A Study on Assessment of Pollution in Godavari Estuary East Coast of India by Using Trace Metals Concentration in the Sediments

Abstract

In recent years there has been a rapidly growing interest on the heavy metallic content in estuaries and on the nature and the pathways by which they are introduced into the system. A total of seven sampling stations were fixed along the longitudinal stretch of the estuary, starting from head to mouth of the estuary for the collection of surface and bottom waters and sediments has done seasonally. In which water and sediment samples were collected during pre-monsoon (March), onset of monsoon (June), monsoon (September) and post-monsoon (December) by using Niskin water sampler and Van Veen Grab respectively for a period of one year during 2016. Hydrographic parameters of temperature, pH, and salinity were analyzed for the collected samples with standard methods. Sediment trace metals like cadmium, copper, iron, nickel, lead and zinc were estimated from the collected sediment samples by atomic absorption spectrophotometer after proper acid digestion. The organic carbon content was determined by the method of El-Wakeel and Riley (1957). Temperature, pH and salinity exhibited distinct spatial and seasonal variations in estuarine waters of the Gauthami Godavari. Temperature and pH showed an increasing trend from post-monsoon (winter) to pre-monsoon (summer) in accordance with the variation of atmospheric temperature in the study region. Enrichment factors of the metals were calculated based on the data, cadmium in Stations. 1, 2 are moderately polluted during monsoon season due to the anthropogenic source. Compared to all metals were studied, zinc and cadmium are more enriched. All the metals are moderately enriched in the upstream of the estuary due to natural and anthropogenic sources and also higher enrichment was observed during pre and post-monsoon season except cadmium which is in the monsoon season.