Document 3Qe43yMkZxKzRnN71VnVXZpxy

cljf of for wo ind the Iter nur nal une the IV71 siyts in*. i* of LiOtl, mtsd Ucn 1P00 uU) trul Jlant long live* Ennnrtrntntot Health Prrif>rctiiri Toxicology of PCBs for Mammals and for Birds by J. G. Vos* falroduction In the early days of ita use, little work was done on the toxicology of the PCBs, and this was only in relation to the risks of occupational exposure. As will be shown many more studies were made as soon as it appeared that the extremely stable PCB'a became a threat to the environment and its wildlife, and accidents occurred of acute poisoning in man and animals. These studies have been made with material with different contents of chlorine, from different manufacture, and--as we can now say in retrospect--with different and unknown contents of toxic im purities. For this reason the toxicological infor mation of PCll'a is difficult to summarise, but since the character of some important impurities has recently been elucidated, it is well to discuss these first in order to be able to consider their contribution to the overall toxicity of the dif ferent preparations studied. ' These studies were started because iff the analogy between the effects of the PCBs (1-6) and some toxic efforts associated with toxic factors in crude chloropbcnole and in "toxie fat". Effects of the Utter arc liver damage (7), chloracnc (7,8) and edema formation (9). toxicity of three commercial PCB samples (con taining 60% chlorine on the average); Phcuoclor DP6 (sample I), Clophcn A60 (sample 11) and Aroclor 1260 (sample 111). These three mixtures showed a marked resemblance in their gas chroma tograms and mass spectra (10). In this compara tive feeding test in one-day-old chicks (11), it was found that 100% mortality, subcutaneous and abdominal edema, and ccntrolobular fiver necrosis oceured in only two groups (fed the samples I and II). Hydropericardium (Fig. 1), a common effect of these two mixtures, was only occa sionally aeon in the chicks fed the sample 111. The Chemical, Tufeettglcit, mul Petfceteglcal Mefttificatim mi ivahutiw if Texic Imparities In Technical PCI PrtpmiliMS The first indication of the presence of toxic impurities was obtained in a comparison of the * Institute of Veterinary Pathotogy sad Institute of Veterinary Diartnarolin.r and Toxicology, Slat# Uni versity of Utreelit, The Netherlands, Fiona 1. Hydropericardium la a chick fed 400 ppm of sample I. Apr!) 1972 105 Table 1. Mortality, end Petholoalr Oburvetione of Cblrt* Fed 400 ppm PCII for 60 Day. PCB sample Number of Number of bird* with edems Number of N duthi bird* with Hydro- Abdominal Subcutaneous liver necrosis periesrdium 1 11 111 Control 34 34 18 8 8 B 22 22 30 7 B 30 . 3 3 0 0 0 30 0 0 0 0 0 mortality in thin group was only 15% (Table 1). The excretion of coproporpltyrin and protopor phyrin in the feces was increased. Examination of tissues under Wood's light showed the presence of red fluorescence indicating porphyrins in the liver and other tissues of especially the birds that died. This hepatic porphyria was found in all tit rec experimental groups. Jn the subsequent study (12) by means of column and gas-chromatography the presence of relatively more )>olar compounds was demon strated in the 25% dicthylethcr fraction of samples 1 and 11. In a chick embryo assay (Table 2), the difference in toxicity between the three samples was confirmed; the high toxicity of the 25% dicthylcthrr fraction of sample 11 is demon strated by the similarity between the mortality levels in the group injected with 3.5 sample 11/ egg and the group injected with the 25% diethylether fraction from 3.5 mg sample 11/egg. Mass apcctromctric analysis revealed that Table t Chick-Embryo AMay of Three fCB aamplea and (lie 8S% Diclliyiether Fraction from Sample II PCD cample Doac Number (mg/agg) ef agga treated Percentage batch ef fertile egfi I 11 in Fraction Iras Mmjilt 11 Klhanol control Untreated control 8.8 8.8 8.8 86 8.5 0.86 0 035 0 15 30 16 16 15 15 16 30 30 0 5 80 0 1 n 100 84 B0 identical chlorinated compounds were present in the 25% dicthylethcr fraction from samples I and II but not in that from sample III. They included compounds with mass number 3(M and 338.. The proposed identity of these compounds, tctrachlorodihensofuran and pcntachlorodibentofuran, is indicated by the following chrtnical-analytical, pathological, and toxicological data. From exact mass measuremen's it was found that the formulae of these peaks were CU11,0"CI, and CnHjO"Cl. The formulae of the fragment ions 241 and 275 were Cul]<uCli and Cullt^Cb. From this data it can be concluded that the parent ion has a preferential fragmentation for the Ion of a single CICO unit. Mass spectra were oomptrod with the spectrum of a chick edema factor 1,2,3,7,8,9-hcxachlorodibcnco-p-dioxin. The mass spectrum of this compound has a similar fragmentation pattern, i c. the loss of two suc cessive mass units of 83 suggests s loss of two ClOO units. With microcoulomctric analysis a certain maximum level could be indicated. This maximum level was found to be five ppm of the oompound with man nuimhcr_338 in sample II and 20 ppm in sample 1. " Polychlorinated dibentofurmns arc strong hepatotoxic and acnegcnic compounds. Tri- and tetraehlorodibcnsofurans in a single oral dose of 0.5 1.0 mg/kg caused severe and often lethal liver necrosis in rabbits (7,13), and application to the ear resulted in ehloraenc. Tctrachlorodibcnsodioxin was about 10 times more toxic (7). In jection of the 25% dicthylethcr fraction obtained from 35 mg samgdc II into the airccll resulted in 100% mortality (Table 2). It can be calculated that the maximum dosc/cgg is 0.2 pg pentachlorodibcusofuran (taking five ppm as the maxi- 106- Environmental Health Perspective* HONS 2072*1 muin value). This confirms the order of toxicity found by Higginbotham ct al. (9) in Die case of chloro-dibcnsodioxins. Tetra and pcntachloridibenaofurans were considered responsible for Die higher toxicity of samples I and 11. Confinnation is also obtained from the sub* sequent comparative toxicity study in rabbits (14). Again samples 1 and 11 were more toxic; the liver and skin lesions were more severe. Por phyria, csj>ecially of the liver, was present in all toxicity of 2,4,5,2',4',5'-hcxaclilorobiphcnyI. From the increased fecal excretion of cogiroporphyrin in both cx|icrimrnln1 groups (Table 3), it is very likely that PCBs themselves arc responsible for the porphyrogenic action of crude prepara tions. From the presence of slight skin lesions induedd by 2,4,5,2',4',5'-hcxachlorobipliciiyl when compared with the Aroclor sample, it can be concluded that the major tcnrgciiic action of crude mixtures comes from a possible eon land na three groups (Fig. 2). A remarkable finding was tion with chlorinated dibensofurans. It can also the intense red fluorescence of small foci inside be concluded that PCBs themselves have a nl hepatic cells. They probably represent nuclei. This slight acncgcnic action. Liver dtmsgr was es - I was confirmed in an additional cell culture experi sentially the same after treatment with both cy ment with the Aroclor sample and with 2,4,5,- 2,4,5,2',4',5'-hcxachlorobiphcnyl and the iid 2',4',5'-hcxachlorobiphcnyl. (This experiment was Aroclor mixture. The conclusion that the liver th, carried out by my colleague Dr. J. 0. Wit of the injury, caused by crude preparations, is pre di Biochemical Section). dominantly due to the contaminants, is based m Application of the 25% diethylcther fraction on the differences in liver toxicity between the es! on the skin of rabbits resulted also in differences three rCB preparations (11,14). in toxicity (Fig. 3). So the presence of the hepato- The probable contribution of polychlorinated nd toxic and acncgcnic polychlorinated dibensofurans dibenzofuran (PCF) and pure polychlorinated n. as impurities in samples I and II was found to biphenyl (PCBs) in the toxicity of crude prepara nl be established. tions is summarised in Table 4. A proper evalua \ In another experiment (15), the toxicity of the tion of toxicity data and residue data can be I Aroclor (60% Cl) sample was compared with the hindered by the possibility that PCB samples may for CPf na in. Im uc* wo .0 hi* Jir II ;w- re- vci llit lo llt- iwj Lod ted WnfIHltiliniiffi liliiiiiiHitti hi La- uti- Fionas 3. Fhioceeeenee of porphyrins under ultraviolet light in liven from rabbits treated with M% chlorinated PCH'i, 1, Aroclor; 2, Clophon; 3, Pheooclor; end 4, Control liver (14). April 1972 107 MO NS 207262 fllilfSI TlOOStE I, Rwponm of the inside of U>6 rabbit's tor oftar lopiril application of the 25% dlelhylelher fraction* from tfrliaieal PCH'a. Ifermotoxylin and aoatn. XHO. (a) Skin of control oninud treated, with ethanol. Note the hair follicle ot I, seabaceoof gland Uaaue at 3, and earlilaga at 3. (b). Ear akin of the animal treated with the fraction from sample Jll. Some hyperplasia and hyperkeratosis of the follicular epithelium can be Men. (e). Ear akin of Uic rabbit treated with the frarlion from sample II. Considerable hyperplasia and hyperkeratoaia of tha follicular epithelium, (d). Hr akin of the rabbit treated with the fraction from sample 1. Part of a Melton that ihowt the moat Mvere lesion. The gravity of. the reaponae wu in general tha aame aa aaen in (e). Nolo tha eyslio dilated hair follicle with prominent hyperplasia and hyperkeratoaia of the follicular and apidermal epithelium (M). 108 Environmental Health Perspectives HONS 207263 ji/fer in an important respect: the presence of losir imjHiritics, The possibility of distinguishing |>rt'ccn the effects of PCBs and their impurities ran he further improved by using pure isomers with known positions of the chlorine stoma. Mortality, Urn Effects, Edema Formation and Other Effects These data, as presented by different authors, are summarised in Tables 5, 6, and 7. Aa can be aocn in Table 5, the acute and subacute toxicity dr .a of PCC a arc poor. The established values ire high. Semichronic oral toxicity studies are summarised in Table G. Dermal and inhalation studies arc given in Table 7. Table 3. Coproporphyrin Content* (ug/g Dry Weight) of f'ecti of It alibit* Treated will, PCll for * weeks, and of Control*.* 3I4(S,i'I4\S'-Hexehtorol)i|>hcnyl Aroelor Control (30% Ct) 43.0 6.3 ao.s toe Mean 37.01 24.1 SO 20.4 16.0 I8.3 4.S 3.7 3.6 S.S 3.3 * Figure* an the contents of fees*, oollected from the cecum of the individual animal*. * Significantly different from control*, P 0.02$. It is very probable that the results of these studies may have been influenced by the presence of polychtorodibcniofuraiis or other toxic im purities. Tor example, in the study of ltclifcld ct al. (23) general edema was already found in chicks fed M ppm Aroelor 4M<% Cl. whit.. Kohanawa and co-workers (22) noted edema formation at the 100 ppm level of another 48% chlorinated mixture. Mortality in the Utter study was also lower (Tabic 6). Liver Effect a The most important Ever effects, summarised in Tables 6, 0, and 7, we weight increase, fatly degeneration, hyalin degeneration and nccroyw Increased liver weights, as noted in several studies, Table 4. Probable Contribution of Polyehlorlnatrd Dibenaofurali (TCP) and Pure Polychlorinated Biphenyl (l*CH) In the Toxicity of Crude FCB Mixture*. Chlor- Edema Liver Hepatic itn forms- damage porphyria lion Polychlorinated Dibsatofurtn Polychlorinated Biphenyl ++ + + + + ++ ++ Table I, Acute and Subaeula Oral Toxicity Studies of PCB Preparations. Prqiaratioo Animal Treatment Mortality Liver effect* References Unknown Atoelor 34% Ct Mouse Rat Aroelor 43, 34,30, and Mallard 38% Ct 43% Cl Rat 43% a Otrinanpig % a Rat single dose of LDS0 approx. 3000 mg/kg aingi* dose of 0% Increase of weight and HO mg/kg lipid; potent ration of OCl* toxicity single dose of 0% 2000 mg/kg 20 dally dose* of 133 mg 2 do*** of 00 mg 0% in 3 Hyalin bodies in liver cell* month* 100% between Patty metamorphow1, I weak apart 11 end 20 centra] atrophy day* 6 daily doer* of 70% in 14 Increase of weight; cell 300 mg day* swelling: hyalin granules (10) (ID (IS) (W) (10) <) April 1972 109 HONS 207244 Tabic (, Scmlclironle Oral Tovlrlly Sludle* of PCI! Preparation*. Pre|i*ration Animat Treatment Mortality Liver effect* Other effects Refer. ence* 65% Cl lut 48% C! 48% Ct Cynomolgue monkc* Squirm' monkey 48% Cl Mouse Aroelor Chicken 42% Cl Aroelor Chicken 42% Cl 48% a Chicken Aroelor Chicken 48% a Aroelor Chicken m% a Arod* Wwf1-- *4% a inch Pbmoder Japancae eo% a quail Doses of SO mf 80% In 5 weeka 33% weight increase; very eocond day From 041 m( in 40 daya 'o 248 not given cell awaiting; 1 hyalin globule* Enlargement; SKK proliferation Main eauar of dealt,: pnfumoiiii or mg in 230 day* From 320 mg in 40 daya to 47 mg in 48 daya not given Enlargement; 6KH proliferation BEK proliferation diarrhea Main cause of death: pneumonia or diarrhet; bral edni* in Daily doaet of 0.001 ml for 0% Enlargement; 8ER proliferation 1 animal Skin: toes of hair, erosion and 13 to 20 week* RER reduction; ulceration after myelin figures; 3 month* increase of micro- bodtea, lyaoaomcs 100, 200. 400, and 0, 0, 50, 00, and and 1000 ppm 00% respectively and lipid Enlargement;. damage at the Edema formation from 200 ppm; at in diet for higher level* high level* internal 4 ireeke haemorrhage and tubuUr dilatation in kidney* 200 and 400 ppm 0 and 12% in diet for respectively Pronounced edema at 400 ppm; en- 3 week* larged kidneys; small apleen; (Weathering and dermatitis 1, 8, 10, 25, SO, 0% from I to 100 Edema formation 100, 300, 000, ppm; 100% from 100 ppm level 1200, 2400, and - the 100 ppm level 4800 ppm in diet for 30 day* 10, 30, 30, 50, 100, After 3 week*: 0, 0, Enlargement General edema and and ISO ppm in diet for 4.5-5 weeks 30. 30 and 20%; at the and 0,0, 80, 00, and 80% depression of the secondary sexual eharactcriatice mpeelivaly from tha 30 ppm level 250 and 150 ppm 250 ppm 100% be- 500 ppm at and: la diet for 0 to tween 8 and 10 comb weights 20- 13 weeks weeks; 800 ppm fold and teeter earn mortality at waighU 2-fold the and lower than controls Estimated dose 80% tala at 50 day* N ydropcrieardium in some birds of *54 mg/kg/ day 2000 ppm in diet 100% between 8 and Hydropericardium 85 daya (20) (21) (21) (21) (5) (5) (22) (23) (24) (25) (10) 110 Environmental Health Perapccllvca MOWS 207265 :upii i.i 'Wty; Table 7. Dermal Toilrlly and Inhalation Stud lea of FCR Preparations, I'rd*rstioa Animal Treatment Mortality Liver effects Skin effects Refer ences 42% Cl Guinea pig 42% Cl Rabbit Arector Rabbit Aroclor Rat 65% Cl 11 daily ekin applications o( 24.5 mg Skin application at alternate day*, total doac from 940 to ISM mg Daily akin api di estions of 0.3, 0.0, and 0.9 c Inhalation of 0.57 mg/eubic meter for 10 hour* for 37 to 124 day* 100% between 11 and 21 days 100% between 17 and 98 days High dose died be fore liver necrosis developed 0% Fat; central atro Occasional thicken phy; perinuclear ing of the basophilic granu epidermis lation; focal ' necrosis in a few animals Fatty degeneration; Thinning of prickle central atrophy cell layer and thickening of outer eonufk-d layers Moderate dosee: Reddening; forma mottled liver, sub tion of amall acute yellow papules snd atrophy, fatty blister*; finelly degeneration, and desqusmalir.n of marked necrosis external epidermal layers Pale end yellow; eetl swelling; hyslin degenera tion; potentiation of CCU and Ctlf<OH toxicity (19) (19) (20) (20) are well explained by the proliferation of smooth surfaced membranes of the endoplasmic reticu lum (SEli) as was found by Niehisumi (21) in mice and monkeys and by Norbeck and Allen (27) in rats. The latter workers found a prolifera tion of the SER in rats fed PCB for 1 to 5 weeks. Concomitant with tljc structural changes, the activities of measured drug metabolising ensymes (nitroreductase and aromatic hydroxylase) were increased. The induced level of drug metabolising activity persisted as the proliferation of the BEK decreased and concentric arrays pervaded the cytoplasmic reticulum (27). These concentric membrane arrays, probably representing the hyslin bodies describod by Bennet et al. (20) and MiRer (19), eould have an cnsymatic func tion amikr to that associated with the 8EK (27). Similar formations, the so-called myelin fig ures, were demonstrated in mouse liver by electron microscopy; in monkey liver they were not found (21). In both mouse and monkey liver a proliferation of the SER was found. In our comparative dcnnal toxicity study (IS) in rabbits with 2,4,5,2',4',5'-hcxachlorobiphcnyl and Arodor (60% Cl), the light microscopic findings included necrosis, hydropic degeneration (Figs. 4 and 5) as well as a peripheral and perinuclear shift of cell organelles (Fig. 5) and focal cyto plasmic hyalinisation. In electron microscopy, the shift was found to be due to s proliferation of the SER resulting in a displacement of rough surfaced membranes (RER) and mitochondria. The focal cytoplasmic hyalin degeneration, often seen in hydropic cells, was recognised as tightly parked tubule* of proliferated SER (Fig. 6). This very probably repreoents hypertrophic, hypoactivc 8ER. Sublcthal effects caused by induction of hepatic ensymes have been noted by several authors. Increased steroid metabolism in pigeon liver homogenate* has been demonstrated by Risebrough et si. (26). Linccr and Pcakall (29) confirmed the effect of PCB on the hormone metabolism in birds at very low dose levels. They fed kestrels for 5 months with Arodor 54% and 62% Cl at levels of 0.5 and 5-0 ppm. The higher April 1972 111 *ONS 207266 mmm m* .it* )'i<h/ke 4. liver damage in a killed rabbit treated with 150 mg Aroelor (00% Ct), 5 time* per week, for 28 days. Note the eontrolobuiar necroaia (1) and the hydropie edit (2) at the margin of the necrotie and vital liasue. Haemoloxyiin and oosin, XI60. 2 * nT r.;-: '-Ifij a! V- w# A/s^ ' t1 A \ r-r.* - * 'Via,' Promt $() Liver relb of a control rabbit. Clear area* may represent negative Images of glycogen (arrow). Totuidine blue. XMO. (b). Liver rellaof an Aroelor treated killed rabbit. Note the hydropic cell* (I) and the perinuclear and peripheral displacement of oel) organelle* with aomelimea hyabn foci (2) inside hepatic erlla. Toluidine blue. XMO, Hi J|WT Environmental Health Perspective* NOUS 2072*7 i,l,g U ' lip<P ,M l*l'M|* FiOtiBi'. 0. Hydropie liver celt* from the ume inimil a* teen in Figure fib allowing lirgs number of vecuoie* (VI wirl periveeuoter localisation of mitochondria (erruer). Note the strong proliferation of the BElt, consisting of tightly periled tubule*. Uranyl acetate and lead dtrate. XW00. doac being roughly equivalent to 2 mg/kg PCBs to each kestrel. A doac dependent in vitro break* down of estradiol to a more polar metabolite occurred in the liven from kestrels fod cither Aroclor 1254 or Aroclor 1252, No such conversion took place in the liven of the control birds. The increase in hepatic ensyme activity correlated with an increase in cytoplasmic RNA, as was measured cytophotomctricatly. A shortened sleep ing time after treatment with hexobarbital, and enhanced in vitro rates of aniline hydroxylation and p-nitroeniaok: demcthylations were demon strated by Street and eoworken (30). These authon also found an increase of these effects with increasing chlorine content of the different PCB preparations (Aroclor 21 to 68% Cl). Using ensyinc induction as parameter, so- effect levels of some PCR preparations were established in the rabbit, rat, and Japanese quail. Oral administration of Aroclor 21% Cl and 64% Cl (1.0 and 10 mg/kg) for 28 days to pregnant rabbits resulted in liver enlargement and in creased activities of the drug metabolising cusymes aniline hydroxylase and aminopyrinc D-demetbylaac at the 10 mg/kg level of the 54% chlorinated Aroclor, The no-cffcct level for cnxyuic induction in the pregnant rabbit appeared to lie between 1.0 and 10 mg/kg in the case of Aroclor 54% Cl, and higlwr than 10 mg/kg for Aroclor 21% (31). Another parameter for ensymo induction was used by Komatsu and Tanaka (32). They found that the hexobarbital induced eleeping times in rata were reduced by pretreaInvent with PCBs. April 1972 113 MONS 207268 The minimal effective dose wa* 5 mg/kg for 3 days with Kanrchlor 400 (48% Cl) and 2 mg/kg for 3 day* with the higlier chlorinnu-d Knncchlor 600. Tim por|)liyrugenic action of PCUs wn further evaluated in a study with Japanese quail (33). The results (Table 8) indicate that the hepatic porphyria is closely associated with an increase of mitocliondtial ALA synthase activity. A significantly increased activity of this ensyme was already noted after administration of dsily doses of 1 mg/kg Aroolor 60% Cl for 1 week. Mean PCB content of the liver at that dose was 1.41 ppm. A less sensitive parameter is tissue fluorescence due to excess quantities of porphyrins. Liver fluorescence was only seen at the 100 mg/kg level. It develop, probably, only in animals allowing clinical symptoms, such as loss of weight. A rimilnr finding was done in the prior experi ment with chickens (11). Edema Formation The most striking finding in birds is the ac cumulation of fluid. The pathogenesis of the edema formation is discussed by Flick and co workers (0). The primary site of the edema caus ing factor could be the heart by increasing the permeability of the vascular bed, leading to cardiac congestion. Pulmonary edema could be tiic result of the cardiac congestion. The pul monary edema might be followod by a flow of fluid into abdominal and subcutaneous air sacs. Decreased scrum protein values (34) could also contribute to the edema formation. Liver damage can be responsible for reduced scrum albumin levels. As mentioned in Table 4, the edema formation is probably due to the presence of polycldorodibensofurans. In our study the edema formation by the 00% chlorinated Aroclor sample was minimal at the 400 ppm level. As can be seen in Table G, chick edema-like leaiona were noted at low fooding levels and were caused by lower chlorinated Aroclora. Tliercfore the presence of toxic impurities in these Aror'or samples has to be considered. Other Effects An Interaction of PCUs with duck hepatitis virus was found by Friend and Trainer (35). Ten-day-old ducklings were fed a 54% chlorinated Aroelor mixture at levels of 25, 50 and 100 ppm. The birds suffered no apparent clinical intoxica tions. Five days later they were challenged with duck hepatitis virus, and they suffered signifi cantly higher mortality than birds which were not exposed to PCUs. Effects of PCUs on the lymphoid system were noted in some studies. Feeding of PCUs to chick ens resulted In small spleens (0,11). Lymphopenia, atrophy of the cortex of the thymus, and a re duction in the number of germinal centers in spleen and lymph nodes was found in rabbits (14). Therefore, an immunosuppressive action could be present. In an experiment with guinea pigs, this was established (30). Feeding of 10 ppm Aroclor 00% Cl, for 8 weeks resulted in a Table S. Formation of l-Amlnocvullnic Acid by Liver Mitochondria, Liver Residues, and Tissue Fluorescence In Female Japanese Quail Orally Doted with PCS for Seven Days. Aroelor (60% Cl) ALA formed (ms moles (n*/k* body weight) ALA/f livef/br) PCB eontent liver (ppm) Tissue fluorescence incidence ------------------------------------------------------ Macroscopic Microscopic (liver) 0.1 1 100 4.40*1.64 (.76*4.06 10.60*1.31* 17 .((.4* 116.0* Moan vsites* 8D, 6 lards per (roup. a SifniCeantly different from :ontrots, PgO.Ol. * Pooled samples 0.16* 0.45*0.37 1.41*0.67 37.0*0.4 476*204 0/6 0/5 0/5 0/5 6/5 0/6 0/6 0/5 0/6 2/5 114 Environmental Health Perspectives *0 " ' '* c . 0v " y* v w '>' k fm m jwi',^]ijap.<; Jgf|.w I' i1 n y e ,-. > r\ ^'^` wi 11 - irf^iifrifr - * Fiotmx J, Repreientetive hhi of letanu* toxoid cumulated popliteal lymph node* of prince pip. (a) large number of antibody formine nib in a control animal, (b). Itcdueed number of antibody formas cell* in an animal fed 10 ppm Aroefor (60% Cl) (or 6 track*. Direct fluorcacent antibody tochniqu*. Cryoatat aeclkit*. x 676. (36), A]>rU 1972 HONS 207270 115 !*' p viiiprijpppnipcptp.^;app^r>i1. fwvijpr wxwin--9VW.*> pL.tp..J!ti6pwgBffy-M decreased number of antibody-forming cells in the poidjtcel lymph node, aflor stimulation of tlio humoral lymphoid system with tetanus toxoid (Fig. 7). This suppression may explain the higher sensitivity of PCB-fed ducklings for duck hc|>atitis virus (35). In a comparative toxicity Study in guinea pigs, an indication for an effect of PCB (Clophcn and Aroclor 00% Cl) on the eell-mcdiatcd immunity was obtained. Feeding of tlicsc mixtures at 50 ppm levels for 6 weeks resulted in a decreased number of circulating lymphocytes (unpublished data). An estrogenic activity of PCBs (Aroclor 21-48% Cl) was demonstrated by Bitman and Cecil (37). The estrogenic activity was evaluated using the iS-hr glycogen response of the immature rat uterus after a single subcutaneous injection. The minimum effective dose was 8 mg. The higher chlorinated PCB mixtures were inactive at the 8 nig level. In Die above mentioned subacute fooding study of 60% chlorinated mixtures in guinea pigs, wo found significantly increased uterus weights in the PCB treated animals. Both Increased steroid metabolism, as mentioned by Rehfcld and coworkers (23), and the estrogenic activity could be responsible for the depression of secondary sexual characteristics (decreased development of comb and wattles) noted in cockerels (24). Administration of Aroclor (84% Cl) at levels of 12.5,25, and 50 mg/kg body weight during the fuel 28 days of gestation had embryotoxic effects in the rabbit (31). Edema and beak deformities in chicken embryos have been described after yolk-sac injection of 10 and 25 mg 42% chlori nated Aroclor, resulting in respectively 85 and 100% embryonic mortality (38). An effect of PCB on the nervous system was noted by Ogswa (30), Oral administration of PCB (0.3-0.5 m)/kg/day) to rats for 14 or 21 days, resulted in marked or moderately impaired motor function, decreased motor conduction velocity and leas of large nerve fibres. He eoneluded that PCB caused neuropathy in rata. CmhlSlM Because of the possible presence of poly chlorinated dibensofurans (PCK) or other toxic impurities in crude ]*CB preparations, it ia difficult to interpret many of the toxicity studies. Pure samples are required for comparative in vestigations. Also the fate of the toxic impurities in the environment has to be determined. As presented here, l'CBs have several sublctlial effects, such as microsomal entyrne induction, porphyrogeme action, estrogenic activity, and immunosuppression. Since porphyria seems to be an effect of PCBs themselves and not from PCF, the induction of ALA synthase could be used as criterion in the approximation of a nocffcct level (at least for the 00% chlorine type of PCBs). The no-effect level could be about 0.1 mg/lcg (mean PCB content of Die liver in Japa nese quail about 0.2 ppm). This is in the same order of magnitude as found in t]>c other studies. Additional research is needed to determine fully the significance of there sublcthal effects. More over, chronic and reproduction studies are neces sary. The present results also make clear that manufacture of commercial PCB mixtures that are free from impurities is urgently requested. Acknowledgment The author gratefully acknowledges the helpful suggestions and critical reading of Prof. H. van Genderen, Head of the Institute of Veterinary Pharmacology and Toxioology, Many thanks are also due to oolleaguca of the working party of the Institute of Veterinary Pathology and the Institute of Veterinary Pliamiaeology and Toxi cology*. Dr, J, H. Koemsn, Mr. H. L. van dcr Maas, and Dr. J. G. Wit. The author also thanks the student* who studied for their degree in biological toxicology and Mr. M. C. ten Noever de Brauw, Mr. R. H. de Vos, and Dr. R. J. C. Kleipool of the Central Institute for Food and Nutrition Research, T. N. O., Zeist. REFERENCES ]. Jones, J, W, and Aldm, H. R 1030. An tcudorm dsrmatorcMM. Arch. Derm, fiyphil. 33:1022. 2. Schwarts, L. 1036. Dermatitis from synthetic resins and waxao. Amer. J. Public Ilenllh 26; 536. I. Motes, J. K., Albom, J. J. and Kartin. B. L. 1054. CMoroene from an unusual exposure to Aroclor. J. Amer. Med. Assoe. 154:1417. 4. Pueemelli, V. 1054. DeU'ocoo claries. Med. Lavore 45:131. 5. McCune. E. b. Savage, J. E. end O'Dell. B L. 1002. Hydroperieordiutn end neeitee in chicks fed chlori nated hydrocarbon. Poultry Science 41:205. 116 ( setn.umimuss', ^ qgm Environmental Health Perspective* HONS" 207271 ''Twjhb sWui. iln>Mdfi>fiii i e> Wf*- fc Flick. D, P., O'Dell, R, G. and Cl.ild., V. A. 1W6, Studies of the chick edema disease. 3. Similarity of symptoms produced by feeding ehlorinated biphenyl. Poult. Sci. 44:14(0. 7. Bauer, II., Scliula, K. H. and Spicgrlberg, U, 1961. Bcruflirhe Vergillungcn bci der Hcrtlcllung von Chlorpltcnot-Verbindungen. Arch. Gcwcrbepalliol, Oracrbchyg. 18: 338. 8. Behrbohm, p. ltsi. Ober Gcfahren belm Umgang nit Chloncrtcn I'licnokn. Dtuh. Gcsundlicitmv. 14: 014. V. Higginbotham, G. It. ct al. 10G8. Chemical and toxico logical evaluation* of ieolnled and synthetic ehloroderivative* of dibenio-p-dioxin. Nature 220: T02. 10. Koeman, J. H., Ten Noever de Brau*. M. C. and Voa, It. 11. dc. I960. Chloric Hied biphenyl* in 6*h, mussel*. and bird* from the River Rhine- and the Nethcrlaiida coaxial area. Nature 221: 1120. 11. Voa, J. G. and Koeman. J. H. 1070. Comparative ___ toaicologic study with polychlorinated biplicnyl in eliiekena with *|cial reference to porphyria, edema formation, liver neerosin, and tissue residues. Toxicol. Appl. Phxrmieol. 17:058. 12. Vos, J. G. et si. 1070. ldentiBcstion and toxicological evaluation of ehlorinated dibenxofursn and ehlorinated naphthalene in two commercial polychlorinated bijtltcnyls. Pood Coamet. Toxicol. 8: 025. 13. Hofmann, H. T. 11157. Ncuere Erfahrungen mit hoch- loxiar.hen Chlorkohlenwaaseratoflen. NaunynSchmiedebeTga Arch. Exp. Pathol. Pharmakol. 232: 228. 14. Voa, J, G. and Bcctn*, K, B. 1971. Dermal toxicity studies of technics] polychlorinated biphenyls and frartiona thereof in rabbit#. Toxicol. Appl. Pliannaeol. 19:617. 15. Voa, J. G., and Notenboom-Ram, K, Comparative toxicity atudics of 2,4,5,2',4\5'-bcx*chlorobiphenyl and a polyclilorinated bi|>hcnyl mixture in rabbila. (Submitted for publication). 10. Tanaka, K. et al. 1909. Experimental subacute poboning by chtorobiphcnyls, particularly the influence eo the eerum bpida in rata. Fukuoka-Igsku-Zaasbi. BO: 544. 17. Grant, D. L,, Phillips. W. E. J. and Vilieneuve, D. C. 1971. MrlsbolitJn of a polychlorinated bi|ihenyl (Aroelor 1254) mixture m tbs rat. Bull. Environ. Contamin. Toxicol. 0:102. 16. Ttoeker, K. K. and Crabtree, D. 0.1970. Handbook of Toxicily of Ptotkidet to Wildlife. U.8. Dept, of In terior, Buna* of Sport Fisheries and Wildlife Roaoureea Pab. Na. 14. p. 19. 19. Miller, J. W. 1944. Pathologic ebongee in animal* ex ' posed to a eommercitl ehlorinated diphenyl. Public Health RpU. 59: 1085. 20. Bennett, G. A., Drinker, C. K. and Warren, M. F. 1988. Morphological change# in the liver# of rats re sulting from exposure to certain ehlorinated hydro carbons i. Indus', llyg. Toxicol. 20: 97. 11. Nishuumi, M. 1970. Light and electron microscope study of ehlorobipltenyl poisoning. In mouse and monkey liver. Arch. Environ. Health 21:820. 22. Kohanawa, M. el al. 1909. Poisoning due to an oily by-product of rice-bran similar to chick edema tliwnac. I). Tctrschlorodiphrnyl as toxic substnnrc. Nat. Inst. Anim. Health Quart, ft: 220. 23. Rehfcld, B. M., Bradley, 11. L and Sundc, M. L. 1971. Toxicity studies on polychlorinated biphenyl* in the chick, I. Toxicity and aymptoma. Poul. Sci 50 1090. 24. Platonow, N. 8. and Funndl, H. 6. 1971. Anti-androgcnic-liko affect of polychlorinated biphenyls In cockerela. Vet. Rec. 88: 109. 25. Presat, Jefferies, P. J. and Moore, N. W. 1970. Polychlorinated biphenyls in wild birds in Britain and their avian toxicity, Environ. Pollut, 1: 3. 20. Wedel, H. von, Holla, W. A. and Denton, J. 1943. Observations on the toxic effects resulting front cx|*oaure to chlorinsted naphlhtlenc and chkirinalcd phenyl* with suggestions for prevention, Rulibcr Agr 53: 419. 27. Norbaek, D. H. end Allen, J, R. 1070, Knsynintie end morpholigic alteration* of hepatic endoplasmic reticulum induced by s chlorinated aromatic hydro carbon. >`ed. I*roc. 29: 818 28. Rtscbrough, R. W. cl si. 19G8, Polychlorinated bi phenyls in the global ecosystem. Naturr 220:1098. 29. Lincer, J. L. and Peak all, D. H. 1970. McUbolic efleeu of polychlorinated biphenyls In American kestrel. Nature 228:783. 30. Street, J, C. et al. 1909. Comparative effect* of poly chlorinated biphenyl* and orgnnochlorine pesticides in induction of hepatic microsomal cniytnc. Presented at ACS meeting September 8-12, New York. 81. Vilieneuve, D. C. el al. 1971. Efleet* of PCB adminis tration on tnSetoaomal eniymc activity in pregnant rabbit*. Bull. Environ. Conlsmin, Toxicol. 0:120. 82. Komatsu, F. and Tanaka. K. 1971. Shortening of bexobarbital sleeping time and change of scrum tri glyceride. level in chlorobipbenyls-intoxic*ted rat*. Fukuoka-lgsku-Zaeahi, 02: 35. 83. Voa, J. G. et al. 1971. Polychlorinated bi|ihcnyU as indueen of hepatic porphyria in Japaneee quail, with special reference to 1-aminolevulinic acid synthetase activity, fluorescence, and residues in the liver. Toxicol. Appl. Pharmacol. 20:232. 84. Flick, D. F. and O'Dell, K. G. 1908. Studies of the chick edema dieeaac. 6. Preventive treatment with oral diuretics. Poult. Sci. 47:621. 85. Friend, M., and Trainer, D. 0.1970. Polychlorinated biphenyl: interaction with duek hepatitis virus. Sei sm 170: 1314. 36. Vos, J. G. and Roij. Th. de. Immunosuppressive activity of a polychlorinated biphenyl preparation on the humoral immune response In guinea pigs. Toxicol. Appl. Pharmacol. (In press). >7. Bitman, J. and Cecil, 11. C. 1970. Estrogenic activity of DDT analog* and polychlorinated biphenyl*. J. Agrie. Food Chem. 18: 1108. 38. MeLaughlin, J. et al. 1903. The injection of ehcmicata into the yolk tae of fertile egga prior to inrulvlion a* a toxicity test. Toxicol. Appl. Pharmacol. 5: 700. 89. Ogaw*. M. 1971. Electropliyaiological and histological studies of experimental ehlorobipltenyl poisoning. Fukuoka-Igaku-Zosahi 02: 74. April 1972 MOMS 207272 117