Document 2xkL7dY7yyo8MJEoprr1ODMb

FOR DU FONT USE ONLY AR226-2902 Copies Co E. I. du Font de Nemours and Company Haskell Laboratory for Toxicology and Industrial Medicine Elkton Road, Newark, Delaware 19711 Study Initiated/Completed ------4/27/81 - 5/15/81------ Material Submitted by Fo^Ber^ffoduets Department ESL 269/306 INHALATION MEDIAN LETHAL CONCENTRATION (LC50) Procedure; Male albino Crl:CD rats were housed in pairs in 8" x 8" x 14" stainless steel wire oesh cages< Purlna Certified Rodent Chow ?5002 and water were available i libitun. Bats were weighed and observed for general suitability for 1 week prior to testing* Groups of 10 rats, weighing between 241 and 298 grains, were placed \ awtimreosmpheeshresrecsotrnatianienrinsgajBadB^aBtpUoBgemd^ih^eBad^.oBnlBy^^fo^r^sB^igAlell 4r-haotsurwpereeriowdesightoed and observed daily (except weekends) for 14 dayspost exposure. Generation; Dust atmospheres oi |were generated by passing air through a single-stage, glass, cyclone generator which contained the test material. An electric motor and steel rod with plastic paddles agitated dust in the generator. Additional houseline air introduced at the cop of the generation apparatus carried airborne dust into the exposure chamber. Analytical; Samples of chamber atmosphere were collected at 30-minute intervals. Calibrated volumes of atmosphere were drawn through preweighed Gelman glass fiber filters (Type AE 25 mm). The atmospheric concentration of test material was determined from weight gain of the filters. Particle size Company Sanitized. Does not contain TSCA CBI (mass median diameter) was determined with a Sierra Cascade Impactor during one exposure. Results and Discussion; Ho deaths occurred as a result o^exposure to atmospheric concentrations of^BB----i^BBHIHHiHIBWHF5 high as 15 mg/L, the highest concentration which could be generated under these test coaditioas. Concentration mg/L Mean S.D. Range Mass Median Diameter ----------TO-------------- Fractional Mortality (.f Deaths/it Expos'-d) 9.6 6.7 3.0 23 5 3.1 9.0 19 0/10 0/10 On the basis of the single particle size analysis, it was calculated that approximately 182 of the reported concentrations were particles of respirable size. The mass median diameter of that fraction was approximately 1 micron. Consequently, the concentration of inhalable particulafces in these atmospheres may be more appropriately expressed as 1.7 and 2.7 mg/L.^Thus, since no mortality occurred, the LC50 oqHBBBHBHHBBHIIBfel^ expressed in terms of respirable particles is greater than 2.7 mg/L. Observations; Observations could not be made during exposures due to the denseness of the dust atmospheres. Rats at both test levels showed a severe weight loss 24 hours post-exposure followed by weight gain. Observations in the first 72 hours included yellow-stained perinea! area, dried red ocular discharge, and brown-stained nose and mouth. Several rats had brown-stained fur throughout the observation period. One rat exposed co 15 mg/L had a cloudy eye beginning on the 10th day post exposure. .SumaarylGroups of 10 aale^rl;CD rats were exposed to dust atmospheres of flH----------------|--------|for single, 4-hour periods. An LC50 could not be determined since no deafens resulted from exposure to concentrations of 9.6 or 15 mg/L, the latter being the highest concentration which could be generated under these experimental conditions. Since approximately 182 of the concentrations reported were particles of respirable size, the LC50 of this material expressed in terms of respirable particles is greater than 2.7 mg/L. - 2 QHipany Sanitized. Does not contain TSCA CB1 Work and Report by: W4 ~T^/\^^~ _ Robert Turner Technician Reviewed by: ^4^ /m^/l.DLL / 'flruce 'A. Airge Research Toxicolo^ist RT:jrg:WP:3.5 ,Date Issued; July 29. l^gl 'Report No. 306-81 Approved by: S&^A^.Y^--^ Gerald L. Kennedy Chief, Acute Investigations Section - 3 - pompany Sanitized. Does noi contain TSCA CBi