Effect of some nutrient cations on uptake of cadmium by Chlorella pyrenoidosa

Abstract

The effects of the cations calcium, iron, manganese and zinc on the uptake of cadmium by the alga C. pyrenoidosa and on the toxicity of cadmium were studied. Calcium at a level of 16 mg 1^-1 reduced the short- term uptake and, in dilute cultures, the long-term uptake as well and caused a modest reduction in cadmium toxicity. Iron at a level of 1 mg I^-1 greatly reduced cadmium toxicity and reduced both phases of uptake in dilute cultures. Manganese at a concentration of 0.5 mg I^-1 had no consistent effect on uptake and tended to enhance cadmium toxicity. Zinc at a concentration of 3 mg I^-1 reduced short-term uptake, had no consistent effect on long-term uptake, and exerted a toxic effect that was additive to that of cadmium. Factors such as coprecipitation and the physiological state of the culture were found to have an important bearing on the nature of the interaction of nutrient cations with cadmium.