Field Evaluation of Lead Effects on Canada Geese and Mallards in the Coeur d'Alene River Basin, Idaho

Autor: Daniel J. Audet, L. J. Blus, Louis Sileo, Mark R. Snyder, David J. Hoffman, Charles J. Henny
Rok vydání: 2000
Předmět:
Zdroj: Archives of Environmental Contamination and Toxicology. 39:97-112
ISSN: 1432-0703
0090-4341
DOI: 10.1007/s002440010085
Popis: Hatch year (HY) mallards (Anas platyrhynchos )i n the Coeur d'Alene (CDA) River Basin had higher concentra- tions of lead in their blood than HY Western Canada geese (Branta canadensis moffitti ) (geometric means 0.98 versus 0.28 mg/g, wet weight). The pattern for adults of both species was similar, although geometric means (1.77 versus 0.41 mg/g) were higher than in HY birds. HY mallards captured in the CDA River Basin in 1987 contained significantly lower lead concentrations in their blood than in 1994 -95 (0.36 versus 0.98 mg/g); however, some very young mallards were sampled in 1987, and concentrations in adults were not significantly dif- ferent in 1987, 1994, or 1995 (1.52, 2.07, 1.55 mg/g, respec- tively). Both species in the CDA River Basin in 1994 -95 showed significantly reduced red blood cell delta-aminolevu- linic acid dehydratase (ALAD) activity compared to the refer- ence areas: Canada geese (HY 265.4 to 286.0%, adults 282.3%), and mallards (HY 290.7 to 295.5%, adults 294.1%). Canada goose goslings were divided into size classes, and the two smaller classes from the CDA River Basin had significantly elevated free erythrocyte protoporphyrin (pro- toporphyrin) levels compared to the reference area (15.23 and 6.93). HY and adult mallards both had significantly elevated protoporphyrin (5.93 and 7.53). Recognizing that interspe- cific differences exist in response and sensitivity to lead, it appears (at least for hemoglobin and hematocrit) that Canada geese were more sensitive to lead than mallards, i.e., adverse hematologic effects occur at lower blood lead concentrations. Only Canada geese from the CDA River Basin, in spite of lower blood lead concentrations, had significantly reduced mean hemoglobin and hematocrit values. No euthanized Can- ada geese (all HYs) from CDA River Basin were classified as clinically lead poisoned, but 38 Canada geese found dead in the CDA River Basin during a concurrent study succumbed to lead poisoning between 1992 and 1997. Only 6 (15.8%) of these 38 contained ingested lead shot, which contrasts greatly with the 75-94% incidence of ingested lead shot when mortality was due to lead shot ingestion. Lead from other contaminated sources (i.e., sediments and vegetation) in the CDA River Basin was strongly implicated in most Canada goose deaths. Based on the 31 live mallards and Canada geese collected in the CDA River Basin, which were representative of the live populations blood sampled only, the prevalence of subclinical and clinical lead poisoning (as determined by liver lead con- centrations, excluding birds with ingested lead shot) was higher in mallards: subclinical (4 of 8, 50% HYs and 6 of 11, 55% adults); clinical (0% HYs and 4 of 11, 36% adults), with less data available for Canada geese (only 1 of 9, 11% HYs mar- ginally subclinical). The clinically lead-poisoned mallards had extremely high concentrations of lead in blood (2.69 - 8.82 mg/g) and liver (6.39 -17.89 mg/g). Eight mallards found dead in the CDA River Basin during a concurrent study were diag- nosed as lead poisoned, and only one (12.5%) contained in- gested lead shot, which again strongly implicates other lead sources. The finding of dead lead poisoned Canada geese together with the high percentage of live mallards classified as subclinically or clinically lead poisoned, in combination with the low incidence of ingested lead shot causes us concern for both of these species, which live in association with lead- contaminated sediment in the CDA River Basin.
Databáze: OpenAIRE
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