Micro-wave assisted digestion, followed by determination of Pb, Cd and As by ICP-MS and Al by ICP-OES, analysis of Hg by gold-amalgamation method, using DMA and determination of six arsenic species including As(III), As(V), AsB, AsC, DMA and MMA by LC-ICP-MS were quite efficient techniques to be followed in edible seaweed samples studied.