Document 2JODOeDEJGY3BaDzGNZM3ynBg

Polychlorinated Biphenyls Another Long-Life Widespread Chemical in the Environment David B. Peakall and Jeffrey L. Lincer The recent finding that pelagic birds dying on the coasts of Great Britian had polychlorinated biphenyls (PCBs) in their livers in concentrations of several hun dred parts per million (Bourne and Mead, 1969) shows that these compounds are present in the ecosystem in large amounts. Thus, it seems worthwhile to summarize and evaluate our current knowledge of these compounds. Structural and Physical Properties The picture is complicated by the fact that we are not dealing with a single com pound. The basic structure of PCBs is shown in Figure I. Any of the positions marked with an x can be substituted by chlorine. Widmark (1968) has calculated that of the 210 possible combinations 102 are probable. His criteria for these lim itations are those compounds containing five to eight chlorine atoms per molecule and the number of chlorine atoms per ring differing by not more than one. The commercially available Aroclors (Monsanto Company Trademark) are des ignated by numbers (Monsanto Technical Bulletins). The first two digits represent the molecular type: 12 - chlorinated bi phenyls; 25 and 44 blends of chlorinated biphenyls and chlorinated terphenyls (75% biphenyl and 60% biphenyl, re spectively); 54 - chlorinated terphenyls. The last two digits give the weight per cent of chlorine. Thus, Aroclor 1242 is a chlorinated biphenyi containing 42% chlo rine. The biphenyls commercially avail able from Monsanto range from 21% to 68% chlorine. Mass speclrographic studies of Aroclor 1260 (Koeman et al., 1969a) show the presence of 11 isomers; five con taining six chlorine atoms, five containing seven chlorine atoms, and one containing eight. Bagley et al. (1970), studying Aro clor 1254, found 18 compounds: one con taining three chlorine atoms, four contain ing four chlorines, four containing five chlorines, five containing six chlorines, and four containing seven chlorines. Thus, The mhon trt currently (t Ihc Unpndr Lafcoratetjr, CotmII lihtct, N.Y. the number of compounds present is. for- - Swann Company in 1930. In that year the tunately, much smaller than is theoretical physical characteristics and commerical ly possible. possibilities of these materials was de PCBs are chemically inert, are not hy scribed by Penning (1930). PCBs are now drolyzed by water, and resist alkalies, manufactured by Monsanto in the United acids, and corrosive chemicals. They have States (Trade name Aroclor), Prodel6e in low volatility, their boiling points ranging France (Phcnochlor), and Bayer in Ger from 278 C for Aroclor 1221 to 415 C for many (Colphen). Other manufacturers Aroclor 1268 (Penning, 1930). All are are located in Japan and the Soviet Union. stable to prolonged heating at 150 C, and No figures of the amount of these mate the lower Aroclors can be distilled at rials produced annually are available, but atmospheric pressure without appreciable to judge from the uses listed in Table I decomposition. PCBs are described as in they may be very large. The uses listed in soluble in water and very soluble in hydro the table are only suggested applications carbon solvents, although no exact figures taken from Technical Bulletin 306 of the appear to be available. Nothing is known Monsanto Chemical Company, and again about the biological decomposition of there is no information on the extent to PCBs, but it is likely that they are more which these recommendations are acted stable than DDT and its metabolites since upon by the manufacturers of plastics they lack the ethane component between and resins. the aromatic rings, which is the site of The use of highly chlorinated Aroclors action of most of the transformations or for extending the kill-life of formulations DDT. Thus, PCBs have the necessary containing chlordane, aldrin, and dieldrin physical and chemical characteristics for are mentioned under miscellaneous appli persistence and accumulation up the food cations of Aroclors. This possibility has chain. been considered in a number of papers. Sullivan and Hornstcin (1953), Mornstein and Sullivan (1953), and Tsao et al. (1953) Use of PCBs found that the chlorinated terphenyl Aro clor 5460 increased the residual persis Polychlorinated biphenyls were first de tence of lindane. Tsao el al. (1953) consid scribed in the literature in 1881 (Schmidt ered that there was some indication that and Shultz, 1881), and the successful com chlorinated polypheny! may have a syner mercial production was achieved by the gistic effect with lindane. Duda (1957) PC8 X XX X oo* K VX X x Posaea pouts k* SUBSTITUTION OF GK4RJNE M. co I CI-C-CI DOT I Cl QSV, 030986 O Rt COMBINATION "0-0 -iO* o-c-ci TREE RADOLS re) cxatvonootPutnyv Hg. I. Basic structure of PCBs(A) snd possible reactions of PCBs IB). 958 *'1 BioScience Vol. 20 No 17 STLCOPCB4014948 r sprayed elm saplings with a lindane Arc elor 5460 mixture (1:4) and then tested the residual effeel on the leaves to infes tation with elm leaf beetle (Gatcmcclla xanthomelaena). He found that leaves treated with lindane plus Aroclor were protected longer and that the insecticidal effeet was more rapid than with lindane alone. Peaks corresponding to Aroclor 5460 have not been delected in the envi ronment. However, under conditions of temperature and flow-rate commonly used for gas chromatographic analysis these compounds would not be detected (Reyn olds, 1970). Nearly 25 years ago it was noted that, Aroclor 1242 was one of 175 compounds out of 6000 tested that was effective against mosquito (Aegyps) larvae (Deonier el al,, 1946). Lichtenstein ct al. (1969) tested the effect of adding a variety of biphenyls and tcrphenyls to DDT and dieldrin with respect to their toxicity to house and fruit flies. It w'us found that PCBs had very low toxicity to house flics when given alone but PCBs increased the toxicity of dicldrin and DDT, especially the latter. The effectiveness of these com pounds decreased us the chlorinated level increased. For example, Aroclor 12^4-in creased the mortality of fruit flies from 59% to 93%, whereas Aroclor 1268 in creased it to only 77%, Analytical Methods I) Identification. Since various com pounds with electron-capturing properties have been tentatively identified in atmo spheric samples in the past (Abbott et al., 1966). and some pesticides are capable of hybridizing in the soil to form a new com pound (Bartha, 1969), it is important that the presence of PCBs in field samples be proven beyond doubt. Identification by means of a combination of high resolution gas chromatography and mass spectrom etry has been carried out by three inde pendent laboratories in Sweden (Widmark. 1967), Holland (Koeman et al., 1969a), and the United Slates (Bagley ct al., 1970). Widmark's report states that all peaks were identified by mass spectrom etry (although no data were given), but Koeman and co-workers gave full experi mental details, and Bagley et al. (1970) demonstrated that most chemicals in the eagle samples examined were components of Aroclor 1254. Thus, despite a recent statement by the Monsanto Chemical Company (in Risebrough, 1970) that the case for labeling the peaks in question us PCBs was not proven, there is enough evidence to convince an unbuised scienti fic jury. September I, 1970 -) Separation. The chemical techniques preliminary to quantitation of residues in samples containing both PCBs and chlo rinated hydrocarbon pesticides fall into two groups those necessitating the de struction or alteration of one or more of the compounds, and those which do not. Included in the first group is nitration. Treatment with a 1:1 mixture of sulfuric acid nitric acid at 0 C for 5 min destroys or alters aldrin, p,p'-DDE, p,p'-DDD (TDE), p,p'-DDT, and dicldrin such that they can no longer be detected at the original position on the chromatogram. This procedure leaves unaffected PCB, lindane, and BHC (Jensen and Widmark, 1967). A more rigorous nitration with a 1:1 mixture of sulfuric acid-fuming nitric acid for 15 min at room temperature re moves, in addition to DDT and its related products, aldrin, hcptachlor, Kelthane, Perthane, Tedion, Telodrin, and Trithion while lindane, hcptachlor epoxide, loxaphene, and Strobane are not removed (Erro cl al,, 1967). Risebrough el al. (1969) reported that this nitration also removed the chromatographic peaks of PCBs. Rey nolds (1969) reported that his attempts to nitrate samples were not fully successful in that there appeared to be loss of some of the more volatile PCBs while peaks with longer retention times appeared. Armour and Burke (1969) reported that complex chromatograms resulted after nitration which could nbt be related to the unreacted DDT-PCB mixture, and nitra tion'was not pursued as a practical means of separating DDT and PCB for further tests. Saponification with alcoholic NuOII or KOH will dchyrodrochlorinate Perthane, Toxaphenc. DDD, and DDT to their re spective olefins (Archer and Crosby. 1966: Klein and Watts, 1964). Risebrough ct al. (1969) reported that PCB peaks arc not removed or displaced but gave no data. The second, and in some instances more desirable, group of analytical tech niques allows the special separation of many chlorinated hydrocarbon pesticides from PCBs. Reynolds (1969, 1970) re ported on an activated Florisil column technique which separated heptachlor, aldrin, DDE, and PCB with the first elu tion (60 ml n-hexane) from lindane; hcp tachlor epoxide, DDD, and DDT with the second elution (40 ml 50% ethyl ether in hexane). Armour and Burke (1970) devel oped a method utilizing a silicic ucidCelite column eluting aldrin and PCB with the first fraction (250 ml petroleum ether), and lindane, heptachlor, hcpiuchlor epoxide, dicldrin, endrin. p.p'DDE, o.p'-DDT, p,p'-DDT, and p.p'DDD with the second fraction (200 ml acelunilrile hexane methylene chloride 1:19:80). Koeman et al. ()969a). using an activated Florisil column, eluted the upolar compounds including DDE and PCB with hexane, and then dieldrin and endrin with 10% diethyl ether in hexane. Mulhern (1968) reported on a method which utilized silica gel-coated thin-layer plates^ Tabu t Mrtorid wttci ILacM to M.tolxl HWii Mitradbto* tommt MpM MM Ittoftot thft MMM t*V AdyaiM tad* Edydr--a ti|iitto touAi u Mi-- Cm* Mtet VmM Vtoi rto \ bMto 1211, 11M i im ir ru fctthr III! |ft| And* mi. mi 1142 (IIV And* I1M (41%) Ami* till A UU tmi Ami* tm ntitti fcKtu IlM Hi m) W mt I2%1 Amtor 1 tU IMAX) Jto*to> IIM (BV A*d U44 KIN) Ami* VtM 11IX) And* UU (MTU Ami* IW ins d tm And* 1141 ItV iw IttMiir ptoitow* to IU* ninMw tod tMated ravftoac* C+dtftdrto to dwa toWtoat* Ito'iH ftod ft*-to tod hntotwitoa dtodto. lacmM ttoaiui mi Hdttwa mum mi MMmi toAdi (Hath* tod acaaaaacd b* r*tto4**t hviMMf itrtoqrk a< (Aa> fton Mdaid Atotom (totoit .matt Mm rtttoAma mi m*mm totfctod wadaM| MM*n tofim Maacd Adatom Im nwiAtoM NMtoaa **** ftottoiw to p*M Mwaira>m 11 ! IAUm Mtf II Ml*-- DSW 030987 959 STLCOPCB4014949 I and a he.xanc/cthyl cllicr (98.2) solvent system. The plates were developed, sprayed with a silver nitrate solution, and fact many of the original samples con epoxide generally represented a majority tained little or no p.p'DDT. it was pos . of the apparent values. Before and after sible to estimate relative PCB values. values for p.p'-DDE and dicldrin were 1 exposed to UV light. The plates were then Anderson and his co-workers also saponi not significantly different. Obviously, the divided into live horizontal sections. Di- fied samples to remove interfering p.p' magnitude of error may vary depending cldrin, endrin, "V-BIIC, heptachlor DDT and p,p'-TDE and then quantitated on the trophic level sampled and certainly epoxide. p.p'-DDD. p.p'-DDT, o.p'- PCBs as Aroclor 1254 by relating sample with the area from which a sample is col DDT. and p.p'-DDE (in that order) were peaks 9 and 10 to the corresponding peaks lected (Risebrough et al., 1968, Jensen et found in the first four fractions, while of an Aroclor 1254 standard. Reynolds al., 1969). Since the publishing of ade most of the interfering compounds found (1970) employed a method similar to quate separation techniques, there is no in wildlife samples were found in the fifth zone. Bagley et a!. (1970) used this meth od but mentioned that zones three and Koeman et al. (1969a) but based his quan reason why there should be any error in titation on an average of two or more pesticide quantitation contributed by peaks. In addition, his results were re -PCBs. four contained practically all unknown ported as Aroclor 1254 or 1260 depending components as well as p,p'-DDT (zone on the overall pattern of the chroma Toxicology three) and p,p'-DDE (zone four). Armour tographic peak profile. It is clear that we and Burke (1969) used precoated (alu are still relatively unsophisticated in our Despite some recent studies, the toxi minum oxide) sheets and n-heptane and PCB quantitation methodology and will cology of PCBs remains rather poorly 2% acetone/n-heptane for solvent sys continue to estimate only relative amounts known as compared to that of the chlo tems. PCBs (Aroclors 1254 and 1260) and of PCBs in field samples until we synthe rinated hydrocarbon pesticides. For ex DDE were not separated, but p,p'-DDT size the individual PCB components com ample, no definite work has been done to and p.p'-DDD were completely sep monly found in the ecosystem and are establish LD50 values for the various arated from PCB by both solvent systems. ' able to speak in terms of these individual formulations of PCBs. Another possible means of separating in peaks as we do for most pesticide residues. 1) Acute, single dose experiments. terfering substances is to use a series of However, it has been kindly pointed out Tucker and Crabtree (1970) found that a differing polarity columns in the gas chro (Risebrough, pers. comm.) that, with ref single dose of 100 mg/kg Aroclor 1254 matograph at the time of determination. erence to biological significance, the cor (stomach tubed in oil) was fatal to two out This is less time consuming and may be rect order of magnitude and accurate rela of three rats, while 500 mg/kg was not useful when operating conditions can be tive amounts of PCB give the essential fatal to three rats. Aroclor 1268 killed one selected such that PCB peaks are absent information. This is because biological rat out oT three at 500 mg/kg, 1000 mg/ in the region where sought pesticides effects, such as enzyme induction, are re kg, 2000 mg/kg, and 4000 mg/kg. Smyth emerge (Simmons and Tatton, 1967). lated to degree of chlorination, and the (1931) found that a 4 g/kg (degree of chlo 3) Quantitation. Kocman et al. (1969a) existing methods give some indication of rination not slated) was nontoxic to guinea semiquantitalively measured the residues this activity. Therefore, that information pigs and rabbits, but this appears to be in Japanese quail fed phenochlor DP6 by would be lost if stress were placed only due to the fact that material which was using one of the peaks in a phenochlor upon quantitating individual peaks. given as a paste passed through the intes DP6 mixture as a standard. Risebrough 4) Magnitude o] Error. Ever since PCB tine unabsorbed. Tucker and Crabtree (1969) quantitated relative levels of PCBs peaks were recognized for what they are, (1970) found that Aroclor 1242, 1254, by assuming that each PCB compound residue chemists and other researchers 1260, and 1268 al a dose of 2000 mg/kg produced the same peak height with the interested in pesticide residues have was not fatal to mallard ducks (four electron capture detector as the same asked what magnitude of error is likely to groups of three birds each). amount by weight of p,p'-DDE. After result from ignoring the presence of 2) Acute, feeding experiments. Mon summing the heights of the individual PCBs. Only recently have studies either santo Bulletin 306 states that 100 ppm peaks, the total was multiplied by a factor directly or indirectly resulted in an esti diet had no effect on rats, although no derived from measurements of standard mate of this error. Anderson ct al. (1969) details of the studies were given. The ex solutions with electron capture and micro- quantitated p.p'-DDE, p.p'-DDD, and periments of Bennett el al. (1938) in which coulometrie detectors. Jensen ct al. (1969) p,p'-DDT in five egg samples before and 0.05 g/rat of 65% chlorine biphenyl was reported PCB amounts as the sum of all after saponification. There was no appre given orally every other day led to 50% PCB components and based the estimate ciable change in the p.p'-DDE, but ap mortality. If one assumes a body weight on a combination of mass spectrometry parent p.p'-DDD was reduced by ap of 200 g, then the alternate day dose is and microcoulometric and electron cap proximately 58% and p.p'-DDT by 90%. roughly 250 mg/kg. which can be com ture detection. Even with this elaborate Reynolds (1970) looked at a large number pared to oral LD50 for DDT of 113 mg/kg approach, these investigators suggest that of samples before and after his PCB- (Frear, 1968). Miller (1944) found that the method is still rough and may be cor Florisil separation and found that the two oral doses of 69 mg of 42% chlorine rect only within a factor of 2. Anderson el actual p.p'-DDD residue (relative to the biphenyl a week apart were fatal to guinea al. (1969) devised a method for obtaining apparent residue) represented from 0 to pigs. At an estimated body weight of 400 a crude estimate of PCB residues as Aro- 7% in California gull (Larus occidentalis) g. this gives a dose of 170 mg/kg Tucker clor 1254 from chromatograms where sep fat, 0% in cormorant (Phalacrocorax auri- and Crabtree (1970) fed rats diets contain aration had not been attempted. On an tus) eggs, 80%'in 10 pooled mallard (Anas ing 10 and 1000 ppm Aroclor 1254. One empirical basis, it was found that Aroclor platy/hynchos) duck eggs, and from 0 to rat out of six on the low dose died; this 1254 could be quantitated by considering 104% in great blue heron (Ardea cinerea) mortality was considered to be due to peak 10 as p,p'-DDT and multiplying that eggs. Respective values for p,p'-DDT other causes. Four out of four of the high value by 10. Since this peak had originally wereO to 53%, 13 to 41%, 100%, and 18 to group died within 53 days and the cal been quantitated as p,p'-DDT, and in 102%. Actual residue levels of heptachlor culated intake was 1330-1520 mg/kg. The 960 DSW 030988 P BioScience Vol. 20 No. 17 \ STLCOPCB4014950 food intake of the I(XX) ppm proup tv;;;; excess of 2000 ppm. This finding is in only 79% of the control group. agreement with the findings of Dale, Press! ct al. (1970) have examined the Stickel, and co-workcrs that the brain toxicity of Aroclor 1254 to Bengalese levels arc the best indication of acute finches (Lonchura striata). This is u diffi toxic levels. cult species for which to calculate the McCunc et al. (1962) found no mor- dietary intake. Due to their dependence ' talily with chickens fed 100 or 200 ppm upon unshelled food, it is only possible to Aroclor 1242 in their diet for a 4-weck present the PCB-ladcn food for a few period. On diets of 400 ppm and 800 ppm, hours a day (Jefferies, 1967). Loss by the mortalities over a 4-wcck period were, evaporation and loss by spillage must be respectively, 50% and 90%. During the allowed for. and increase of weight by def first 3 weeks, the mortality figures were . ecation must be kept to a minimum. 10% and 50%, respectively. Flick et al. Thus, the calculated dietary intake is sub (1965), using the same material at 400 ject to more error than is usually the case? ppm in the diet, had three birds out of 24 Presst et al. (1970) also measured the con die in a 3-week period. Koeman ct al. centration of PCBs in the liver; they (1969a) found that a diet containing 2000 found that the range was large (i.e., 70 ppm Phenoclor DP6 caused complete 697 ppm in birds that died compared to mortality with Japanese quail (5/5) in 5 3-634 ppm in those that survived). These 13 days and rats (8/8) in 1-56 days. authors conclude that Aroclor 1254 has Schoettger (unpublished) found that the only 1/13 the toxicity of DDT, although 96-hr TLm for Aroclor 1221 using cut the different shape of the mortality throat trout w'as 1.2 mg/1 and for Aroclor . curves--sleep with DDT, gradual with 1260 was 60.9 mg/I. In general, they PCB-- makes comparison difficult. Jef found that the toxicity of Aroclors was feries and Walker (1966) found good cor inversely proportional to their percentage relation between calculated dietary intake chlorination and directly proportional to and liver concentrations for pp'-DDT in (heir solubilities. These figures suggest the Bengalese finch. However, other that PCBs are two to three orders of mag workers (Dale et al., 1963; Stickel et al., nitude less toxic to fish than DDT. Work 1966; Stickel and Stickel, 1969) have con by Lichtenstein et al. (1969) on house and sidered that levels in the brain are a more fruit flies found that PCBs were 40-300 reliable index of toxic levels than those in times less toxic than DDT, the toxicity the fiver or whole carcass. decreasing as the chlorine content in De Vos and Koeman (1970) fed Pheno- creases. Thus, it appears that the lower clor DP6, Clophen A60, and Aroclor 1260 vertebrates and invertebrates are much to chickens at a dosage of 400 ppm. Mor less susceptible than mammals to direct tality was complete (20/20) for those birds toxicity from PCBs. on Phenoclor in 12-58 days and in 13-29 3) Sublethal effects. As with the chlo days for Clophen. The mortality for Aro rinated hydrocarbon pesticides, the most clor was only 3/20 for a 60-day period. important effects are long-range sublethal This differential effect is unexplained and effects. The pathologic changes in various is surprising in view of the fact that all organs are summarized in Table 2. The three formulations contain 60% chlorine. table shows some interesting differences These workers measured the residue lev between mammals and birds. The most els in the liver, and, for some birds, in the striking finds in mammals are alterations brain, for chickens dying during the ex to the liver, whereas fluid in the peri periment. Although there was consider cardial sac, kidney damage, and reduced able variation, most of the brain levels spleen was found in birds. were between 210 and 420 ppm, which McLaughlin et al. (1963) found that 25 can be compared to 50-80 ppm for DDT mg Aroclor 1242 injected into the yolk (Stickel et al., 1966). On the basis of this sac of chicken eggs caused complete mor work, PCB is 1/4-1/5 as toxic as DDT. Little difference was noted between the three different PCB formulations, al though the numbers of determinations involved was rather small. If this finding is borne out by subsequent work, it would tality, whereas 10 mg caused 95% failure and tcralogenelic effects were noted among the young that hutched (beak deformity, edema, and growih retardant). Induction of hepatic hydroxylating en zymes has been demonstrated in the pi suggest that differential absorption from geon (Riscbrough et al., 1968), rat (Street the gut or differential penetration of the ct al., 1969), and American kestrel (Falco blood brain barrier is involved. The liver sparverius) (Lincer and Peakall, 1970). values were more variable. There was a Street and co-workers studied the effects , considerable number in the 200-400 ppm of a diet of 50 ppm and 100 ppm on sleep range, but there were several values in ing lime induced by a standard dose of hcxobarbital, in vitro rales of aniline hydroxylation and dcmctbylation of p-nitroanlsolc, and the rate of excretion of1 dieldrin. These workers studied 10 com pounds ranging in chlorine content from 21% to 68% and found that all the effects increased with increasing chlorine con tent. For example, 50 ppm of Aroclor 1221 reduced hcxobarbital sleeping time by 11%, whereas for Aroclor 1248 and 1268 the figures were, respectively, 35% and 48%. Thus, the sublethal effects have direct correlation with chlorine content, while the lethal effects appear to be in versely correlated (Tucker and Crabtree, in press). Lincer and Peakall (1970) noted an increase of (he in vitro rale of metabo lism of estradiol in kestrels fed 0.5 and 5 ppm Aroclor 1254 in their diet and also demonstrated increased levels of cytoplas mic RNA with the higher dietary level using a cytophotometric technique. Tucker (unpublished) found that a sin gle oral dose of 500 mg/kg Aroclor 1254 caused regular egg laying of Japanese quail (Coturnix coturnix) to turn first to scattered egg production and then to slop completely for a week. The scattered eggs had shells 9% thinner than normal, but thickness returned to control values when regular laying was resumed. Mallard^ ducks dosed with 1000 mg/kg of Aroclor laid one or no eggs before stopping for 1 2 weeks. The few eggs laid after the sin gle large dose of Aroclor had shells 18% thinner, and again eggshell thickness was normal after resumption of regular laying. The period before egg laying has been noted to be increased in the ring dove (Peakall, unpublished). It is possible that the mechanism involved is increased rate of metabolism of circulating estradiol in the liver (Peakall, 1970). Anderson et al. (1969) had suggestive evidence that PCBs affected eggshell thickness, al though to a less extent than DDE. Pre liminary results with ring doves support this conclusion (Peakall, unpublished). Levels ol PCBs Found in Nature Roburn (1965), comparing total chlorine (by concentration cell techniques) with results calculated from gas chromatog raphy, found that some unknown chlorine compounds were present in several tissue samples and eggs of wild birds in Great Britain. The first identification of these materials was by Jensen and it is staled (Anonymous, 1966) that residues in feath ers collected in Sweden go back to 1944. PCB residues have been reported in wild life from Canada (Holden and Marsden. 1967: Anderson et al., 1969; Reynolds, 'September t. 1970 v") DSW 030989 W 961 STLCOPCB4014951 . f/' ii v* u; T ABLE 2. Pathologic ehangos inducod by PCBt Ttalttninl Amml lh*l Kititiy Paricardiam M4 ParHaantm Othtr Obitrvsbla Changes Raftrancvt * Singfi irtl fait 1II mg |42 d) Gump* Pi| R*t ftahhit Small fat drapfatt through fobulei. tlight lo modirati control atrophy, focal nacrosis nottd m a fow awmall. Elianliaity anrmni Np aotawtrthy tkanppi Airmail. iy(ian. a*4 piKtiii thawtd M .Mianrptlhy thanpal. MWit (1144) 300 mp *Hy Itl 1 Pay, (ISS a) tut Colit twoltan, hyalina granidot proiant. moil diod within faw days. lanaalt St at. (tl3l) BO mg dally Hr up to 6 menthl IBS O) Alt 21, 50. i 100 ppm is 4itt hr 15 4ayl (21-IIS a Arptipri) M Enlarged 133% weight introoie), large number of hyalina gfohWoo m cytoplasm. Sevorol fad during oxperiment. Incraate in weight, tffacl terming with tereasmg (Marine content. Arocte 1232-10%, 1242-12%, 1284 14%. 1281*24% at S ypi. tannatt -Na V lira*! at il. |la prnu) 100 ppm is 4it 200 ppm is titt 400 ppm in dpt 100 ppm in lit! (ArPdcr 1242) CMchai Na aftact Np pltict Eniirpid pul mnttlpl D*m*ft4 0am*pal Slight Hydroporicardium Hydreperieardiom Hydroporicardium. hydroporilanoam, Enlarged. McCtma at al. I1P42) 200 A 400 ppm hr tift for 3 midi (42S. Andtt) dieItan Na diaitgM naiad Patanoaa at 200 ppm. oitanahro hemorrhage, and enlargement t 400 ppm. teraaiad fluid m paricardial sac at the higher epneontfotion. Patonatt at pancreas. onlorgem*nt of adianil and small spleen at low concen trations. At highar concen trations poll croam-coforad pancraaa, adronafs bamorrhagic- Hick at at. (1UU Viriitti tom (14% Cl. Andtr) mptliM Np wpipfit chpnppt finch Waipht wai 32.4S al kraht anight for cantrots t*4 13.5% (at tkoi* 4yi*| lr*m PCB poiM*m|. Slight might mctptip, law ihanral ligaM hr parkirtid Ur. Pttsit it al. (In pnu) 400 ppm k tilt fn lOAtyt (m% a*i Chichi* Cintrptpb.tpr nicrpii. (compd t ml 2). thrar wrtight ittcrallad trim 2.70 p/100 |ta 4.31 |/I00 f (camp4. 3). Fatty dapanaratlM. Tabtdit titilitip*, (campd. t 4*4 I) Anrp nritk t*mp4. 3. Hydrepericerfim common with compd*. 1 and 2. fUra with compd. 3. Incraattd porphyria, ipfttft small with reduction at tod ptdp and atrophy of whito ptdp (campd. 1 and 2). Spfom docroasod from 0.146 g/100gt 0.136 g/IOOg. oamptf. 3). Vei i*4 Katana (ti priul *Pl**tictr Of I {"mp4 t|. Otphtn AIO )l *M Ar*di 1210 )| *t4 plift uapd Mnbfn AN rtklwi ft4 m nmp4. 1 mi 2 vitWn 10 - ***r f *m*ilr m itm$l 9 1970), Germany (Fiuczynski and Wendland, 1968; Koeman el al., 1967), Great Britain, (Holmes el al.. 1967; Presst and Jefferies, 1969; Presst et al., 1970; Holden and Marsden, 1967), Netherlands (Koe man et al,, 1967; 1969), Sweden (Anony mous, 1966; Jensen ct al., 1969), and the United Slates (Anderson et al., 1969; Risebrough et al., 1968; Risebrough, 1969).. Biological Magnification No detailed studies, such as those for DDD at Clear Lake (Hunt and Bischoff, I960) and DDT and its metabolites in Lake Michigan (Hickey ct al., 1966), have yet been made for PCBs. The most detailed studies currently available are those of Jensen et al. (1969). The figures (mean, range of values, and sample size) given in the table below are taken from their paper. PCBt (ppm in extractable fat) Baltic Stockholm Archipelago Muitel 4.)(1.9*8.6) (40) 5.2(3.4*7.01 (15) Herring Seat GuiHematoggt 6.1(0.5*23) (18) 34(16-44) ( 3) 250(t40-)60)( 9) 5.M3.3-8.3) 30(16-56) -- (4) ( 3) White-tailed Eagle Pectoral mmde Brain -- -- 14.000 (8400*17.000) ( 4) 910(490*1500) ( 3) Egg* Heron --- 540(250-800) < 5) -- 9400 ( I) The levels in three species of fish in Clear Lake in 1968 were 0.03-0.005 ppm (wet weight) compared to 0.098 ppm in the breast muscle of a western grebe (Rise brough et al.. 1969). Anderson et al. (1969) found that in most fish extracts the levels of PCBs were less than 0.1 ppm. whereas the levels in the eggs of cormorants (Phalacrocorax auritus) were 5-9 ppm. Presst. Jefferies, and Moore (unpublished) found that the livers of fish-eating birds in the British Isles ranged up to a maximum of 900 ppm (wet weight), bird feeders up to 70 ppm, mammal eaters to 50 ppm, and insectivores to I ppm. Unfortunately, no average values or prey items were in cluded. The physical properties of PCB and the available residue data clearly indicate that these materials are capable of bio logical magnification up the food chain. 962 OSW 030990 BioScicncc Vol. 20 No. 17 STLCOPCB4014952 Ratio ul 01)1 In I't ll Risebrough et ill. (1968) and Risebrough (1970) have examined the ratio of total DDT, i.e., DDT and its metabolites to PCB. He has found that the ratio DDT/ PCB was 1-2 in San Francisco Bay and 5-, 10 for seabirds in the Pacific: in the Gulf of California, a region relatively remote from contamination, the ratio was 9-10. Vermeer (quoted in Reynolds, 1970) in western Canada found a DDE/PCB ratio of 7 for California gull tissues and 13 for great blue heron eggs. In the Baltic the ratio was 1-2 (Jensen el ul., 1969), al though along the west coast of Sweden the ratio was as low as 0.15. In grebes in' the British [sics the ratio was 0.4-0.8 (Prcssl and Jefferies, 1969). For sea-bird eggs. Press! et al. (unpublished) found ratios of 0.06 to 0.5. The overall impression is that the amount of PCB in tissues lends to paral lel that of DDE. at least in local ecosys tems, and the DDE/PCB ratio is lowest near industrial areas suggesting that PCB is not carried quite so readily to remote areas. Nevertheless, the variation of the ratio is small enough to suggest that the routes of dispersal are similar. Since the evidence points to aerial fallout as the route of dispersal of the chlorinated hy drocarbon pesticides (Risebrough et al., 1968; Frost. 1969), it is likely that this is also the main route for PCBs. The path ways by which PCBs escape into the eco system are poorly known, although the possibilities have been recently discussed at some length (Risebrough, 1970; Rey nolds, 1970). Since a large number of plastics and resins may contain PCBs (Table I), the most likely route is combus tion of these materials. This supposition remains to be tested. The possibility that PCBs could be derived from DDT should also be considered. The possibility that this conversion occurs in tissue is most unlikely for two reasons. First, it has never been detected despite the detailed work on the metabolism of DDT. Second, the only mechanism likely to give rise to a biphenyl is via free radicals and this is unlikely to occur in tissue. However, in the atmosphere under the influence of UV light, such a breakdown is more prob able. A possible reaction is shown in Figure I. Tautomeric shift could lead to a variety of isomers of dichlorophenyl, but it is difficult to envision the formation of more highly chlorinated biphenyls by this route. Since PCBs extracted from biological material match well with higher Aroclors (i.e., 1254), it seems unlikely that PCBs found in nature could be derived from other materials. Significance of Current Levels fn view of the similarity of PCBs to DDT and its metabolites, the addition of PCB residues to the environment is rough-* ly equivalent to an increase of DDE resi dues. However, since a synergistic effect of PCBs on DDT has been demonstrated in insects (Tsao et al., 1953), this pos sibility should not be overlooked in higher organisms. The enzyme induction effects of PCBs have been well documented, and carbonic anhydrase inhibition is likely. The effect of PCBs on photosynthesis is a critical experiment that has not been done. Wurstcr's (1968) experiments with phytoplankton should be repealed with PCBs. The most critical area for research on PCBs is to discover the major source(s) of escape into the environment. Legislative control of a material escaping as a side effect of its use may have a different set of problems than the control of pesticides which are broadcast as a function of their normal use. The evidence suggests that it is important to find the leak and stop it. Acknowledgments We are grateful to Dr. Koeman (Uni versity of Utrecht), Drs. Presst and Jef feries (Nature Conservancy, Great Britian). Dr. Reynolds (Ontario Research Foundation), Dr. Street (Utah State Uni versity), and Dr. Tucker (U.S. Fish and Wildlife Service) for advance copies of important material. Some of the work presented here was carried out under NIH Grant ES00306, Dr. T. J. Cade, Principal Investigator. The review was written while one of us (D.B.P.) was an Established Investigator, American Heart Association. Thanks go to Dr. T. J. Cade for reviewing the manuscript. References Abbott, D. C,, R. B. Harrison, J. O'G. Tatton, and J. Thomson. 1966. Organochlorine pesti cides in the atmosphere. Nature. 211: 259 261. Anderson, D. W., J. J. Hickey. R. W. Rise brough, D. F. Hughes, and R. E. Christen sen. 1969. Significance of chlorinated hydro carbon residues to breeding pelicans and cormorats. Can. 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Possible interference by chlorinated biphenyls. J. Assoc. Ojfic. Anal. Chem.. 5U: 1069. 1968. Determination of number of com pounds which can result from the chlorination of biphenyl, and development of a simple sys tem by which these may be codified. OECD report Sweden. Wurstcr, C. F. 1968. DDT reduces photosynthe sis by marine phytoplankton. Science. 159: 1474-1475. r/ MICROBIAL CULTURES COMPLETE BSCS LISTINGI GUARANTEED PURITYI OVER 200 SPECIES AVAILABLE I MOST ORDERS FILLED WITHIN 48 HOURS NOTICE c.................. ? - BACTERIA and FUNGI cultures---------$3.oo per culture ($2.50 par culture for orders of 6 or more cultures) C s--o BACTERIOPHAGE -- -- $4,00 per 5 ml filtered broth suspensions C---------------S--------- o BACTERIOPHAGE culture sets---------- Available at special prices COMPLIMENTARY CULTURES One complimentary culture (bacterial or fungal) will be included for eoch tlx cultures ordered. Compliments may be selected if so desired. Free CATALOGUE OF CULTURES Available Upon Request (PRESQUE ISLE MICROBIOLOGICAL ASSOCIATES ||------------------------O P.O.BOX B007PRESQUE ISLE, PENNSYLVANIA 16505 Telephone 814-833-6373 964 DSW 030992 BioSciencc Vol. 20 No. 17 STLCOPCB4014954