Distribution of Mercury in different abiotic and biotic sectors of the Mandovi-Zuari estuary (Goa)

This study highlights the behaviour of Mercury in the abiotic and biotic segments of the Mandovi-Zuari estuarine system. Spatial, seasonal (Premonsoon and Postmonsoon) and tidal, distribution of THg in dissolved/particulate fractions, sediment concentrations were mapped of the river mouths, Mormugao Port, inner and outer environs of this estuarine system. Observed seasonal partition studies provided an insight into the removal of the metal into the particulate fraction and subsequent deposition in sediments in the postmonsoon. Bioconcentration factor provided a link in the Hg cycle between the abiotic and biotic compartments of this ecosystem. Metal contaminations in different tissues of biota representing different trophic levels were evaluated by calculating the bioconcentration factor. Although biomagnification and bioaccumulation was observed in the representative biota of commercial importance, the observed total mercury levels are well within the safety limit 0.5 ppm set by WHO and 0.3 ppm set by UNEP for fish products for human consumption, there by indicating no apparent mercury contamination.