Document G53q38Gq4rXX6KYz6kgMmx87n

Feature Article ^' Polychlorinated Biphenyls: How Do They Affect Human Health? ;' . Until 1971, polychlorinated biphenyls (PCBs) were different composition from commercial products. Most' ' used commercially in the U.S. in capadtots and trans- are similar, but not Identical to Arodor 1254. formers, carbonless copying paper, paints, andhydraulk .t..t ... v . ; _ fluid. While many countries have since restricted PCB . ^ Studies In laboratory animals^ ... . , . - use, die-compounds arc still found In old traiufdm(as,l^^VJ Tolearnhow PCBsmigfrt affect health, investigators capacitors, and other produm.--;----^ have studied PCB exposure expertrriehtany In animals ' ' PCBs'are a group of 209 stable, fat-soluble chemicals. .. and In humans occupationally or acddentaHy exposed to _ Not easily broken down, they have accumulatedJn fish^-^ :i the compounds. ......... . ; from polluted waterwa'ysiin wildlife, ahd in human*I;., Except forfeeding studies In'hitok, which used PCB- ~organs; fatty tissue; biood; and milk. In the late 1polluted fishi moit animal rnidleshave tested commeri food source of PCBs for Mixtures with much less chlorination, on the other hand, SecaiBe'chcy iefatsoiubierPCBs tend to concert-- yield a much lower cancer tocidence/wlih a tumor *. _trate to fairy tissue, and to a great extent, PCB levels In - incidence similar to' that in unexposed rats. Most tests " different organs depend on theorgans* fat content. Thus, have not demonstrated any ihutagmlc properties for ' to humans, fatty tissues contain the highest PCB concert-.. .PCBs/. __ nations, to fish, the highest levels art found to body fat ' . * Other adverse effect* observed in different animal . * and the hepato-pancreas, not the edible portion. ` : - . v spedm vary"While all mixtures "ahd eongehers* tested - . Arodor is the commercial name for the American .. induce mixed-ftinction oxldases in the liver, the type of - - produa of PCB mixtures. .Different mixtures are further, .. enzymes induced varies. PCB hqmm that ftppear more VI identified by codes, suchas 1242,1016,1254, that designate die percent of chlorination of the mixture. ` toxic and thatare retained longer in the body seem to. ; ` r. induce aryl hydrocarbon h'ydroxyfascTUverchJargemcnr" Because the time necessary for different components of seems to accompany enzyme induction, in some species' PCB mixtures to break down in the environment varies;' *" fed* high dosesof PCBs,*investigator* have observed liver PCB mixtures found to soils, sediments, and biota have a - cell necrosis and fat accumulation in liver cells. : ' Editorial Board aMMts h. aa, OMtlm W Cme mmii UfaHtongyn NllnilCiAe*r|nMu* omWr rS.Maiw.wj. Wwiu me Owmc Owum WittonM . MwBmXMJ.IIiJ. . OfwrWBM l MMIlfMogr VMutnqr : Kna wcoow C*am VkmUMw^WJ. . CmWr far EnaMeawnul Mmiw Cmn wr 0>u Conn* Malt X MnUkM.0. MJUt' Omr PtawnwwwowimWBty scmoi wniMe Hnim UMvtrMrNo>e(>WW . aMt>ICMMwgihMA ' DtfdW . ' ' HMlUm* .. OtiMWMAonMMrtwr . RokMt W U*. DV.U. DipTWn* H ftMtegf McMenSMMIMutniqr ' ' WWaitf llnKIU>.lUH PpmimtSpiAntiMPwr ChwiUtW *r wWgt* l MttaMKS SeftgtfIMsMt*M . IUIamSh mJ IsImwtusmwIii i tofNWSMBW.OL.DtM O* - . ewmwe PMnMi mcmh "vWW*MW.U0. MMW * SOtiV MMMM MiwM<bmnmMwaoCcpwMOjinoWt MMMM BBRN003110 Art** & Uptm, M.D. MM* l Emtanmmtt MMcm Nwt UwfayiAy ll,sm c--> iuMtaiaaM OMmoiWllMemrjir ONE E X H IB IT 0 I Fxm nMnNinn^n-n Rhesus monkeys exposed'to technical Even workers with exposures two orders byRceateD. ' ' Kltabrough, MJ>. VJ. Znvlroniaental Protection Agency, Office of Regional Optra** tloos, Director, - Health A Risk Capabilities transformed into pancreatic cells. This effect. persistenfskih disease that primarily affects i- '"; on cell differentiation, apparently modified by hair follicles. VHieihcr the chloracne resulted .... V. the epithelial growth factor, is more pm-.'. . front PCS exposure or from exposure to - nounced in rats exposed to Arocior 125-L Because the mixtures tested may have been . .chlorinated dibenxoforans, a known musepf cMoracnc and a possible .coniaminaitiTOf the' ' contaminated with chlorinated dlbcnapfufi^,. PCBs,'Is' unclear. There is reason to tielleye ^' such conauttinatlon may have contributed.to ^ -* 'that chloracne and other health effects pop'u-7. the toxic effects and be partly-responsible for; lariy associated with PCBs are really.caused by' ;.v the variation in effects seen betwecnjnberar.es `chlorinated dibenzofurans. ......... _ and between animal speefcs. v. ` ' In 1968 In Japan and In l978:79,.in ' n: " In experimental animals, some mixtures v 1 ' Taiwan, two poisoning outbreaks took place s V -> _ - affect reproduction more than others, but all in people who accidentally ate rice oil con- Chlorinated dtbenzofurani ' may be responsi ble tbr the health effects attributed to PCBs. I TWO . have been demonstrated in people:wwho carry . "Ugatldriteabllshed chlorinated dibenioftiraris]'-'* r~ -rrrdr-Ji" a$'dwi(^^(^po^diiu.^-r,''r^ v^-~: ''Qntrcasdn for thh'condusion frihatU.S.*7/' .workersexposedto'much'higjwrPCBdoseS nh...-- . dunpdtlenawidiVlaiidaiMyhHCheii^'diS'1 ' * t* ***^'af; I* . *p !'.'* 'f.U >, % * ease .do not show the same health effects.;- -- r Some workers complained ofbunting pyes,?' ' - nose, and tKroat. SomestudJc* reported - ". . ]d>normailiver lhnctlon'tests.Onettudy, in a ..*" apa'dtdr plant,vnoted ^6rinal lung ftinetion ' -. ; tests among the workdri. However, these . 'workers had also had other exposures that '. could have resulted in abnormal lung-function'; ; . _ gyg- ' Attempts to conclusively demonstrate :,::v ' health effects ip populations that eat' fl'sh from -: -* body burdens of PCBs from environmental polluted waterways have generally felled.* - : exposure to trace amounts of PCBs. Such _ "Occasional reports have noted behavioral '<_ exposure ismuch less than that received by changes and shorter pregnancies with higher.; workers who made transformers dr capacitors fish consumption or higher intake of PC8*>\ from the 1?4Os through the 1970s. ' However, because these studies couldn't rule EBRN003111 -> 1 Fxm nynMnmm/i ^ out other causes, the.significance of their / - finding b'undear.* ' ` r \Vv.l.'/a^enr.beeuplonal studies hare pre- ' - rented no conclusive scientific evidence that and whole serum PCB levels increase with age. They are usually higher in males than in females, which corresponds with population survey findings that females usually have have caused cancer In humans.* While lower cholesterol levels than males In the I..;"',; one study found s positive association same age group. Finally, the prevalence of - -r.'-beiweenPC$ blood levels and high Wood elevated blood pressure also increases with '/I'.; V pressure,* the association appears spurious. age. In essence, all the associations go in --`The levels .of fCBs in serum are primarily a tandem and appear to be spurious. ftinction of the amount of fat present in Thus, despite positive laboratory animal J'-.serum. Serum PCB levels arej for instance,- data and except for chloracne, exposure to .-V- - positively tprreiaredwhh blood cholesterol- - PCBs has led to no convincing, dlnJcally .*. " - levels.** The associations disappear when PCB demonstrable, chronic health effects In * r.r levels art expressed as a function of fat in humans. " l f Senifn rather than as whole serum. In popula``dons on Western diets, both serum fat levels `Mcffiben ofdie nine chemical hmltr. ecb member <Slfen la iht auiiihff or lonitoe oTiubtUniwm. Mqlaat, AM. ter. Pharmocot. Tokiral. 21.t7`lll, /0f7( 4. Jmevtmm K at. DK. prrtot so.srj.5js. !9Ht *#W M At, J. Pedlur. I02.-J/5-JM JCMtfrfal.J. Am. Mtd iwe. . 2*fJf0f-2f09, !9ttj 7. UactO* H at, (mri- imlMkhn*. S0.-/AS./M nb Commentary r Harnessing Natural Processes To Degrade PCBs. by Michael A. Kamrin, Ph.D., ' Protestor, Center , tor Eavt/vamcn- : taj Toxicology,-'. Michigan State University " . "."Al nutiieruu* analytes uf alt, . water, sediments, wildlife,-and other * " .-..environmental samples have shown, -- FCBs are extremely persistent com ' pounds found in ah parts of the . * environment. '.. - . .. . -In ambient air and water, PCB - levels are quite low. Even if one - assumes a lifetime exposure to the highest measured levels all day every day,'air and water offer a low risk Of human exposure. Fish, however, appear to be a more significant source " _ of PCBs.' Why? First, PCBs bloaccu- . ` mulate and biomagnify in the aquatic ' i food chain. FUnher, as many people become more health conscious, they ' tend to eat more fish. For people who subsist almost entirely on fish they catch themselves, high environmental FCBs in fish are the sediments in levels plus high consumption can lead contaminated rivers, lakes, streams, : 'to*significant exposure. - - ' andestuariea. About one-third of aD -^Because fish are such an impor PCBs in the global environment are tant source of FCBs, government contained in fresh and saltwater agencies have taken steps to minimize sediments.- " this exposure. On the federal level, Most remaining environmental the Food and Drug Administration has PCBs seem to be stored in open set maximum tolerance levels for waters around the world, largely as a ' PCBs In fish sold in interstate com result of ltmotphrrlr transport and merce. To address intrastate consump deposition. Despite worldwide disper tion, some states publish fish ' sal, however, studies of oceanic Ufe advisories that recommend limited or ` suggest that PCBs'are not evenly dis no consumption of fish from bodies tributed: the highest levels are In the of water significantly contaminated northern hemisphere, especially at lat with PCBs and other chemicals of itudes that encompass the industrial concern. A number of states border* nations. ing Lake Michigan have collaborated In addition to the large quantity on a common advisory for lake Mich of PCBs in the environment, an igan fish. approximately equal amount is still in use, mainly in dielectric fluids in PCB reservoirs sealed electrical equipment. The most Limiting exposure by regulation Important step for limiting future - or recommendation does not address exposure entails exercising great care the fundamental reservoirs of expo* In disposing of all PCB-containing sure--where PCBs are stored in the materials still in service, in most. environment. Available data dearly cases, users of electrical equipment indicate that die main sources of are taking care; continued vigilance GBRN003112 LEXOLDMON003015