Die Aufnahme von Quecksilber, Cadmium und Nickel durch Chlorella pyrenoidosa

Mercury proved to be the most toxic element and cadmium and nickel damaged the algae more than nickel in 24 hour synchronous cultures of Chlorella pyrenoidosa.

Abstract

The uptake of 203Hg, 115Cd and 63Ni and the influence on dry matter production was investigated in 24 hour synchronous cultures of Chlorella pyrenoidosa. All the elements investigated decreased, even in low concentrations, the dry matter production (Fig. 1). Mercury proved to be the most toxic element. Dry matter production stopped at a concentration of 8 μM Hg per liter nutrient medium. Concentrations of 72 mM Cd/l and 48 mM Ni/l did not stop the growth of the algae. Cadmium damaged the algae more than nickel. With rising concentrations in the nutrient medium mercury was taken up in a progressive, cadmium in a linear and nickel in a degressive increasing function (Fig. 2). Nearly all the mercury in the nutrient medium was taken up by the algae excluding the highest and lowest concentrations. In the case of cadmium the uptake was close to 10% of the available amount and of nickel 1% (Fig. 3). We suppose, therefore, that the different damage to the algae by the three heavy metals was mostly due to the different uptakes and partly to the degree of toxicity of the heavy metals taken up. The separation of the algae extracts on Sephadex coloumns showed a high molecular binding of mercury and cadmium, which eluted nearly totally in the exclusion volume of the coloumns, whereas nickel was distributed amoung at least three organic substances.