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MERCURY CYCLING AND BIOMAGNIFICATION
Citation:
HOFF, D., J. M. JOHNSTON, AND C. DUCHENEAUX. MERCURY CYCLING AND BIOMAGNIFICATION. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Montreal, QC, CANADA, November 05 - 09, 2006.
Impact/Purpose:
The objective of this task is to develop, support and transfer a wide variety of tools and mathematical models that can be used to support watershed and water quality protection programs in support of OW, OSWER, and the Regions.
Description:
Mercury cycling and biomagnification was studied in man-made ponds designed for watering livestock on the Cheyenne River Sioux Reservation in South Dakota. Multiple Hg species were quantified through multiple seasons for 2 years in total atmospheric deposition samples, surface water, shallow ground water, sediments, soils, plankton, macroinvertebrates and fish. No point source contamination of Hg was found during the investigation. Atmospheric deposition was the only documented source of Hg loading to the systems. The highest concentrations of methyl Hg occurred in plankton samples, while the average percent methyl Hg of total Hg was similar to that of water. These findings suggest that plankton is a key component to understanding the biological biomagnification of Methyl Hg in these systems. Additionally, plankton Hg concentrations varied temporally with water concentrations. Fish burdens of Hg ranged up to 1.5 ppm in Northern Pike and were not temporally dependent.