Document 1Qz5no6pNR8b6dMXbDd1GZq9q

/ TQWlO Chemical Pollution: Polychlorinated Biphenyls Polychlorinated biphenyls (PCBO arc The major uses of PCBs derive from for PCBs within the environment, al widely used industrial chemicals that were never Intended for, rctease Into the environment, but they have nonetheless been found in rainwater, In human tis their nonflammability, high dielectric constant, and plasticizing abilities These uses Include applications as dielectric fluids In capacitors and transformers, though Ihe atmosphere also appears to be a means of dispersal Adel Saroflm of the Massachusetts Institute Of lechnology has estimated thal from 1000 sue, and In many species of birds and as hydraulic fluids, and as heal transfer to 2000 tons per year escaped tnto the fish. How PCBs caiyse to be widely fluids; also PCBs have been widely atmosphere in past years from pluiidistributed In the environment and used as plasticizers and solvents in cited materials containing PCBs, and what biological effects they have are adhesives, sealants, paints, and printing thal about 4000 tons per year entered still largely unknown. |)ul like DDT, inks. Some 95 percent of the targe waterways from dumping and leakage PCBs apparently degrade very slowly phase correction capacitors used in of lubricants, hydraulic fluids, and heat under natural condition^. They tend to transmitting electric power, for exam transfer fluids. Other sources may In accumulate in the food chain, and once ple, contain PCBs--amounting in 1968 clude teaching from dumps and land ingested, they are sloped In the body's to almost 2.5 million gallons in the fills, where, Saroflm believes, aboul fatty tissues. As Is tru$ with many other United States atone'; replacement of half of the PCBs produced eventually chlorinated hydrocarbons, even small PCBs by other dielectric fluids, accord end up. Although measurements of j dotes of PCBt can be 'ionic, although ing to Marlin Broadhursl of the Na PCBs In air and water are scant, the ' it is not clear that the amounts found tional Bureau of Standards, would re general pattern from these measure In fish or birds have had ddnmenlai quire that the capacitors be rebuilt and ments and from more extensive mea effects. The only epidpiJnologieal Infor that they be 50 percent larger. Alter surements of PCB residues m biotas is mation aboul PCBs' effects on man nate materials for plasticizer applica consistent, according to Saroflm,-with comes from an accidental poisoning tions of PCBs, on the other hand, are the hypothesis that discharge of PCBs Incident In Japan In which some 1000 readily available. into the environment occurs mainly persons were affeclei). Industrial use of PCBs has grown near industrial areas. A similar padern Pol) chlorinated biphenyls are rela steadily since their intrc&uciion In was found by Oilman Veiih of the Uni tively inert compounds'that have low 1950 U S. tales in 1970 came to aboul versity of Wisconsin in his studies of solubilitici In water. The PCBs pro- 54,000 tons, with cumulative produc Lake Michigan watersheds; he also de doced commercial!) are mixtures. In- tion over the years amounting to an tected PCBs in the sewage of all mu corporating some SO op more of the estimated 4x10- tons. (By compari nicipalities studied. 210 different PCB compounds that are son, U.S. production or DDT In recent Once in the environment, PCBs ap theoretically possible frdm chlorinating years has been about 70,000 tons) pear to persist for a long time Labora b!phcn>], The most cpmmon Industrial Less, In fact almost nothing, is known tory studies by 0, Hutzinger of the mixtures average between 40 and 60 about the quantities produced world National Research Council of Canada t percent chlorine cont(ni, but their Iso wide; lit addition to the production in in Halifax and others have indicated meric compoiilion is only partially the United Slates, PCBs are made in hit PCBs can be dechlorinaled by known, thus complicating the problems Europe, Japan, and the U.S.S.R. The ultraviolet light end lead to the forma or sampling and analysis. Cas chroma only U.S. producer of PCBs, the Mon tion of hydrAtyl derivatives and other tographic techniques are now' most santo Chemical Corporation, refused poiarcompounds that are more readily commonly used to deicjminc the pres until recently to release production fig- degraded by microorganisms, but the ence and Ihe amount {of PCBs in I lire*, 'but 'the company hat taken the extent to which this occurs under nat sample. The method is hot specific for unusuet step of refusing to sell any ural conditions is not known In many Identifying particular PfB compounds more PCBa for plasticizer application areas, however, PCB residues in fish because of the lack of samples of she and those heat transfer application! In are equivalent to or higher than DDT different Isomera as reference standards. volving Tobd preparation. Current an and Other pesticide residues. David There appears to be spine variability In nual U^S. sales, as a result, have fallen Stalling of the Bureau of Sport Fish biological and chemical activities among to about 20,000 tons per year, although eries and Wildlife, Columbia, Missouri, the compounds, highly chlorinated exports have continued to Increase. found PCB residues as much as 100 ' PCBs seem to persist in the environ How PCBs are released into the en limes larger than DDT residues in fish ment the longest and ire less toxic vironment it not known, but several from heavily industrialized areas, with than the more rapidly' degraded low aclenliits believe that sewage outfalls roughly equal residues of both sub chlorine forms There I) also evidence and indutiria! disposal into waterways stances In fish from many other regions that some commercial g*CB mixtures, arc major sources. Rivers and Stream* The highest PCB residues in fish especially those manufactured In Eu may be the primary means of transport seem lo occur In highly polluted coastal rope or Japan, may contain irao* waters--like Tokyo Bay and Long is , amounts iOf diticniofurajts or other ex M<*< t*ffttrtct to *uny of lit ifudlci mrntlMrJ tor* cm to found 1ft ito land Sound--and in some inland water tremely toxic Impurities, which may be feJHl' l*aut Of fmjNrr/iri, ways--such as the Creat'Ljkes-- where the came of some of tjie toxic effects * Jrwrnit to to ^bftutoJ by to NiUotul [toti* *1 HrftKh ScJ(nct itKJ'Ck coho salmon have been found with ascribed to PCBs Ihefnsdvea. TriMjl* Ptrt, Konb CirotJfl* PCB concentrations in excess of 5 parts 1 fu ianuasv mi 41-11/ SC*EKE wm. m HONS 205060 s'" r f per million, (he limit it ' Ji the U.S rood and DrUg Administration attempts to seize cohi^minatcd fish and poultry (old In Jtyt^nlate commerce More typical concentrations, in most species of fish in tlje North Atlantic, range from 0.01 to 1,0 ppm. f-ith taken from undisturbed Arctic lakes have been found to contain comparable residues, Both surfare-feedin| flsh and those that dwelt al greater depths Contain PCBs. Even (i.gher concentrations are found in birds (hat Teed on fish, reach ing 300 to 1000 ppm in cormorants and ospreys, According to Robert Risebrough of tf|c University Of California's Bodega Marine Laboratory, residues re generally highest m bird specimens from the North Atlnntic or from along (he California coast, and generally lower in birds from the South Atlantic and Cenlral Pacific Oceans, Residues appear to be lowest In wildlife from the Antarctic region. Most U.J, inhabitants apparently have tome Residues, if only 1 races, of PCBs In thejr [bodies, Preliminary data from a nations! idc monitoring program being coordinated by the Environ mental Protfcjion Agency show th.it 33 percent qf more than 600 samples of human |adipose tissue contained PCB residue^ of at least t ppm. One Individual. a(t old man with no known industrial expojutv to PCBs. was found by the Michigan Department of Health to have 100 ppm in his fatty tissues. The source of PCB residues in hu man tissue is presumably food. Studies in Sweden hqvi indicated that fish are the primary ynpree of PCBs for .most, Swedes, with average intake of PCBs from all source^ estimated to he about I microgrant her kilogram of body weight per (jay. Individuals who ate large amounts if Ash consumed about ten times as much PCBs, Babies re ceived the highsst doses per kilogram of body w eight, (largely from milk. Resi dues of PCBs In food were somewhat smaller than tjtosa of DDT and metabo lites of chlorinated pesticides. , In the United Stales, the pattern appears to bq jthc same, with PCBs common In [freshwater fish such as ^oho salmon and lake (rout. Small residues in equals have' been traced (o the recycled paper used In packag. Inf and theneb to the ink ip a brand,of carbonless carbon paper, among other outers The ink no longer contains, PCBs, and eftons are being made to separate out <|la stocks of the carbon paper in the manufacture of recycled paper. Several patches of pouftry arid eggs wuh high PCB residues h. been PCB mixture, which Vos believes to be traced to contamination of the poullry dibenzofurau. feed by leaking heat exchangers, ex Jliejesuits of a 3-year study funded cept In one instance where the source bj^Monsaruojih.owed liver damage and of the PCBs rcinaios undetermined. ` tome dtHercnce in weight grin in rats Residues are present in dairy milk in some localities Officials of the Food and Drug Ad and dogs whose feed contained 100 ppm of PCBs, but no teratogenic or mutagenic effects. At a dose rate of ministration characterize PCBs as a 10 ppm, there were apparently no ef "potential but not immediate health fects of any kind, except for some im hazard," and claim, on the basis of pairment to the hatching of ehieken thetr monitoring programs, that except eggs, Reproduction was affected most for his eating of fish the American by low-chlorine PCB nu*lur*s, but consumer receives no systematic ex long term damage to the fiver teemed posure to PCBs, However, FDA au to be due to high chlorine mixtures By thority extends only to interstate sales contrast, In one of the field occurrences of food, and FDA guidelines tend to Of PCB contamination, ihe hnchabiliiy reflect Only the average consumer. It of eggs al Holly Farms in North Caro seems likely, because of the localized tin* was noticeably ciurcascd, even nature of PCB sources and variations though the concentration of PCBs in in individual diet, that heavy fish eaters the feed was less than the no-eflect and some other individuals experience levels reported In the Monsanto study. more substantial exposures. Although most birds and mammals The only clinical experience with human illness that is directly trace able to PCB consumption occurred in 1968 In southern Japan. More than 1000 persons who had eaten rice.oil contaminated with PCBs thal leaked from a heat exchanger during manu appear (o be relatively rcsislaot to PCBs, some species, such as mink, seem to be more susceptible Fish are also more susceptible; Stallings found that bluegdl and catfish died when exposed for several weeks to concentrations be tween 20 and 30 parts per billion, that facture developed darkened skins, eye discharge, severe acne, and other symp toms of what came 10 be called Yusho, oil disease Patients were found to have consumed an average of 2 grams of PCB. with symptoms appearing at a minimum dose of about 0.3 g. The PCBs can readily cross the placental barrier, and several infants were born with Yusho symptoms, some to ap (rout died at about 8 ppb, and that lethal doses for shrimp were at low as I ppb. The biological actions of PCBs in side the body are also relatively un known. PCBs have been shown to alter liver tissue, inhibit the growth of cul tured celts, and aflect a variety of en zyme systems; but in most instances the mechanism of action Is stilt uncer parently unaffected mothers. Recovery tain Paul Lichtenstein of the Univer appears to be difficult, according to sity of Wisconsin has shown that PCBs Miqanori Kuralsune of Kyushu Uni versity In Fukuoka, Japan, with symp toms still present in many cases 3 years Interact with DDT and other chlori nated pesticides; nontoxic amounts of PCBs In Insects increased ihe toxicity later: no methods of treatment are of DDT and some organo phosphate known. It U not clear whether any of pesticides by as much as 100 percent. the subsequent deaths among the pa Much of the research on PCBs has tients can be attributed to acute PCB pointed to the similarity of PCBs and poisoning, and it Is still not known DDT In their environmental effects whether the commercial PCB mixture They ire both widely distributed in the involved contained traces of dibctuo- environment, they both affect the re furans or other Impurities. productive system of buds, end they Although PCBs have been in use for enter the human diet primarily through more than 30 years, detailed studies of residues in fish. But PCBs. unlike DDT, their toxic properties have only recent w-ere seldom deliberately released into ly been undertaken. The studies are the environment. Their presence and complicated by variability In the tox persistence there reemphasize Ihe like icity of different commercial samples of lihood that any widely used industrial PCBi. Experiments in the Netherlands chemical may become an environmental by J. G. Vos of the University of pollutant, and increase the responsibil Utrecht showed liver damage and ity for public disclosure of produenon redema in chickens and skin festons in quantities and use patterns when similar rabbits. The worst cITects teemed to be situations occur in the future. Caused by art impurity in the European --Allen I Hxmmond ' SCIENCF. vot ns HON 5 205061