Interference of magnesium on zinc adsorption by pond sediment and on zinc accumulation in a freshwater teleost, Labeo rohita (Hamilton)

Two experiments were conducted to evaluate the interference of magnesium on zinc adsorption in freshwater fish pond sediment and zinc accumulation in the freshwater teleost Labeo rohita (Hamilton). The study demonstrated that increasing the concentration of magnesium as magnesium sulfate from 100 to 400 mg kg–1 decreased the adsorption of zinc in sediment. The maximum adsorption was found at a concentration of 100 mg kg–1 of Mg2+ and the minimum with 400 mg kg–1 of Mg2+. This study also demonstrated that the exposure of fish to 0.25 mg L–1 of zinc as zinc sulfate with different concentrations of magnesium (100, 200, 300, and 400 mg L–1) for 14 d resulted in the minimum accumulation of zinc in L. rohita (2.97 mg kg–1 dry weight) at 200 mg L–1 of Mg2+, while the maximum accumulation (8.47 mg kg–1 dry weight) occurred with no magnesium treatment.