Spatial analysis of trace element contamination in sediments of Tamiraparani estuary, southeast coast of India

The impact of industrial effluents on the Tamiraparani estuary was investigated by determining the degree of trace element contamination in the estuarine sediments. Surface samples were taken from 30 locations covering the entire estuary. Grain size and trace element (Ni, Pb, Co, Cu, Zn, Cd, Mn, Fe, Al) variations were analysed, and enrichment factors (EF) as well as geo-accumulation indices (Igeo) calculated to understand the contamination level of the study area. A geographical information system (GIS) mapping technique was employed to highlight the spatial distribution patterns of trace elements in the estuarine sediments. Vulnerability maps prepared from the Igeo values revealed that the estuary is extremely contaminated with Cd and moderately contaminated with Zn and Pb. The sources of these metals are associated with nearby chemical plants and harbour activities. The cumulative effect of anthropogenic activities has led to a serious threat to the whole estuarine environment.