Bioremediation of Heavy Metals by using the Microalga Desmodesmus Subspicatus

All around the world natural water bodies are contaminated with heavy metals from previous and recent mining activities. These contaminants not just can reach our drinking water supplies but endanger aquatic ecosystems and also other organisms. The recent technologies used for the removal of heavy metals are expensive and also causing harm to the nature. To avoid the negative impacts caused through the removal of contaminants, environmentally friendly methods, bioremediation should be applied. Using microbial processes for the removal of contaminants is still not widely used and enough studied. The objective of this work was to investigate the bioremediation properties and behavior in different environmental conditions of the microalga Desmodesmus subspicatus. The heavy metal (300µg/l Pb, 30µg/l As, Cd, Hg) solution chosen was similar with the values found in the River Oker, which originate from previous mining site of the Harz Mountain in Lower Saxony, Germany. The heavy metal uptake by Desmodesmus subspicatus biomass was not efficient at pH 5 since the final uptakes were (4.5±0.67) µg/l As, (21.1±2.89) µg/l Pb, (7.33±1.96) µg/l Cd and (6.25±1.28) µg/l Hg (15% As, 7% Pb, 24% Cd, 21% Hg). However, its initial biosorption showed good results with Pb (<79%) and Hg (