Radioactive and non-radioactive contaminants in migratory and resident waterfowl inhabiting the Oak Ridge reservation, East Tennessee

The concentrations of radionuclides and metals accumulated in tissues of waterfowl inhabiting the Oak Ridge Reservation (ORR) were determined in addition to the composition and density of waterfowl species using ORR waste ponds, streams, and lakes. Waterfowl using the ORR may serve as a vector in transporting contamination off the ORR and into the human food chain. Weekly observations of ORR aquatic areas were made to determine the composition and density of waterfowl species. More than 16,000 observations of waterfowl have been recorded for the designated locations. Both migratory and resident birds inhabit the waste ponds and streams on the ORR, especially during winter. Resident Canada geese (Branta canadensis) at the ORR and surrounding areas were fitted with neck-collars to determine their movement patterns. The available data indicated that the collared Canada geese use both the ORR and areas accessible to the public. Migratory waterfowl and coots (Fulica americana) were collected from White Oak Lake (WOL) at the Oak Ridge National Laboratory (ORNL) to determine radionuclide and metal concentrations in their tissues. Resident Canada geese from ORNL were also analyzed for radioactive and non-radioactive contamination. Cesium-137 and ⁹⁰Sr were the primary radionuclides detected in waterfowl. The maximum ¹³⁷Cs concentrations in breast tissue from a dabbler species (gadwall, Anas strepera) collected from WOL was 340 Bq/kg in comparison to 272 Bq/kg of ¹³⁷Cs in breast tissue of a WOL wood duck (Aix sponsa). The highest concentrations of ¹³⁷Cs in breast tissue (146,000 Bq/kg) and ⁹⁰Sr in bone (40,000 Bq/kg) were detected in a pair of Canada geese nesting on a waste pond within the ORNL enclosure. Detectable levels of mercury, selenium, cadmium, and lead were found in wild waterfowl collected from the ORR. Cadmium concentrations in kidney and selenium concentrations in breast tissue were significantly higher in adults than in immature wood ducks. Two groups of domestic mallards (Anas platyrhynchos) were released on WOL to determine the uptake of ¹³⁷Cs, ⁹⁰Sr, and mercury by tissues over time. The contaminant levels increased in tissues with time. The concentrations of radionuclides and metals detected in the tissues of the domestic mallards were comparable to levels in tissues of migratory waterfowl. Therefore, the length of time migratory waterfowl resided on WOL was probably less than 60 to 95 days; the maximum time the domestic mallards resided on WOL. The maximum effective dose commitment to humans from the consumption of 1600 grams of breast tissue from a Canada goose collected from ORNL's Basin 3524 would be 3.1 mSv. Consumption of 298 grams of breast tissue from a migratory gadwall collected at WOL would only give a potential effective dose commitment of 1.4 μSv. Concentrations of mercury, selenium, cadmium, and lead detected in ORR waterfowl were generally below acceptable levels for ingestion by humans. Elevated levels of silver and lead were detected in tissues from several WOL domestic mallards.