Geology topics

D. V. Weseloh

Publications and source records attributed to D. V. Weseloh.

4 recordsLinked to original sources

USGS1992

Polychlorinated biphenyl residues and egg mortality in double-crested cormorants from the Great Lakes

We evaluated the overall potency of polychlorinated biphenyl (PCB)-containing extracts from double-crested cormorant ( Phalacrocorax auritis ) eggs with an in vitro bioassay system, the H4IIE rat hepatoma cell bioassay. Results from the H4IIE bioassay were strongly correlated with the hatching success of eggs in the colonies, whereas conventional methods of PCB analysis correlated poorly with hatching success of eggs from the same colonies. These observations suggest that even though concentrations of total PCB residues have declined in almost all compartments of the environment, their effects are still being observed. The significance of this observation is that the adverse symptoms presently observed in certain Great Lakes fish-eating waterbird populations do not appear to be caused by some as yet unidentified industrial chemical or chemicals and seem not to be the result of pesticides, but rather to the dioxin-like activity of PCBs. Evidence is presented to suggest that the relative enrichment of the potency of PCBs in the environment may play a role in the persistence of the observed adverse symptoms.

Environmental Toxicology and Chemistry↗

USGS1991

Reproductive outcomes in colonial fish-eating birds: A biomarker for developmental toxicants in Great Lakes food chains: I. Historical and ecotoxicological perspectives

Colonial fish-eating birds have been used as convenient model populations in which to study the impact of chronic exposure to complex mixtures of persistent lipophilic environmental contaminants within the Great Lakes ecosystem. To date, published reports of contaminant-induced adverse reproductive outcomes exist for six species. We briefly review the studies of the herring gull ( Larus argentatu s), Forster's tern ( Sterna forsteri ), and the double-crested cormorant ( Phalacrocorax auritus ) to illustrate the use of reproductive outcomes in fish-eating birds as a biomarkerfor developmental toxicants in Great Lakes food chains. We discuss the management implications of using various species for such purposes. We recommend that cormorants be used more extensively in biomonitoring programs to measure exposure and effects of polyhalogenated aromatic hydrocarbons and other contaminants in aquatic food chains in the Great Lakes.

Great Lakes↗

USGS1991

Reproductive outcomes in colonial fish-eating birds: A biomarker for developmental toxicants in Great Lakes food chains: II. Spatial variation in the occurrence and prevalence of bill defects in young double-crested cormorants in the Great Lakes, 1979–1987

Congenital malformations are relatively uncommon in most wild bird populations. Here we document the occurrence of bill malformations in double-crested cormorant ( Phalacrocorax auritus ) chicks from colonies in Green Bay and elsewhere in the Great Lakes and in reference areas off the Great Lakes, in the years 1979 through 1987. In the Great Lakes, 31,168 cormorant chicks were examined during 147 visits to 42 colonies. Seventy of these chicks had crossed or deflected bills or bills in which the mandibles differed in length. Only two of the 20,962 chicks examined during 82 visits to 35 colonies in reference areas located in the prairies and northwestern Ontario had bill defects. The probability of observing a malformed chick on a visit to a colony in Green Bay was 10 to 32 times greater than on a visit to a colony in the reference areas. Bill defects were observed at only two (6%) of the colonies in the reference areas. This proportion was exceeded in six of eight geographic regions within the Great Lakes and was highest (73%) in Green Bay colonies. The prevalence of malformed chicks in Green Bay (52.1 per 10,000)was markedly greater than in all other regions during this period. These bill defects are an example of developmental asymmetry and are an indicator of developmental stability within local populations. Other investigations in Lake Michigan suggest that chemicals such as polyhalogenated aromatic hydrocarbons (e.g., PCBs) that induce aryl hydrocarbon hydroxylase are responsible for the defects observed defects.

Great Lakes↗

USGS1989

Organochlorine contaminants in eggs of common terns from the Canadian Great Lakes, 1981

To determine if contaminant levels in Common Terns had changed over the last decade, we collected and analyzed eggs from four nesting colonies on the three lower Great Lakes during 1981. DDE and PCBs were detected in every egg from the four colonies. Dieldrin, mirex and trans -nonachlor were detected in more than 45% of the eggs. Seven other organochlorine contaminants (DDD, DDT, hexachlorobenzene, oxychlordane, cis -chlordane, cis -nonachlor and toxaphene) were detected in less than 25% of the eggs. Eggs from the Lake Ontario colony were generally the most heavily contaminated. Comparisons of DDE and PCB data with earlier studies of Common Terns indicated that contaminant levels in eggs from the four sampled colonies, or nearby sites, have decreased by up to 80–90% from 1969–1973 to 1981. Interspecies comparisons showed that Common Tern eggs have lower organochlorine residue levels than eggs of Caspian Terns or Herring Gulls. Dietary variation and migratory status are possible explanations for the differences in residue levels among species. Eggshell thickness, log-PCBs, and log-DDE were not significantly intercorrelated. Elevated contaminant levels in the early 1970s might be at least partly responsible for the decline of the Great Lakes Common Tern population over the past decade. Stabilization of population numbers during the early 1980s suggests that organochlorine pollution levels have been reduced to a point where they are no longer an important factor in the population dynamics of this species on the Great Lakes.

Fighting Island, Georgian Bay, Great Lakes, Lake E↗