RedN NAWQA
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Red River of the North Basin
National Water-Quality Assessment Program
Goldstein, R.M., and Brigham, M.E., 1995, Comparison of Mercury
Concentrations in Liver, Fillet Tissue, and Whole Bodies of Fish from the Red
River of the North: Mercury Pollution in the Upper Great Lakes Region,
June 9, 1995, Minneapolis, MN. p.14
Abstract
As part of the U.S. Geological Survey's National Water-Quality Assessment
program, carp (Cyprinus carpio) and channel catfish (Ictalurus
punctatus), collected from along the Red River of the North in 1994, were
analyzed for mercury content to compare total concentrations among body
compartments (liver, fillet, whole body); between size classes (small, large);
and among geographic locations. Seven carp from each size class were collected
at four sites, and seven channel catfish from each size class were collected
from one site. Analysis of variance of logarithmically transformed mercury
concentrations in carp indicates that concentration differences among body
compartments and between size classes are significant (p<0.001). Mean
mercury concentrations (wet weight basis) were as follows: fillet (0.31
micrograms per gram (µg/g)); whole body (0.18 µg/g); liver (0.11 µg/g). Mean mercury concentrations
were significantly greater in large carp (mean weight=1.87 kg) than in small carp (mean weight=1.18 kg) in
both fillets (0.34 µg/g versus 0.29 µg/g; p=0.08) and liver tissue (0.13 µg/g versus 0.087 µg/g; p=0.001).
Whole-body concentrations were not significantly different (p>0.1) among size classes. No clear
geographic differences in mercury concentration were identified along the Red River of the North, which
may be reflective of diffuse mercury sources or fish mobility. The mercury-concentration distribution in
catfish differed from that of carp. Fillet and liver tissues had mean concentrations that were not
significantly different (0.18 and 0.16 µg/g, respectively), but were significantly greater than whole-body
concentrations (mean=0.11 µg/g; p<0.0001).
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U.S. Geological Survey