Document dn6BxwXbknpn0ZZzYJa4nxDZ6

Chemical Pollution: Polychlorinated 'Tb iphenyls Polychlorinated hmhenvlv [PC&ii arc The major uses of PCBs derive from widely used industrial chemicals that their nonflammability, high dielectric were never intended far release into the constanCand plasti.izing abilities. These environment, but they have nonetheless uses include application* as dielectric been found in rainwater, in human tis fluids in capacitors and transformers, sue, and in many species of birdi sod as hydraulic fluids, and as heat transfer fish. How PCBs car.te to be widely fluids; also PCBs have been widely distributed in the environment and used a* plasticizers and solvents in what biological effects they have are adhesives, sealants, paints, and printing atilt largely unknown. But like DDT, inks. Some 95 percent of the large PCBs apparently degraoo very slowly phase correction capacitors used m under natural conditions. They tend to transmuting electric power, for exam accumulate in the food chain, and once ple, contain PCB*--amounting in I96S ingested, they are stored in the Jtadyjs to almost 27s million gallons in the faltjf tissues. As is Hue with many other United Stales alone*! replacement of "chlorinated hydroesroons, even small PCBs by other dielectric fluids, accord doses of PCBs can be toxic, although ing to Martin Broadhurst of (be Na it is not clear that the amounts found tional Bureau of Standards, would re in fish or birds have had detrimental quire that the capacitors be rebuilt and effects. The only epidemiological infor that they be 50 percent larger. Alter mation about PC3s' effect** on inan nate materials for plasticizer applica comes from an accidcmal poisoning tions of PCBs, ou the other hand, arc incident in Japan in which some 1000 readily available. persons were affected. Industrial use of PCDs has grown Polychlorinated biphenyls are rela steadily since their introduction in tively inert compounds dial have low . 1950. U.S. sales in [970 came to about solubilities in water. The PCBs pro . 34 000 ton*, with cumulative produc duced commercially are mixtutes, in tion over the years amounting to an corporating some _J9 or more of the estimated 4 X 10* ions. (By compari 210 different PCB compounds that are son, US. production of DDT'in recent "theoretically poss-ble from chlorinating years has been about 70,000 tons.} biphenyl. The most common industrial Less, in fact almost nothing," is known mixtures average between 40 and 60 bout the quantities produced world percent chior.nc content, but their iso wide; in addition to the production in meric composition is only pattially the United Stales, PCBs are made in known, thus complicating the problems Europe, Japan, and the. US.S.JU The of sampling and analysis. Gas ehrocna- only U-S. producer of PCBs, the Mon tegrpphic_techniques are now most santo Chemical Corporation, refused commonly used to determine the pres until recently to release production fig ence and (be amount of PCBs in a ures, but the company has taken the sample. The method is not specific for unusual step of refusing to sell any identifying particular PCB compounds more PCBs (or plasticizer applications because of the lack of samples of the and those heat transfer applications in different isomen as reference standards. volving food preparation. Current an There appean to ba soma variability in nual U.S. tales, ai a result, have fallen biological and chemical activities among to about 20,000 tons per year, although the compounds: highly.. chlorinated export* have continued to increase. PCBs seem to persist in the environ How PCBs are released into the en ment* the longest and are less toxic vironment is not known, but several than the more rapidly degraded,jow scientists believe that sewage outfalls chlonne_formt. There is also evidence and industrial disposal into waterways that some commercial PCD mixture*, re major sources. Rivers and streams especially those mar.ufaeiured In Eu may be the primary means of transport rope or,.Japan,- may contain uace amounts of dibenzofurans or other ex tremely toxic'impurities, which may be the cause of some of the toxic effects ascribed to PCBs themselves. * Moft IhuM reference to mr of jht ttotfirt (MfltiAAL j hr* rn be found in the forthtwiuaf niMi umic fit fh' Nnlih /rfj/WJfirj, Kuritt io bt putrhihcd by ihe NariOfidt jnw- luif ot Environment Jl'iUA Scicoce*, Ancortt TnMfk Pork, North CoroUnt. for PCB* within rhe environment, ilihoufh ih< atmosphere aho a^pcir. be a means of dispersal fAdd Saro.im of the Massachusetts Insult,:,.1 y.` T*, inoiogy has estimated that from JOGO to 2000 tons per year escaped into t.ic atmosphere in past years from p| ,vucized materials containing PCD,, anj that about 4000 tons per year entered waterways from dumping and leai.i-c of lubricants, hydraulic f.u.ds, and beat transfer fluids. Other sources may in clude leaching from dumps and land fills, where, Saroffm believes, about half of the PCDs produced eventually end up. Although measurements ot PC3s so air and water ate scant, me general pattern from these measure ments and from more extensive mea surements ot PCD residues in biotr* consistent, according io Saroflm, mn the hypothesis that discharge of PCBs into the environment occurs mainly near industrial areas. A similar pallet.i was found by Ciiman Veuh ot the Ui..versity of Wisconsin in his stud.es o: Lake Michigan nni.>rv!sh also .i.-. tccted PCBs in the sewag; ot all mu nicipalities studied. Once in the environment, PCBs ap pear to persist for a long ume Labora tory studies by O. Hutzing:,* oi the National Research Coun.i; of Canaua in Halifax and others nave indicated that PCBs can be dcchlo,'mated by ultraviolet light and lead to the forma tion of hydroxyl derivatives and uincr polar compounds that are more readily degraded by microorganism*, but the extent to which this occurs under nat ural condition* is not known. In many areas, however, PCB residues in fnh are equivalent to or higher nun DDT and other pesticide residues. Dav'd Stalling of the Bureau ot Sport Fish eries and Wildlife. Columbia, Missouri, found PCB residues as much as 100 umes larger than DDT retinues in :isli from heavily industrialized areas, vvuh roughly equal residues of both sub stances in fish from many oihcr region; The highest PCB re-dues m r a seem to occur in h.chlv po.'.u'cd contai waters---like Tokyo Bay and Long is land Sound--and in some in,.mu water ways---such as the Grcrit Lakes--where coho salmon have been found vvi.h PCB concentrations ia eveevt of 5 pans lAt-UAftY im - iss MONS 207S05 ihe iiiriii at which tint U S ,uu ant) Slug Arii.`.inisiral,on a'.lempis to seize contaminated fish ant) poultry sold in interstate commerce. More ijpical concentrations, m most species of fish in the North Atlantic, range from 0 01 lo 1.0 ppm. Fish taken from undisturbed arctic lakes na\e been found io contain comparable residue*. Itoih surface-feeding fish and those that dwell at greater depths contain rCBi. Even higher conccnt,\,:tons are found m birds Utat feed on Ash, rescu ing 100 to 1000 ppm tn cormorants and ospreys. According lo Robert Risetrough of llte University of California's Hodcga Marina Laboratory, residues arc generally highest its b.rd specimens from ihe North Atlantic or front along the California coast, and generally lower in birds front the South Atlantic and Centiat Pacific Oceans Residues appear to be lowest in wildlife from the Antarctic region. Most U.S. inhabitants apparently hate sonic residues, if only traces, of PCRs in their bodies. Preliminary data from a nationwide monitoring program being coordinated by the Environ mental Protection Agency show lh.it 33 percent of more than 000 samples cf~ human ad-pose tissue contained PCS res-dues of at least I ppr.i. One individual, an old man witjT~nO~i.nown industrial exposure to PCBs, was found by (lie Mich.g.m Department of Health to have ICOjtpm m his fatty tissues. The source of PCB residues in hu man tissue is presumably food. Studies n Sweden have indicated that fish ate the primary source of PCBs_for most Sw*dc*. with average~rh<ake~of PCBs from all sources estimated to be about t micropram per kilogram of body weight per day Individuals who ata large amounts of Ibh consumed about ten times as much PCB*. Babies re ceived the highs st doses per kilogram of body weight, largely front milk- Resi dues of PCBs in food were somewhat smaller than those of DDT and metabo lites of chlorinated pesticides. In the United States, the pattern appears to be the same, with PCBs common in freshwater fish such as coho salmon and Jake trout. Small residues in cereals have been traced to die recycled paper .used jo package mg and ihe nee to the ynkin a brand of carbonless carbon paper, among other lotuses ^ The ink po_ longer contain* PCBs. and efforts arc being made to separate out old stocks of the carbon paper in ihe manufacture of recycled paper, Several batches of poultry and iw egi,s sum nigti TCd residues hate been traced io contaniinuiion of the poultry feed hy leaking heat exchangers, ex cept in one instance where the source of the PCBs remains undetermined Residues are present in dairy milk in some localities. Officials of the Food and Drug Ad ministration characterize PCB* as a "potential but not immediate hcaiih hazard," and claim, on the bans of their monitoring programs, that except ior his eating of fish the American consumer receives no systematic ex posure to PCBs. However, FDA au- tlionty extends only to interstate sales of food, and FDA gu.delmes tend to reflect oi.iy the average consumer, ft seems likely, because of the localized nature of PCB sources and variations in individual diet, that heavy fish eaters and some other individuals experience more substantial exposures. , The only clinical experience with human illness that i* directly trace able to PCB consumption occurred in 1968 in southern Japan. More than 1000 persons who had eaten nee oil contaminated with PCBs that leaked <'CU m,\;arc. wine!) Vos oc.mvcs lo be tf.ociizofursH, The results of x 1-ycar studs funded by Monsanto showed Jncr damage and some difference in weigh; gam m ran and dogs whose feed coniamcd ] 00 ppm of PCBs, bul no teratogenic or mutagenic effects. At x dose rate of 10 ppm, there were apparently iiq ef fects of any kind, except for some im pairment to the hatching of chicken eggs. Reproduction w affected most by low-chlonne PCB mixtures, but long-term damage to the liter seemed to be due to high chlorine mixtures. By contrast, in one of the field occurrences of PCB contamination, the hatehability of eggs at Holly Farms in North Caro lina was noticeably decreased, cvco though the concentration of PCBs in the feed was lets than 'he r.o-effect levels reported in the Monsanto study. Although most birds and mammals appear to be relatively resistant to PCBs, some spee.es, such as mink, seem to be more susceptible. Fish are also more susceptible; Stallings found that blucgtll and catfish died wJicn exposed for several tteexs to concentrations be front a heat exchanger during manu facture developed darkened skins, eye discharge, severe acne, and other symp toms of what came to be called Vusino, oil disease. Patients were found to have consumed an average of 1 grams of tween 20 and 50 parts per billion, that trout died at about 8 ppb, and that lethal doKS for shrimp were as low as 1 ppb. Thc _biolo;icjf actions of PCBs in side the body are also relatively un PCB. with symptoms appearing at a known. PCBs have been shown to alter minimum dose of about 0.5 g. The liver tissue, inhibit the growth of eui> PCB* can readily cross the placental lured cells, and affect a variety of n- barrier, and several infants were born tyme systems; but in most instances with Yusho symptoms, some to ap 'tJse~rncchanisin of action is still uncer parently unaffected mothers. Recovery appears lo be difficult, according to Masanon Kuratsune of Kyushu Uni versity in Fukuoka, Japan, with symp tain. Paul Lichtenstein of the Univer sity of Wisconsin has shown that ?C2s interact with DDT and other chlori nated pesticides; nontoxic amounts of toms still present in many eases 3 yvai* PCBs in insects increased the tovcity later; no methods of treatment arc jaf ` DDT~*nd some organo phosphate known. It is not clear whethcr any of pesticides by as much as 100 percent. the subsequent deaths among Ihe pa Much of the research on PCBs has tients can be attributed lo acute PCB pointed to the similarity of PCBs and poisoning, and u is still not known DDT in tJieir environmental effects. whether the commercial PCB mixture They are both widelv distributed in the involved contained traces of dtbetuo- environment, they both affect the re furaru or other impurities. productive system of birds, and they Although PCBs have been in use for more than 30 years, detailed studies of their toxic properties have only recent ly been undertaken. The studies arc complicated by variability in the tox icity of different commercial tarn plat of PCBs. Experiments in the Netherlands by J. G. Vos of the University of Utrecht showed liver damage and enter the human diet primarily through residues in fish. But PCBs, unlike DDT, were seldom deliberately released into the environment. Their presence and persistence there reemphasize the like lihood that any widely used industrial chemical may become an environmental pollutant, and increase the responsibil ity for public disclosure of production edema in chickens and skin lesions in quantities and use patterns when similar rabbits. The worn effects seemed to be situations occur in the future. caused by an impurity in the European --Allen L. Kxmmond ~~ scirscr \c._ HONS 207006