Dicofol residues in eggs and carcasses of captive American kestrels.

American kestrels (Falco sparverius) were fed diets containing 0 (control), 1, 3, 10, and 30 microgram/g (wet wt) of Kelthane. Residues of dicofol and its metabolites were then analyzed in the eggs and carcasses of females. Significant differences occurred among treatments for residues of both p,p'-dicofol and p,p'-dechlorodicofol (DCD) in both eggs and carcasses and for p,p'-dicholorbenzophenone (DCBP) in eggs. Residue concentrations increased with increasing treatment exposure. Residues of p,p'-dicofol, p,p'-DCD, and p,p'-DCBP in eggs were significantly correlated with eggshell quality parameters. Significant correlations also occurred among contaminants in eggs and for individual contaminants between eggs and carcasses. The lowest-observed-dietary-effect concentration for eggshell thinning was 3 microgram/g, whereas 1 microgram/g may be considered to be near a no-observable-adverse-effect concentration. Concentrations of dicofol in potential prey items and eggs of wild birds generally have been lower than dietary-effect concentrations or concentrations in tissues or eggs associated with eggshell thinning and reduced reproductive success.

Clarification of effects of DDE on shell thickness, size, mass, and shape of avian eggs.

Moriarty et al. (1986) used field data to conclude that DDE decreased the size or altered the shape of avian eggs; therefore, they postulated that decreased eggshell thickness was a secondary effect because, as a general rule, thickness and egg size are positively correlated. To further test this relationship, the present authors analyzed data from eggs of captive American kestrels. Falco sparverius given DDT- or DDE-contaminated or clean diets and from wild brown pelicans Pelecanus occidentalis collected both before (pre-1946) and after (post-1945) DDT was introduced into the environment. Pertinent data from other field and laboratory studies were also summarized. DDE was not related to and did not affect size, mass, or shape of eggs of the brown pelican or American kestrel; but the relationship of DDE to eggshell thinning held true. Size and shape of eggs of brown pelicans from the post-1945 era and those of kestrels, on DDT-contaminated diets showed some significant, but inconsistent, changes compared to brown pelican data from the pre-1946 era or kestrels on clean diets. In contrast, nearly all samples of eggs of experimental kestrels given DDT-contaminated diets and those of wild brown pelicans from the post-1945 era exhibited significant eggshell thinning. Pertinent experimental studies with other sensitive avian species indicated no effects of DDE on the size or shape of eggs, even though the high dietary concentrations caused extreme eggshell thinning and mortality of some adult mallards (Anas platyrhynchos) in one study. These findings essentially controvert the argument that decreased eggshell thickness is a secondary effect resulting from the primary effect of DDE-induced changes in the size or shape of eggs.

Combined extraction-cleanup column chromatographic procedure for determination of dicofol in avian eggs.

Dicofol in avian eggs was completely oxidized to dichlorobenzophenone (DCBP) when a hexane Soxhlet extraction procedure was used. This degradation did not occur with other avian tissues (muscle and liver). For this reason, a combined extraction-cleanup column chromatographic procedure, without added heat, was developed for the determination of dicofol in avian eggs. Homogenized subsamples of eggs were mixed with sodium sulfate, and the mixture was added as the top layer on a column prepacked with Florisil. The dicofol and other compounds of interest were then eluted with ethyl ether-hexane. The extracts, relatively free from lipids, were quantitated on a gas chromatograph equipped with a 63Ni electron-capture detector and a methyl silicone capillary column. Recoveries from chicken eggs, fortified with dicofol and other DDT-related compounds, averaged 96%. Analysis of eggs of eastern screech-owls, fed a meat diet containing 10 ppm technical Kelthane, showed that both dicofol and DCBP were present. Results were confirmed by gas chromatography/mass spectrometry. This method is rapid and reliable, involves a minimum of sample handling, and is well suited for high volume determination of dicofol in eggs and other avian tissues.

Environmental pollutant and necropsy data for ospreys from the eastern United States, 1975-1982.

Twenty-three ospreys (Pandion haliaetus) found dead or moribund in the eastern United States during 1975-1982 were necropsied and selected tissues were analyzed for organochlorines and metals. Major causes or factors contributing to death were trauma, impact injuries, and emaciation. DDE was detected in 96% of the osprey carcases, DDD in 65%, DDT and heptachlor epoxide in 13%, dieldrin, oxychlordane, and cis-nonachlor in 35%, cis-chlordane in 52%, trans-nonachlor in 45%, and PCB's in 83%. Carcasses of immature ospreys from the Chesapeake Bay had significantly lower concentrations of DDE, DDD + DDT, cis-chlordane, and PCB's than carcasses of adults from the same area. Concentrations of some organochlorines in ospreys from the Chesapeake Bay declined significantly from 1971-1973 to 1975-1982. Significant differences in concentrations of certain metals in the ospreys' livers were noted between time periods, and sex and age groups for birds from the Chesapeake Bay. During 1975-1982, adults had significantly lower concentrations of chromium, copper, and arsenic than immatures and nestlings, and adult males had higher mercury concentrations than adult females. Adult females had lower zinc concentrations in 1975-1982 than in 1971-1973. Immatures and nestlings had higher concentrations of chromium and lead in 1975-1982 than in 1971-1973. A slightly elevated concentration of chromium (1.7 ppm) or arsenic (3.2 ppm) was found in the livers of individual ospreys. Several ospreys had elevated concentrations of mercury in their livers; two ospreys had more than 20 ppm which may have contributed to their deaths.

Acute oral toxicity of sodium cyanide in birds.

Sensitivities of six avian species, black vulture (Coragyps atratus), American kestrel (Falco sparverius), Japanese quail (Coturnix japonica), domestic chicken (Gallus domesticus), eastern screech-owl (Otus asio), and European starling (Sturnus vulgaris), to acute poisoning by sodium cyanide (NaCN) were compared by single dose LD50's. Three species, domestic chickens, black vultures, and turkey vultures (Cathartes aura), were dosed with NaCN to determine cyanide residues in those that died and also in survivors, in addition to postmortem fate. Three flesh-eating species (black vulture, American kestrel, and eastern screech-owl; LD50's 4.0-8.6 mg/kg) were more sensitive to NaCN than three species (Japanese quail, domestic chicken, and European starling; LD50's 9.4-21 mg/kg) that fed predominantly on plant material. Elevated concentrations of cyanide were found in the blood of birds that died of cyanide poisoning; however, concentrations in birds that died overlapped those in survivors. Blood was superior to liver as the tissue of choice for detecting cyanide exposure. No gross pathological changes related to dosing were observed at necropsy.

Environmental contaminants in surrogates, foods, and feathers of California condors (Gymnogyps californianus).

California condor (Gymnogyps californianus) foods and feathers, and turkey vultures (Cathartes aura), common ravens (Corvus corax), and their eggs were collected within the condor range to determine exposure of condors to environmental contaminants. Samples were analyzed for organochlorines and trace elements. Food items contained low concentrations of organochlorines and generally low concentrations of lead. DDE was detected in all vulture carcasses and nearly all raven carcasses at generally moderate concentrations. Other organochlorines occurred infrequently in carcasses and generally at low concentrations. Turkey vulture eggshells were 16% thinner than the pre-DDT mean; there was no change in shell thickness of raven eggs. Vulture eggs contained an average of 6.9 ppm DDE and two contained excessive concentrations of endrin. DDE concentrations were low in raven eggs. Residues of As, Cd, Cr, Cu, Fe, Hg, Ni, Se, Tl, and Zn in tissues of vultures and ravens appeared normal when compared with reference values for other species. Lead concentrations in bone of turkey vultures and feathers of condors appeared to be elevated above normal background concentrations in some cases. Current exposure of condors to organochlorines appears low; however, we are concerned about the excessive exposure of turkey vultures to organochlorines, possibly in Central America. Lead exposure to vultures and condors has occurred, but its significance to their populations is unknown.

Effects of fluoride on screech owl reproduction: teratological evaluation, growth, and blood chemistry in hatchlings.

The effects on reproduction in screech owls (Otus asio) of chronic dietary sodium fluoride administration at 0, 40, and 200 ppm were examined. Fluoride at 40 ppm resulted in a significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were apparent. Skeletal clearing and staining revealed significantly shorter tibiotarsus lengths in the 40 ppm and 200 ppm groups and a shorter radius-ulna length in the 200 ppm group. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter. No significant differences were detected in hematocrit, hemoglobin, plasma calcium or alkaline phosphatase. Plasma phosphorus levels were higher in the 40 ppm group than in controls. These results, in combination with the findings of Pattee et al. [25], revealed significant impairment of overall reproduction, suggesting that sodium fluoride could cause slight to moderate reproduction disorders in owls in fluoride-polluted areas.

Effects of lead shot ingestion on delta-aminolevulinic acid dehydratase activity, hemoglobin concentration, and serum chemistry in bald eagles.

Lead shot ingestion by bald eagles (Haliaeetus leucocephalus) is considered to be widespread and has been implicated in the death of eagles in nature. It was recently demonstrated under experimental conditions that ingestion of as few as 10 lead shot resulted in death within 12 to 20 days. In the present study hematological responses to lead toxicity including red blood cell ALAD activity, hemoglobin concentration and 23 different blood serum chemistries were examined in five captive bald eagles that were unsuitable for rehabilitation and release. Eagles were dosed by force-feeding with 10 lead shot; they were redosed if regurgitation occurred. Red blood cell ALAD activity was inhibited by nearly 80% within 24 hours when mean blood lead concentration had increased to 0.8 parts per million (ppm). By the end of 1 week there was a significant decrease (20-25%) in hematocrit and hemoglobin, and the mean blood lead concentration was over 3 ppm. Within as little as 1-2 weeks after dosing, significant elevations in serum creatinine and serum alanine aminotransferase occurred, as well as a significant decrease in the ratio of serum aspartic aminotransferase to serum alanine aminotransferase. The mean blood lead concentration was over 5 ppm by the end of 2 weeks. These changes in serum chemistry may be indicative of kidney and liver alterations.

Dieldrin and DDT: effects on sparrow hawk eggshells and reproduction.

Patterns of reproductive failure in declining populations of several European and North American raptorial species were duplicated experimentally with captive American sparrow hawks Falco sparvcrius that were given a diet containing two commonly used organochlorine insecticides. Major effects on reproduction were increased egg disappearance, increased egg destruction by parent birds, and reduced eggshell thickness.