USE OF FEEDING RATE AND RE-PAIRING OF PRECOPULATORY GAMMARUS-PULEX TOASSESS TOXICITY OF GAMMA-HEXACHLOROCYCLOHEXANE (LINDANE)

Feeding rate acid re-pairing of physically pre-disrupted precopulatory Gammarus pulex were applied as response criteria to assess toxicity o f Gamma-hexachlorocyclohexane (lindane). Animals were exposed to eithe r high [0.5 - 2.0 mg 1(-1)] concentrations for 2 - 20 min or low [0.5 - 5.0 mu g 1(-1)] concentrations for 48 h at 15 degrees C. Feeding rat e was significantly reduced during 48 h exposure to 5.0 mu g 1(-1) lin dane (6% of the 48 h LC(50)) although precopulation was essentially un affected. The majority of pre-disrupted couples re-paired after the fe eding period, and no significant disruptive effect on non-disrupted pa irs exposed to low concentrations occurred. Feeding rate was also sign ificantly reduced during the first 24 h post brief-exposure [2 - 20 mi n] to lindane at 2.0 mg 1(-1) and at 1.0 mg 1(-1) for 20 min. Re-pairi ng was affected by treatments combining higher concentrations and long er exposures. The median survival time of briefly exposed animals vari ed with concentration and exposure period.