Document jgarpm3wbvMe575gL7j1okRO9

SUMMARY OF TOXICOLOGICAL STUDIES ON COMMERCIAL PCB'S November 10, 1975 J. C. C&landra The need or additional toxicological data becam e apparent in 1966 when the refin em en t of a n aly tica l techniques m ade p o ssib le the identification of PCBs in the environm ent. To a s s e s s the h azard s of these m a te ria ls , c la s s ic a l feeding studies w ith A ro c lo rs 1242, 1254 and 1260 in ra ts and dogs w ere conducted according to accepted trad itio n al p ro ced u res. In addition, th re e -g e n era tio n , two litte r reproduction studies and teratology studies in albino ra ts and a dominant lethal m utagenic study in m ice were considered to be necessary for this purpose. Effects such as d ecrease in eggshell thickness described in certain avian species suggested that toxicity and reproduction studies in chickens would be helpful in evaluating possible untoward effects in birds. The findings included the following: 1. No evidence of terato g en ic o r m utagenic changes w ere noted with any of the PCBs a t m axim ally tolerated dose levels in ra ts and m ice. 2. In the ra t reproduction study, th e re w ere low m ating indices a t 100 ppm A ro c lo r 1242 and d e c re a se d pup su rv iv a l a t 100 ppm of A ro c lo r 1242 and 1254. 3. Egg production in hens fed 100 ppm A ro c lo r 1242 o r 1254 w as decreased with hatchability reduced severely. Poor hatchability of eggs NEV 006567 707819 J. C, Caiandra fro m hens fed 8 ppm A ro c lo r 1242 w as found. The sp ecific g ra v ity of the eggs obtained from the te st group was not affected; how ever, A roclor 1242 a t 10 and 100 ppm lev els and A ro c lo r 1254 at 100 ppm lev el w ere associated with reduced eggshell thickness. 4. In the dog studies the only findings w e re in dogs fed A ro c lo r 1260 a t 100 ppm and th ese showed in c re a s e d se ru m alk alin e phosphatase activity and liv er weights without concom itant histopathologic changes. 5. In the chronic ra t studies a w eight d ep ressio n was observed at the 24 m onth point in fem ales fed 100 ppm of A ro c lo r 1254. Food consumption, m ortality and hem atologic, urine and blood chem istry studies did not differ among treatm ent and control groups. L iver weight in creases w ere noted in m ales and fem ales fed 100 ppm A ro c lo r 1254 o r A ro c lo r 1260, and in fe m a le s only in the 100 ppm group fed A roclor 1242. As expected, the im portant histopathologic changes w ere present in the liv e rs of the 24 m onth sa c rific e an im als and co n sisted of h epato cellular alterations such as focal hypertrophy, cytoplasm ic lipid changes and in som e an im als a t 100 ppm , hep ato m as o r cholangiohepatom as. No evidence of hepatocellular carcinogenicity of the A roclors was found in this study. NEV 006568 707820