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Metallothionein in brook trout (salvelinus fontinalis) as a biological indicator of inorganic chemical contaminant stress

Thesis/Dissertation ·
OSTI ID:6943411
A technique for quantifying metallothionein was evaluated with fish tissue. Adult brook trout were administered 3 mg /sup 109/cadmium/kg body weight by intraperitoneal injection over a 5 day period to induce metallothionein concentrations in liver and kidney tissues. The method was modified so cadmium bound to unsaturated metallothionein could be measured. The method gave precise measurements and was used to evaluate the toxicological significant of metallothionein in two 30-day chronic toxicity studies of cadmium on brook trout. In particular, metallothionein was evaluated as a biological indicator of inorganic chemical stress in brook trout. Pathological effects in animals resulting from exposure to inorganic chemicals is thought to occur when metallothionein's sequestering ability is exceeded; a phenomenon explained by the spillover hypothesis. The presence of free cadmium in tissues of fish from all exposures suggests metallothionein was not saturated with cadmium perhaps because of competition for binding sites on metallothionein between cadmium and other inorganic chemicals such as copper and zinc. Based on results of the two toxicity studies, the spillover hypothesis should be redefined to a continuum of toxic responses to varying balances between the relative abundance of inorganic chemicals present and their respective binding affinities for metallothionein.
Research Organization:
Missouri Univ., Columbia (USA)
OSTI ID:
6943411
Country of Publication:
United States
Language:
English