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The current study worked on heavy metals concentrations in sediments of the alpine lakes in Gilgit-Baltistan, Northern Pakistan. Sediments samples (n = 41) from alpine lakes: Sadpara Lake, Rama Lake, Upper Kachura Lake, and Shausar Lake were collected. Sediments samples were digested according to standard protocol and analysed by atomic absorption spectrometry. Among heavy metals, Mn exhibited the highest mean concentration (333 mg/kg) in the sediments of alpine lakes, while Cd showed the lowest (1.48 mg/kg). The Ni, Cu, Cr, Mn, and Zn showed the highest mean concentrations in Sadpara Lake compared to other lakes. Sediments heavy metals concentrations were used for the calculation of pollution factors of alpine lakes, such as contamination factor (CF), pollution loads index (PLI), and ecological risk assessment (ERA). Among alpine lakes, the Sadpara Lake showed the highest PLI and CF values for most of the heavy metals. However, the highest mean (74.2 and 104) values of ERA and risk index (RI) were noted in the Rama Lake and exhibited a low-level risk to the alpine lake's system. Statistical analyses showed that weathering of bedrock and rich mineralised zone in the vicinity were dominating contributors of heavy metals contaminations. [ABSTRACT FROM AUTHOR]

Radon (222Rn) is a ubiquitous radioactive gas and could threaten human life due to its potential for cancer and non-cancer risks. This study examined the measurement of 222Rn concentration and associated health risks in the hot springs of Hunza-Nagar valley. For this purpose, the hot springs water of Hunza and Nagar districts and the background sites were analyzed for 222Rn concentration using the RAD7 detector (Durridge Company, USA). The average concentrations of 222Rn were 46.1 ± 0.94, 65.3 ± 0.45, and 5.47 ± 0.25 Bq/L in the Hunza district, Nagar district, and background sites, respectively. Results showed that 222Rn concentrations of hot springs water were multifold higher than the background sites. 222Rn concentrations for hot springs water in Hunza-Nagar valley had surpassed the maximum contamination level set by the US environmental protection agency (USEPA). Humans' annual mean exposure dose rates of various age groups were calculated for the estimated lifetime cancer risk (ELCR) and non-cancer risks. The total annual mean exposure doses from 222Rn in water (EwTotal) values were (187 ± 3.80, 265 ± 1.84, and 22.2 ± 1.02 μSv/a) for infants (143 ± 2.92, 203 ± 1.40, and 17.0 ± 0.78 μSv/a) children, and (138 ± 2.80, 196 ± 1.35, and 16.4 ± 0.76 μSv/a) adults in the Hunza district, Nagar district, and background, respectively. Among the age groups of humans, infants showed a higher risk than others. Results showed that hot springs water consumption surpassed the world health organization threshold of 100 μSv/y for chronic or non-cancer and USEPA 0.1 × 10–3 for ELCR risks. The concentration of 222Rn showed a positive correlation (> 0.68) with hot springs' water temperature and pH suggesting a common origin. [ABSTRACT FROM AUTHOR]

Determining the water contamination of a river that threatens the dependent ecological community is a pillar for sustainable management. For this purpose, the present study aimed to examine the water quality of the Ghizer River Basin (GRB), Gilgit-Baltistan, northern Pakistan, for drinking and irrigation. Water samples (n = 55) were collected from the GRB and analyzed for physicochemical parameters. Water basic parameters and anions were measured using the multi-parameter analyzer (CONSORT 6030, Belgium) and cations by the atomic absorption spectrophotometer (AAS, AAnalyst 700, PerkinElmer, USA). Physiochemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), iodide (I), chloride (Cl), fluoride (F), nitrate (NO3), sulfate (SO4), bicarbonate (HCO3), turbidity, calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na) were noted to be within the drinking water permissible limits set by the World Health Organization (WHO). However, pH and turbidity surpassed their respective limits in 2% and 48% of water samples, respectively. Samples were assessed for water quality index (WQI) and irrigation water quality (IWQ) indices. The WQI values for most samples in the GRB were noted in the excellent (38.2%), good (58.2%), and poor (3.6%) categories. Similarly, most IWQ indices revealed that water is suitable and recommended for irrigation. Gibbs plots showed that most water samples in the GRB were noted in the precipitation dominance zone. The piper plot revealed the calcium–chloride (Ca–Cl) dominant hydrochemical facies. [ABSTRACT FROM AUTHOR]