Acute toxicity of the pesticides endosulfan and ametryne to the freshwater prawn Macrobrachium rosenbergii De Man

Prawns Macrobrachium rosenbergii were exposed to endosulfan and ametryne at concentrations ranging 0 4.2 and 0 30.0 mg/l, respectively, and acute toxicity was determined. In the static and renewal bioassays, the LC sub(50) values for endosulfan ranged 1.64 2.08 and 0.93 0.20 mu g/l at 24- and 96-h exposures, respectively, while those for ametryn ranged 27.81 19.62 and 7.54 6.25 mu g/l, respectively. The variations between static and renewal tests were statistically significant, except for endosulfan at the 24-h exposure.