Bioaccumulation of metals by Scenedesmus, Selenastrum and Chlorella algae

Three species of algae were investigated for their ability to accumulate metal ions. Scenedesmus, Selenastrum and Chloretla species were found to be capable of accumulating metals such as Cu2+, Pb2+, and Cr3+ with 67 to 98% efficiency. Although Chlorella was less capable of accumulating these cations than the other two organisms, it possessed a greater capacity for the Cr2O2' anion. A suspension of Selenastrum was used to accumulate Cr3+ from a sample of post-anaerobic digester tannery effluent. The algae removed 39% of the chromium from solution. The rate of metal (Cu2t, Fb2+, Cr3+) accumulation by Scenedesmus was rapid, occurring in the first 4 min. Of the 4 metals investigated, Cu2+, Cr3t, Pb2t and Cr^O;. the former 2 were more toxic to the algae than the latter two.