92.
The present study focuses on the determination and abundance of trace metals (viz. Cu, Ni, Zn, Cr, Co, Cd, Mn and Fe) in the
surficial sediments of west coast of Arabian Sea along the Indian subcontinent. Sediment samples were collected from three
transects along the western continental shelf of Arabian Sea. The enrichment of Fe and Mn in coastal oxic-sediments indicates
the precipitation of these redox sensitive elements as Fe- and Mn-hydroxides and oxides, whereas the low Fe and Mn concentrations
in the oxygen deficient sediments of deeper stations reflects the dissolution of their hydroxides and oxides. Concentrations
of fairly redox insensitive trace metals like Cu, Ni, Zn, Cr and Cd (with the exceptions of Cr) showed higher values at nearshore
sediments, then it decreased towards seaward and again showed a slight increase at oxygen minimum stations in all the three
transects. This geochemical variability in their distributional characteristics is mainly associated with the extent to which
the precipitation or dissolution of Fe- and Mn-oxides/hydroxides occur since the scavenging or releasing effects of Fe- and
Mn-oxides/hydroxides act as significant ‘sinks’ or ‘sources’ of heavy metals. The change in wind pattern, coastal upwelling
and increased productivity are also the reported factors which influence the biogeochemical cycling of trace metals in the
surface sediments of west coast of India. Enrichment factor generally showed a high gradient accumulation from nearshore to
shelf.
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