International Journal of Environment and Development

In the present research the concentration of Cu,Zn,Pb,Cd and Hg were determined in water, sediment and Zooplankton of Rushikulya Estuary,Odisha. Water, sediment and zooplankton samples were collected seasonally premonsoon, monsoon and post monsoon from four fixed stations of this Estuary as it receives contaminated effluents from Chloroalkali plant (M/S. Jayashree Chemicals Pvt. Ltd.) and residual agrochemicals from its catchment area. In water samples low Cu contents were encountered during the premonsoon season and high content found in the monsoon period. Zn, Pb and Cd content were found to be higher in monsoon season than the premonsoon and postmonsoon seasons which could be ascribed to their entry through the surface ranoff. High concentration of Hg was obtained during pre-monsoon season than other seasons due to inputs through the effluents discharged from the nearby Chloro-alkali plant. The positive correlation (p=0.01) between different metals except Hg denoted their common sources of origin and coexistence.

In the sediment sample the season wise pooled data showed that higher concentrations of Cu , Zn, Pb and Cd were found in the monsoon season than premonsoon and postmonsoon season. Higher Hg content was found in premonsoon as compared to monsoon and post monsoon . A strong positive correlation (p = 0.01) was observed between different metals denoting their co existence. But the relationship of Hg with other metals remained inverse. In the Zooplankton sample ,the higher concentrations of Cu , Zn, Pb, Cd and Hg were found in premonsoon season than monsoon and post monsoon season. This was also referred to their accumulation by surface adsorption and ingestion of phytoplankton.

Keywords: Rushikulya Estuary, Zooplankton, Correlation, Concentration