Spatial Distribution, Source Characterization, and Risk Indices of Heavy Metals Pollution in the Sediments of the Hindu Kush Lacustrine Ecosystem

Lakes are among the most susceptible freshwater ecosystems to heavy metal (HM) contamination. Sediment acts as a sink and a source of HM contamination in an aquatic environment. This study investigated HM contamination in the six Hindu Kush Lacustrine (HKL) sediments. HM contaminations in sediments were examined using atomic absorption spectrophotometry. Mn showed the highest average contamination of 984 ± 71.8 mg/kg in the Sosot Lake (SL), while Cd displayed the lowest of 0.58 ± 0.20 mg/kg. The SL showed elevated levels of Mn, Cr, Ni, and Zn, while Cu, Pb, Co, and Cd were dominant in Lower Katora Lake (LKL). The contamination factor (Cf) of Cd reached a maximum level of 6.01 ± 0.63 in Saidgai Lake (SGL) and a minimum of 0.70 ± 0.10 in SL. Results of pollution load index (PLI) values were reported as less than 1 for the studied HKL ecosytem, showing no HM pollution in sediments. Ecological risk index (E_r^i ) and risk index (RI) values identified the SGL sediments as the most affected, mainly due to Cd enrichment. Statistical analyses revealed that geogenic and mixed anthropic factors governed HM contamination in these HKL. The findings provide baseline information on sediment quality in the HKL, supporting future monitoring and conservation efforts in this ecologically important region under a climate change scenario.