Heavy metal burden in coastal marine sediments of north west coast of India in relation to pollution

Abstract

Human activities in the marine zone of India are mainly confined to the inner shelf where water depths are <50 m. Considering the vastness of the coastal area, the data on contaminants including metals in seawater, marine sediments and biota is scanty. Of these, Mumbai- Bassein region that is highly urbanized and industrialized has received relatively greater attention though exhaustive studies in recent years have been missing. The research scheme for the Thesis was planned (i) to establish the baseline concentrations of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb and P in sediments of the drainage basin of the Mumbai region, (ii) to assess the present load of sewage-associated trace metals and P to the marine environment of Mumbai, (iii) to evaluate seasonal changes in metals and P in the Thane Creek-Mumbai Harbour (Hereinafter referred as Bay) sediments in relation to high monsoon-derived lithogenic flux, (iv) to investigate spatial heterogeneity in distribution of the metals if any, in the sediment of Docks and Bunders, of the Mumbai Port, (v) to examine whether the Bay is a passive link between the anthropogenic metals and the coastal Arabian Sea or a sink for trace metals, (vi) to quantify anthropogenic fraction of trace metals and P in the sediments of the Bay and the Ulhas estuary based on Enrichment Factor (EF) and Index of Geoaccumulation (Igeo), (vii) to assess the fraction of bio-available Cr, Mn, Fe, Cu and Zn in selected surface and core sediments of the Bay, (viii) to identify trends in distribution of metals and P in nearshore sediments of the northwest coast of India between Porbandar and Ratnagiri, and (ix) to establish levels of metals and P in the sediments of the fast-industrializing biorich Gulf of Kachchh.