Qi Liu

Groundwater plays an indispensable role in daily life. However, with the continuous advancement of industrialization, more attention should be paid to the quality of groundwater and the associated potential health risks in areas surrounding industrial parks. In this study, groundwater samples collected in the city of the Tibetan Plateau during the wet season (WS) and dry season (DS) were analyzed using Piper diagrams, Gibbs diagrams, and correlation analysis. The results elucidated the hydrochemical characteristics, formation mechanisms, and controlling factors of groundwater in the area. Groundwater potability was assessed using the Entropy-weighted Water Quality Index (EWQI) method. In addition, the health risk assessment model was applied to evaluate potential risks for four population groups, with NO₃⁻ and F⁻ selected as representative groundwater pollutants. The findings revealed that groundwater in the study zone was typically moderately alkaline and characterized primarily as soft–fresh and hard–fresh. The groundwater in both seasons mainly exhibited HCO₃–Ca chemical facies. Water–rock interactions involving silicate and carbonate minerals were identified as key processes controlling the hydrochemical composition in both seasons. EWQI results showed that groundwater quality for drinking purposes was excellent in the seasons. Sensitivity analysis further showed that Cl− exerted the greatest influence on the drinking water quality evaluation in both seasons. Health risk assessments revealed that the risks posed by NO₃⁻ and F⁻ to infants, children, adult females, and adult males remained within acceptable limits (with max values of 0.63, 0.39, 0.28, and 0.33 in the WS, and 0.59, 0.36, 0.26, and 0.31 in the DS, respectively). However, infants exhibited greater susceptibility than the other groups across seasons, with a risk index approximately twice that of adults. Overall, the findings contribute valuable insights for the sustainable management and planning of groundwater resources in the study zone. Future research could refine the risk assessment model with localized data and explore mitigation strategies for elevated risks in specific seasons or regions.

Potentially toxic element (PTE) contamination in topsoil poses non-negligible risks to both the ecological environment and public safety. This study integrated multiple methods to conduct geochemical analyses and assess the presence of PTEs in topsoils of an urban area. The findings show that the average concentrations of PTEs were as follows: 8.21 mg/kg for As, 0.23 mg/kg for Cd, 92.26 mg/kg for Cr, 0.22 mg/kg for Hg, 35.99 mg/kg for Pb, 37.83 mg/kg for Cu, 42.85 mg/kg for Ni, and 111.99 mg/kg for Zn. Zn exhibited the highest mean concentration among PTEs in the topsoil, followed by Cr and Ni, while all PTEs exceeded their background levels. Utilizing the positive matrix factorization (PMF) model, four distinct sources of PTEs were quantitatively determined: F1, representing industrial emissions, had the highest contribution rate (30.73%) and mainly provided Cr and Ni; F2, representing agricultural activities, ranked second with a contribution rate of 23.31%. The Nemerow geo-accumulation index (NI) varied between 0.26 and 2.07 (mean = 0.73), with over 88% of the samples classified as slightly polluted; the potential ecological risk index (PERI) was in the range of 119.98–511.07 (mean = 158.95), with more than 95% classified within the low-to-moderate ecological risk range; and the soil environmental capacity index (PI) ranged from 0.47 to 1.40, with an average value of 1.0. These results suggest that the pollution level of and potential ecological risk posed by PTEs are low overall, reflecting a robust soil carrying capacity and minimal adverse effects on the ecosystem. In addition, the hazards of PTEs to public health were quantified based on the human health risk assessment framework. The potential health risks posed by PTEs fell into the acceptable range for both children and adults. Notably, elevated risk values were predominantly observed in the southern portion of the study area, with arsenic (As) being the principal contributor.