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.

Impact of metals on the biodegradation of organic pollutants.

“…Similarly, magnesium reduced toxicity of nickel to bacteria and yeast (Abelson and Aldous 1950), to filamentous fungi (Babich and Stotzky 1981, 1982a, 1983b, 1983c, and to a filamentous alga (Say and Whitton 1977). Calcium has been reported to reduce cadmium toxicity to an alga (Gipps and Coller 1982) and to reduce zinc toxicity to a cyanobacterium (Shehata and Whitton 1982) and algae (Harding and Whitton 1977;Rai et al 1981). The protective effect of divalent cations such as zinc against metal toxicity is not limited to microorganisms.…”

Cadmium toxicity in Nostoc UAM208: protection by calcium

“…In onistic interaction between Cd and Ca. It has been both heterocystous and non-heterocystous cyanosuggested that this antagonism could be explained by bacteria, respiratory Og consumption appears to be a competition phenomenon due to their very similar significant in limiting O^ damage to nitrogenase ionic radii (Gipps & Coller, 1982). This antagonistic (Gallon, 1992).…”

Cadmium induced inhibition of ammonium and phosphate uptake in anacystis nidulans: Interaction with other divalent cations.

“…Ca2+ ions are known to antagonize Cd2+ toxicity in the green alga Hormidium rivulare (25) and Chlamydomonas (26), and Zn2+ toxicity in Chlorella (27). The suggested mechanisms for the ameliorative behaviour of Ca2+ ions are a) competition for transport across the biomembranes, and b) protection of target sites in the cell interior (24). The latter investigators also suggested that a nutrient cation that reduces the long-term uptake of Cd2+ should alleviate its toxicity, but a reduced toxicity may also result through a mechanism other than the reduced uptake.…”

“…The antagonism between Zn2+ and C2+ with respect to various enzyme systems, is well established (29). Recently, Gipps and CoLLER (24) observed that notwithstanding Zn2+ ions competing with Cd2+ for short-term uptake, did not obstruct the influx of Cd2+ in the cells. Similar interaction studies on the crustacean Daphnia magna revealed that zinc-cadmium mixtures were less toxic than the expected additive toxicity of both metals (30).…”

“…The apparent increase in the Vmax value suggests an antagonistic interaction between Ca2+ and Cd2+. Such interactions are attributable to a competition between Ca2+ and Cd2+ for the same uptake system owing to very similar ionic radii (24) or to their homologous chemistry (18). Ca2+ ions are known to antagonize Cd2+ toxicity in the green alga Hormidium rivulare (25) and Chlamydomonas (26), and Zn2+ toxicity in Chlorella (27).…”