Evaluation of groundwater quality and health risk assessment in southeastern Tibet, China

The assessment of groundwater quality and potential human health risks is crucial for the development and utilization of groundwater resources. Due to expanding human activities, groundwater quality is deteriorating in southeastern Tibet. In this study, a total of 200 groundwater samples were collected to analyze the spatial distribution characteristics of hydrochemistry, assess groundwater quality, and evaluate potential human health risks in southeastern Tibet. Hydrochemical analysis showed that the groundwater was alkaline and moderately hard type, and fluoride and arsenic were identified as the main pollutants. The entropy-weighted water quality index (EWQI) results revealed that most groundwater samples reached excellent quality (86% in total). The non-carcinogenic human health risk assessment results indicated a low potential threat to human health. The total hazard index (HITotal) values for children, adult females, and adult males were 0.9024, 0.878, and 0.7445, respectively. Children were more sensitive at risk than adult females and males. The arsenic hazard index (HIAs) was higher than the fluoride hazard index (HIF-) in different groups. Monte Carlo simulations further indicated that each influencing parameter followed the order of arsenic (As) > fluoride (F) > exposure frequency (EF) > ingestion rate (IR) > body weight (BW). This study provides a valuable reference for groundwater protection in southeastern Tibet and other similar regions.