Toxicological Response of the Green Alga <i>Chlorella vulgaris</i>, to Some Heavy Metals

Abstract

Problems statement:The disturbance of aquatic ecosystems provoked by heavy metals pollution from industrial and domestic sources, has as consequence the loss of biological diversity, as well as increased bioaccumulation and magnification of toxicants in the food chain. The aim of this study was to evaluate the effect of some heavy metals on some physiological activities of Chlorella vulgaris beyerinck with special references to metal bioaccumulation. Approach: Chlorella vulgaris Beyerinck was isolated from Al-Asfar Lake, Al-Hassa, Saudi Arabia. A standard initial inoculum of the isolated algae was inoculated to culture flasks. The culture flasks were supplied with various concentrations of Cobalt, Copper and Zinc ranging from 10 −6 -10 −9 M. At the end of the incubation period cultures were filtered and washed several times by distilled water for measurements the various experimental parameters. Results: The data show that the lower doses of the three tested metals had stimulatory effect in biomass yield of Chlorella vulgaris, whereas the higher doses were inhibitory depending on the type of the metal. The inhibitory effect of copper to the growth parameters of Chlorella vulgaris was more pronounced than other two tested metals. The total protein content, total carbohydrate and the total free amino acids of the tested green alga Chlorella vulgaris gradually decreased in a manner dependent on the metal concentration in the medium. On the other hand, bioaccumulation of cobalt, copper and zinc by Chlorella vulgaris cells were parallel to increasing the concentrations in the culture medium. Conclusion: The inhibitory and stimulatory effects of either of the used heavy metals depend on concentration. Different organisms, however, have different sensitivities to the same metal and the same organisms may be more or less damaged by different metals. The uptake of an element from the surrounding medium is seldom exactly proportional to the amount present in the water.

ABOLISHING TOXICITY OF COPPER BY SOME ENVIRONMENTAL FACTORS USING GREEN ALGA <i>CHLORELLA VULGARIS</i>

“…Emissions of heavy metals can then enter all ecosystems and bring about severe problems in plants, especially algae depending on the concentrations of a given element (Muwafq and Bernd, 2006). There are a remarkable number of investigations demonstrating the toxic effects of heavy metals on different species of algae (Fathi et al, 2005;Osman et al, 2004;Akira et al, 2005;Muwafq and Bernd, 2006;Anne et al, 2006;Afkar et al, 2010).…”

“…A variety of environmental factors are known to modify the toxicity of heavy metals on algae (Fathi, 2002;Janssen et al, 2003;Fathi et al, 2000;Afkar et al, 2010). One of the most important of these factors concerns the determination of biological availability and the metals physiochemical state (Langston, 1990).…”

Phytoremediation of sewage sludge in soils contaminated with heavy metals

“…Thus, phytoremediation is the use of green vegetables for the in-situ or ex-situ treatment of contaminated soils, sediments and polluted water and to detoxify inorganic and organic metals (Salt, et al, 1995;Damian, 2007;Afkar et al, 2010). Phytoremediation is a green technology which has been used to facilitate the removal of heavy metals from soils and plants.…”

Biosorption of Arsenic by Living and Dried Biomass of Fresh Water Microalgae - Potentials and Equilibrium Studies

“…Bioaccumulation of metals by algae may create a feasible method for remediating water contaminated with metals [18,19]. It is well established that several marine and fresh water algae are able to take up various heavy metals selectively from aqueous media and to accumulate these metals within their cells [20][21][22]. Microalgae have been shown to accumulate arsenic and could potentially remediate through adsorption and biotransformation of inorganic arsenic [23][24][25].…”