Lead toxicity at different life stages of the giant prawn (Macrobrachium rosenbergii,de Man): considerations of osmoregulatory capacity and histological changes in adult gills

This study evaluated the acute toxicity of lead in different life stages of the freshwater prawn Macrobrachium rosenbergii, determined the effect of sublethal Pb concentrations on osmoregulatory capacity (OC), measured the Pb level in gills, and investigated the effect of Pb on the structure of the gills of adult prawns. The 24-, 48-, and 96-h LC50 values for Pb to M. rosenbergii increased progressively with increasing life stage, from post-larvae (PL), juvenile to adult. The 24- and 48-h LC50 values for post-larvae ranged from 0.01- to 0.09-mg Pb/L. The 24-, 48-, and 96-h LC50 values for Pb were lower at 12 ppt than those at 0 ppt for either the juveniles or the adults. At 12 ppt, the 96-h LC50 values in PL11, juvenile and adult were 0.47-, 0.58-, and 2.03-mg Pb/L, respectively. Meanwhile, at 12 ppt, the 96-h LC50 values in PL11, juvenile and adult were 0.63-, 4.44-, and 7.98-mg Pb/L, respectively. In adults, the OC values of controls and prawns exposed to 2- and 4-mg Pb/L at 0 ppt were not signi...