BIOACCUMULATION OF METALS BY SCENEDESMUS, SELENASTRUM AND CHLORELLA ALGAE

Three species of algae were investigated for their ability to accumula te metal ions. Scenedesmus, Selenastrum and Chlorella species were fou nd to be capable of accumulating metals such as Cu2+, Pb2+, and Cr3+ w ith 67 to 98% efficiency. Although Chlorella was less capable of accum ulating these cations than the other two organisms, it possessed a gre ater capacity for the Cr2O72- anion. A suspension of Selenastrum was u sed to accumulate Cr3+ from a sample of post-anaerobic digester tanner y effluent. The algae removed 39% of the chromium from solution. The r ate of metal (CU2+, Pb2+, Cr3+) accumulation by Scenedesmus was rapid, occurring in the first 4 min. Of the 4 metals investigated, CU2+, Cr3 +, Pb2+ and Cr2O72-, the former 2 were more toxic to the algae than th e latter two.