oooo P C r* P a 4) f-- X) 05 CD CO r--> O e CD E o 4) < OO 9h rH u rH H rH o m -p 3 O .x: P ir* > o C ro <d E >N O) 05 m D> r-- S s u 3. N O) 03 r o> 3L 2. CL in 3. r-. rH O P O O .3 o rH O to O -C p 1- 1 1 1 1 .C 4) S- o r-- *r^ -C o p CD rn 3 f-H T3 &. N p 4) ai "O .c roCD +-> o r- r* P r- o o <d o <c 2e LU VO CU r-- P P O P PB7/A 7-84 &o c1ao00>) VIu--) >1 SC P c r m p c CcuP *1-- > c tu cCO e3 a> p c 3 co 4) p uorse au> s3- O C/> 12-15-82 TEH 0530470 DUP050031383 TABLE 7 -22b. TWO HYPOTHETICAL EXAMPLES OF ESTIMATES OF CONTRIBUTIONS OF SPECIFIC SOURCES OF EXPOSURE TO TOTAL ABSORPTION OF LEAD FOR SUBSETS OF THE GENERAL ADULT POPULATION 4- "OTTOO "00) PTUCO t- f--(t UoW uTO po pTO a- p "D PO* -^Q <0 +C3i UUro)N*oD <so "O two wn. CO r-s CM CO CO CO CM CO o iH tjp rH rH ID CM O CO in CO W U3 irHi cn o 00 O CM O O CM CO CO .c o r- L. 4-> O CsO-LuP(0 o j 4- JQC t H H tH' O H tH rH Q o PB7/A *ToO T5 m +j -c </> >, c cu r- Dl"a c +J-r- Sco 3 S. O. oo E <c c o +> r- c P'r- (U <0 E i-tl C +> 0 O C (0 sQ) r-- O> CP C to o 4- a> O 5- 3 t o u> P c> 3 Cl. O >C OC U1 CO e CD in Cn cn O r CM V o H O.A O o CM CM CM <0 to p p a? s- (0 cn r-- U t o ro E cn cn r-- oN Ns D> u E O r^* cn Ns 10 3. N CL CD Ol 05 CL 3 o in a in JC rH O in 36 o o % rH O m 10 p c 0) -o (0 0) s- e <0 JQ 5- p 10 TO 3 o -- c. o o N uP 0) -o TO 10 *- p *-- X) 1-- <0 >r- TO o O O < 2: tu vo h~ 05 O) 00 .o E o CM iH o A O CM CM CV o a) o 6 (0 P O 00 cE \ Ol o O) N *o 3 Ol O) o ro N 07 3 N 05 03 3. tn 3. o tH O O V> o iH <3 in P c to "O r-- (0 to &. r" TO &3 P (0 3 i-- t-H "O ra fc- N 0) TO "O o <0 s- P o r-- i-- TO r* TO o O 3R u. 00 7-85 $ 00) u ,TeO *r** u CO "<DT(O0O <0 Co *r 4-3 <0 Z A P c a> E C o (a > C LU C TO E s3c <D P C *r-- o TO TO P C o TO TO P P *rs 5 O O TO %J S3 O VO 12-15-82 TEH 0530471 DUP050031384 PRELIMINARY DRAFT For perspective, the environmental concentrations in Table 7-22 can be compared with estimated levels during natural, pre-industrial conditions. Such information is shown in Table 7-22. Note the wide concentration ranges, attributed to actual variation within each category as well as overall un certainties in the estimates. It is apparent from Tables 7-22 and 7-23 that the greatest increase in human exposure to lead since pre-industrial times has occurred in the food category. Unfortunately, the food concentrations given in Table 7-22 vary over three orders of magnitude; obtaining a quantitative estimate of the increase relative to natural exposures is difficult. Nevertheless, the natural concentration estimates suggest that modern lead exposures are considerably greater than pre-industrial exposures, a conclusion in agreement with the retrospective studies discussed earlier in the chapter. PB7/A 7-86 12-15-82 TEH 0530472 DUP050031385 TABLE 7-23. COMPARISON OF ESTIMATED NATURAL LEVELS OF LEAD IN THE ENVIRONMENT WITH TYPICAL PRESENT-DAY LEVELS C fd O ~ *r* 3 PP rd fd or z <y >> P ro rd Q E1 r~ p xc O 07 fc. tn CL 07 CL *< Q_ o oo o* o *tH H 1 IO oo rH rH o o <M CM 1I-1 ICNI O OO rtHH 03 >> fO C O1 O *r- P -P C0> (0 S-. CO P <y c S- 0) CL. O 1--(0 c o o u 1- *o p. ro h- P <o Hd E cn\ C O) CL O o rH iH l1 t H t--1 oo 05 O) ro a. e "'n O OlO 3.0 O in m1 oi IOH r*> N cn r-- 3. "V 05 COLT) z l iH os oa o rS O O 1 J tH into i O O i-H ooo ... OOO 0) >> fd "P b c uw ro - PP <d c s Of r-- U PC V) o LU (J PB7/A E zs *rX3 oj sc CO 30 Sv s C CO c r-i *O O1 rl H1 O tH oo . 05 05 05 05 a.-a. uom CM CM il Art If) 05 N <-- 05 a. 05 3.r- t H . O 050 rH ZL 1 i r-i iflHO ooo ooo OOO <v P rd E r- Pi0n> PSO~ V) ro PO X3 C<d +J p oo S T3 E "O HI at CD dJ 4. 4J i- P N-- -O N *r~ f-- .Q JZ C ro to fd rd in <d 4- JZ $. s- a; 07 u) 3 e I-* 3 C <y 5- o S-QC-lr-CSCH-IPLL.O O t-- o <d o < to 3: a- <y 3 (0tV0o) 7-87 12-15-82 TEH 0530473 DUP050031386 PRELIMINARY DRAFT 7.8 REFERENCES Acra, A,; Dajani, R.; Raffoul, Z.; Karahagopian, Y. (1981) Lead-glazed pottery: A potential health hazard in the Middle East. Lancet 1: 433-434. Akland, G, G. (1976) Air Quality Data for Metals, 1970 through 1974, from the National Air Surveillance Networks. 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