Document Qkzv1a7m2NXJqq1ENOv3j62O5

AR226-2924 CENTRAL RESEARCH AND DEVELOPMENT DEPARTMENT HASKELL LABORATORY FOR TOXICOLOGY AND INDUSTRIAL MEDICINE THE EFFECT OF PARTICLE OF A 1ATION TOXICITY INTRODUCTION . in this study nad been shown to be extremely tjoxic by inhalation when tested as a highly respirable aerosol (ALC of 4Z mg/m ). The purpose of the present study was to determine the effect of particle inhalation toxicity of Two forms of t h e H ^ ^ H M e r e tested; one was a 40% ^ e o u ^ ^ ^ ^ ^ ^ ^ f r a one fA!Sr ? pure "jatenai;* For both materials, Approximate Lethal Concentrations (ALL s) were determined for various particle size atmospheres. The ALC was defined as the lowest atmospheric concentration tested which caused the death of 1 or more rats either on the day of exposure or within 14 days post exposure. Further, the relationship between expected pulmonary deposition (based on particle size) and mortality was investigated. PROCEDURES A. Animal Husbandry Young adult male Crl:CD(SD)BR rats were received from Charles River Breeding Laboratories, Kingston, New York. Each rat was assigned a unique 6-digit identification number which corresponded to a numbered card affixed to the cage. Rats' tails and cage cards were color-coded with water-insoluble markers so that rats could be identified after exposure. Rats were housed singly in 5" x 11" x 7" suspended, steel-mesh cages in rooms targeted to have temperatures of 25 + 2C and 50 + 10% relative humidities on timer-controlled 12 hour/12 hour light/dark cycles. Rats were quarantined for one week prior to testing and were weighed and observed twice during the quarantine period. ' Except during exposure, Purina Certified Rodent Chow #5002 and water were available ad libitum. Page 1 of 12 Company Sanitised. Sees m i contain TSft& ire * Exposure Protocol grams, were restrained in perforatL s t r e s s s r ^ 6 ?-" 224 and 297 conical nose pieces. Each Z Z Z ' neStee C* linclers w ^ h 4-hour period to an aerosol ^ t m Z Z e ^ e f t Z ^ r ^ fr 3 sinS,e* or the solid in air. Rats were weiahpHnrfIth? th atlueous suspension for clinical signs durina exoncura ^ c -r exPsure and observed observed daily for 14 d S s X 2 S u m v l n ? rats were weighed and deemed necessary by the rats' condition!* W6ekendS e*c1uded except when C. Test Material Physical Form: Compos iti on : usponsion Aqueous suspension Purity: Contaminants: synonym: Stability: JJe te^ material was assumed to be stable throughout the exposure phase of the study. Physical Form: Purity: Contaminants: Synonym: Stability: Waxy solid ie test material was assumed to be stable !Baisseedd9oonnUithhethse uep\pPl?ySu'rse sppheasceifiocfattihoensstudtyh.e nne^eld!e!d aifoerriaglene"raaSti?otn3.Me 3t the `iKSrrtireess Atmospheric Generation X ^ B B B B B B B ^uspension Aerosol atmospheres of . generated by pumping the liquid ^ t ^ ^ o r ^ u ^ m USpen! 100 were Air introduced at the nebulizer aprneni/ nebulizer. swept the aerosol stream t h Z g h a c cW oi ? ^ material* a"d exposure chamber. Paarrttiiccllee ssiizzee ddiisctrtiMbuhtTioen1sutwnearteorshiafntdedinttoowatrhde ffipasy Ssn&efj. Page 2 of 12 not eenfsin TSCA o b ? tp1h3aerrumtmicomwleeertseeir'z`cdeaulcdriuanltgaat.eedacChfhraomemxbpetorhsetuermtec.p&^ra'ltPdrn^^i jrlilar icWcmo no^n^ iffit|^o^||fp He !fS"i-t Ifit RESULTS^ A. Exposure. Coddittions and Associated Mortal ity. ;H:'I! 'Mlifiifl ^9|d;^:^^ospheric concentration, partple?ize d i st ri bu ti ^a ndi ds so c^ -, r ^ - mort.a l n y for each exposure. Data are grouped wlihj:simi.lan;:particle size distributions. The i n c r e a s i n TM s s > m ^ i a P aerodynaniic;ydrameters indicate a shift: in the particle size distribution^ from mailer?to larger particles. * ** . . .?'&!? `it: Page" 3-of 12 Company Sanitised. Boas nriebriiafn l^^fecB i ^ : ^jjj^ Totajl ; Particulate : Cncen|||tin 16 + 6.6 .42 + 7.8 b73 + 25 330 + 110 58 + 42 77 + 5.3 170 + 40 ,*S?'**fght of Particl^s;yf t ^ -i . ^ yff Krrejjiftision 99 92 99' "95 98 93 95 75 76 ` 45 86 52 so: : 51 - 73 79 77 44 18 20 CC .v.-:# . }*?f^ "S:- ' ':vi; 21 30 21 8.1 3.0 4. 9: 2.31 1.7 urn I j 6 urn 19 un 0/6 ' 3fffi S-'. 3*4 um 6/6 6|6 um 58 um ; 6|0 um 0/6 0/ f r ; 4/6 * -f '9.4 + 1.9 24 + 21 66 48 110 + 72 110 + 48 140 + 34 48 + 10 72 + 8.7 110 + 56 190 .+_ 88 320 + 56 390 +_ 100 520 _+ 140 57 + 18 84 + 31 190 + 33 360 i 33 610 + 82 620 + 42 0/687 76 98 93 98 93 99 96 92 76 98 89 68 81 77 83 53 62 56 37 26 34 20 13 l-.l urn 11.7 urn 2.1 urn 1.7 urn 2.9 urn 2.7 urn 6/6 6/6 6/6 6/6 6/6 0/667 50 78 52 73 50 88 60 89 56 2277 48 79 54 34 32 29 26 27 28 18 5.2 urn 0/6 17 13 5.1 urn 5.5 urn 0/6 5.8 4.7 urn 0 /6 3.9 4.9 urn 5/6 1.6 5.4 urn 4/6 2.9 5.5 urn 4/6 0/657 29 70 43 63 39 74 46 71 41 75 42 10 23 19 22 18 17 5.0 9.7 urn 7.4 6.6 urn 4.8 6.9 urn 0/6 2.5 5.6 urn 3/6 1.1 7.1 urn 1.3 6.1 urn iS;:: duMn9 9e"erat|"- Page 4 of 12 'SaspsRy S'anHfeedl. oss ^ centrer* s Estimated Lung Deposition2 and Associated Animal Mortality The fractional deposition of particles within the respiratory tract depends in part on the particles' aerodynamic sizes. However, literature sources vary widely in their estimates of the size-limits of particles able to be inhaled and to be deposited into various regions of the respiratory tract. Further, data indicate that deposition varies widely amoung individuals and amoung species. The Environmental Protection Agency has adopted the following criteria to define the approximate size-limits of particles which may deposit into the various regions of the human respiratory tract: particles smaller than 15 um can be inspired and deposited throughout the respi ratorjr tract; and particles smaller than 2.5 - X 5 um (nose and mouth breathing, respectively) are expected to deposit predominantly in the alveolar region. Deposition of particles smaller than 3 um is similar in rats and humans. Deposition data in rats for particles larger than 3 um are not available. To investigate the relationship between the aliphatic carbamate toxicity and particle size, the following assumptions have been made: particles smaller than 3.1 um will provide predominantly alveolar deposition, particles smaller than 13 um (including particles <3.1 um) represent total respirable particulate, and particles larger than 13 um will not be inhaled. The 3.1 um and 13 um size-limits were chosen because they are the experimental cut-points provided by the cascade impactor used in these tests which most closely approach the EPA criteria. For each exposure, the atmospheric concentrations of particles smaller than 3.1 and 13 um were estimated by multiplying the total atmospheric concentration by the mass percent of particules smaller than these cut-points. As shown in Table !, within groups of similar . particle size atmospheres, mortality generally increased with increasing concentration. Further, as particle size distributions shifted towards larger particles, the concentration needed to cause death increased. The ourpose of back-calculating the atmospheric concentration of particles smaller than 13 and 3.1 um was to investigate whether the apparent decrease in toxicity can be explained by the inability of a large fraction of these atmospheres to either be inhaled or be deposited in the alveolar region. For the aliphatic carbamate suspension exposures, the atmospheric concentration of particles smaller than 3.1 um was most closely associated with animal mortality; regardless of total atmospheric concentration and MMD, as the concentration of particles smaller than 3.1 um increased, mortality increased. For exposures to the solid, as the concentration of particles smaller than 3.1 um increased from 32 to 58 mg/m , mortality increased. However, one exposure containing only 19 mg/m of particles smaller than 3.1 um caused 6/6 deaths. The deaths at this concentration were unexpected, and the cause of death is difficult to explain. For both the aqueous suspension and the solid, total Page 5 of 12 Genmany Sanitized. Does not eenfain TSftfl e'.w ite (all particles smalle r thgn 3 ub| A -, relationship with m o r t a lit s the total rsplr e f illjjartlculate Increased* a corresponding aortalIty was net Observed. ' Table i i presents the atisstphfic concentration of particles soaller thartr 13and 3.1 um and"associated rat aortal 1ty for represnj tlve exposures. Data for a ll exposures are presnted 1n AppendljrT Page 6 of 12 'Gawvgism? WsnM zed. Bees fsfanfari & Table II ^ mospheric Concentrations of Particles Smaller Than 13 and 3.1 um and Associated Rat Mortality----- Atmospheric , Concentration ( m o / m V Mortality Data Calculated F m m [Aqueous Suspension) Particles smaller than 13 um: 66 0/6 42 3/6 140 72 4/6 6/6 Particles smaller than 3.1 Um: 15 0/6 33 3/6 37 4/6 56 6/6 77 mg/nu3 9 5.8 um MMD 42 mg/nu @ 1.6 um m 170 mg/m, 9 6.0 um IWID 73 mg/m @ 1.9 um MMD 2 77 mg/m, 9 5.8 um MMD 42 mg/m3 9 1.6 um MMD 170 mg/m3 <a 6.0 um MMD 73 mg/m @ 1.9 um MMD [Solid) Particles smaller than 13 um: 80 120 0/6 0/6 170 24 0/6 6/6 65 6/6 100 6/6 particles smaller than 3,1 ..m- 32 0/6 36 0/6 49 0/6 19 51 58 6/6 6/6 6/6 110 mg/m3 9 5.5 um MMD 190 mg/m3 @ 6.9 um MMD 190 mg/m3 9 4.7 Um MMd 24 mg/m3 9 1.7 um MMD 66 mg/nu @ 2.1 um f#1D 110 mg/m @ 2.9 um MMD 110 mg/m3 @ 5.5 um MMD 190 mg/m3 9 6.9 um MMD 190 mg/m3 9 4.7 um MMD 24 mg/nu 0 1.7 um MMD 66 mg/m3 9 2.1 um IWD 110 mg/m 3 2.9 um MMD a s a s s s ' total es Page 7 of 12  * C. Clinical Observations In general, very few clinical signs were observed in rats that survived exposure to the aliphatic carbamate (suspension or solid). During or immediately following both lethal and non-lethal exposures, some rats in several groups had test material on their faces and heads and had a diminished startle response. Most rats expbsed to i f u ] concentrations had labored breathing, and a few rats exposed to lethal concentrations had red nasal and ocular discharges, ruffled fur decreased activity and pallor. A few rats exposed to non-lethal * concentrations had red nasal and ocular discharges . During the recovery period, most rats which survived exposure to either form of the test material had slight weight loss (less than 5) for 1 day after exposure, and had no major clinical signs. However a few rats had greater than 5% body weight loss, facial discharges, ' diarrhea, wet perineum, ruffled or discolored fur, hair loss and labored breathing. For the solid material exposures, most deaths occurred during exposure or 1 day post exposure, although a few rats died between 2 and 8 days post exposure. For exposures to the aqueous suspension, most deaths occurred from 1 to 2 days post exposure, with the latest death occurring 6 days post exposure. Rats that died lost approximately 7-15% of initial body weight 1 day after exposure, and continued to lose weight until they died. Clinical signs for rats that died included labored breathing, facial discharges, limpness, ruffled or discolored fur, wet or stained perineum, diarrhea, pallor and lethargy. DISCUSSION Based on total ati Concentrations for boti size: heric :oncentration, the Approximate Lethal " I n c r e a s e d with increasing particle Aqueous Suspension Solid MMD 1.6 urn 6.0 urn l." urn 5.6 urn ALC 42 mg/m~ 170 irig/nr 24 mg/ml 36U mg/nr Although the s o ] i A p p e a r e d to be more toxic than the rc2onnsci?dHefrreSdUSepxet?rSe1me-ly *totxhic swmhe1n1eardmPianrifsTtcelreedsiazse hriagnhgel,y rbeostphirmaabtlereiaalesroswoelrse Page 8 of 12 orapany SaniUzs. Bess nei centelrv T3CA CSr When the particle size distribution was shifted toward larger particles, these materials were considered moderately to highly toxic. The apparent decrease in toxicity with larger particle sizes is best explain^ by considering the fraction of the test atmosphere expected to deposit in the alveolar region. Regardless of total atmospheric concen tration, the concentration of particles smaller than 3.1 um was most closely associated with mortality. Except for one exposure to the solid material, as the concentration of particles smaller than 3.1 um increased, mortality increased. The cause of death in the outlying exposure to the solid material cannot be explained. In conclusion, i r n de ^h^onditionsof this test, the Approximate Lethal Concentrations of^ t h e M ^ H | j ^ ^ H ^ l j ^ H H ^ s u s p e n s i o n or solid) increased as particle size d i s t ribunon^^^We^TroWPnaller to larger particles. Regardless of total atmospheric concentration, the atmospheric concentration of particles expected to enter the alveolar region was most closely associated with mortality. However, one exposure to the solid material caused death at a much lower concentration than was expected, end the cause of death in this exposure can not be explained by this model. SUMMARY ^ o u p ^ o ^ ^ n a l ^ C r ^ C ^ ( S D ) B R rats were exposed to aerosol atmospheres of t h e j H M f ^ J ^ H H M M h e r as an aqueous suspension or as a solid for a s i n g f e ^ n o u ^ p a n o a ^ U T W e r e n t particle size distributions were generated to determine the effect of particle size on the toxicity of these materials. Further, the relationship between expected pulmonary deposition (based on particle size) and mortality was investigated. For both the aqueous suspension and the solid, the ALC increased with increasing particle size. For the3aqueous suspension, the ALC increased from 42 mg/m at 1.6 um MMD,to 170 mg/m at 6.0 um MMD, For the solid, the ALC increased from 24 mg/m at 1.7 um MMD to 360 mg/m at 5.6 um ffiD. For these materials, the fraction of the total test atmosphere expected to deposit in the alveolar region (particles smaller than 3.1 um) was most closely associated with mortality. However, this relationship was unequivo cal only for the-joueou^suspension exposures; one exposure to a low concentration f H 9 H H H ^ H H 0 1 > & r t i c l e s smaller than 3.1 um caused deaths which can not be explaTnec^y^xpected pulmonary deposition. The atmospheric concentration of total respirable aerosol did not show a clear dose-response. Page 9 of 12 Does no! contain T S C A CBS ^ CalGulationidescribed in Sierra Instruments, Inc. Bulletin 7-79-219IM, Ki^iuctibn^nual: Series 210 Ambient Cascade Impactors and Cyclone PresgparatdijSS 2 Air Quality Criteria for Particulate. Hatter and Sulfur Oxides, External Revlsw Oraft No. 2, Uftice of Research and Development, u. s. Environmental Protection Agency, February, 1981. Date Issued: April 1, 1985 Number.of pages in this report: 12 r> Page 10 of 12 ;SarnpaRy Sanitize^. Dasa not contain TSCa CBi Appendix I Atniospherlc Concentrations of Particles Smaller Than lAaueous Suspension) Concentration of particles smaller than 13 um Atmospheric 3 Concentration (mg/nr) 16 44 66 Mortality 0/6 0/6 0/6 Data Calculated From: 3 16 mg/m. 0 1.7 um W1D 58 mg/mf 6 .6 uni MMD 77 mg/m0 0 5.8 um MMD 42 3/6 42 mg/m3 0 1.6 um MMD 140 4/6 170 mg/m 8 6.0 um MMD 72 6/6 73 mg/m3 9 1.9 um IWD 310 6/6 330 mg/nr 0 3.4 um MMD Concentration of particles smaller than 3.1 um Atmospheric 3 Concentration (mg/nr) 10 12 15 Mortality 0/6 0/6 0/6 Data Calculated From: 3 58 mg/m. @ 6.6 um MMD 16 mg/m3 0 1.7 um MMD 77 mg/m 0 5.8 um MMD 33 3/6 42 mg/m3 0 1.6 um MMD 37 4/6 170 mg/nr @ 6.0 um MMD 3 56 1XJcUn 6/6 73 mg/nu 0 1.9 um MMD 6/6 330 mg/m 8 3.4 urn MMD B. Solid) 1. Concentration of particles smaller than 13 um Atmospheric 3 Concentration (mg/nr) 8.2 32 32 56 59 80 120 Mortality 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 Data Calculated From 9.4 mg/m3 @ 1.1 um MMD 48 mg/m. 0 5.2 um MMD 57 mg/mu 0 9.7 um MMD 72 mg/m3 0 5.1 um MMD 84 mg/m3 0 6.6 um MMD 110 mg/m3 0 5.5 um MMD 190 mg/nu 0 6.9 um MMD 190 mg/nr 0 4.7 um MMD Page 11 of 12 Company Sanitized. Does not contain TS CA CBI Appendix I (cont'd) Atmospheric Concentrations of Particles Smaller Than 3.1 and 13 urn and Associated feat Mortality B ^ J H ^ c o n t 1d) 1. Concentration of particles smaller than 13 urn (cont'd) 24 6/6 24 mg/mf 0 1.7 urn MMD 65 6/6 66 mg/m @ 2.1 um m o 100 6/6 110 mg/m 0 2.9 urn MMD 110 6/6 110 mg/m 0 1.7 um HMD 140 270 6/6 140 mg/m 0 2.7 um HMD 3/6 360 mg/m 0 5.6 um W D 280 5/6 320 mg/m 0 4.9 um MMD 300 4/6 390 mg/m 0 5.4 um MMD 390 6/6 400 mg/mr 0 2.5 um MMD 410 430 460 4/6 520 mg/m? 0 5.5 um MMD 6/6 610 mg/m 0 7.1 um MMD 6/6 620 mg/m 0 6.1 um MMD 820 6/6 900 mg/m 0 2.6 um MMD Concentration of Particles Smaller than 3.1 um Atmospheric , Concentration (mg/nr) Mortality Data Calculated From 5.7 6.4 16 19 23 32 36 49 0/6 57 mg/m 0 9.7 um fWD 0/6 9.4 mg/m 0 1.1 um MMD 0/6 48 mg/m 0 5.2 um MMD. 0/6 84 mg/m 0 6.6 um MMD 0/6 72 mg/m 0 5.1 um MMD 0/6 110 mg/m 0 5.5 um MMD 0/6 190 mg/m, 0 6.9 um MMD 0/6 190 mg/m0 0 4.7 um MMD 19 6/6 24 mg/m 0 1.7 um MMD 51 6/6 66 mg/m 0 2.1 um MMD 58 6/6 110 mg/m 0 2.9 um MMD 79 3/6 360 mg/m 0 5.6 um KHD 86 5/6 320 mg/m 0 4.4 um MMD 86 4/6 390 mg/m 0 5.4 um MMD 87 6/5 140 mg/m 2.7 um MMD 91 6/6 110 mg/m 0 1.7 um MMD 110 6/6 610 mg/m 0 7.1 um MMD 110 6/6 620 mg/m 0 6.1 um MMD 150 4/6 520 mg/m 0 5.5 um MMD 260 6/6 400 mg/m- 0 2.5 um MMD 570 6/6 900 mg/m 0 2.6 um MMD Page 12 of 12 feel. 00snet e m 'M a TSG/4eg?