Annual and regional variation in mercury concentrations in wood stork nestlings.

Mercury concentrations were measured in blood, down, and feathers from approximately 300 wood stork nestlings in one South Carolina, USA, and four Georgia, USA, colonies from 1996 to 1999. Coastal nestlings generally had lower mercury concentrations than those from inland colonies. Inter-year differences were also apparent, particularly for coastal colonies, where nestling mercury concentrations were higher in 1998 than in 1997 or 1999. In 1998, a wet winter followed by a dry spring and summer produced ideal freshwater foraging conditions and mercury concentrations in coastal nestlings were higher than during the two dry years. There was little inter-year variation in mercury concentrations in nestlings from inland colonies, as parent storks from these colonies forage exclusively in freshwater habitats regardless of rainfall patterns. These results suggest that greater risk of mercury exposure to nestlings is associated with use of freshwater foraging habitats.

Detrimental effects associated with trace element uptake in lake chubsuckers (Erimyzon sucetta) exposed to polluted sediments.

Lake chubsuckers (Erimyzon sucetta) were exposed to coal ash-polluted sediments under conservative experimental conditions (filtered artificial soft water and abundant uncontaminated food). After 4 months of exposure, fish grazing the polluted sediments had significantly elevated body burdens of Se, Sr, and V. Selenium levels were particularly elevated, reaching mean whole body concentrations of 5.6 microg/g dry mass by the end of experimental manipulations. Twenty-five percent of fish exposed to pollutants died during the study. All surviving fish exposed to ash exhibited substantial decreases in growth and severe fin erosion. Total nonpolar lipids were two times higher in fish from the control treatment, but percent lipid did not differ between treatments. Because fish were presented with the same amount of food during the study, it appears fish exposed to ash utilized more energy for daily activities and/or were less efficient at converting available energy to tissues for growth and storage. The results were particularly interesting because we were unable to detect differences in standard metabolic rate (SMR) of fish between treatments. Increased energy expenditures not detectable in estimates of maintenance based on SMR, such as costs of digestion or activity, may have contributed to decreased energetic efficiency. Our findings corroborate previous studies which have documented the toxicity of ash-derived pollutants in fish.