Distribution and Source Identification of Heavy Metal Concentration in Chilika Lake, Odisha India:An Assessment Over Salinity Gradient

Extent of heavy metal contamination in Chilika Lake was assessed to conserve the eco-dynamics of the lake. Distribution of heavy metals, cations and total organic carbon were analysed in the sediment samples collected from three sites that represent a salinity gradient. Analysis of environmental indices, viz. enrichment and contamination factors, geo-accumulation (I_geo) and pollution load indices showed that the concentrations of Cd and Hg were significantly high with geoaccumulation index being greater than one in all three stations. Levels of Pb and Co were also found to be elevated with I_geo value of 0.025 and 0.048 respectively. Among the three sampling stations, Kaluparaghat witnessed the highest pollution load index followed by Balugaon and Rambhartia. Principal component analysis revealed that the high-salinity zone was associated with high concentration of Hg and decreased concentration of other toxic metals, indicating that source of pollution of Hg is different from that of other metals.