Assessment of heavy metals in some natural water bodies in Meghalaya, India

Abstract

Water samples were collected from thirty different freshwater sources of Meghalaya, India for three seasons (pre-monsoon, monsoon and post-monsoon). Seven parameters including four heavy metals (Cadmium, Copper, Zinc and Chromium) and three physiochemical parameters (Temperature, pH and DO) were assessed. The order of abundance of the heavy metals on an average was Cr (956 μg L−1) > Zn (715 μg L−1) > Cu (416 μg L−1) > Cd (61.5 μg L−1). The monsoon season showed the highest concentration for all the heavy metals as compared to the other two seasons. The average concentrations of Cadmium, Copper and Chromium were found to be higher than the national standards for all the seasons. Significant pollution was evident from pollution assessments by using indices like heavy metal pollution index (HPI) and degree of contamination (Cdeg). The mean HPI of West Jaintia Hills district for the three seasons viz pre-monsoon, monsoon and post-monsoon were 531.29 ± 152.12, 1862.28 ± 587.06, 525.86 ± 152.44, respectively. The mean HPI of Ri-Bhoi district for the three seasons were 518.26 ± 219.19, 1824.69 ± 618.17 and 1937.14 ± 534.26, respectively. Principal component analysis (PCA) showed a high anthropogenic induced pollution in water sites studied. Highest concentrations of the heavy metals were found in samples collected from urban areas. Cadmium, Copper and Chromium were found to be the main pollutants of concern in this study, hence, remedial measures for sustaining a healthy aquatic ecosystem which harbours aquatic living organisms are recommended.