Document 8qaXZgr62X7qDwLEK1qJ2a2e

jfUU,. I - ~sJ, I U\tf, L^VI'^J ^ *1 WU 1 *--"w u TW I I* Suite 304 AiUflfton, Wjirua 22249 Dwn 1702) 5174430 HicMlcfits of the PCS Health Effects Stu {Executed for NEmft/EEI by DFHJ5, inC. Introduction Mixtures of chemicals known as polychlorinated biphenyls (PCBs) wart msnufsetured cwmercialiy in the united States until 1977 and they are used throughout the world In variety of applications. Over the years, people have been exposed to these chemicals both in the workplace and in the natural environment. Exposures In the workpiece were generally fir more Intensive, tspedally in terns of initiation and skin contact, than the typical low-level or occasional exposure in the natural environment. Much information on possible health effects resulting from PCS exposures has acorrulated in the scientific literature, starting back in the 1970s. This report reviews this Information and uses it ts the baeis fbr an objective assessment of the potential health effects of PCBs on people. Methodology of the Study Two teams of specialists, representing the disciplines of medicine, toxicology, pharmacology, biochemistry and epidemiology, participated in the study. The first team reviewed the PCS health effects literature in detail through 1981, end prepared draft reports on the relationships between PCS exposure and specific health affects in test animals and in exposed people. The second team of scientists from universities independently reviewed the draft materiel. Conclusions and opinions In the final report reflect contributions from both teams, The health effects Information reviewed was of two major types: first, results from large numbers of studies in which laboratory test animals wets exposed to graded dosages of PCBs for variable time periods; second, date on effects detected in occupationally exposed workers as deduced from epidemiological end clinical studies. In the major recent studies, which ere continuing, several thousande of occupationallyexposed workers era being followed. From the entire collection of date on people end test animals, conclusions and opinions as to the possibility of occurrence of specific potential health effects in peoplt from exposures to HCfis have bean drawn. T) results fall into two categories of effects, as follows: omens HUB. HnmDwm Hrr, *. Hn*. two. kaarlM A. C*CM.n, WUB. HfMUtaSA *c*w>cf cwctow Hwry W. fen T4 a. Im MX*., PkO. Cl MOWS 216452 W.D 2 - Health Effects Observed In People and Anlrol Tim health effects, neither of them serious, have been observed 1a workers occupationally exposed to PC* and in experimental animals. They are: 1, ... A skin disorder known ts chloracne. The intensity of this effect is related to degree of exposure md to PC8 chemical structure. Chlorecne diminishes on termination of exposure, end is not e serious health problem. 2. . . . In ihe process of metabolizing PCBs, excess entxjits of proteins (enzymes) known as mixed function oxideses (^Oe) ere produced, chiefly in the liver. TTils condition, even following extended industrial exposures, is not of significance to health over tt* : lifetime of PCS-#xposed person. At most, elevated IFO levels can cause changes in the required dosages of medicine* or other therapeutic agents that are subject to ready oxidation in the body. Similar FO elevations are caused by certain drugs, hydrocarbons, end other substances. Health Effects Observed Only in Test Animals Several health effects have been observed in test animals, but have not been observed in people, even after many years of occupational exposure. These ere: 1. The possibility that exposure to PCBs can lead to cancer ha* been studied in te*t animals end in exposed people. The bulk of the studies on animal a yielded negative results on cancer in ell tissue* _ in all species, with tn exception of some unverified result* on liver cancer in mice end ret*, in studies of occupationally-exposed workers, the test result* werv elso negative with an exception of a single report of excess skin cancer in one group of workers. This report wee not confirmed in other studies. It can be concluded that there ere no demonstrated connection* between PCS exposure and cancer in people, even when occupationally exposed. 2. Adverse effects on reproduction have been observed in experimental animals, generally at very high dosages. These ere: e. Effects of PCfis on the developing embryo or fetus leading to birth defects (terstologlcal effects) have been observed in e limited riurrber of experimental animals. b. Toxic effects on the developing fetus in test snimels can be produced by hip: dosages of PCB. No evidence for such effects in people has been recorded, even for pregnant woman occupationally exposed to PCS*. It is concluded that the probtoillty of such effects occurring in people is very low. HONS 216453 -3- 3. PCBs art *01# to product adverse effects on liver tissues in test animals, reversible at low doiu and Increasingly Irreversible at hitter exposure levels. No adverse effects on liver functions have bean observed in oocupationelly-exposed workers, leading to the conclusion that these chemicals do not cause futatn liver disease under these conditions. a. PCSe erfilblt a low to moderate degree of acuta toxicity In test anixmls. However, there is little evidence in people of any acute toxicity in the course of PCS intake, storage in tissues, metabolism mv* excretion. Further, there is no evidence to Indicate the PCS# produce any adverse effect# on the htman ienune system or blood supply. Other Observation# end Conclusions Mitaoenesis: The possibilities of harmful, heritable changes In genetic materiel of cells end tissues under the action of PC8s have bean studied in biological test systare, experimental animals, and occupationally.exposed workers. All test result# ere negative fbr such changes. The risk of genetic damage in people from PCS exposure is negligible. This conclusion Is consistent with the lack of a demonstrated connection between PCS exposure and cancer. Yusly Disease; Because of the uniqueness of the Yusho episodes In teime of the level of contamination of the PCSe, the dosage patterns and the symptom observed, Yusho cannot be considered node! to reflect the possible effects of PCS exposure in nan. It is Impossible to stlpuleta whether n^ of the health effects observed ere causally related to PCS exposure. Surmarv At huien exposure levels as hljfi as those previously encountered In occupational setting#, PCSe can cause chlorecne end increases in the lavele of one or note liver enzymes, feither effect represents a serious or life-threatening health problem. From peasant evidence, no firm associations can be made between PCS exposure end any other human health afreets, even after long-term occupational exposures. Since the risk to hunan health from even hiept ltvtl occupational exposure* has been shewn by the studies available to be low. It may be concluded that much lower human exposures to PCS# In today's workplace and In the natural environment do not present si(pifleant huran health risks. For tfmFirm, Seymour L. Frless/President fetch 9, 1982 HONS 216454