Lawrence J. Blus

Further interpretation of the relation of organochlorine residues in brown pelican eggs to reproductive success

Abstract This study was conducted to provide additional interpretation of the relation of organochlorine pollutants to reproductive success and population stability of brown pelicans Pelecanus occidentalis in the southeastern United States from 1969 to 1977. The sample egg technique was employed in South Carolina; it involved collecting an egg from each of 156 marked nests, analysing the eggs for residues and relating residue levels to nest success. All of the organochlorines appeared to induce adverse effects on reproductive success of brown pelicans, but the correlative evidence indicated that DDE was responsible for most of the pollutant-related nest failure. Close intercorrelation of each of the organochlorines presented a problem in the separation of the effects of each pollutant. The critical level of DDE in brown pelican eggs was 3 μg g −1 , this level was associated with substantially impaired reproductive success and 4 μg g −1 of DDE was associated with sotal reproductive failure. The critical level for dieldrin was not determined, but it appeared to exceed 1 μg g −1 . Dieldrin, DDT, DDD and the PCBs apparently exerted a minor effect on reproductive success of brown pelicans in South Carolina. Endrin seemed to induce reproductive impairment in brown pelicans in Louisiana in 1975. The critical level in eggs is only roughly estimated at −1 because it was not possible to use the sample egg technique in this small population. Significant declines in organochlorine residues in South Carolina during this study were associated with increases in eggshell thickness, reproductive success and the breeding population. Of those avian species studied, the brown pelican remains the most sensitive to organochlorine contaminants, particularly DDE and endrin; factors related to this sensitivity are poorly known.

Brown pelican: Population status, reproductive success, and organochlorine residues in Louisiana, 1971-1976

Brown Pelican: Population Status, Reproductive Success, and Organochlorine Residues in Louisiana, 1971-1976 L. Blus ~, E. Cromart ie 2, L. McNease 3, and T. Joanen 4 t2U. S. Fish and Wildlife Service, Patuxenf Wildlife Research Center, 480 SW Airport Road, Corvallis, Ore. 97330, and 3,4Louisiana Wildlife and Fisheries Commission, Rockefeller Wildlife Refuge, Route 1, Box 20-B, Grand Chenier, La. 70643

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.

The effects of heptachlor and lindane on birds, Columbia Basin, Oregon and Washington, 1976-1981

The effects of heptachlor seed treatments on birds in the vicinity of the Umatilla National Wildlife Refuge, Oregon and Washington, were investigated from 1978 to 1981. An egg was collected from each of 60 nests representing six species. Heptachlor epoxide (HE) residues were detected in 35 eggs and were particularly high (8-13 micrograms g-1) in a few eggs of the black-billed magpie, mallard, and ring-necked pheasant. These residues were within the range that induced reproductive problems in other species in the area. Diagnostically lethal residue levels (greater than or equal to 9 micrograms g-1) of HE were detected in the brains of nine birds (four species). Most of the avifauna in the area contained residues of HE and related compounds. Lindane, the replacement chemical for heptachlor, did not produce adverse effects in birds, and residues were not detected in either their eggs or brains.

Short-tailed shrews: Toxicity and residue relationships of DDT, dieldrin, and endrin

Experiments involving dietary toxicity and residue relationships of DDT, dieldrin, and endrin were conducted with short-tailed shrews. Dietary concentrations of DDT dissolved in vegetable oils were usually more toxic than diets containing comparable amounts of powdered DDT. Younger shrews, particularly females, were more tolerant of powdered DDT than older animals; yet, there were no conspicuous age differences in toxicity of DDT dissolved in oils. In comparison to other mammals, short-tailed shrews are not unusually sensitive to DDT, dieldrin, or endrin on the basis of two-week feeding tests.The influence of age and sex on toxicity of DDT, endrin, and dieldrin was sometimes more important than body weight. Of those shrews of the same age and sex that were fed the same dietary dosage, heavier shrews were more tolerant than lighter individuals; and, heavier shrews tended to lose a greater percentage of body weight before death.There was a range of 15 to 105 DDT equivalents in brains of shrews dying on dietary dosages of DDT. Six shrews fed a high level of DDT seemed to have unusual metabolite capabilities and died with apparent lethal levels of DDD in their brains. Levels of dieldrin in brains of shrews that died on a dietary dosage of dieldrin ranged from 3.7 to 12.6 ppm.In the rates of gain and loss experiments where shrews were given diets containing 400 ppm DDT or 50 ppm dieldrin up to 17 days, high residues were noted in tissues of shrews after two weeks on a contaminated diet and a few died at that time. After shrews were placed on clean food, it was determined that >50% of the dieldrin residues in carcass and brain were lost in <2 weeks. Males and females fed DDT for 17 days lost >50% of residues of DDT and metabolites in brains after 2 weeks on clean food; males lost nearly 50% of residues in carcasses after two weeks on clean food compared with a loss of only 11% in females.

Rise and fall of endrin usage in Washington State fruit orchards: effects on wildlife

A study of the effects of endrin on wildlife was conducted from 1981 to 1983 in fruit orchards in central Washington State. The single post-harvest application of endrin as a rodenticide resulted in both acute and chronic toxicity to a variety of avian species. Of 194 birds found dead, brains of 125 were analysed; endrin toxicosis accounted for > 24% of the total and 37% of those analysed. Most mortality occurred soon after application, but several raptors died during the spring and summer. Most wildlife sampled in the orchard system contained residues of endrin. There was no evidence that endrin depressed reproductive success. Use of endrin abruptly declined during this study and its use is currently limited to emergency situations. Wildlife mortality from endrin also decreased; only six endrin-related mortalities were detected the last year of the study and there have been no reports of die-offs since the study ended.

Ruptured-yolk peritonitis and organochlorine residues in a royal tern

Ruptured-yolk peritonitis was responsible for the death of a royal tern. Lodgment of eggs in the oviduct was probably due to reverse peristalsis brought about by breakage of the thin-shelled eggs and secondary bacterial infection. The thin shells were apparently not related to the low levels of DDE and other organochlorine pollutants found in tissues and egg contents.

Avian cholera and organochlorine residues in an American oystercatcher

Pasteurella multocida, the causative bacterium of avian cholera, was isolated from cultures of the liver and heart blood of a female, adult American oystercatcher (Haematopus palliatus) found dead on the Cape Romain National Wildlife Refuge, South Carolina, in May 1973. This is apparently the first record of avian cholera in the oystercatcher. Low levels of DDE were identified in tissues of the oystercatcher.