Sorption and removal of heavy metals by algal biosorbents largely depend on the initial concentration of metals in the solution. Metal sorption initially increases with increase in metal concentration in the solution, and then becomes saturated after a certain concentration of metal (Mehta and Gaur, 2001). The metal uptake by the biomass for different heavy metals is shown in Fig. 1. Cadmium exhibited lowest metal uptake at 20 mg l-1 (q=2.192) in 30 min and highest at 40 mg l-1 (q=9.832) with contact time of 90 min. The minimum metal uptake for Hg was recorded at 20 mg l-1 i.e. q=5.396 with contact time of 30 min which shooted to 39.212 (q) at 40 mg l-1 in
120 min. For Pb, the metal uptake increased with increasing initial concentration of the metal, with least uptake at 20 mg l-1 (q=5.495) at
30 mins contact time and highest at 80 mg l-1 (q=15.471) at 120 min. Metal uptake for As was lowest at 20 mg l-1 (q=1.416) in contact time of 30 min and exhibited peak at 40 mg l-1 (q=8.719) in 120 min. The minimum Co uptake was observed at 20 mg l-1, (q=2.628) in 30