Combined effects of water pH and alkalinity on the accumulation of lead, cadmium and chromium to Labeo rohita (Hamilton)
Influence of pH (5.5, 7.0 and 8.5) and alkalinity (40 to 200 mg/L as CaCO3) on the accumulation of Pb (NO3)2, CdCl2, H2O and K2Cr2O7 to Labeo rohita (Hamilton) was investigated in the laboratory. Highest accumulation of Pb and Cr in whole fish occurred at pH 5.5 and at alkalinity level of 40 to 46 mg/L as CaCO3 compared to 7.0 and 8.5. In case of Cd maximum accumulation occurred at pH 7.0 and at alkalinity of 100 mg/L as CaCO3 than that of pH 5.5 and 8.5 and alkalinity 42 and 156 mg/L as CaCO3. Maximum accumulation of lead and chromium occurred at total alkalinity level of 40 and 46 mg/L as CaCO3, respectively while maximum accumulation of cadmium occurred at an alkalinity level of 200 mg/L as CaCO3. A significant (p<0.05) linear relationship was demonstrated between increasing pH/ alkalinity and decreasing accumulation in Pb and Cr treatment at all exposure period while for Cd there was no significant linear relationship established.