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M. T. Finley

Publications and source records attributed to M. T. Finley.

14 recordsLinked to original sources
USGS2013

Lead in tissues of mallard ducks dosed with two types of lead shot

Mallard ducks (Anas platyrhynchos) were sacrificed one month after ingesting one number 4 all-lead shot or one number 4 lead-iron shot. Livers, kidneys, blood, wingbones, and eggs were analyzed for lead by atomic absorption. Necropsy of sacrificed ducks failed to reveal any of the tissue lesions usually associated with lead poisoning in waterfowl. Lead levels in ducks given all-lead shot averaged about twice those in ducks given lead-iron shot, reflecting the amount of lead in the two types of shot. Lead in the blood of ducks dosed with all-lead shot averaged 0.64 ppm, and 0.28 ppm in ducks given lead-iron shot. Lead residues in livers and kidneys of females given all-lead shot were significantly higher than in males. In both dosed groups, lead levels in wingbones of females were about 10 times those in males, and were significantly correlated with the number of eggs laid after dosage. Lead levels in contents and shells of eggs laid by hens dosed with all-lead shot were about twice those in eggs laid by hens dosed with lead-iron shot. Eggshells were found to best reflect levels of lead in the blood. Our results indicate that mallards maintained on a balanced diet and dosed with one lead shot may not accumulate extremely high lead levels in the liver and kidney. However, extremely high lead deposition may result in the bone of laying hens after ingesting sublethal amounts of lead shot as a result of mobilization of calcium from the bone during eggshell formation.

Bulletin of Environmental Contamination and Toxico↗
USGS2009

Sublethal effects of chronic lead ingestion in mallard ducks

Mallard drakes (Anas platyrhynchos) fed 1, 5, or 25 ppm lead nitrate were bled and sacrificed at 3‐wk intervals. No mortality occurred, and the pathologic lesions usually associated with lead poisoning were not found. Changes in hematocrit and hemoglobin concentration did not occur. After 3 wk ducks fed 25 ppm lead exhibited a 40% inhibition of blood δ‐aminolevulinic acid dehydratase activity that persisted through 12 wk exposure. After 12 wk treatment similar enzyme inhibition was present in the ducks fed 5 ppm lead. At 3 wk there was a small accumulation of lead (less than 1 ppm) in the liver and kidneys of ducks fed 25 ppm lead; no further increases occurred throughout the exposure. No significant accumulation of lead occurred in the tibiae or wing bones. Groups of ducks fed 5 and 25 ppm diets for 12 wk were placed on clean feed and examined through a 12 wk posttreatment period. After 3 wk on clean diet δ‐aminolevulinic acid dehydratase activity and lead concentrations in the blood had returned to pretreatment levels. Even though lead concentrations in the blood, soft organs, and bone were low, a highly significant negative correlation between blood lead and blood enzyme activity was obtained. This enzyme bioassay should provide a sensitive and precise estimate for monitoring lead in the blood for waterfowl.

Journal of Toxicology and Environmental Health↗
USGS1980

Reproduction and residue accumulation in black ducks fed toxaphene

Three sets of 15 pairs of black ducks ( Anas rubripes ) were given 0, 10, or 50 ppm toxaphene in a dry mash diet for a period of 19 months, which included two breeding seasons. Survival of adults was not affected, but the weights of treated males were depressed during the summer months. Egg production, fertility, hatchability, eggshell thickness, growth, and survival of young did not vary with toxaphene ingestion in either breeding season. However, the mean number of days required to complete a clutch was lower in birds fed toxaphene than in birds on the control diet. Clutches of hens fed 50 ppm toxaphene showed improved hatching success in the second year of the study. Carcass wet-weight (70% moisture) residues in adults and the young birds averaged from 50 to 100% of the dietary concentration (7% moisture); egg residues showed a similar trend. Carcass residues did not reflect those found in the livers or brains of the adults, which seldom exceeded 0.5 ppm. Toxaphene residues were found in the brain of only one 10 ppm bird, but were present in nearly all of the 50 ppm birds. Toxaphene residues were present in the liver all all birds ingesting toxaphene.

Archives of Environmental Contamination and Toxico↗
USGS1979

Delta-aminolevulinic acid dehydratase enzyme activity in blood, brain, and liver of lead-dosed ducks

Mallard ducks were dosed with a single shotgun pellet (ca. 200 mg lead). After 1 month there was about 1 ppm lead in blood, 2.5 in liver, and 0.5 in brain. Lead-induced inhibition of delta-aminolevulinic acid dehydratase enzyme in blood and cerebellum was much greater than in cerebral hemisphere or liver and was strongly correlated with the lead concentration in these tissues. The cerebellar portion of the brain was more sensitive to delta-aminolevulinic acid dehydratase enzyme inhibition by lead than were the other tissues examined. There was also a greater increase in the glial cell marker enzyme, butyrylcholinesterase, in cerebellum than in cerebral hemisphere, suggesting that nonregenerating neuronal cells were destroyed by lead and replaced by glial cells in that portion of the brain. Even partial loss of cerebellar tissue is severely debilitating in waterfowl, because functions critical to survival such as visual, auditory, motor, and reflex responses are integrated at this brain center.

Environmental Research↗
USGS1979

Bone development in black ducks as affected by dietary toxaphene

Black ducks, Anas rubripes, were exposed to dietary toxaphene concentrations of 0, 10, or 50 μg/g of food for 90 days prior to laying and through the reproductive season. Toxaphene did not affect reproduction or survival, but reduced growth and impaired backbone development in ducklings. Collagen, the organic matrix of bone, was decreased significantly in cervical vertebrae of ducklings fed 50 μg/g, and calcium conentrations increased in vertebrae of ducklings fed 10 or 50 μg/g. The effects of toxaphene were observed only in female ducklings. In contrast to effects on vertebrae, toxaphene exposure did not alter tibia development. Toxaphene residues in carcasses of these ducklings averaged slightly less than the dietary levels.

Pesticide Biochemistry and Physiology↗
USGS1978

Survival and reproductive success of black ducks fed methyl mercury

A diet containing 3 ppm mercury was fed to black ducks (Anas rubripes) for periods of 28 weeks during two consecutive breeding seasons. Clutch size, egg production, number of eggs incubated, hatchability and survival of ducklings were lower during both years in hens fed mercury. Reduced hatchability and poor duckling survival were the most harmful effects. During 2 years, 13 pairs of breeders fed mercury produced only 16 ducklings that survived 1 week compared with 73 ducklings from 13 pairs of controls. Mercury residues in eggs, embryos and ducklings averaged about 30% lower during the second breeding season compared with first year results. Third eggs laid by treated hens contained a mean of 6?14 and 3?86 ppm mercury during the first and second years. Whole embryos that failed to hatch contained means of 9?62 and 6?08 ppm mercury during the first and second years. Brains of dead ducklings contained between 3?25 and 6?98 ppm mercury and exhibited lesions characteristic of mercury poisoning. Relative tissue mercury levels for treated adult breeders were: feathers > liver > kidney > breast muscle > brain. Mercury levels in males and females did not differ.

Environmental Pollution↗
USGS1978

Uptake and retention of dietary cadmium in mallard ducks

Adult mallard ducks fed 0, 2, 20, or 200 ppm of cadmium chloride in the diet were sacrificed at 30-day intervals and tissues were analyzed for cadmium. No birds died during the study and body weights did not change. The liver and kidney accumulated the highest levels of cadmium. Tissue residues were significantly correlated in all treatment groups and residues increased with treatment level. Hematocrits and hemoglobin concentrations were normal in all groups throughout the study. Little cadmium accumulated in eggs of laying hens, but egg production was suppressed in the group fed 200 ppm.

Environmental Research↗
USGS1978

Influence of laying on lead accumulation in bone of mallard ducks

Paired mallard ducks (Anas platyrhynchos) were given No. 4 lead shot, and bone lead concentrations were compared in drakes and in laying and nonlaying hens. Lead accumulation was significantly greater in bones with a high medullary content (femur and sternum) compared with bones with a lower medullary content (ulna-radius or wingbones). In dosed groups, hens always contained higher bone lead residues than drakes. After dosage with one shot (approximately 200 mg lead), lead in femurs of laying hens averaged 488.4 ppm compared with 113.6 ppm in nonlaying hens. Femurs of drakes averaged 9.4 ppm lead. Dosage with the second lead shot did not result in further accumulation of bone lead in hens, but increased bone lead concentrations threefold in drakes, suggesting that saturation levels for bone lead had already been reached in the hens after ingestion of one shot. There was no demonstrable relationship between egg production and bone lead residues. The high lead residues, found in medullary bones of laying hens indicate that sex and physiological condition are major factors influencing lead absorption by bone.

Journal of Toxicology and Environmental Health↗
USGS1978

Histopathologic effects of dietary cadmium on kidneys and testes of mallard ducks

Mallard ducks fed 2, 20, or 200 ppm cadmium chloride were sacrificed at 30, 60, and 90 d. No mortality occurred during the study and body weights remained unchanged. Kidney weights of the 200-ppm group were significantly greater after 60 and 90 d than those of controls; also, testis weights were significantly lower after 90 d. Kidneys of ducks fed 2 and 20 ppm cadmium were relatively unaffected; however, slight to severe kidney lesions were found in the 200-ppm group after 60 d of treatment. No significant lesions were found in mallard testes after feeding 2 ppm cadmium in the diet, and only a few birds in the 20-ppm group showed slight to moderate gonad alterations. After 90 d of treatment, however, testes of males fed 200 ppm had atrophied and the spermatogenic process had ceased. This study should provide important information for the interpretation of cadmium levels found in kidneys and testes of wild ducks.

Journal of Toxicology and Environmental Health↗
USGS1978

Erythrocyte δ-Aminolevulinic Acid Dehydratase Activity in Mallard Ducks: Duration of Inhibition after Lead Shot Dosage

Inhibition of a lead-specific blood enzyme, 8-aminolevulinic acid dehydratase (ALAD), has been utilized to indicate the incidence and degree of lead contamination in canvasback ducks ( Aythya valisineria ) (Dieter et al. 1976). This variable was found to be more sensitive to lead than previous tests that have been employed with waterfowl (Locke et al. 1966, 1967), and has proved to be completely reliable (Finley et al. 1976a,b). However, it is not yet known how long ALAD enzyme inhibition persists after a source of high head contamination is removed. The duration of inhibition is critical because too brief a response would result in underestimating the extent of lead contamination in a given year's survey. Moreover, the ALAD enzyme bioassay can be used to identify ducks that have ingested lead shot, as well as those that have ingested low levels of lead in their forage, and this information used to help remove the source of the environmental contamination.

Maryland↗
USGS1976

Delta-aminolevulinic acid dehydratase: Inhibition in ducks dosed with lead shot

Lead concentration in blood and erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was measured in mallard ducks dosed with one all-lead shot or one lead-iron combination shot. For 2 weeks after dosage, lead in blood of ducks given an all-lead shot was fourfold higher than in those dosed with lead-iron shot. At 3 and 4 weeks, the differences in lead residues were directly proportional to lead content of the shots. ALAD activities measured at these intervals were inversely correlated (P < 0.01) with the concentration of lead in the blood, suggesting that biochemical responses to the two types of shot were dependent upon the quantity of lead present.

Environmental Research↗