Coastal macrophytes as bioindicators of trace metals in the Asia's largest lagoon ecosystem

Coastal trace metal contamination is of serious concern and the role of new bioindicator species in monitoring of trace metals is essential. The present study quantified the concentration of trace metals (Co, Cr, Cu, Mn, Ni, Pb and Zn) in the sediment and the macrophytes of Chilika lagoon, India, and investigated the bioindicator potential of the seagrasses, saltmarshes and macroalgae. The Igeo values for sediment indicated significant contamination of Cu and Zn in seagrass, Cu, Ni and Zn in saltmarsh and moderate contamination of Cr, Cu and Pb in macroalgal ecosystems. In general, the Bio-Sediment Accumulation Factor (BSAF) indicated that the macrophytes accumulated higher concentration of Mn and Ni from the sediments. The high concentration of trace metals in the sediment of the three macrophytes ecosystems did not result in higher accumulation of the same metals in the tissues of the respective macrophytes suggesting metal specific and species-specific behaviour.