Effects of heavy metals on some physiological and biochemical parameters of Lymnaea stagnalis and Clarias gariepinus

The aims of the present study were to determine the effects of heavy metals on some physiological and biochemical parameters of Lymnaea stagnalis and Clarias gariepinus. Reproductive success, tissue protein levels and enzyme activities were determined under the effect of Cu, Ni and Pb over 4 and 42 days. Metal and total protein levels and Na+/K+-ATPase and Ca+2ATPase activities were determined using spectrophotometric methods in hepatopancreas, muscle and mantle tissues, all of which decreased compared to control levels. Sublethal levels of Cu, Ni and Pb decreased the reproductive success while decreasing or eliminating the effects of metals did not have any positive effect on the numbers of eggs hatching. Accumulation of selenium, zinc and nickel in gill liver and kidney tissues of C. gariepinus after exposure to sublethal levels of metals over 7 and 14 days and metal depuration for 7 days after 14 days of exposure in metal free water were determined together with changes in total protein levels and Na+/K+-ATPase activities. Metal accumulation increased with exposure period and decreased to a certain level during the elimination period, level during one week of depuration period but not eliminated to the control level. Tissue total protein levels differed depending on exposure period and metal, whereas Na+/K+-ATPase activities decreased compared to control. Both total protein levels and enzyme activities increased at the end of depuration period.