The effects of water temperature (5 or 15 °C) on the toxicity of arsenate to rainbow trout were examined over an 11-wk period. The fish were exposed to nominal arsenate concentrations set as fixed proportions of the 144-h LC50s for arsenate at their respective temperature (5 °C: 0, 1.5, 18, and 36 mg∙L−1; 15 °C: 0, 1.5, 9, and 18 mg∙L−1). Arsenate toxicity was assessed in terms of mortality, total arsenic concentration, wet weight, condition factor, liver and muscle glycogen levels, hepato- and splenosomatic indices, and histopathology. Contrary to the previously reported relationship between acute toxicity and temperature, trout were more tolerant of chronic exposure to arsenate at 15 °C than at 5 °C. While the high-exposure concentration (5 °C, 36 mg∙L−1; 15 °C, 18 mg∙L−1) fish at both temperatures attained the same internal arsenic concentration (2 to 3 μg∙g−1), up to 50% of those fish tested at 5 °C died. The whole-body arsenic concentrations in moribund trout were found to vary between 4 and 6 μg∙g−1, suggesting that a critical arsenic body-concentration is reached before death or toxicant insult occur.
Effects of urbanization of coastal watersheds on growth and condition of juvenile alewives in New England