The Cosumnes River Preserve in the California’s Central Valley contains a mosaic of managed wetlands where conditions may promote high levels of methylmercury bioaccumulation. In order to document potential environmental health risk in these wetlands due to mercury, we analyzed dragonfly larvae, western mosquitofish, and tree swallow eggs collected from wetlands and rice fields of the Preserve from 2011 to 2013.

During 2010-2014, tree swallow (Tachycineta bicolor) reproductive success was monitored at 68 sites across all 5 Great Lakes, including 58 sites located within Great Lakes Areas of concern (AOCs) and 10 non-AOCs. Sample eggs were collected from tree swallow clutches and analyzed for contaminants including polychlorinated biphenyls (PCBs), dioxin and furans, polybrominated diphenyl ethers, and 34 other organic compounds. Contaminant data were available for 360 of the 1249 clutches monitored. Markov chain multistate modeling was used to assess the importance of 5 ecological and 11 of the dominant contaminants in explaining the pattern of egg and nestling failure rates. Four of 5 ecological variables (female Age, Date within season, Year, and Site) were important explanatory variables. Of the 11 contaminants, only total dioxin and furan toxic equivalents (TEQs) explained a significant amount of the egg failure probabilities. Neither total PCBs nor PCB TEQs explained the variation in egg failure rates. In a separate analysis, polycyclic aromatic hydrocarbon exposure in nestling diet was significantly correlated with the daily probability of egg failure. The eight sites within AOCs which had poorer reproduction when compared to 9 non-AOC sites, the measure of impaired reproduction as define by the Great Lakes Restoration Initiative, were associated with exposure to dioxins and furans, PAHs, or depredation. Only 2 sites had poorer reproduction than the poorest performing non-AOC. Using a classic (non-modeling) approach to estimating reproductive success, 82% of nests hatched at least 1 egg, and 75% of eggs hatched.

This dataset includes daily nest attendance (proportion of time females spent at the nest), incubation constancy (proportion of time females maintained their nests at nest-specific incubation temperatures), nest temperature variation, and the duration of individual incubation bouts for three species of dabbling ducks (mallard, gadwall, and cinnamon teal) nesting in Suisun Marsh, California during 2015-2019.

The dataset includes specifics on bird blood and aquatic invertebrate tissue mercury concentrations measured using direct mercury analysis.

This dataset includes bird species, invertebrate order and family, sample identification codes, collection date, latitude, longitude, site name, bird age, invertebrate life stage, invertebrate trophic group, carbon and nitrogen stable isotopes in birds and invertebrates, total mercury concentrations in bird blood, and methylmercury concentrations in composite invertebrates.

This dataset includes bird species, invertebrate order and family, sample identification codes, collection date, latitude, longitude, site name, bird age, invertebrate life stage, invertebrate trophic group, carbon and nitrogen stable isotopes in birds and invertebrates, total mercury concentrations in bird blood, and methylmercury concentrations in composite invertebrates.

Tree swallow, Tachycineta bicolor, nestlings were collected from 76 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 12 sites not listed as AOCs from 2010 to 2015. Livers were harvested and analyzed for 21 elements. Mercury concentrations differed among AOCs; however, all livers analyzed had concentrations well within background and generally comparable or lower than most sites outside of the Great Lakes. Mercury, the only element specifically identified in the designation of AOCs, does not seem to pose a threat to birds at any of the AOCs monitored. In contrast, selenium (Se) concentrations were elevated at sites on the southwest shore of Lake Michigan to levels that could be harmful to reproduction. Other toxic elements were elevated at selected AOCs, but the concentrations were not at toxic levels. Multivariate analysis identified concentration pattern differences among 8 AOCs that had 3 or more sites sampled. Of 29 possible AOC comparisons, 11 were significant and clear differences in patterns were evident. Concentration patterns of sites within AOCs appeared closely associated with one another. Additionally, Se was the primary contributor to the differences among the 8 AOCs for 9 of the 11 comparisons.

Tree swallow, Tachycineta bicolor, nestlings were collected from 76 sites in the Great Lakes which included multiple sites at 27 Areas of Concern (AOCs) and 12 sites not listed as AOCs from 2010 to 2015. Livers were harvested and analyzed for 21 elements. Mercury concentrations differed among AOCs; however, all livers analyzed had concentrations well within background and generally comparable or lower than most sites outside of the Great Lakes. Mercury, the only element specifically identified in the designation of AOCs, does not seem to pose a threat to birds at any of the AOCs monitored. In contrast, selenium (Se) concentrations were elevated at sites on the southwest shore of Lake Michigan to levels that could be harmful to reproduction. Other toxic elements were elevated at selected AOCs, but the concentrations were not at toxic levels. Multivariate analysis identified concentration pattern differences among 8 AOCs that had 3 or more sites sampled. Of 29 possible AOC comparisons, 11 were significant and clear differences in patterns were evident. Concentration patterns of sites within AOCs appeared closely associated with one another. Additionally, Se was the primary contributor to the differences among the 8 AOCs for 9 of the 11 comparisons.

The dataset includes the bird species, region where sampled, sampling site, capture location, mercury concentration in whole blood, lead concentration in whole blood, sulfur stable isotope concentration in blood plasma, carbon isotope concentration in blood plasma, whole blood ALAD activity, and fecal corticosterone concentrations.

Data used in the Maumee River omics publication, Multi-omics responses in tree swallow (Tachycineta bicolor) nestlings from the Maumee Area of Concern, Maumee River, Ohio. Tseng et al. 2023 Sci. Total Environ. 856:159130