Dunaliella salina as marine microalga highly tolerant to but a poor remover of cadmium

Abstract

Cadmium tolerance and removal in the marine microalga Dunaliella salina were studied in cultures exposed to different metal concentrations (5-120 mg Cd l(-1)) for 96h. This microalga can be included in the group of microalgal species most tolerant to cadmium due to the high value of EC50 that it possesses (48.9 mg Cd l(-1) at 96 h of culture). The greater percentage of cadmium removed was obtained in cultures exposed to 5 mg Cd l(-1) at 96h, but removing only 11.3% of the added cadmium. In all cultures, the quantity of cadmium removed intracellularly was much lower than the bioadsorbed quantity and it was proportional to the sulfhydryl group levels. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of cadmium by living cells of D. salina.

Biosorption of zinc and copper from aqueous solutions by two freshwater green microalgae Chlorella pyrenoidosa and Scenedesmus obliquus

“…This is consistent with the results of the previous studies on the freshwater alga S. subspicatus (Ma et al 2003) and the marine alga Dunaliella salina (Folgar et al 2009). These results demonstrate that non-metabolic absorption plays an important role in the metals removal by algae.…”

“…The high tolerance to these two metals suggests the possibility of using these two microalgae in bioremediation processes in freshwater polluted with zinc or copper. The effect of metal on algal growth depended on the algae species and the metal concentration in the medium (Folgar et al 2009). The results of the present study indicated that S. obliquus was more resistant to the toxicity of zinc and copper than C. pyrenoidosa.…”

“…The kinetics of metal uptake by biologically active algae usually take place in two readily identifiable stages: an initial physical adsorption at the cell surface followed by a slow bioaccumulation via intracellular transport and chelation (Folgar et al 2009;Nourbakhsh et al 1994). Physical adsorption is fast and occurs in a short time after the alga come into contact with the metal.…”

Phytoremediation of Cadmium‐Contaminated Soil by Two Jerusalem Artichoke (Helianthus tuberosus L.) Genotypes

“…Owing to the rapid industrial emissions and the application of sludge or urban composts, pesticides, fertilizers, emissions from waste incinerators, wastewater irrigation, and residues from metalliferous mining, and the metal smelting industry, heavy metal pollution has been considered as one of the most serious environmental problems worldwide [4,5]. Compared with some other heavy metals, cadmium (Cd) is not an essential nutrient for higher plants [6,7], and the exposure to relatively low concentrations results in high toxicity because Cd is easily transferred from soil into the food chain, potentially threatening human and animal health [8][9][10].…”

“…Compared with some other heavy metals, cadmium (Cd) is not an essential nutrient for higher plants [6,7], and the exposure to relatively low concentrations results in high toxicity because Cd is easily transferred from soil into the food chain, potentially threatening human and animal health [8][9][10]. Moreover, Cd can enter human diet and accumulate gradually in the human body [4,[11][12][13], resulting in a number of adverse health effects, such as nephrotoxicity and osteotoxicity [14]. Thus, there is an urgent and imperative need to develop efficient techniques for Cd removal from the environment.…”