Document dne6NQOOkKB30vY435EYgJk2R

SAL 0C0C1943! of about 55 ugWX) ml would seem to provide another physiological basis to support the recent OSHA proposal"'\lhat "the maximum upper blood lead levels workers should remain below 60 ug/ 100 g " \ A semi-log plot (fHgure 2) converts the arithmetic dose-response Cxirve to a straight line. There is the usual scatter here, characteristic of biological responses, but,the correlation coefficient for the direct relationship between log ZP and lead content is quite good (0.8), which suggests that blood might be substituted for blood lead as''* ,- eferred biological index of exposure. Several advantages would be offered: (!) 'ZP more directly reflects the metabolic damage caused by lead and is thus a more useful indicatoKof the effects of lead absorption. f2>Contaminati\n. an ever-present source of concern and care Vith lead analyses, is minimal in the determinatiomof ZP. (.)) ZP assays are simpler, less costly, an more rapidly performed than blood lead, there by permitting more effective use ol resources and enhancement of any monitoring program. The foregoing findings, it should be noted, were developed for an industrial population chronically exposed to inorganic lead. Organic lead compounds may follow a somewhat different course through the body, and may not exert their major toxic effects on the hematopoietic system. Hence, a biochemical index such as ZP. may not be appropriate as a monitor for the effects of organic lead absorption. In some other disease states (e.g., erythropoietic protoporphyria or severe iron deficiency anemia), the use of ZP may also not be suitable, since elevated ZP levels can occur in such conditions without concomitant lead absorption/'" Such situations are unusual, however, and likely to be well known to the worker. Hence, the ZP test should be generally applicable to most workers exposed to lead, and should be given serious consideration as the biochemical test of choice in monitoring such populations. chnowledgmer>tt Special thanks are extended to Dr. Donald Sherman lor providing the blood specimens of (he workers used in this study, and to Erodiia Empaynado lor excellent technical assistance. reference* 1 U.B. Department of Health, Education, end WeHere: Cntaria tor $ Recommended Standard Occupational Exposure to Organic Lead Public Heellh Service. National Institute tor Occupational Safety end Health <1972) 2 Joeeiper, MM: Problems ot Stood Lead Level*, in Haatrh {Meets ot Occupational Lead and Anamc Cnpoture U 5 Department ot Health. Educatin'' and Welfare. HEW Publication No |NI0SH|6 134 <1976) 3 Beioh, R. W Laboratory Diagnosis ol Increased Lead Absorption Arch Envrrpn Health ^198 <1974) 4 PipmoW, S [a) Micromethod tot Free Erythrocyte Porphyrins Chn /fas 70 497 (1972), <b) A micro tnelhod lor free erythrocyte porphyrins the FEP test J Lab Chn Med 8f 932 (1973| S\ Increased lead absorption and lead poisoning m froung children Center (or Disease Control. Public Belth Service (March 1975) $ Lawnsla. A , M Joeelow and T. Yimane Zmc Prdtoporphyrin |ZPP| a Simple. Sensitive f luoNmetni: Screening Test for lead Poisoning Chn fthem 2( 93(19751 7 HeeaelXo. W A Simple and Rapid Quantitative Deiermikaiion ol Lead >n Blood At Absorpt News! 7 85 <1! 8 Joaetow. h*. M. and J D Bogden Simplified Micro method for Colleclion and Determination of teed in Bloo^ Using a Paper Disk in Delves Cup Technique At'\Absorpt Xfew*( (7 99 (1972) 9 Porphyrin Products, lrc.. P O Bo* 31, Logan. Uiah 84321 \ 10 load Occupational Eipoeure; Proposed Siendard Federal Register 40W 193.45934 45940iOct 3 1975) \ 1 I Magnus, I A . T JartaM. A. J Prenherd and C Rimlnton: Erythropoietic Protopotphynns Lencet 2 448 (1961) CTewe tiiim 2s i97 68 in) "ry Alloc I i.l& (DiuJcy 19?/ On (ha job benzene vapor exposures of lass than 5 ppm wars measured concurrent with tha 24 hour eo/7#cfzon of urlna from 52 employees. Urinary phanof favafs of tha collective study group, maasurad as either concentration or weight, showed % positive statistically significant corrafation with bansana exposure. However, due to variances in individual baseline phenol favafs. determination of benzene exposure at these tow concentrations is relatively weak Since baseline phenol concentrations exist over a range of values, adjustment for a single value of each individual's baseline did not improve correlation for tha collective study group. A study of benzene exposure versus urinary phenol levels GORDON J ROUSH and M GERALD OT7 HER Industrial Hygiene Laboratory. Corporate Medical Department The Dow Chemical Corporation Midland Michigan 4B640 (M 6-. cf CPr--^ o o c introduction The 1474 NIOSH proposed standard for benzene1 requires the monitoring of urinary phenol levels of employees with time-weighted average <1 WA) exposures exceeding 5 pans pet million (v v air). The correlation between benzene exposure and increased urinary phenol levels has been reported previously.' A level of 75 mg phenol - iilei of urine (mg. I) is proposed as a signal ol unacceptable benzene absorption requiring close medical surveillance. This study was designed to evaluate the proposed technique of "biological monitoring" in an industrial environment. It was also intended to determine il concentrations in the area of 75 mg phenol liter ol urine are indicative ot unacceptable benzene exposure. mechanic, and material transfer operator Usually, samples were obtained from two employees in each job. Participation was voluntary since the collection ot unne depended on each person's willingness to cooperate Urine samples and breathing zone air samples were collected on the same day Increases in urinary phenol levels were expected to correlate directly with inhalation of benzene vapors Skin adsorption was assumed to be negligible since most jobs required the wearing ot rubber gloves when handling benzene. Potential exposure to other chemicals should not have allected urmarv phenol levels since none were known to interfere with, or contribute to the metabolism of benzene to phenol. benzene vapor Mmpfing procedure Actual TWA exposure to benzene was determined via personal samplers worn on each Benzene is widely used as a raw material and solvent by The Dow Chemical Company, hive benzene-consuming production facilities were selected lo represent industrial environments where benzene is handled along with othei chemicals. (>\ei a six month period, benzene exposures were si udied for 52 employees from 2<i job classifications, including laboratory technician, ptsultictmn operatoi. plant rrm* *iforrr4MM> About vufHoB m employee's collar throughout the course of his workday Workdays varied from 8 to 12 hours in length A small battery powered vacuum pump provided a low air How rate. 100 to 250 milliliters per minute (ml- min), ihrough charcoal packed stainless steel lubes A f.w "extra large" commercially available sample tubes were lived, but most of the sample collection tubes were custom-packed with Pittsburgh, coconut ba-c tfea i*#vO i AJ 4u lo4uyii*l Hyyierx A*gcMlf0n JOURNAL i38l <' 87 SAL activated charcoal. 12-30 mesh Charcoal was used because of its suitability for collection of a wide langc of aromatic compounds which were likely to be encountered. The custom packed tubes were approximately 47cm(3/16 in | in diameter by 12.7cm <5 in.) in length and contained approximately one gram of charcoal. Efficiency of the total sampling system, including error of analysis, was determined by spiking sample tubes and submitting them for analysis with tubes used in monitoring. "Spiking" of the sample tubes wasaccornplished by preparing in a 100 liter Saran* bag a known concentration of benzene, both by itself and with a mixture of other chemicals found in the work place. Air from the bag was drawn through a sample tube at the same flow rate used in the plant studies. Collection of urine began when the employee started work, and continued for 24 hours. The "day" sample was collected in a hospital specimen container while the employee was at work. A second container for the "night" sample was taken home and used until he returned to work the following day Thus, the two "combined" urine samples represented approximately 24 hours of urine. A baseline urine sample was collected by each employee after being away from work fora minimum of48 hours No other restrictions were placed or the collection of the baseline urine sample. Information concerning consumption, within (he last 24 hours, ofany medication, tobacco, or alcohol was recorded by each employee for each urine sample. Any known chemical exposure was also noted. Information concerning previous or present health problems, particu larly of the liver, kidney, or heart, was requested for each volunteer. 10% SP 1000 5% FAPP 5% QP 11 SF 0 10% UCW 9K 10-20% Carhowax 20.000 5% SI* 1200. I 7S%. Benlone 34 10% LAC 2R446 15% Carhowax 4000 10% DC 200 Durapak OPN. Poracil C 80.'300 The columns ranged in length from I 83m (6 fi.) to 4.57m (15 ft.) and were prepared from .95cm (1/8 in) inside diameter stainless steel tubing. Column temperatures ranged from 18.3 to 68.3C (65 to I55"F). Selection of a column depends on the combination of chemicals absorbed on the charcoal. A column packed with SP 1000, Durapak or SP 1200/Bcntone would be suitable for benzene alone urina fimpkj Urine phenol analysis was based on the NIOSH proposed standard for benzene.1 The urine samples were hydrolyzed with perchloric acid at 95"C for two hours, saturated with sodium chloride, and extracted with isopropyl ether. The ether extract was analyzed for total phenol using a flame ionization gas chromatograph. The only modification of the NIOSH method was the saturation of the hydrolyzed urine with sodium chloride This step increased the extrac tion efficiency of the isopropyl ether The chromatograph column consisted of a lube .95 cm (1/8 in.) in diameter. I.B3m (ft ft.) long and filled with 2% F.CiA CC-AW-PMCS (980-100 mesh) packing. The following temperatures were utilized: column at !60eC. injection port ai 230250"C, and detector temperature at 290-300C. Maximum sensitivity under these conditions was about 2 mg phenol/liter urine. analysis of samples air samples The charcoal absorbent used in air monitoring was desorbed with cold carbon disulfide and analyzed by gas chromatography using a flame ionization detector. Specific chromatographic conditions varied over the several months of personnel sampling. Column packings included: Carhowax 20,000 ruulti data Table I lists data collected from air and urine sample analysis fWA benzene vapor exposure concentrations are given as ppm (v/ v) and they arc grouped according lu the length of the workday. Concentrations of phenol in urine ere "Atfiucrcd tf The !>* OrmKjl Cumppns iomttl 68 Am intf Atjrtf j tVf. fftjrujr 0BA2BA4 TWA Rsnoa *0 2 20 ' l i 1 1 0 06 <0 6 TABLE I Ratulta of Air Sampling |ppm| and Urine AnWysia (mg/t) Number of Paooia 1 1 1 1 1 1 2 7 16 Hours Workad 12 12 12 12 12 12 12 12 12 Baadins J 3 6 6 9 50 1-6 2 36 1-32 Concantratien flanaa of Phaool m Urina mm/l UiwdjuiM NIOSH Adlustad Oav Naaht Cwritenad Oav Nnrtit tambiuM SI 28 14 17 16 67 4-6 2 65 2 39 26 14 6 2 17 30 2 20 2 83 2 <8 39 23 11 6 17 38 3-10 2 73 2 70 51 37 26 14 16 73 7-TI 4-66 2 36 23 16 13 13 28 <0 .. -1* 5-60 3-16 37 30 21 14 22 66 6 15 5 71 3-16 44 3a 38 3e 3h 30 2 2 2 20 1 1 10 0 6 0 5 1 1 1 1 1 1 1 1 2 > 1 4 5 6 27 51 35 27 51 35 e 2 41 22 25 S6 26 34 8 4 49 22 32 51 22 33 82 9 6 7 17 13 37 46 45 45 61 N 63 8 4 24 21 22 36 26 32 8 3 M 12 13 22 17 <9 8 6 10 5 7 10 6 6 8 46 1 23 9 10 9 15 18 20 1 l '5 ib-ie 8 75 40 64 57 34 56 49 82 25 t4 6 8 11 46 25 30 37 18 21 26 21 4 24 4 73 4.16 4 19 4 18 3 80 IE 4-12 413 6 15 6 11 6 12 expressed as milligrams of phenol per liter of urine (mg/I) The concentrations are listed as measured, and as adjusted according to the NIOSH proposed benzene criteria. The following equation was used to calculate the adjusted values. Adjusted Concentration I asi 2 digits Measured of NIOSH averConcen- ' age specific tration_________ graviiy I asl 2 digit'. f mcasu.rd spec11ic gravity TABLE II RatuNs of Air Sampling (ppm) and Urina Analysis <mg| Santana TWA Ranga 40 26 20 15 13 12 11 1 0-0 6 <0 6 Numbar ot Hows jsagts___ Worbad 1 12 1 12 1 12 1 12 1 12 t 12 2 12 7 12 15 12 W--afti ot PlwW <n China, mg _____ AcluH _ Adjusted lo> Baaaljrta Dajr_ Nighty Pay_______ Ntghl 32 21 22 8 12 <6 6 3 65 2-28 '6 7 7 3 18 25 2 11 4 77 2-9 28 19 14 4 5 2 1 to 4 51 10 39 10 lo 23 12 5 1 7 8 23 1 io 8 -20 to 57 20 lu 5 44 39 38 36 35 30 26 25 21 20 13 12 1 0-0 8 <0 5 1 1 1 1 1 1 1 1 2 > 1 1 4 5 8 21 20 17 6 8 13 31 12 28 6 674 6 17 2 13 8 32 67 6 15 e 17 7 14 14 e 12 '8 9 13 8 32 1 8 12 in n 3 lu 1C 5 lu 6 8 IS 52 13 6 14 9 1 8 6 16 f 6 8 6 28 O ro fi 1 IO / 8 6 5 10 24 in 2 56 io 3 Arntf'Cin (ntfuxuul HtgifOB AAS0C*t<on JOUHMI 13th ?<?? SAL 0 0 0 0 1 9 4 3 3 TABLE ill CM^titnU from Comlblkm o< Bantarw TWA Expo*ur wKh Weight of Urmery Phenol end Urinery Phbnot Concentration) TWA Of 6 flour worldly 122 mnl UrVw S*9mini Dir Nlfhl Combamd Phenol WmgM Coafflciaot# 0 66 04a 0 S3 Phenol Coneendation Coefficient!____ Mmuns 0 65 060 0 52 NIOSH Adtuilld oae 0 63 0S4 TWA Ot 1 2 f>oor worldly |30 mini TWA cmtn*lton o* ft and 1 2 hou* WOftdtV! Dm Comb,"Id Oi* Comb, nod 044 0 IS 0 37 038 040 0 47 04J 0 IS 0 34 046 0 3? 043 0S1 0 23 041 0 se 0 42 0 60 TWA of combination q4 S and 1 7 workrMy*. S civil of umcopubl) pMnol concnlr|ior,| d4f*Md Or, Nifii tombnM 0 ST 0 89 0 77 0 ss 0 66 0 S< 0 69 0 69 0 T7 TWA of comtxnetton of S tnd 1 2 hour worldly!. 5 o' pKrtOl cACPATHion* ^2 hozt workday data adiuaiad to gr B hour workday Oir 0 TO fiolr A ptrlfti conditio* ci 11 0 no cvfftUr ion 0 0 Etch producl momeni correlation eneOrtirni above lLglitrd m follow* t orr - x, y. x,v. + Xn Y r ^JrrwMrt value of 1 ftTKin >lur of ) i rn-f) (Sid d,yi*non of X) iSid tnnimn ol Yl Whtft n - number of obeervirtoni X. Y ' peiimrtrri bcinj iorrrlid The average specific gravity of urine used by NIOSH is 1.024. Asa comparison, (he respective average specific gravities of urine samples included in this report were 1.021, 1.021, and I 022. for the day samples, night samples and baseline samples. These values are similar to those recently reported' for a large work population. The weight of phenol measured in the urine samples is shown in Table II. Phenol weight was of interest as an alternative to concentration as a means of measuring benzene exposure. Measuring weight instead of concentration would eliminate the problem of low phenol concentration due to the intake of large volumes of liquid This dilution of urinary phenol levels is handled in the NIOSH criteria by measuring .oecific gravity, comparing it with a traditionally used average, and adjusting the measured concentration accordingly. correlation of data parameters Two main parameters, urinary phenol concentration and phenol weight, were correlated with measured employee TWA benzene exposures. The correlation coefficients and the equation used in calculating them are shown in Table III. A correlation coefficient is a measure of the strength of relationship between two variables. In Table HI. most of the coefficients exceed 0 3, a value representing the highest correlation which would be expected if random numbers were substituted for the reported sample values. This value assumes a sample size of S2 observations and a confidence level of 95% or p <0.05. Since most of the coefficients exceed 0.3, in most instances a positive significant correlation exists between TWA benzene exposure and the two different measures of urinary phenol levels. Figures I and 2 are plots of the strongest relationships for phenol concentration and phenol weight respectively. Besides comparing two methods of reporting urinary phenol levels. Tahle III indicates the different ways in which the experimental data was analyzed Obvious subgroups exist in the total of 52 observations reported. Examination rihryji)170 Am InO )*tQ J i3&> Figure f - TWA beniene eipsoure versus adjusted con centration of phono! <n urine 15 cases of high baseline concentrations deleted! of the data included analysis of these subgroups as well as (he total group. Two of the sub-groups in Table 111 resulted from the sampling of employees with two different length, 8 and 12 hour, workdays. A third sub-group with the high baseline urinary phenol levels became evident after the data had been collected. High baseline levels are apparently normal for some individuals and these individuals may exceed (he concentration of 75 mg/I. proposed in the NIOSH document as an unacceptable level of "absorption." The five individuals with high background phenol levels will be discussed in more detail later. They were deleted in the last two correlation groups in Table III in order to determine the degree of influence they exerted on (he collective group. The last correlation in Table III was an effort to further examine the relationship between excreted phenol weight and bertzene exposure. Since the data had been collected using two different length workdays, it was logical to expect a higher weight of phenol to be excreted in the "day" samples by persons working the longer day. This was assuming vapor exposures were fairly equal throughout the workday. The individual phenol weights collected during the 12 hour workdays were reduced by 1/3 to equalize them with the 8 hour workday. The correlation of this adjusted "day" weight of phenol is reported as the last section of Table III This study agrees with previous studies showing a good correlation between benzene exposure and urinary phenol levels. The highest correlations in Table III occurred when the five persons with high background phenol levels were deleted from the data. These correlations are statistically significant at the critical level, p <0.005. If persons with high baselines are included in the data field, the best correlations are significant at 0.0005 <p ^0.005. However Figures I and 2 show the unpredictability of this association at relatively low exposure levels. These figures are plotg'of;di|^fjxcluding high baseline phenol leve%-;Wljieii|i'generaied the highest correlation between -phenol concen tration/weight and TWA benzene exposure. Plots of data which included persons with high baseline phenol levels showed in even wider and more unpredictable scattering of points. The solid line in Figures I and 2 is a least-squares plot, or regression line. The broken lines represent plus or minus two residual standard deviations and should contain between them approximately 95% of the data points. Efforts to use the regression line to predict benzene exposure resulted in (he equations shown in Figures I and 2. Theppmvaluefortwostandard deviations is given below each equation. Two standard deviations for these, the best two correlations, represent an unacceptable 35-40% of the experimental (0-5 ppm benzene) data range. For example, assume an employee's urine was monitored and it contained 25 mg I of phenol. Based on Figure I, the best conclusion that can be drawn is (hat the employee is 95% sure his TWA benzene exposure was between 0 4 and 3.9 ppm. Or. if 100 employees were monitored for one day. and all of the urine Figure 2 - TWA beniene exposure versus weight of phenol in urine 15 raxes of hipn henel'iie concenpetion. deletedI SmeiCin Indui'fUl Hyg*n As!bC.41*on JDIMKAL t3t> lift 71 SAL 000019434 1 SAL 00C G 194?5 TABLE (V Corrafafton Coefficient* for TWA Bnzn* V*r*ua Urinary Phenol Weight. Adjunad end Unadjueted for Background Phenol level* TWA of 8 houf (2 m+n> TWA of 1 7 hour workday (30 manl TWA of cornt>*f'*tK3n 0* 8 JnO 12 hour TWA of com&>rwd B ind t J rxK* awVtni. 5> cttei o< unaceaptaWa phenol cor>cnniiaint dafad TWA of cointxnttion of 8 and t J Sou' wldavs 5 ciaai of gnaceapfaWa Crhnol co^Ctnu#iiorift diNtiad I? worker rlf# *d|ult*J 10 in 8 ^ckji v*t*ktj#v Urtna >**n*nt Day Nigfii Combrrvad Day Magftl Camprnad Nijhr Cwnbmad Oay Niphi Combrnad Day Urtadjuatad for baa# DM 0 *6 0 53 044 0 18 0 37 038 0 40 0 47 0 S7 0 54 0 65 0 70 Adfuatad to< baaa 0 59 059 0 80 0 IS 0 79 040 041 053 0 46 I figure J- TWA b&nieno exposure versus uned/usied weight of phenol m urine Siiif Perlec* cnn<|j(ion t ?t0 ho corirbhon uOO samples contained 25 mg/1 of phenol, one could assume that approx imaiely 95 out of the 100 had had a I WA benzene exposure between 0.4 and 3.9 ppm l.ess than 10% of the time will an employee's actual exposure fall on (within 0.1 ppm of) the regression line. Urinary phenol levels arc not an accurate method of predicting TWA benzene exposures in Ihc range of 5 ppm or less. Another observation exists. It is that NIOSH's recommended procedure foradjusling "spot" urine samples to a standard speedic gravity slightly improved the correlation of the 24 hour urine samples. NIOSH recommends this TABU V Summary of Employ**** with High BaMiirt* Urinary Phenol Levels Bantana. 02 Aa 67 08 4* Madlcaiton need at tfma of fturvvy Efidi 2 Aepem fey 0< lit (mm HMory of markka1 probfama Hi Wood v ******* No ProMam* t2 23 0*1 madwa No lion during PrsWamt vorkdav M'npfa. Rota'fe on 3rd baaa 70 33 Nona No Pobl*rr> 35 ?/ 7 Ao-><" day Nc nl 2'><J btege Pruf.iam* All fP^lf <mpb.*vf-N Unnary Phono! Lavota, m . Woa* houra pa* dor 8 12 12 Maaautad Oar N%M 44 te 12 80 17 6 3 28 99 82 87 30 M 44 83 NIOSH Adiuafed Day Nfgfrt Bom IS 12 86 73 60 roe 84 M 8 40 84 76 59 38 84 37 B 46 45 37 61 64 47 67 a* 7? procedure when a single urination is sampled, lo allow for dilution of phenol concentrations due to large volumes of liquid intake. When this adjustment was applied to the various urine segments. Table 111, the resultant concentration correlated better with TWA benzene exposure. background phono/ lovolw Table IV. and Figures 3 and 4 present the result of adjusting measured urinary phenol levels VWuma *f UHw________ BppbMIb fvWv Day Nlfh4 tw* D*V Nfgfe aaa 375 860 44 1 028 1 026 1 026 26 1 031 1000 926 7B 140 226 1 024 1 022 1 019 t 022 1 023 236 1460 238 266 1 022 1 012 1.016 1 021 1 026 3C6 870 690 '1675 .1. 280 65 366 696 13 445 1 028 i oia 1 028 1 01 7 1 028 t 022 1 027 1 019 1 021 1 026 according to each individual's normal baseline level. A baseline urine sample was collected after each volunteer had been away from work or any known chemical vapor exposure for 48 hours. Each baseline phenol weight was calculated and subtracted from the total weight of phenol in their "day" and "night" urine segments. Theoretically, this adjustment should have compensated for persons with normally high urinary phenol levels, leaving the adjusted weights of phenol entirely related to benzene absorption. Figure 3 is a plot of unadjusted urinary phenol weight for all 52 observations. Figure 4 illustrates the effect of subtracting the baseline ground weights of these 52 individuals. Table IV compares group correlation coefficients for TWA benzene exposures versus both unadjusted and adjusted weights of urinary phenol. In most cases, the unadjusted measured . weights have a higher group correlation than the " adjusted weights. This finding indicates the difficulty in using a single value for baseline; ;:* ^ urinary phenol levels. For any individual, a : baseline range should he determined to accurately assess what phenol level is "above** w. normal. The negative phenol weights in Figure4 also indicate that unknown factors are causing greater fluctuations in baseline levels than those resulting from low benzene exposures. A study of non-cxposed controls is underway and will he reported in a future publication 72 Am tnet g Auer j ; H* FrDruai, 1977 Am**can Indutlnal Hfpxnt AssociM-on JOUHNAl t.lii 7-77 73 SAL 000019436 references 1 National Institute tor Occupational Salat-y and Health Cnlena lor n Recommended Standard (or Ornupaiionai posure io Oenrrme HEW Putiti cei'ori No 74 t 37 2 Walkley.J E l D Pagnotio and H B Elkim The Measurement ot Phenol m Urirx; as an Indea hi Ben ran* Exposure Am irvd Hyp Assoc J 22163 (19611 3 Fiahbecfc. W. A , R. R. Langnai and R. J. Kotib* Elevated Urinary Phenol Levels not Related to Ban. rene Exposure Am tnd Hyg Assoc J 36 820 I 19761 ai-i Figure 4 - TWA beniene exposure versus *dtuslt} weight q! phenol m urine While consideration of baseline phenol levels for a large group docs not improve correlation with benzene exposure, its consideration can very heavily influence correlation for individuals with naturally high baseline phenol levels. Urinary phenol levels approached or exceeded the criteria action level of 7 5 mg/m* in one or more urine samples of five different persons, or about 10% of the total number of persons sampled in this study. Several urine sample concentrations of ihese five persons are shown in Table V, both as measured and adjusied according to NIOSH formual. The baseline concentrations indicate that these five individuals frequently, but not always, have higher than normal 030 mg, I) phenol concentrations in their urine. Average levels for these individual's varied from 40 to 60 mg/I. but the full range of measured "normal'' urinary phenol levels varied from 5 to 100 mg/1. Analysis of the sample data, Table V, did not indicate a one-to-one correspondence of high urinary henol with any of the known parameters, such ' sample volume, specific gravity, medications, edical problems, or age. There is no indication in this study as In why normal urinary phenol levels flucluate over a relatively broad range, and are characiertisticiilly high for certain individuals. conclusions I. A positive statistical correlation exists for urinary phenol levels versus TWA benzene exposures, at exposures of less than 5 ppm This correlation is statistically significant at the 0.005 level for a large group of people Both total weight of phenol in the urine, and phenol concentration in urine gave similar results. 2. The correlation between individual benzene exposure and urinary phenol levels is not strong enough to assess past TWA benzene exposures less than 5 ppm. Assessment improves if individuals with normally high sbackground phenol levels can be identified and treated as special cases. Even so, the actual TWA exposure may be 40% of (he exposure determined from urinary phenol levels. 3. Urinary phenol levels, which have been adjusted for baseline values resulting from a single measurement, do not have a higher group correlation with benzene exposure. 4 Baseline phenol levels for a group and an individual can vary over wide range Approximately 10% ot the persons in this study exceeded the `unacceptable" level of 7S mg; l, as expressed in the NIOSH proposed hen/cne standard, even though ihev had no known exposure or their TWA benzene exposure was less than 5 ppm. 74 Am im) n,q A\sei J .30. fibiuirr i9ZV ABIH annual certification examinations . . . Examination* for certification by the American Board of Industrial Hygiene will be held in New Orleans on May 27 and 22, 7977. The following examinations will be conducted. * CERTIFIED INDUSTRIAL HYGIENIST -- This consists of a two day written examination The first day is Ihe CORE examination in the basic principle* of industrial hygiene practice. The second day consists of examination* in th# Comprehensive Practice or in an Aspect of industrial hygiene, e.g., Acoustic*!. Air Pollution. Chemistry, Engineering and Toxicologic*!. Persons who have completed one part of the examination successfully need take only the other pan. INDUSTRIAL HYGIENIST IN TRAINING -- This consists of th* CORE examination covering the basic principles of industrial hygiene practice. Qualifications for admission to the above examinations include a baccalaureate degree in a science closely related to industrial hygiene and industrial hygiene experience varying from five years for a candidate for Certified Industrial Hygienist to one year for Industrial Hygienist in Training Up to one year credit may be allowed lor * completed graduate degree. INDUSTRIAL HYGIENE TECHNOLOGIST This consist* of a one day written examination covering the principles of various technical aspects of industrial hygiene, e.g., air sampling, laboratory analytes, air monitoring, etc. Qualifications for admission totyiis examination are a high school diploma andfive ormore years of experience involving at least 25% of the time m industrial hygiene activities during each year The Board may accept alternative education experience requirement* for persons having an associate degree or who have completed two years in an accredited college. application cut-off data All applications for examination must be received before March 21, 1977 All candidates accepted for examination in New Orleans must have their faea paid at least 30 days before the examination data Specific information about eligibility require ments. th* examinations and application forms may be obtained from American Board of Industrial Hygiene. 66 S. Miller Rd., Akron, OH 4431312161836-9339. Enamimtioct will b* ha*d at tha Fairmont Haiti z'iiFXiS.dfiilW'* Amriicm lndv*til Myjun* Aisocijtiwi JOtMNAl i.W ?r7t 75