Potentially toxic elements contamination, risk assessment via consumption, and spatial distribution of pollution and evaluation indices in the alpine lakes, Pakistan

Abstract

he current study investigated potentially toxic elements (PTE) contaminations in the water of alpine lakes of Gilgit-Baltistan, Northern Pakistan. Water samples (n = 46) of various alpine lakes were collected and analysed for PTE determination through atomic absorption spectroscopy (AAanalyst 700, PerkinElmer, USA). Arsenic (As) in water was measured using a mercury hydride generation system. PTE concentrations in water of alpine lakes were observed below the upper limit of the world health organisation (WHO) drinking water guidelines, except for iron (Fe, 14%), chromium (Cr, 10%), and As (2%) of samples. The highest mean concentrations of Fe (233 ± 22.4 µg/L) and Cr (36.3 ± 4.20 µg/L) were noted in the water of Rama Lake and the As (6.20 ± 0.65 µg/L) in the Lower Kachura Lake. PTE concentrations in the water of alpine lakes was evaluated for the elements pollution index (EPI), elements evaluation index (EEI), and risk indices. The values of EPI and EEI for PTE in the water of alpine lakes were found far below the threshold limits. Higher mean chronic daily intake (CDI) values were observed for Fe and zinc (6.67 ± 1.09 and 4.95 ± 2.65 µg/kg-day) in the Rama and Upper Kachura Lakes, respectively. Determined hazard quotient (HQ) values for PTE were noted as> 1. However, the HQ value for As was (1.4 ± 0.06) which may have a detrimental effect on the health of children. Cancer risk of As and HQ values for other elements were found within the allowable limits of consumption in drinking water. Statistical analysis revealed that geogenic sources are the main PTE contaminations contributors in the water of alpine lakes.