Heavy Metal Assessment in Water, Sediment and Biota from Ennore Creek and Vellar Estuary, Southeast India

Abstract

The impact of anthropogenic activities on the accumulation of heavy metals in water, sediment and fish of both Ennore creek and Vellar estuary were observed in this study. Water and sediment sample were collected from both sampling stations and fish was collected just from only Ennore creek. Sediment and fish samples were subjected to a total digestion technique (HNO3 – HCl – HF conc.) and analysed using a spectrophotometer. Four elements Cu, Cd, Zn and Pb (trace elements) were determined. Heavy metal concentration of Ennore creek was significantly higher than the concentration of samples from Vellar estuary. The order of metal levels in water sample from Ennore creek is Cu > Zn > Cd > Pb and the sequence order of Vellar estuary water sample is Zn > Pb > Cu > Cd. The concentration of heavy metals in the sediment samples of Ennore creek showed in the following sequential order: Zn > Cu > Pb > Cd and the sequence order of Vellar estuary: Zn > Cd > Cu > Pb. In the Ennore creek, the accumulation of Zn in the muscle tissue is observed in the order, O. mosambique (7.3mg/g), M. cephalus (7.13mg/g) and A. djedaba (6.76 mg/g). M. cephalus showed high levels of Cu (5.25 mg/g) followed by A. djedaba (4.63mg/g) and O. mosambique (4.24mg/g). Based on the overall average of heavy metals present in different organs of the fish samples, trend of metal accumulation in different organs are observed as follows: Cu: Muscle > liver > gills and Zn: Muscle > liver > gills.