Charles J. Stafford

Environmental contaminants in bald eagle eggs—1980–84—and further interpretations of relationships to productivity and shell thickness

Bald eagle (Haliaeetus leucocephalus) eggs were collected in 15 States in the United States in 1980–1984 and analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), and mercury. Data were compared and combined with data from earlier studies to examine trends and refine relationships of contaminants to shell thickness and young production. Moderate shell thinning occurred in eggs from several States. The frequency of occurrence of detectable residues of several contaminants declined during 1969–84. DDE concentrations declined significantly in Wisconsin, Maine, and the Chesapeake Bay region. Some other contaminant residues declined, but usually not significantly. During 1980–84, DDE, PCB, and mercury concentrations were highest in eggs from Maine, whereas most contaminant concentrations were lowest in eggs from Arizona. DDE was most closely related to shell thickness and young production at sampled breeding areas. Fifteen percent shell thinning was associated with 16 μg/g DDE (wet weight) for eggs collected early in incubation. Young production was normal when eggs at sampled breeding areas contained < 3.6 μg/g DDE (wet weight), was nearly halved between 3.6 to 6.3 μg/g, and halved again when concentrations exceeded 6.3 μg/g. Several other contaminants were also associated with poor reproduction and eggshell thinning; however, their impact appeared to be secondary to that of DDE and was probably related to their high correlation with DDE. Data relating contaminant concentrations to mean 5-year production are applicable only to breeding areas where eggs are collected after failure to hatch, because such breeding areas are not representative of all nesting bald eagles in a given population.

Environmental contaminants in California condors

Five wild California condors (Gymnogyps californianus) that died in 1980-86 were necropsied and tissues were analyzed for environmental contaminants. Three died of lead (Pb) poisoning, 1 presumably of cyanide (CN) poisoning, and 1 nestling of handling shock. Organochlorine concentrations were low in 4 condors that were analyzed for these contaminants. Blood samples from 14 wild and 14 captive condors were analyzed primarily for Pb. Five of 14 wild condors sampled had elevated (>0.70 ppm) concentrations of Pb in blood whereas Pb concentrations in all captive condors were low. Lead levels in individual birds often fluctuated over time. Lead exposure, especially poisoning, was a major factor affecting the wild California condor population during 1982-86. The probable source of Pb was bullet fragments in carrion on which condors were feeding. J. WILDL. MANAGE. 52(2):238-247 The wild population of California condors has been declining for many years (Koford 1953, Wilbur 1978, Snyder and Johnson 1985). In the winter of 1984-85 it declined from 15 to 9 individuals and 4 of 5 known breeding pairs were lost. Since 1985 1 wild California condor has died and the remaining 8 were placed in captivity to enhance the captive flock. Many causes have contributed to the decline of the condor although most are poorly documented (Wilbur 1978, Ogden 1983, Harlow et al. 1984). Some causes that appear to have contributed to the decline are shooting, loss of habitat, disturbance, inadequate food supply, and environmental contaminants. The role of contaminants in the decline of California condors has only been partially assessed (Kiff et al. 1979, Wiemeyer et al. 1983, 1986b). Contaminants such as 1,1-dichloro-2,2-bis(pchlorophenyl)ethylene (DDE); strychnine; sodium monofluoroacetate (Compound 1080); and Pb have been implicated in the condor decline but little corroborative evidence has been provided. The contaminant levels in potential condor food and in the tissues of turkey vultures (Cathartes aura) and common ravens (Corvus corax) that occur within the condor range were assessed in 1980-81 (Wiemeyer et al. 1986b). Wiemeyer et al. (1986b) determined that, in some cases, Pb concentrations in bones of turkey vultures and feathers of California condors were elevated above normal background levels. Elevated levels of organochlorines were also found in turkey vultures, but not in potential condor food. These findings prompted us to sample tissues and determine causes of mortality of all dead condors, and obtain blood samples from all condors captured for telemetry studies during 198286 or for use in captive flocks. Our objective was to identify contaminants that may have been involved in the decline of the condor population. For field assistance we gratefully acknowledge L. Andaloro, D. B. Barbour, D. A. Clendenen, J. Grantham, J. A. Hamber, S. B. Kimple, D. B. Ledig, V. J. Meretsky, J. C. Ogden, L. A. Riopelle, G. D. Sanders, H. A. Snyder, N. F. R. Snyder, and J. J. Woods of the Condor Research Center and veterinarians B. Gonzales of the Los Angeles Zoo; J. L. Allen, D. L. Janssen, and J. E. Oosterhuis of the San Diego Wild Animal Park; P. K. Ensley of the San Diego Zoo; and P. A. Gullett of the National Wildlife Health Center. N. J. Thomas provided analytical methods used at the National Wildlife Health Center. We thank S. H. Fritts, R. M. Jurek, H. R. Perry, J. E. Semberski, and M. G. Holmes for administrative support. We owe special thanks to the ranchers of Kern County who allowed us to trap California condors on their property. We thank J. Grantham, C. E. Grue, L. F. Kiff, O. H. Pattee, and S. R. Wilbur for reviewing the manuscript. The Idaho Cooperative Fish and Wildlife Research unit is funded and supported by Idaho Department of Fish and Game, University of Idaho, U.S. Fish and Wildlife Service, and the 1 Present address: Idaho Cooperative Fish and Wildlife Research Unit, College of Forestry, University of Idaho, Moscow, ID 83843.

Contaminant levels in colonial waterbirds from Green Bay and Lake Michigan, 1975-80

Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated styrenes (PCSs), and mercury were measured in the eggs of 10 species of colonial waterbirds nesting in areas around Green Bay or Lake Michigan from 1975 to 1980. Residues also were measured in the carcasses and brains of black-crowned night-herons (Nycticorax nycticorax). The highest residues were of PCBs, DDE, mercury, and dieldrin; for some species, levels of these chemicals possibly were high enough to have caused reproductive effects. Other organochlorine pesticides were found at low levels. Only trace amounts of PCSs and PBBs were found. Eggs of herring gulls (Larus argentatus) collected in 1977 from an island in Lake Michigan contained an average of 100 ppm PCBs and 33 ppm DDE; this was the most-contaminated species. Cattle egrets (Bubulcus ibis), the only bird that is not a fish eater, contained only small quantities of DDE and mercury.

Persistence of DDT and metabolites in wildlife from Washington state orchards

Residues of the DDT group, particularlyp,p′-DDT (DDT) were detected in high or unusual amounts in some wildlife samples collected in fruit orchards near Wenatchee, Washington from 1979 to 1983. Samples of birds containedp,p′-DDE (DDE) and DDT in ratios (DDE:DDT) as low as 2.6:1 in eggs and 1.9:1 in brains. An unexpectedly high number (about 50%) of some samples, such as fat of adult waterfowl, contained unusually low DDE:DDT ratios (≤10:l). At the lower sensitivity level (0.01 μg/g), 96% of the samples contained DDE and 46% contained DDT. From about 1946 to 1970, technical DDT was applied at very high rates to orchards in Washington (56 to 73 kg/ha/yr); some areas probably received 5≥1000 kg/ha over this period. Considerable wildlife mortality from DDT was documented during the period of intensive use, but only one DDT-related mortality was recorded during this study. The possible origin of the residues is discussed. Occurrence of DDT and its metabolites in resident wildlife and its food indicates continuing contamination that probably originates largely from past legal applications in the orchard system.

Survey and evaluation of contaminants in earthworms and in soils derived from dredged material at confined disposal facilities in the Great Lakes Region.

Soils derived from dredged material were collected, together with earthworms from nine confined disposal facilities located in the Great Lakes Region. These samples were analyzed for 18 elements, 11 organochlorine pesticides, PCBs, and 24 polycyclic aromatic hydrocarbons. The concentrations detected in earthworms were evaluated in terms of their potential hazard to wildlife, which for the sake of the evaluation were assumed to prey entirely either on earthworms or on other soil invertebrates having similar concentrations. The soil concentrations (dry wt.) of the contaminants of greatest concern were <1.9 to 32 ppm Cd, <0.053 to 0.94 ppm Hg, 4.6 to 550 ppm Pb, and <0.1 to 1.0 ppm PCBs. The concentrations in earthworms (dry wt., ingested soil included) were as high as 91 ppm Cd, 1.6 ppm Hg, 200 ppm Pb, and 1.8 ppm PCBs. Based on laboratory toxicity studies of relatively sensitive species, and on concentration factors calculated from the earthworm and soil data, we estimated that lethal or serious sublethal effects on wildlife might be expected at concentrations of 10 ppm Cd, 3 ppm Hg, 670 ppm Pb, and 1.7 ppm PCBs in alkaline surface soils derived from dredged material. Concentrations of polycyclic aromatic hydrocarbons in earthworms were well below those in soil.

Gray bats killed by dieldrin at two additional Missouri caves: Aquatic macroinvertebrates found dead

We learned previously (CLARK et al. in manuscript) that mortality due to dieldrin poisoning occurred during 1976-78 in two maternity colonies of the endangered gray bat (~otis grisescens) at Bat Cave No. 2-3 and Roaring Spring Cave, Franklin County, Missouri. Residues of heptachlor-related chemicals in bats increased markedly in 1977 to potentially dangerous concentrations and remained elevated in 1978. The colony that showed the greater mortality disappeared in 1979 and was not present when the roost caves were visited in 1982.

Reproduction and organochlorine contaminants in terns at San Diego Bay

-In 1981, we studied Caspian Terns (Sterna caspia) and Elegant Terns (S. elegans) nesting at the south end of San Diego Bay, California. Randomly collected Caspian Tern eggs contained significantly (P<0.05) higher mean concentrations of DDE (9.30 ppm) than did Elegant Tern eggs (3.79 ppm). DDE may have had an adverse effect on Caspian Tern reproduction but the relationship between hatching success and DDE concentration was not clear. We found an unusually high incidence of chicks (4.6%) that died in hatching. Caspian Tern eggs that broke during incubation or contained chicks that died while hatching had shells that were significantly (P<0.05) thinner than eggs collected before 1947, and DDE was associated with reductions in shell thickness index (i.e., lowered eggshell density). Fish brought to Caspian Tern chicks contained up to 3.0 ppm DDE and 1.1 ppm PCBs. Organochlorine concentrations in brains of terns found dead were not high enough to suggest such poisoning as a cause of death.

Organochlorine concentrations in prefledging common terns at three Rhode Island colonies

-Concentrations of DDE, polychlorinated biphenyls (PCBs), and polychlorinated diphenyl ethers (PCDPEs) in carcasses of prefledging Common Terns (Sterna hirundo) at three Rhode Island colonies support the hypothesis that local contamination is responsible for among-colony differences observed in eggs in an earlier study. The highest concentrations of DDE and PCBs (mean = 0.24 and 2.8 ppm wet weight) were found in prefledging terns from Providence, a highly industrializedd area, and the lowest (DDE range = nd-0. 11, PCBs mean = 0.85) in terns from Price Neck, an undeveloped area 40 km to the south. PCDPEs were detected in 3 of 14 tern carcases from Providence and were not detected in carcasses from 2 other colonies. The occurrence and concentrations of DDE and PCBs in killifish (Fundulus spp.), a major dietary item of Common Terns, qualitatively demonstrated the same trend among locations.

Phthalate plasticizers: Accumulation and effects on weight and food consumption in captive starlings

Phthalate plasticizers have recently been recognized to be widespread environmental pollutants (see, for example, GIAM et al. 1978). These compounds possess certain characteristics that are cause for concern: they are produced in massive quantities, they eventually reach the environment, and they have biomagniflcatlon factors at least as great as DDT within invertebrate food chains of model ecosystems (BOOTH et al. 1976, METCALF et al. 1973). Fortunately, however, in common laboratory mammals phthalates are rapidly metabolized, do not accumulate appreciably, and are of very low toxicity (for reviews on the toxicity and metabolism of phthalates see AUTIAN 1973, DANIEL 1978, FISHBEIN and ALBRO 1972, PEAKALL 1975, THOMAS et al. 1978).