To address the need for dietary arsenic (As) research on freshwater fish, experiments were conducted to examine the uptake and toxicity of dietary As exposure in two species. First, a short-term preliminary experiment was conducted to compare the accumulation, distribution, and toxicological effects of dietary As exposure in lake whitefish ('Coregonus clupeaformis') and lake trout ('Salvelinus namaycush'). Dietary As concentrations that fish would consume, and the influence of brine shrimp on consumption of As were also determined. Based on the results of this study, a longer term experiment was conducted to investigate the uptake and toxicity of As in lake whitefish fed contaminated diets at nominal concentrations of 0, 1, 10, and 100 [mu]g As/g food (d.w.) for 10, 30, and 64 days. As residues in pyloric caeca, intestine, liver, and scales, hepatic MT induction, and histopathological alterations in liver and gallbladder are recommended for use as indicators of As exposure and toxicity in environmental monitoring programs. (Abstract shortened by UMI.)