Use of Gammarus pulex (L.) in safety evaluation tests: culture and selection of a sensitive life stage.

A simple and effective method for the laboratory culture of Gammarus pulex is described. Over 70% of juveniles survived, reaching sexual maturity within 130 days at 13 degrees C, and animals of different ages were available for toxicity tests throughout the year. The acute toxicity of cadmium to cultured animals of several known ages and to field-collected animals of unknown age was determined. Juveniles (1 day old, 48 hr LC50 0.019 mg Cd liter-1) were found to be almost 250 times more sensitive than the oldest age group tested (220 days old, 48 hr LC50 4.7 mg Cd liter-1). In view of its ease of culture and sensitivity to pollutants, it is proposed that G. pulex should be more widely employed as a standard toxicity test species in the hazard evaluation process.