Document B4qX3RB7rG1Er7gajZ6qqBoJ

I i i Organochlorine Pollutants in Peregrines and Merlins Migrating through Wisconsin Robert W. Risebrough Department of Nutritional Science* Institute of Marine Resources ti University of California Berkeley, California 94720 ' Gregory L. Fiorant Laboratory uf Ornithology. ( ornell Universiij. Ithaca. New York Daniel D. Berger 1328 N. Jefferson ' Milwaukee. Wisconsin 33202 ' The discovery that the Peregrines (Fa/co pere- cm Canada (Hall, this issue), the United States f- ilrinus) breeding in the eastern Arctic are laying (Hickey and Anderson, 1968) and Great rI . 1|ffiin-shelled eggs and are showing symptoms of Britain (Ratcliffe, 1970). ^reproductive failure (Berger et al., this issue) At the conference convened in Madison, IWlMfeiurthat this population is beginning to be Wisconsin, by J. J. Hickey in 1965 to examine uMTby the same extinction process that 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, Hickcy'1969; ^a,c*`^c' 1970). The only environmental pollution was consistent PereSE* 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 stuped that eggshell thinning had been asso- ductive failure now appears to threaten the aaS with the population decline (Hickey and survival of the Arctic populations, it has be ?n, 1968). In Great Britain there was come imperative to determine more precisely i jiderable amount of evidence that exces the particular pollutants responsible. 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 I955,||j|ggging 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 tural us(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 coosist primarily 6f polychlorinated mortality may be contributing to the decline in biphenyls which have become widespread and reproductive oapacity of the Ungava Peregrines locally abundant pollutants (Jensen et al., (Berger4ef al., this issue) the pattern of egg 1969; Kooman et al., 1969; Risebrough et al.. 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 t DSW 332397 STLCOPCB4078973 ---- -J- - -- - 248 The Canadian Field-Naturalist Vol. 84 is more widespread in the environment than was previously suspected (Fimreite et al., this issue). Waterfowl may accumulate lead from ingested shotgun pellets (Baglcy and Locke, 1967) and Peregrines preying upon them might acquire dangerous concentrations. There is as yet, however, no evidence that links either metal at environmental concentrations to the shell thinning phenomenon. Proof is rapidly accumu lating, however, that one or more of the chlor inated hydrocarbons, particularly the DDT compound DDE, may induce shell thinning under both environmental and experimental conditions (Hickey and Anderson, 1968; Porter and Wiemeyer, 1969; Heath et al., 1969; Anderson et al., 1969). Very small concentra tions of DDE are associated with significant changes in shell thickness in eggs of the Brown Pelican (Pelecanus occidentalis) (Risebrough, Anderson and Schreiber, unpublished observa tions). The role of DDE and of other chlorin ated hydrocarbons found in the environment such as dieldrin and the polychlorinated bi phenyls in producing additional sublethal effects that might interfere with reproduction is as yet unclear. Delayed breeding or abnormalities in behaviour could be associated with the high rate of steroid degradation caused by the liver enzymes induced by these compounds (Jefferies, 1967; Peakall, 1970). The volume that emerged from the 1965 conference in Madison (Hickey, 1969) concludes with the statement by Hickey and Roelle "How much industrial pollutants like the polychlorinated biphenyls have also contri buted to some of these phenomena promises to be an absorbing chapter in the research of the immediate future" (Hickey and Roelle, 1969). The present paper reports on the polychlorina ted biphenyls and other chlorinated hydro carbons in fat biopsy samples obtained from ten Peregrines and seven Merlins (Pigeon Hawk, Falco cotumbarius) trapped at the Cedar Grove Ornithological Station on the western shore of Lake Michigan during the fall migrations of 1968 and 1969. Materials and Methods All of the Peregrines were immature birds of the year and therefore approximately three months old. Seven were biopsied in 1968 and three in 1969. Ail of the Merlin samples were obtained in 1969. Three were adult males, one an adult female, and the remaining three were immatures of the year. The biopsy technique has been described previously (Endcrson and Berger, 1968). There have been no indications that this procedure harms the birds in any way. Biopsy samples have been obtained from Harriers (Circus cyaneus) that have been observed for many months afterwards (Frances Hamerstrom, per sonal communication). The adipose tissue biopsy samples were frozen, either in acetone-washed glass vials capped with aluminum foil, or in sterile packets lined internally with aluminum foil which are used in medicine for antiseptic gauzes. The samples were weighed in the laboratory to ob tain wet weights and then ground in a Waring blendor with anhydrous sodium sulfate. Lipids were obtained by soxhlet extraction for at least six hours with a hot mixture of two parts of hexane and one part of acetone. The organic solvents were removed by evaporation. When small amounts of sodium sulfate were carried over into the extract, the lipid was dissolved in petroleum ether and washed with water. The biopsy samples were small. The Pere grine samples averaged 0.49 grams, with a range from 0.0496 to 0.983 gm, and the Merlins averaged 0.162 gm, with a range from 0.0497 to 0.5608 gm. Some samples were found to consist mainly of connective tissue rather than lipid. The Peregrine samples consisted of an average of 69% by weight of extractable lipid, with a range from 31 % to 91 %. One Merlin sample consisted of only 5% lipid, the average percent lipid among the Merlin samples was 35%, and the highest value was 68%. The lipid extracts were dried at 65 for 8-12 hours, weighed in the beakers, dissolved in hexane and divided into one or more aliquots. The aliquot analysed for the DDT and PCB compounds was passed through a modified Davidow column (Stanley and LeFavoure, 1965). This column, consisting of celite, sul furic acid and fuming sulfuric acid, permits rapid cleanup with quantitative recov- Inirii iH m itofiumimUmttkttim lihfaiai-**-- * i*1""11 rnnwmmmmmm mm DSW 332398 i STLCOPCB4078974 . 84 and were one were ibed here dure iptes reus lany per- vere vials kets are The obring pids east s of anic hen ried d in eremge ' lins 7 to isist pid. age ha iple ;ent and -12 in ots. CB tied jre, sulnits ov- i. I t l. i i 1970 Risebrough et. al.: Pollutants in Peregrines and Merlins 249 1 cries of the DDT compounds and PCB. of the polychlorinated biphenyls encountered in ! Although not an important factor for the environmental samples. DDE frequently con j present study, it permits much larger amounts stitutes 90% or more of the DDT compounds ! of lipid material to be treated at one time than present in wildlife. The electron capture re 1 ' docs the florisil method. This procedure, how- sponse of DDE is considerably greater than i ever destroys dicldrin and to determine this that of PCB, and although one of the PCB i compound another method must be employed. compounds emerges at approximately the same : Another aliquot of the lipid extract, in hexane, time as DDE, the error introduced in the DDE i was partitioned twice with acetonitrile, the determination is less than experimental error j combined acetonitrile fractions were evaporated even when the total PCB concentration is up to j to dryness, redissolved in petroleum ether, and five times that of the DDE. Vermeer and Rey l applied to a florisil column. The column was nolds (1970) have commented upon the diffi I rinsed first with 200 ml of petroleum ether and culty in separating the DDT compounds p.p'- ' 200 mi of 6% ethyl ether in petroleum ether. DDD and p.p'-DDT from PCB. On the DC-200 ! Dicldrin was eluted by passing 200 ml of 15% column, both DDT compounds emerge at | ethyl ether in petroleum ether through the col- approximately the same time as a PCB peak i umn. Controls had indicated that 90% or more (Anderson et al., 1969). On the QF-1 column, Ji of the dieldrin applied to a florisil column eluted however, there is no interference between p.p'- in this fraction. DDT and any of the polychlorinated biphenyls ! Blank samples consisting of redistilled petro- usually encountered in environmental samples. J leum ether analysed through the entire proce- Although many different chlorinated biphenyl i dure showed no substances that might interfere compounds are released into the environment, | with the determination of any of the chlorinated relatively few persist in the higher levels of food ! hydrocarbons reported here. chains. Moreover, these are found in approxi The extracts were analysed with a Microtek mately the same proportions in environmental gas chromatograph equipped with a tritium and samples over wide areas of the world. The 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 j mixture of 3%. QF-1 and 10% DC-200, on therefore similar to the chromatograms of Pere j Chromosorb W, 80-100 mesh, acid washed and grine extracts from Mexico, California, and : HMDS treated. Amchitka Island (Risebrough, unpublished re Other laboratories (Reynolds, 1969; Armour and Burke, 1970) have developed methods for separating the polychlorinated biphenyls from some or alt of the chlorinated hydrocarbons of insecticide origin. The polychlorinated biphenyl sults). Moreover, the chromatograms are similar to those obtained from extracts of Brown Pelican eggs from several areas in both North and South America (Risebrough, unpublished results). It is frequently possible, therefore, to compounds emerge at different times from the treat the PCB mixture as a single compound gas chromatograph and occasionally a peak may and to obtain accurate relative concentrations 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 . possible, however, to quantify PCB, DDE, on the QF-1 column is almost always of the p.p'-DDD, p,p'-DDT, dieldrin and endrin on same height as two of the other peaks. It is the basis of the procedure outlined above, with therefore possible to obtain a crude estimate of out any attempt at separating the PCB. Dieldrin the DDD present without initial separation of and DDE emerge at exactly the same timfc on the PCB. This assumption may be tested and the the DC-200 column, but on the QF-1 column identification of p.p'-DDT and p.p'-DDD con - there is no significant interference between firmed by saponification (Anderson et al., 1969; ! dieldrin and DDE, or between dieldrin and any Risebrough et al., 1969). An aliquot of the I f I 0S'<N mm OPPJPP* mm STLCOPCB4078975 1 250 The Canadian Field-Naturalist Vol. 84 I extract, in hexane or petroleum ether, is re fluxed in '5% KOH in ethyl alcohol. The hexane is then separated from the alcohol and potassium hydroxide by the addition of water and a sample injected into the gas chromatograph. The pro cedure converts both DDT and DDD to their respective ethylene derivatives, DDE and DDMU, but leaves the PCB profile of the chromatograms unchanged. 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 emerging after DDE with the areas of the same 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 absolute amounts. Moreover, the values ob tained can be readjusted as methodology is improved. Results and Discussion Enderson and Berger (1968) have previously reported on the chlorinated hydrocarbon resi dues found in biopsy fat samples from immature Peregrines that were also trapped during fall migration at Cedar Grove, Wisconsin. These samples, analysed by the Wisconsin Alumni Research Foundation in Madison, Wisconsin, contained an average concentration of 19.4 ppm of DDE on a lipid basis. DDE concentra tions in the fat of females at the Arctic breeding grounds are much higher, in the order of 300 ppm or higher (Berger et at., 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 0.68 ppm p,p'-DDT, 18.8 12.5 ppm total DDT (DDE -f p,p'-DDD + p,p'-DDT), and 52.2 32.3 ppm PCB. Seven samples were analysed for dieldrin, which averaged 0.4Q 0.64 ppm. All residues are expressed on an extractable lipid basis, with the 95% confidence limits of the standard error of the mean. The values for p.p'-DDD and p.p'-DDT are lower than those previously reported by WARF, Inc., presum- ably a result of interference by PCB in the earlier determinations (Anderson et at., 1969). The dieldrin values *re equivalent to those previously reported and there is no significant difference in the DDE concentrations. On a lipid basis, the average values reported by WARF, Inc. were 19.3 ppm DDE, 0.8 ppm DDD, 1.2 ppm p.p'-DDT and 0.3 ppm dieldrin (Enderson and Berger, 1968). 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 pounds in various tissues, and the times required 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 accumulate the high concentrations found in adults, and lower levels of contamination found in some of the prey species. An understanding of the pharmacodynamics of DDE and PCB in birds is one of the conspicuous deficiencies in our knowledge in the field of pollution ecology. Within several ecosystems so far studied, the concentrations of DDE in birds tends to parallel the concentrations of PCB. The ratio may be approximately one to one, as in San Francisco Bay (Risebrough et at., 1968). DDE is several times more abundant than PCB in several Pacific marine ecosystems (Risebrough et at., 1968), but in Florida, PCB is approximately three times as abundant as DDE in the Brown Pelicans (Risebrough, Gress, Anderson and Schreiber, unpublished manuscript). The cor relation coefficient between the DDE and PCB concentrations is frequently highly significant. These observations have suggested that the ratios observed reflect the local fallout pattern of the DDT and PCB compounds, and that the DDE and PCB show similar patterns of accu mulation, concentration and excretion in the birds and possibly other members of the ecosys tem. Among the 10 Peregrine samples analysed, PCB was more abundant than DDE by ap proximately three times. The correlation co- I f I t i ti ! I i i I i ii <i i ti i l i i i i 'i l DSW 332400 \ STLCOPCB4078976 f , 84 . the '69). hose icant lipid .VRF, 1.2 rson ating es of t the and comuired The .rines f the m to id in ound iding 'B in es in logy. 1, the rallei iy be cisco vcral veral t at.. lately rown and corPCB icant. t the ittem it the accui the osys- ysed, / ap i co- I 1970 Risebrough et. al.: Pollutants in Peregrines and Merlins 251 j efficient is 0.8897, which is significant at the shell thinning associated with egg breakage, , 0.001 level. Although it is not known from disappearance of the eggs, and eating of the I which area of the Arctic these birds have come, eggs by the adult birds f RatclifTe, 1970). In the the results suggest that over a considerable area Ungava population of Peregrines in the eastern 1 of the tundra ecosystems occupied by the Perc- Arctic, shell thinning and egg breakage are now i grines, this ratio reflects the local fallout pattern contributing to reproductive failures (Berger et \ of DDE and PCB. 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 the shell thinning observed in many populations ! may be compared with an average concentra- of birds. No correlation between thinning and j tion of 392 ppm in the lipid of 9 breeding PCB was found in the eggs of the White Pelican i Peregrines from the Mackenzie River region (Pelecanus erythrorhynchos) (Anderson et al., j (Enderson and Berger, 1968), 725 ppm m 1969) or in eggs of the Great Blue Heron j 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 j most the same level of contamination as the rather than PCB is associated with the shell , , Peregrines and might therefore be expected to thinning (Risebrough, Gress, Anderson and J show symptoms of shell thinning. The concen Schreiber, unpublished ms.) Whenever corre trations of total DDT in the adult Merlins lations between PCB and shell thinning have ! ( averaged 314 ppm. 96% of the DDT residues been observed, as in Double-Crested Cormor I in these Merlins therefore consisted of DDE. ants (Phalacrocorax auritus), PCB is also cor | The PCB concentrations averaged 196 ppm related with DDE (Anderson et al., 1969). (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 early 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, in the Peregrines, all other Merlins contained and that PCB is a more potent enzyme inducer more DDE than PCB. With the one immature than is DDE. Delayed breeding may therefore I excepted, PCB was significantly correlated with be one of the environmental effects of PCB, an l DDE (r = 0.9820, p less than 0.001, four effect that could be critical to Arctic-breeding j degrees of freedom). Most of the Merlins, birds which must complete their reproductive 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 Pcre- biphenyls (Katsuki, 1969). Both the contamin , grines, occasionally in high concentrations, it ated rice oil and the Japanese commercial PCB seemed likely that these pollutants were con produce symptoms when fed to chicks similar tributing to the reproductive failures associated to those observed in the "chick edema" syn with population decline (Risebrough et al., drome (Goto et al., 1969). This disease of -- 1968). The dominant symptom of reproductive chicks was first observed in the United States failures of the Peregrines in Britain has been in 1957, and among the symptoms were accu- mmmmmmmmmmmm mm 0S\N 332401 STLCOPCB4078977 h 252 The Canadian Field-Naturalist Vol. 84 F it mulation of fluid in the pericardial sac and in Goto, M* Sakagurhi, K,, and Ottawa, K. 1969. the abdominal cavity, subcutaneous edema, and liver and kidney damage (Verrett, 1970). Chlorinated dibenzo-p-dioxins have been shown to be one of the groups of chlorinated synthetic Hydropericardium assay of rice oil which caused Yusho and of Kanechlor 400 in Chickens (in Jap anese with F.nglish abstract). Fukuoka Acta Medics 60: 5J3-5J8. HaN, G. H. 1955. Great momenta in action: The I II I compounds that produce this disease (Higgin botham ft. at., 1968). 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-Natural ist 84(3): 213-230. Heath, R. G., Spann, J. W., and Kreitser, I. F. 1969. Marked DDE impairment of Mallard reproduction I I \ I onic deformities in chicks at very low concen trations (Verrett, 1970). A similar group of compounds, the chlorinated dibenzofurans, are almost as toxic (Schulz, 1970). These resemble in controlled studies. Nature 224: 47-48. Hickey, i. J,, editor. 1969. Peregrine Falcon Populations: Their Biology and Decline. University . of Wisconsin Press, Madison. 396 pp. Hickey, I. 1. and Aadtrsou, D. W. 1968. Chlorin i 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 in the research of the immediate future" and fish-eating birds. Science 162: 271-273. Hickey, J. I. and Roelle, 1. E. 1969. Conference summary and conclusions, in Peregrine Falcon Populations: Their Biology and Decline, J. J. Hickey, ed. University of Wisconsin Press, Madison, * (Hickey and Roelle, 1969). pp. 553-567. Higginbotham, G. R-, Huang, AM Firestone, D., Ver Acknowledgements rett, J-, Rcss, Jn and Campbell, A. D. 1968. Chemical and toxicological evaluations of isolated I I 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 5 Literature Cited Anderson, D. W, Hickey, J. J, Risebrough, R. W, the field. Ibis 109: 266-272. Jefferies, D. J. and Prestt, I. 1966. Post-mortems of Peregrines and Lanners with particular reference to 1 Hughes, D. F., and Christensea, R. E. 1969. Sig organochlorine residues. British Birds 59: 49-64. nificance of chlorinated hydrocarbon residues to Jensen, Johnela, A. G., Olsson, M-, and Otterlind, breeding pelicans 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, I. A. and Burke, J. A. 1970. Method for Katsuki, S. 1969. Reports of the Study for "Yusho" separating polychlorinated biphenyls from DDT and (Chlorobiphenyls Poisoning). Fukuoka Acta Medica. its analogs. Journal of the Association of Official 60: 407. Analytical Chemists S3: 761-768. Koemaa, J. H., Ten Noever dc Brauw, M. C., and Bagley, 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 ' Environmental Contamination and Toxicology 2: 297-305. Berger, D. D., Andersoa, D. W, Wearer, 1. D., Risebrough, R. W. and Reynolds, L. M. 1970. `'hell thinning in eggs of Ungava Peregrines. Cana dian Field-Naturalist 84(3): 265-267. Cade, T. J,, White, C. M,, and Haugh, J. R. 1968. Peregrines and pesticides in Alaska. Condor 70: 170-178. Eadersoa, i. H. aid Berger, D. D. 1968. Chlorin ated hydrocarbon residues in Peregrines and their prey species from northern Canada.1 Condor 70: 149-153. FlmreUe, N,, Fyfe, R. W, and Keith, I. A. 1970. the Netherlands Coastal Area. Nature 221: 1126 1128. . Peakall, D. B. 1970. p.p'-DDT: Effect on calcium metabolism and concentration of estradiol in the blood. Science 168: 592-594. Porter, R. D. and Wiemeyer, S. N. 1969. Dieldrin and DDT: Effects on Sparrow Hawk eggshells and reproduction. Science 165: 199-200. Rateliffe, D. A. 1963. The status of the Peregrine in Great Britain. Bird Study IO. 56-90. Ratcliffs, D. A. 1967. Decrease in eggshell weight in certain birds of prey. Nature 215: 208-210. Rateliffe, D. A. 1970. Changes attributable to pesti ! <I 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 Naturalist 14(3): 269-276. Ecology 7: 67-115. I DSW 332402 STLCOPCB4078978 >1. 84 1969. caused n Japvfedica i: The Press. . atural- 1969. luction Falcon versiiy. hlorinptorial erence Falcon J. J. idison. ., Ver1968. olated Jioxin. n proncc in emi of nee to 49-64. erttnd, s from 'usho" tcdica. and iyIs in ic and 1126- alcium in the ieldrin lls and cgrine weight 0. > pestithick.pplied | ; ; ' , . ' 1 . ' j { j ' . j ! , 1 ! j l !> 'j I i | 1 ! i i | ) | [ Ii , 1970 Rjsebrckjgh et. al.: Pollutants in Peregrines and Merlins 253 Reynolds, L. M. 1969. Polychtorobiphenyls (PCB's) and their interference with pesticide residue analysis. Journal of Environmental' Contamination and Toxicology. 4: 128-143. Risebrongh, R. W,, Rckhe, P., Peekall, D. ,, Herman, S. G., and Kirvea, M. N. 1968. Polychlorinated biphenyls in the global ecosystem. Nature 220: 1098 1102. Risebrooch. R. WM Reiche, P* and Otcott, H. S. 1969. Current Progress in the determination of the polychlorinated biphenyls. Bulletin of Environ mental Contamination and Toxicology. 4: 192-201. Scfcub, K. H. 1970. Clinical picture and etiology of chloricne. Reprinted in: Effects of 2,4,5,-T on Man and the Environment Hearings before the Subcommittee on Energy, Natural Resources, and the Environment of the Comipittee on Commerce, United States Senate. Serial 91-60. U.S. Govern ment Printing Office, Washington, D.C. Stanley, R. L. and LeFavoore, H. T. 1963. 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. Organo chlorine 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-T on Man and the Environment. Serial 91-60. U.S. Government Print ing Office, Washington, D.C. Received October. 1970 Accepted October, 1970 ' DSW 332403 mm STLCOPCB4078979