Acute and subchronic toxicity of naturally weathered <i>Exxon valdez</i> crude oil in mallards and ferrets

Abstract

Abstract The toxic properties of naturally weathered Exxon Valdez crude oil (WEVC) were assessed in a battery of acute and subchronic toxicity tests using mallards, Anas platyrhynchos, and European ferrets, Mustela putorius. Adult mallard acute oral toxicity study results indicated no mortalities or signs of toxicity, i.e., no-observed-adverse-effect level (NOAEL) and median lethal dose (LD50) &amp;gt; 5,000 mg/kg. Acute oral feeding and food avoidance tests with ducklings also indicated no toxicity (NOAEL and LC50 &amp;gt; 50,000 mg/kg diet) with no evidence of food avoidance (FAC50 &amp;gt; 20,000 mg/kg diet). No mortalities or toxic signs were noted in a 14-d feeding study with adult birds at dietary concentrations up to 100,000 mg WEVC/kg diet. Among clinical and physiological end points evaluated, the only significant difference noted was an increase in liver:body weight ratios in the 100,000-mg WEVC/kg diet dose group. No differences in clinical chemistry or hematological parameters were noted, and there were no consistent differences in histological evaluations of organ tissues. Daily oral doses of up to 5,000 mg/kg of WEVC over 5 d resulted in minimal effects on ferrets. Increased serum albumin concentrations were observed in the 5,000-mg/kg dose group females and decreased spleen weights were noted in females of all WEVC treatment groups. No other significant observations were noted.