Assessment of Surface Water Quality Using Heavy Metal Pollution Index in Subarnarekha River, India

Surface water samples were collected from 21 sampling sites throughout the Subarnarekha River during pre-monsoon, monsoon and post-monsoon seasons. The concentrations of Al, As, Ba, Cr, Co, Cu, Fe, Mn, Ni, Se, V and Zn were determined using inductively coupled plasma-mass spectrometry for seasonal fluctuation, source apportionment and heavy metal pollution indexing. The results demonstrated that concentrations of the metals showed significant seasonality and most variables exhibited higher levels in the pre-monsoon season. Principal component analysis outcome of four factors together explained 73.13% of the variance with > 1 initial Eigenvalue indicating both innate and anthropogenic activities as contributing factors of metal profusion in the river. To assess the composite influence of all the considered metals on the overall quality of the water, heavy metal pollution indices were calculated. The HPI for surface water of the river considering all the seasons and locations was 32.27. The HPI of the river calculated for the individual locations showed great variations ranging from 3.55 to 388.9. All the locations fall under low to medium classes of HPI except few locations which are under the influence of industries, mining or near the estuary. The enhanced concentrations of certain metals in the Subarnarekha River near industrial and mining establishments may be attributed to anthropogenic contribution from the industrial and mining activities of the area.