Seasonal Distribution of Trace Metals in Groundwater of Dhemaji District, Assam, India

A comprehensive study has been carried out with respect to chromium, manganese, zinc, copper and nickel contamination of groundwater in Dhemaji district of Assam, India. Twenty groundwater samples were collected from tube well and ring well in both dry and wet seasons. The metals were analysed by using Atomic Absorption Spectrometer, Perkin Elmer AA 200 model. Normal distribution and correlation analysis have been employed to nd out the distribution pattern of the metals in the area. It is ascertained that a sizeable number of groundwater samples contain chromium, manganese and nickel at toxic level. Copper and zinc content of groundwater was found to be within the guideline value of WHO. High concentrations of all the trace metals except for chromium were recorded in the dry season than in the wet season. Statistical analyses of the data reveal that the distribution of various metals in the study area is widely off normal. The metal concentration of groundwater in the district follows the trend Zn>Mn>Cr>Cu>Ni in both the seasons.