Document J3xG5295DeR9rR49RzQrxv59O

\ I Organochlorine Pollutants in Peregrines and Merlins Migrating through Wisconsin Robert W. Riskurough Department of Nutritional Sciences InMinite of Marine Resources University of California Berkeley, California 94720 ' . Gregory I,. Florant Laboratory nl Ornithology. r'ornell UniverMD, Ithaca, New York / ' I Jmniel D. Berger 1328 N. Jefferson ' I Milwaukee. Wisconsin 33202 ' . I The discovery that the Peregrines (Falco pere- ern Canada (Hall, this issue), the United States grinus) breeding in the eastern Arctic are laying (Hickey and Anderson, 1968) and Great WjjJtin-shclled eggs and are showing symptoms of '^'.`productive failure (Berger et al,, this issue) ^S>i^bstthat this population is beginning to be afflPfro i>y the same extinction process that Britain (Ratcliffe, 1970). At the conference convened in Madison, Wisconsin, by J. J. Hickey in 1965 to examine the causes of disappearance of the Peregrine has resultedTM the extirpation of breeding Pere from the eastern United States, all conceivable grines in many areas of North America and factors were considered in detail. Among these, EurgM|i(Hickey, 1969; Ratcliffe, 1970), The only environmental pollution was consistent Peregmgs of the eastern United States disap- with the pattern of extinction observed in pearedbefore the nature of the extinction pro Peregrine populations in both Europe and I cess was evident, but subsequent research North America (Hickey, 1969). Since repro showed that eggshell thinning had been asso ductive failure now appears to threaten the ciated with the population decline (Hickey and survival of the Arctic populations, it has be AnjcVson, 1968). In Great Britain there was come imperative to determine more precisely a bopjiderable amount of evidence that exces the particular po)lutants responsible. I sive mortality of adult birds had been a major In addition to the evidence relating excessive reason for the rapid decline that began around adult mortality to the use of several of the more 1955, ^ty($jf)ing with the introduction of highly toxic of the chlorinated hydrocarbon insecti toxic insecticides such as dieldrin into agricul cides, Ratcliffe (1970) has accumulated a con 1 tural use (Ratcliffe, 1963; Jefferies and Prestt, siderable amount of data relating the shell 1966). The surviving birds, however, exper thinning among British birds of prey to the ienced reproductive failures that were charac environmental distribution of organochlorine terized by shell thinning, egg breakage, and eat pollutants, including both insecticides with their ing of the eggs by the adult birds (Ratcliffe, derivatives and industrial compounds. The 1967; Ratcliffe, 1970). Although embryonic latter consist primarily 6f polychlorinated mortality may be contributing to the decline in biphenyls which have become widespread and reproductive capacity of the Ungava Peregrines locally abundant pollutants (Jensen el al., I (BcrgcrVf al., this issue) the pattern of egg 1969; Koeman el al., 1969; Risebrough el al., i breakage associated with shell thinning now 1968). Other pollutants that might be contribu observed in this population appears to be iden ting to the decline of the North American tical to the symptoms noted previously in south Peregrines include mercury and lead. Mercury 247 i q--.mnniiiwi vmmrnmmmmmmmmmfmm . ' ' ' v 0SW 033384 STLCOPCB4017346 248 The Canadian Field-Naturalist Vol, 84 is more widespread in the environment than months old. Seven were biopsied in 1968 and was previously suspected (Fimreite et al., this issue). Waterfowl may accumulate lead from ingested shotgun pellets (Baglcy and Locke, three in 1969. All of the Merlin samples were obtained in 1969. Three were adult males, one an adult female, and the remaining three were 1967) and Peregrines preying upon them might' immatures of the year. acquire dangerous concentrations. There is as The biopsy technique has been described yet, however, no evidence that links cither motal previously (Endcrson and Berger, 1968). There at environmental concentrations to the shell have been no indications that this procedure thinning phenomenon. Proof is rapidly accumu harms the birds in any way. Biopsy samples lating, however, that one or more of the chlor have been obtained from Harriers (Circus inated hydrocarbons, particularly the DDT cyaneus) that have been observed for many compound DDE, may induce shell thinning months afterwards (Frances Hamerstrom, per under both environmental and experimental sonal communication). conditions (Hickey and Anderson, 1968; Porter The adipose tissue biopsy samples were and Wiomeyer, 1969; Heath et al., 1969; frozen, either in acetone-washed glass vials Anderson et al., 1969). Very small concentra capped with aluminum foil, or in sterile packets tions of DDE are associated with significant lined internally with aluminum foil which arc changes in shell thickness in eggs of the Brown used in medicine for antiseptic gauzes. The Pelican (Pelecanus occidentalis) (Risebrough, samples were weighed in the laboratory to ob Anderson and Schreiber, unpublished observa tain wet weights and then ground in a Waring tions). The role of DDE and of other chlorin blendor with anhydrous sodium sulfate. Lipids ated hydrocarbons found in the environment were obtained by soxhlet extraction for at least such as dieldrin and the polychlorinated bi six hours with a hot mixture of two parts of phenyls in producing additional sublethal effects hexane and one part of acetone. The organic that might interfere with reproduction is as yet solvents were removed by evaporation. When unclear. Delayed breeding or abnormalities in small amounts of sodium sulfate were carried behaviour could be associated with the high over into the extract, the lipid was dissolved in rate of steroid degradation caused by the liver petroleum ether and washed with water. enzymes induced by these compounds (Jefferies, The biopsy samples were small. The Pere 1967; Peakall, 1970). The volume that emerged grine samples averaged 0.49 grams, with a range from the 1965 conference in Madison (Hickey, from 0,0496 to 0.983 gm, and the Merlins 1969) concludes with the statement by Hickey averaged 0.162 gm, with a range from 0.0497 to and Roelle "How much industrial pollutants like 0.5608 gm. Some samples were found to consist the polychlorinated biphenyls have also contri mainly of conneotive tissue rather than lipid. buted to some of these phenomena promises to The Peregrine samples consisted of an average be an absorbing chapter in the research of the of 69% by weight of extractable lipid, with a immediate future" (Hickey and Roelle, 1969). range from 31% to 91%. One Merlin sample The present paper reports on the polychlorina consisted of only 5% lipid, the average percent ted biphenyls and other chlorinated hydro lipid among the Merlin samples was 35%. and carbons in fat biopsy samples obtained from ten the highest value was 68%. Peregrines and seven Merlins (Pigeon Hawk, The lipid extracts were dried at 65 for 8-12 Falco colurnbarius) trapped at the Cedar Grove hours, weighed in the beakers, dissolved in Ornithological Station on the western shore of hexane and divided into one or more aliquots. Lake Michigan during the fall migrations of The aliquot analysed for the DDT and PCB 1968 and 1969. compounds was passed through a modified Materials and Methods Davidow column (Stanley and LeFavoure, 1965). This column, consisting of celite, sul All of the Peregrines were immature birds of furic acid and fuming sulfuric acid, permits the year and therefore approximately three rapid cleanup with quantitative recov- DSW 033385 ,1 lt ; I I it 1 i ii i i ) Ii i I ! I I STLCOPCB4017347 , 1970 Risebrough et. al.: Pollutants in Peregrines and Merlins 249 nd :rc >nc :rc i cries of the DDT compounds and PCB. of ihc polychlorinated biphenyls encountered in . Although not on important factor for the environmental samples, DDE frequently conj present study, it permits much larger amounts stitutes 90% or more of the DDT compounds I of lipid material to be treated at one time than present in wildlife. The electron capture re1 1 docs the llorisil method. This procedure, how- sponse of DDE is considerably greater than i ever destroys dicldrin nnd to determine this that of PCB, and although one of the PCB cd J compound another method must be employed, compounds emerges at approximately the same :rc Another aliquot of the lipid extract, in hexane, time as DDE, the error introduced in the DDE ire Ics us ay :r- ! was partitioned twice with acetonitrile, the determination is less than experimental error I combined acetonitrile fractions were evaporated even when the total PCB concentration is up to j io dryness, rcdissolved in petroleum ether, and five times that of the DDE. Vermeer and Reyi applied to a (torisit column. The column was nolds (1970) have commented upon the diffi- rinsed first with 200 ml of petroleum ether and culty in separating the DDT compounds p,p'- ` 200 ml of 6% ethyl ether in petroleum ether. DDD and p,p'-DDT from PCB. On the DC-200 rc \ Dieldrin was eluted by passing 200 ml of 15% column, both DDT compounds emerge at tls i ethyl ether in petroleum ether through the col- approximately the same time as a PCB peak :U 1 umn. Controls had indicated that 90% or more (Anderson et al., 1969). On the QF-l column, .rc i of the dieldrin applied to a florisil column eluted however, there is no interference between p,p'- he | in this fraction. DDT and any of the polychlorinated biphenyls vbng ds j Blank samples consisting of redistilled petro- usually encountered in environmental samples. I leum ether analysed through the entire proce- Although many different chlorinated biphenyl ist ! dure showed no substances that might interfere compounds are released into the environment, of | with the determination of any of the chlorinated^ relatively few persist in the higher levels of food ic | hydrocarbons reported here, chains. Moreover, these are found in approxi in j The extracts were analysed with a Microtek mately the same proportions in environmental id | gas chromatograph equipped with a tritium and samples over wide areas of the world, The in j a nickel-63 electron capture detector. Glass chromatograms of the PCB compounds in the i columns were used containing 3% QF-1, or a Peregrines analysed in the present study are e- j mixture of 3% QF-1 and 10% DC-200, on therefore similar to the chromatograms of Pere je m , Chromosorb W, 80-100 mesh, acid washed and grine extracts from Mexico, California, and HMDS treated. Amchitka Island (Risebrough, unpublished re to Other laboratories (Reynolds, 1969; Armour sults). Moreover, the chromatograms are similar tt and Burke, 1970) have developed methods for to those obtained from extracts of Brown 1 separating the polychlorinated biphenyls from Pelican eggs from several areas in both North je some or all of the chlorinated hydrocarbons of and South America (Risebrough, unpublished a insecticide origin. The polychlorinated biphenyl results). It is frequently possible, therefore, to Ic compounds emerge at different times from the treat the PCB mixture as a single compound it gas chromatograph and occasionally a peak may and to obtain accurate relative concentrations d coincide or interfere with the peak produced of PCB using any one of the several peaks. The by one of the insecticides. We have found it peak emerging at the same time as p,p'-DDD 2 . possible, however, to quantify PCB, DDE, on the QF-1 column is almost always of the n p,p'-DDD, p,p'-DDT, dieldrin and endrin on same height as two of the other peaks. It is s. the basis of the procedure outlined above, with therefore possible to obtain a crude estimate of B out any attempt at separating the PCB. Dieldrin the DDD present without initial separation of d I and DDE emerge at exactly the same tiirfe on the PCB. This assumption may be tested and the -i the DC-200 column, but on the QF-1 column identification of p,p'-DDT and p,p-DDD con i- | there is no significant interference between firmed by saponification (Anderson et at., 1969; 3 I dieldrin and DDE, or between dieldrin and any Risebrough et al., 1969). An aliquot of the DSW . irvx.rc r * 033386 STLCOPCB4017348 250 The Canadian Field-Naturalist Vol. 84 extract, in hexane or petroleum ether, is re- ably a result of interference by PCB in the fluxed in 5% KOH in ethyl alcohol. The hexane earlier determinations (Anderson et al., 1969), . is then separated from the alcohol and potassium The dicldrin values arc equivalent to those hydroxide by the addition of water and a sample previously reported and there is no significant injected into the gas chromatograph. The pro- difference in the DDE concentrations. On a lipid cedurc converts both DDT and DDD to their basis, the average values reported by WARF, respective ethylene derivatives, DDE and Inc. were 19.3 ppm DDE, 0.8 ppm DDD, 1.2 DDMU, but leaves the PCB profile of the ppm p,p'-DDT and 0.3 ppm dieldrin (Enderson chromatograms unchanged. and Berger, 1968). Since the profile of the PCB peaks was similar, but not identical to the profile observed in chromatograms of the commercial prepara- tion Aroclor 1254, PCB was quantified by comparing the total area of the PCB peaks First year immature Peregrines migrating from the Arctic have therefore low residues of DDE. Unfortunately little is known about the relationships among dietary levels of DDE and PCB, equilibrium concentrations of these com- emerging after DDE with the areas of the same pounds in various tissues, and the times required peaks in chromatograms of standard Aroclor 1254. The procedure is therefore arbitrary, but permits the determination of relative amounts of PCB within the correct order of magnitude of to achieve an equilibrium concentration. The low concentrations found in these Peregrines presumably reflect therefore both the age of the birds, which possibly has not permitted them to absolute amounts. Moreover, the values ob- accumulate the high concentrations found in tained cap be readjusted as methodology is adults, and lower levels of contamination found improved. in some of the prey species.' An understanding Results and Discussion of the pharmacodynamics of DDE and PCB in birds is one of the conspicuous deficiencies in Enderson and Berger (1968) have previously our knowledge in the field of pollution ecology. reported on the chlorinated hydrocarbon resi- Within several ecosystems so far studied, the dues found in biopsy fat samples.from immature concentrations of DDE in birds tends to parallel Peregrines that were also trapped during fall migration at Cedar Grove, Wisconsin. These samples, analysed by the Wisconsin Alumni Research Foundation in Madison, Wisconsin, concentrations of PCB. The ratio may be approximately one to one, as in San Francisco ay (Risebrough et al., 1968). DDE is several times more abundant than PCB in several contained an average concentration of 19.4 Pacific marine ecosystems (Risebrough et al., ppm of DDE on a lipid basis. DDE conccntra- 1968), but in Florida, PCB is approximately lions in the fat of females at the Arctic breeding three times as abundant as DDE in the Brown grounds are much higher, in the order of 300 ppm or higher (Berger et al., this issue). The ten Peregrine samples analysed in the present study contained 17.9 12.3 ppm DDE, 0.23 0.34 ppm p.p'-DDD, 0.71 =t 0.68 ppm p,p'-DDT, 18.8 12.5 ppm total DDT (DDE Pelicans (Risebrough, Gress, Anderson and Schreiber, unpublished manuscript). The correlation coefficient between the DDE and PCB concentrations is frequently highly significant. These observations have suggested that the ratios observed reflect the local fallout pattern -j- p.p'-DDD -f p.p'-DDT), and 52.2 32.3 of the DDT and PCB compounds, and that the ppm PCB. Seven samples were analysed for DDE and PCB show similar patterns of accudicldrin, which averaged 0.40 0.64 ppm. mulation, concentration and excretion in the All residues are expressed on an extractable birds and possibly other members of the ecosys- lipid basis, with the 95% confidence limits of tent. the standard error of the mean. The values for Among the 10 Peregrine samples analysed, p.p'-DDD and p.p'-DDT are lower than those previously reported by WARF, Inc., presum- PCB was more abundant than DDE by approximately three times. The correlation co- Mmawmmv w . ...... ................. DSW 033387 i [ I ! 1 i j ' 1 1 ! i , ' I | I j i J 1 I t , i | i j , ( i J ( I i j j j i I i t i i i i STLCOPCB4017349 . 84 the 69). hose iCilllt lipid \KI!. . 1.2 rson uing it of the and omtired The incs tf the m to .d in ound \ding U in in ogy. . the allcl / be lisco 'Cal xral al., itcly own and cor?CB rant, the tern the ecu* the isys- fed, apco- l 1970 Risebrough et. al.: Pollutants in Peregrines and Merlins 251 cflicicnt is 0.8897, which is significant at the 0.001 level. Although it is not known from which area of the Arctic these birds have come, the results suggest that over a considerable area of the tundra ecosystems occupied by the Pcrcgrincs, this ratio reflects the local fallout pattern of DDE and PCB. shell thinning associated with egg breakage, disappearance of the eggs, and eating of the eggs by the adult birds (KatclifTc, 1970). In the Ungava population of Peregrines in the eastern Arctic, shell thinning and egg breakage arc now contributing to reproductive failures (Berger et al., this issue). The evidence available to date The four adult Merlins averaged 302 ppm suggests, however, that PCB is not a cause of DDE (139-704 ) in the lipid fraction. This value Ihe shell thinning observed in many populations may be compared with an average concentra- of birds. No correlation between thinning and tion of 392 ppm in the lipid of 9 breeding PCB was found in the eggs of the White Pelican Peregrines from the Mackenzie River region (Petecanus erythrorhynchos) (Anderson et al., . (Enderson and Berger, 1968), 725 ppm jn ' *969) or in eggs of the Great Blue Heron the fat of four adult Peregrines from Alaska (Ardea herodias) (Vermeer and Reynolds, ! (Cade et al., 1968) and 334 ppm in the lipid of 1970). An analysis of approximately 200 eggs 9 adult Peregrines from Ungava (Berger et al, of the Brown Pelican from both eastern and i this issue). Merlins therefore may possess al- western North America has shown that DDE Ji most the same level of contamination as the father than PCB is associated with the shell . Peregrines and might therefore be expected to thinning (Risebrough, Gress, Anderson and 1 show symptoms of shell thinning. The concen- Schreiber, unpublished ms.) Whenever corre- ' trntions of total DDT in the adult Merlins lations between PCB and shell thinning have ! averaged 314 ppm. 96% of the DDT residues keen observed, as in Double-Crested Cormor- j in these Merlins therefore consisted of DDE. ants (Phalaerocorax auritus), PCB is also cor- j The PCB concentrations averaged 196 ppm related with DDE (Anderson et al., 1969). J, (44-467). The samples were not analysed for Peakall (1970) has reported that p,p'-DDT dieldrin. delays egg laying in the Ringdove (Streptopelia In the three immatures, DDE averaged 49.3 risoria) and that the delay is associated with , ppm (10.8, 18.6 and 119.3), total DDT aver- lower concentrations of estradiol in the blood j aged 50.3 ppm, and PCB averaged 28.6 ppm caily in the breeding cycle. Peakall had earlier (5.7,29.0 and 51.2). With the exception of one reported (in Risebrough et al, 1968) that immature Merlin that contained 18.6 ppm DDE technical DDT, p,p'-DDE, and PCB induce the ! and 51.2 ppm PCB, a ratio similar to that found synthesis of liver enzymes that degrade estradiol, J in the Peregrines, all other Merlins contained am* that PCB is a more potent enzyme inducer 1 more DDE than PCB. With the one immature than is DDE. Delayed breeding may therefore l excepted, PCB was significantly correlated with he one of the environmental effects of PCB, an i DDE (r= 0.9820, p less than 0.001, four effect that could be critical to Arctic-brecding j degrees of freedom). Most of the Merlins, birds which must complete their reproductive j therefore, appear to be coming from a region of cycle within a restricted period of time. { the boreal forest where the pollutant fallout A recent investigation in Japan of the pattern is different from that in the tundra "Yusho" or Rice Oil Disease has traced the ecosystem occupied by the Peregrine. cause to rice oil contaminated by chlorinated When PCB was found to be present in Peregrines, occasionally in high concentrations, it seemed likely that these pollutants were contributing to the reproductive failures associated wiih population decline (Risebrough et al., 1968). The dominant symptom of reproductive failures of the Peregrines in Britain has been biphenyls (Katsuki, 1969). Both the contaminated rice oil and the Japanese commercial PCB produce symptoms when fed to chicks similar to those observed in the "chick edema" syndrome (Goto et al., 1969). This disease of chicks was first observed in the United States in 1957, and among the symptoms were accu- l 1 DSW 033388 STLCOPCB4017350 252 The Canadian Field-Naturalist Vol. 84 | mutation of fluid in the pericardial sac and in Goto, M., Siikiiguehl, K., and Ogawa, k. 1969, the abdominal cavity, subcutaneous edema, and liver and kidney damage (Verrett, 1970), Chlorinated dibouzo-p-dioxins have been shown Hydropcricardium assay of rice oil which caused Yusho and of Kanechlor 400 in Chickens (in Jap anese with English abstract). Fukuoka Acta Medica 60: 533-538. ' ' j to be one of the groups of chlorinated synthetic Hall, G. II. 1955. (ircat moments in action; The i compounds that produce this disease (Higgin botham el. al., 19fi8). These compounds have also been shown to be present in the herbicide 2,4,5-T and induce both mortality and embry story of the Sun Life Falcons. Mercury Press, Montreal (Reprinted in the Canadian Field-Naturalist 84(3): 213-230. Heath, M. G., Spann, J. W., and Kreltzer, I. F. 1969. Marked DDE impairment of Mallard reproduction , . , 1 onic deformities m chicks at very low concen trations (Verrett, 1970). A similar group of compounds, the chlorinated dibenzofurans, are alnu st us toxic (Schulz, 1970). These resemble in controlled studies. Nature 224: 47-48. Hickey, J. J., editor. 1969. Peregrine Falcon Populations: Their Biology and Decline. University of Wisconsin Press, Madison. 596 pp. Hickey, J. i. and Anderson, D. W. 1968. Chlorin , ' the chlorinated biphenyls in structure and might ated hydrocarbons and eggshell changes in raptorial | be derived from them. Whether they are now present in the environment and pose a threat to wildlife promises to be "an absorbing chapter and fish-eating birds. Science 162: 271-273. Hickey, J. 1. and Roelle, I. E. 1969. Conference summary and conclusions, in Peregrine Falcon Populations: Their Biology and Decline, J. J. i ' i in the research of the immediate future" Hickey, ed. University of Wisconsin Press, Madison. , (Hickey and Rocllc, 1969). pp. 553-567. Higginbotham, G. R., Huang, A., Firestone, D., Ver- : ! Acknowledgements rett, J., Ress, J., and Campbell, A. D. 1968. Chemicaland toxicological evaluations ofisolated , ' The research was supported by the National and synthetic chloro derivatives of dibenzo-p-dioxin. ! Science Foundation grants GB 6362 and GB Nature 220: 702-703. , ' 11649. , Jefferies, D. J. 1967. The delay in ovulation pro duced by p.p'-DDT and its possible significance in I Literature Cited the field. Ibis 109: 266-272. ' Jefferies, D. J. and Prestt, L 1966, Post-mortems of Anderson, D. W., Hickey, I. J., Risebrough, R. VV, Peregrines and Lanners with particular reference to i !-> ` Hughes, D. F., and Christensen, R. E. 1969. Sig organochlorine residues. British Birds 39: 49-64. f nificance of chlorinated hydrocarbon residues to Jensen, S., Johncls, A. G., Ol&son, Mf and Otterllnd, j breeding pelienn* and cormorants. Canadian Field- G. 1969. DDT and PCB in marine animals from | Naturalist 83(2): 91-112. Swedish waters. Nature 224: 247-250. Armour, J. A. and llurkc, I. A. 1970. Method for Katsukl, S. 1969. Reports of the Study for "Yusho" 1 separating polychlorinated biphenyls from DDT and (Chlorobiphenyls Poisoning). Fukuoka Acta Medica. i . its analogs. Journal of the Association of Official 60: 407. J Analytical Chemists 53: 761-768. Kocman, J. II., Ten Noever de Brauw, M. C., and J Buglty, G. E. and Locke, L. N. 1967. The occur De Vos, R.' H. 1969. Chlorinated biphenyls in rence of lead in tissues of wild birds. Bulletin of fish, mussels and birds from the River Rhine and i 1 Environmental Contamination and Toxicology the Netherlands Coastal Area. Nature 221: 1126- ; 2: 297-305. 1128. ., Berger, D. D., Anderson, D. W., Weaver, J. D., Peakall, D. B. 1970. p.p'-DDT: Effect on calcium Risebrough, R. W. and Reynolds, L. M. 1970. metabolism and concentration of estradiol in the 1 . Shell thinning in eggs of Ungava Peregrines. Cana- blood. Science 168: 592-594. , ` ' ! , ' dian Field-Naturalist84(3); 265-267. Cade, T. J., White, C. M., and Haugb, J. R. 1968. Peregrines andpesticidesin Alaska. Condor 70: 170-178. Enderson, J. H. and Berger, D. D. 1968. Chlorin- ated hydrocarbon residues in Peregrines and their Porter, R. D. and Wlemeyer, S. N. 1969. Dieldrin and DDT: Effects on Sparrow Hawk eggshells and reproduction. Science 165: 199-200. RatclilTe, D. A. 1963. The status of the Peregrine in Great Britain. Bird Study 10: 56-90. 1 J ' ! prey species from northern Canada.' Condor 70: RatclilTe, D. A. 1967. Decrease in eggshell weight i 1 149-153. in certain birds of prey. Nature 215: 208-210. Flmrelte, N., Fyfe, R. W., and Keltb, J. A. 1970. Ratcliffe, D. A. 1970. Changes attributable to pesti- ' ! Mercury contamination of Canadian Prairie seed cides in egg breakage frequency and eggshell thick- > eaters and their avian predators. Canadian Field- ness in some British' birds. Journal of Applied 1 Naturalist 84(3): 269-276. Ecology 7: 67-115. 1 DSW 033389 \ STLCOPCB4017351 .M 1969. I lived JnpjdlCtt The 'revs, urnl* 96V. .'lion .Icon rsity .Minorul tnee Icon . 1. lison. Ver1968. laled oxin. proe in t of e lo 64. Ind, rom ho" lieu. and t in and 26- ium the It in and int ght Hickied 1970 Risebrouch et. al,: Pollutant^ in Peregrines and Merlins 253 Reynolds, L. M. 1969. Polychlorobiphenyls (PCB's) ami their interference with pesticide residue analysis, journal of Environmental Contamination and Toxicology. 4: 128-143, Rischrough, R. W., Relche, P., Peakall, D. B., Herman, S. G., and Klrven, M. N. 1968. Polychlorinated biphenyls in the global ecosystem. Nature 220: 1098 1102. Rischrough, K. W., Rciche, P-, and Olcott, H. S. 1969. Current Progress in the determination of the polychlorinated biphenyls. Bulletin of Environ mental Contamination and Toxicology. 4: 192-201, Schulz, K. il. 1970. Clinical picture and etiology of chloracne. Reprinted in: Effects of 2,4,$,-T on Man and the Environment. Hearings before the Subcommittee on Energy, Natural Resources, and the Environment of the Comrpittee on Commerce, United States Senate. Serial 91-60. U.S. Govern ment Printing Office, Washington, D.C. Stanley, R. L. and LcFavourc, II. T. 1965. Rapid digestion and clean-up of animal tissues for pesticide residue analysis. Journal of the Association of Offi cial Analytical Chemists. 48: 666-667. Vermeer, K. and Reynolds, L. M. 1970. Organochlorine residues in aquatic birds in the Canadian Prairie Provinces. Canadian Field-Naturalist 84: 117-130. Verrett, J. 1970. Statement before the Subcom mittee on Energy. Natural Resources, and the Environment. In: Effects of 2,4,5-Ton Man and the Environment. Serial 91-60. U.S. Government Print ing Office, Washington, D.C. Received October, 1970 Accepted October, 1970 ' \ *,/ i \ i i i f i i f t 1 t 1 i [ i ( ( 1 1 OSW 03339G mm STLCOPCB4017352