Assessment of drinking water quality “Natural springs and surface water” and associated health risks in Gilgit-Baltistan Pakistan

Abstract

Heavy metals in drinking water are not only detrimental to environment but also to human health. The study was carried out to investigate the quantification of heavy metals in selected springs and surface drinking water sources of Gilgit-Baltistan, Pakistan. Overall, 66 water samples were collected and analyzed. The concentration of heavy metals in 20% of the samples were beyond the National Standards for Drinking Water Quality (NSDWQ) and WHO guidelines. The concentration of heavy metals in 59% of the samples were within the permissible limits and only 21% of samples were free of heavy metals. The highest concentration of heavy metal beyond the permissible limit of NSDWQ was found in Skardu (23%), Nagar (15%), Hunza (15%) and 8% in Gilgit, Diamer and Ghizer respectively. The average concentration of heavy metals in drinking water sources were found in order of Al > B > Mn > Zn > Ba > Ni > Cr > Cu > As > Hg > Sb and > Se. Health risk index (HRI) and chronic daily intake (CDI) was calculated for both children and adults. CDI values detected were in order of Al > B > Mn > Zn > Ba > Cr > As > Ni > Cu > Hg > Sb > Se respectively. In addition, HRI values were in the sequence of Cr > Mn > Zn > Ni > Cu respectively. According to univariate and multivariate statistical analysis, geological activities taking place in the strata of the region were the possible source of HM in drinking water sources.