Document J345Z1RKgXg5zYrnDYMKj8GgB

WtrAKtIVIBI'd Ur nankin, uwuwniw.., --------------------public HEALTH SERVICE. NATIONAL TOXICOLOCT PROGRAM P.O. BOX >22.15 RESEARCH TRIANGLE PARK. N.C. 27709 .-.. '.' Biological Effects of ingested Asbestos ` **->:-.A * *_ Introodduuccttiioon * '. I ' . *' t.?m " ... * . . Status. Report- January-22, 1931 ZHiCtlZS )! W a >-.r* * . "# *-*-.* A ` *. A, v - V- ' "* ^ .* V ... .The NIEKS .is conducting a'vseries of studies^on-the-effects of ingested asbestos. `-These studies-are-part of the-NIEHS commitment that is directed "by the recently established. National Toxicology Program. The Environmental Protection Agency has'contributed approximately IDS of the total funding. -A summary of the evolution- of the study is to be found in Appendix A. A .paper,-given at a Workshop on Asbestos,'Gaithersburg, Maryland, July 1977, ..detailing the studies' design'and implementation is attached (Appendix B). .Current Status }tesf Materials --Two samples of chrysotile, and single samples'of amosite .and crocidolite asbestos plus a tremolite material are being tested. A repository of these materials was established and Ha's also served .as a f.'source for other scientific studies on asbestos. Each material has been extensively characterized as to physical and * - ichcmical properties. The fiber size characterization performed by the Illinois Institute of Technology Research "Institute (I1TRI), Chicago, Illinois, has been completed and a final report received. The'chemical and physical property characterization performed by the U. S. Bureau of Mines is also completed. . .. .\v. Hamster Studies Three asbestos materials are being studied at. IIT Research Institute, Chicago, IL. .The lifetime exposure phase of these experiments has '.been completed.. There was. no. indication of major differences in the mortality rate between'the hamsters receiving the asbestos diet or the control diet.7 Histopathologic'examination pf- tissues from female hamsters has'been completed. The contractor has. reported that a preliminary analysis of the hamster data indicates that no carcinogenic orcocarcinogenic effect was observed. A standard independent quality review or the -pathology results has been completed for the female hamster. .A similar * review of the male hamsters is in progress and is expected to be completed .in l-iaVch 1981. Analyses, of the verified"data and preparation of the draft report is in progress! The report is~expected to be completed and suomitted to the KTP Board of Scientific Counselors'^ Technical Report Sub committee for independent public peer review in May 1931. 1* .*.* ***' ... .. CAP CO JEN 0010951 Rat Studies . * ** Tive test materials are being studied in this species at the Hazleton Laboratories, Vienna, Virginia. In addition, a subset of two studies" includes neonatal as well as lifetime oral exposure to asbestos. The lifetime exposure phase of the study has been completed.-Although data has not yet been statistically analyzed, it appears that longevity was pnt affected bv exposure to the various types of fibers, although the . known carcinogen (OMH) did significantly shorten lifespan. The histo pathologic phase of the study is in progress and is projected to be" v completed in October 1981--there are a total of SJ53 rats to be examined. The histopathologic evaluation is to be completed by group and then sub- ..fccted to pathology quality review. .Sequential issuance of final reports by asbestiform type is being considered with the first reports projected. to be available for public peer review in December T98H .. . *V CAPCO JEN 0010952