Seasonal Behavior of Nutrients and Metals in Gauthami Godavari Estuary

A distinct spatial and seasonal variation of nutrients, dissolved and particulate trace metals (Cd, Cu, Fe, Ni, Pb, Zn) were observed in the present study. Relatively higher concentrations of metals were observed in head of the estuary and low concentrations in mouth of the estuary. Higher concentrations of both dissolved and particulate trace metals were observed during monsoon season followed by onset of monsoon and post-monsoon seasons, Lower concentrations of the metals were observed during premonsoon season. Higher concentrations of all metals during monsoon season due to the river and land runoff along with domestic and agricultural, industrial effluents are more during this season. Lower concentration during premonsoon season due to its utilization by biological activity, or by chemical and physical activity like desorption or flocculation as pH and salinity are increased during this season. It was also supported by significant negative correlations between both dissolved and particulate metals with pH, salinity. Significant positive correlations were observed between metals and with nutrients, attributed that these are originated from the same source of occurrence.