Effect of physical and culture conditions on uptake of cadmium by <I>Chlorella pyrenoidosa</I>

Abstract

The effects of pH, temperature, concentrations of Cd2+ and P43-, and density of algal suspension on the uptake of cadmium by C.pyrenoidosa were studied. Uptake occurred in at least two phases: fast (8 min) and slow (24 h). The slow uptake was dependent on pH (greater at pH 8.0 than 6.5) and temperature (faster at 25 than 4�C) whereas the fast uptake was not. Both phases of uptake were affected by the density of the algal suspension. Dependence on the concentration of Cd2+, at pH 8.0, was limited by the concentration of PO43- and also possibly by the concentration of CO3-2. Results were generally consistent with the model of initial ion-exchange uptake onto the cell wall and much slower transport across the cell membrane.

Influence of low cadmium and zinc concentrations on batch culture Prorocentrum micans (Dinophyta) containing low levels of dissolved organic carbon

“…Similar observations were made by Gipps and Coller (1980) for cadmium by Chlorella pyrenoidosa and by Matzku and Broda (1970) and Findenegg et al (1971) for zinc.…”

Effect of NaCI concentration on cadmium uptake by the halophilic alga Dunaliella salina

“…Bindmg of Cd to the surface coat is of considerable importance as it may block passive or active passage of other micronutrients essential for growth and reproduction of the algae (Gipps & Coller 1980). Cadmium interferes with the uptake of zinc, calcium and manganese in some microalgae in a complex competitive relation controlled by pH, phosphate concentration and the presence of chelators (Hart & Scaife 1977, Hart et al 1979.…”

“…Cadmium was found to exert toxic action on various algae such as ChloreUa (Rosko & Rachlin 1975, Gipps & Coller 1980, Rebhun & Ben-Amotz 1984, Euglena (De Filippis e t al. 1981), diatoms (Rachlin et al 1982(Rachlin et al , 1983, DunalieUa (Jennings & Rainbow 1979), and Monochrysis, Isochrysis, and Phaeodactylum (Wikfors & Ukeles 1982).…”

Total calcium levels inEuglena gracilisL. in relation to cadmium toxicity

“…For both strains, in the absence of cadmium, the growth rate is identical for all the concentrations of calcium used. This part played by extracellular calcium on cadmium toxicity for other algae has already been mentionned by Gipps and Coller (1980) and Hornung et al (1981).…”