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  • 1
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Thick-billed murres (Uria lomvia) originating from breeding colonies in the Canadian Arctic were collected on their wintering grounds off the coast of Newfoundland. Murres had been previously banded such that the age of each bird could be determined upon collection. This allowed us to explore the possible relationships between age and contaminant levels in the thick-billed murre. Samples of breast muscle were analyzed for organochlorines (chlorobenzenes, hexachlorocyclohexanes, DDTs, chlordanes, mirex, dieldrin, and PCBs) and metals (selenium, cadmium, mercury, and lead). Levels of both organochlorine and metal residues were sufficiently low so that toxic effects were unlikely. First-year birds contained lower levels of DDTs, mirex, dieldrin, and PCBs compared with older birds, reflecting lower levels of contamination of these compounds in food chains at breeding colonies located at higher latitudes. Higher levels of chemical residues in older birds may reflect greater direct input of those organochlorines into the wintering grounds via the highly contaminated St. Lawrence River. Levels of chlorobenzenes, hexachlorocyclohexanes, and chlordanes, which reflect atmospheric deposition, were not detected at higher levels in older birds. Of the metals, only cadmium was detected at higher levels in older birds.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Unhatched eggs and plasma samples from prefledged bald eagles (Haliaeetus leucocephalus) from a recovering population in the Canadian Great Lakes Basin were contaminated with organochlorine compounds at levels comparable to those reported for eagle populations in several areas of the United States. PCBs were among the most commonly detected contaminants and occurred at high concentrations in plasma. Plasma PCB concentrations in Lake Erie nestlings were significantly higher than in chicks from Lake Nipigon (0.130 and 0.047 mg/kg wet weight, respectively). Blood levels of mirex were higher in nestlings from Lake Superior compared to those from Lake Erie (0.0012 and 0.0006 mg/kg wet weight, respectively). Migration routes and over-winter locations of avian prey that constitute a part of the bald eagle chick's diet are likely to contribute to these spatial contaminant patterns in plasma. Atmospheric deposition and a cold condensation effect for chlordane compounds may have produced higher levels of these compounds in plasma samples from Lake Superior compared to samples from Lake Erie (0.020 and 0.008 mg/kg wet weight, respectively). Levels of DDE in plasma were generally low, ranging in concentration from 0.02 mg/kg wet weight for lakes Erie and Nipigon to 0.06 mg/kg wet weight for Lake Huron. Concentrations of organochlorines in eaglet plasma remained relatively stable between 1990 and 1996; no significant trends associated with year of sampling were detected. The data from Lake Erie showed no correlation between productivity and plasma levels of PCBs or DDE during this time period. There were no indications that the concentrations of contaminants detected were adversely affecting productivity in Canadian Great Lakes bald eagle populations. Residue levels in eggs from Lake Erie eagle territories were equally or more contaminated than eggs from other highly contaminated environments in the United States such as the Great Lakes and Columbia River estuary. Concentrations of DDE and PCBs in Lake Erie eggs declined significantly between 1974 and 1994. Although dieldrin and chlordane levels showed a similar decline, these relationships were not statistically significant. Mirex concentrations were relatively stable. Eggs from Lake of the Woods were significantly less contaminated than those from Lake Erie (PCBs: 3 and 84 mg/kg wet weight, respectively; DDE: 3 and 24 mg/kg wet weight, respectively). Reproductive success (number of young produced/active nest) remained constant between 1982 and 1996 and productivity is sufficient to maintain an increasing population. The number of active nests has increased during this period indicating that the population is expanding and might be expected to do so until suitable habitat becomes limiting. Reductions in organochlorine levels, reintroduction efforts, immigration from other populations, and changes in habitat quality have likely contributed to the observed growth in the number of breeding pairs.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Liver tissue from male and female adult American white pelicans (Pelecanus erythrorhyncos) were individually analyzed for organochlorine compounds and trace elements. Levels of most organochlorines, specifically ΣDDT, ΣPCB, Σchlordane, Σmirex, dieldrin, and ΣCBz, were significantly higher in male pelicans compared to females. Only concentrations of ΣHCH were not significantly different between sexes. Male livers also contained higher concentrations of mercury, cadmium, and arsenic compared to females. Selenium concentrations were not different between sexes, and lead was not detected in any of the samples. Differences in residue levels between sexes were probably due to the female's ability to excrete organochlorines and some trace elements into the egg prior to laying. In addition, differences in contaminant concentrations in prey available to these birds on their breeding grounds and their wintering areas may be influencing sex-related differences.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 53 (1946), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 53 (1946), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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