Mercury Distribution in Sediments and Bioaccumulation by Fish in Two Oregon Reservoirs: Point-Source and Nonpoint-Source Impacted Systems

Abstract. Mercury pollution was compared in two Oregon reservoirs of similar size and age, located within the same ecoregion. Cottage Grove Reservoir was distinguished by a history of mercury mining and processing within its watershed, while Dorena Reservoir was not. Mercury concentrations in sediments of the reservoirs, tributary streams, and three species of fish were measured. Sediment mercury concentrations in the main tributary of Cottage Grove Reservoir, which drains the subbasin where past mercury mining occurred, was tenfold higher than mercury in sediments from other reservoir tributaries. There were no significant differences between sediment mercury concentrations in the tributaries of Dorena Reservoir. The average mercury concentration in the basin sediment of Cottage Grove Reservoir (0.67 ± 0.05 μg/g dry wt) was higher than for Dorena Reservoir (0.12 ± 0.01 μg/g dry wt). At Cottage Grove Reservoir, maximum mercury concentrations were near or exceeded 1 μg/g wet wt for largemouth bass (Micropterus salmonides) and bluegill (Lepomis macrochirus) epaxial muscle. Muscle mercury concentrations in largemouth bass and crappie (Pomoxis nigromaculatus) from Cottage Grove Reservoir were significantly higher than from the same species from Dorena Reservoir. Numbers of bluegill of the same age available from both reservoirs were too small for statistical comparisons. Mercury concentrations in largemouth bass muscle fluctuated annually in both reservoirs. Fish ages were consistently positively correlated with muscle mercury concentrations in only the point-source-impacted reservoir. These results indicated that a point source, Black Butte Mine, contributed amounts of mercury greatly in excess of mobilization from natural deposits, atmospheric deposition, and small-scale uses of the metal as an amalgamating agent in gold mining.

[1]  T W Clarkson,et al.  Atomic absorption determination of total, inorganic, and organic mercury in blood. , 1972, Journal - Association of Official Analytical Chemists.

[2]  R. Jahnke,et al.  Rate of mercury loss from contaminated estuarine sediments , 1980 .

[3]  G. Bryan,et al.  Bioavailability, accumulation and effects of heavy metals in sediments with special reference to United Kingdom estuaries: a review. , 1992, Environmental pollution.

[4]  W. K. Johnson,et al.  Seasonal replenishment of mercury in a coastal fjord by its intermittent anoxicity , 1986 .

[5]  P. Craig,et al.  Total mercury, methyl mercury and sulphide in river carron sediments , 1983 .

[6]  G. Holcombe,et al.  Long-Term Effects of Methylmercuric Chloride on Three Generations of Brook Trout (Salvelinus fontinalis): Toxicity, Accumulation, Distribution, and Elimination , 1976 .

[7]  William C. Orr,et al.  Geology of Oregon , 1976 .

[8]  S. Allen-Gil,et al.  An ecoregion approach to mercury bioaccumulation by fish in reservoirs , 1995 .

[9]  W. Burrows,et al.  Uptake and loss of methylmercury-203 by bluegills (Lepomis macrochirus) , 1973 .

[10]  Ted R. Lange,et al.  Influence of Water Chemistry on Mercury Concentration in Largemouth Bass from Florida Lakes , 1993 .

[11]  A. Kruckeberg,et al.  Indicator plant-soil mercury patterns in a mercury-rich mining area of British Columbia , 1985 .

[12]  M. Winfrey,et al.  Seasonal and Spatial Variations in Mercury Methylation and Demethylation in an Oligotrophic Lake , 1987, Applied and environmental microbiology.

[13]  M. Winfrey,et al.  Environmental factors affecting the formation of methylmercury in low pH lakes , 1990 .

[14]  Andrew L. Schaedel,et al.  Atlas of Oregon Lakes , 1985 .

[15]  R. Munson,et al.  The mercury cycle and fish in the adirondack lakes. , 1994, Environmental science & technology.

[16]  Lars Håkanson,et al.  Principles of Lake Sedimentology , 1983 .

[17]  G. Bouyoucos Hydrometer Method Improved for Making Particle Size Analyses of Soils1 , 1962 .

[18]  Murray G. Johnson Trace Element Loadings to Sediments of Fourteen Ontario Lakes and Correlations with Concentrations in Fish , 1987 .