Partitioning of mercury in the North Saskatchewan River

Abstract

Mercury levels in fish, water and sediments were determined during 1982 along a 600 km stretch of the North Saskatchewan River (NSR) in the province of Alberta. Migratory fish species such as goldeye, walleye and sauger in the NSR were found to contain total mercury levels ranging from 0.104 to 1.553 mg/kg ( mean ≧ 0.5 mg/ kg ). Northern pike, white sucker, longnose sucker and northern redhorse sucker had total mercury levels ranging from 0.003 to 1.003 mg/kg (mean < 0.5 mg/kg) Regression analysis of the data revealed that neither the sex of the fish nor the location of the sampling site contributed significantly to the mercury burden in fish in the entire study section of the river. Sediment analysis showed a low and more or less uniform concentrations of mercury in Alberta (≦0.1 mg/kg). The total mercury in NSR water averaged 0.09 μg/L in upstream Edmonton and was found to elevate in downstream NSR (0.22 μg/L) near industrial discharge sites and agricultural runoff areas (mean = 0.20 μg/L). Calculated partition coefficients seem to group the fish into two categories, (i) goldeye, walleye and sauger (bioconcentration factor [BCF] =3−3.7×10 3 and (ii) northern pike, longnose sucker, white sucker and northern redhorse sucker (BCF=1.2−1.8×10 3).