Nickel uptake and loss in the bivalvesCrassostrea virginica andMytilus edulis

Nickel uptake and loss byCrassostrea virginica andMytilus edulis were studied at naturally occurring seawater temperatures and salinity to determine their potential as indicators of nickel pollution. After 12 wks treatment with 5 and 10 μg Ni/kg seawater, mean tissue concentrations inC. virginica were 9.62 ±3.56 and 12.96 ±5.15 μg/g dry weight. Mean nickel concentrations inM. edulis treated with 5 and 10 μg Ni/kg seawater for 12 wks were 10.40 ±2.66 and 16.43 ±3.19 μg/g dry weight, respectively. Significant linear relationships were found between nickel uptake byC. virginica andM. edulis and seawater nickel concentrations over the concentration range. A significant inverse relationship exists between tissue nickel concentration and dry weight in bothC. virginica andM. edulis. After holding nickel-treatedM. edulis in ambient flowing seawater for 28 weeks, a 73 and 89% loss of nickel concentration occurred inM. edulis treated with 5 and 10 μg Ni/kg, respectively. When treated similarly,C. virginica from both the 5 and 10 μg Ni/kg treatments lost 48 and 68% respectively, of their tissue nickel concentration. The evidence suggests thatM. edulis would be a better indicator of nickel pollution in its environment thanC. virginica.