Abstract This study aimed to prove the feasibility of Philippine mud crab (Scylla serrata) and tahong (Perna viridis) shells in treating heavy metal content of surface water through the removal of lead (Pb) and chromium (Cr). Surface water samples were collected at Pasig River (at the deepest point at Guadalupe, Makati City, Philippines). The surface water samples were then treated with varying biosorbent dosages and contact time. Based on statistical tests, there was a significant difference in the Pb and Cr concentrations between treated and untreated surface water, this means that both S. serrata and P. viridis shells were effective in absorbing Pb and Cr. However, S. serrata shells were more effective in absorbing Pb while P. viridis shells proved to absorb more Cr content in surface water.