Chromium toxicity to a freshwater prawn Macrobrachium lamarrei (H.M. Edwards)

Experiments were carried out to determine the short-term toxicity of potassium dichromate (K2Cr2O7) to Macrobrachium lamarrei (M. Edwards) and the effect of acute and sub-acute concentrations on haemolymph glucose level of the animal. The LC50 values for 24, 48, 72 and 96 h were 5.44, 3.69, 2.47 and 1.84 mg/l, respectively. Exposure of K2Cr2O7 decreased the haemolymph glucose level up to 24 h but thereafter an increase in haemolymph glucose level was observed that continued up to 72 h. The haemolymph glucose level decreased after 96 h. The effects of K2Cr2O7 in relation to these changes and mortality of organisms were also discussed.