College of Geography and Remote Sensing Science, Xinjiang University, Urumqi, 830046, China; Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, 830046, China.
College of Water Conservancy and Civil Engineering, Xinjiang Agricultural University, Urumqi, 830052, China; Xinjiang Hydrology and Water Resources Engineering Research Center, Urumqi, 830052, China; Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention, Urumqi, 830052, China.
Environ Pollut. 2024 Dec 15;363(Pt 2):125301. doi: 10.1016/j.envpol.2024.125301. Epub 2024 Nov 12.
The Hotan region of Xinjiang is an arid region in northwest China, where water resources are scarce, and groundwater is the main water supply. In this study, a self-organizing map (SOM), positive matrix factorization (PMF), hydrochemical diagrams, and health risk assessment model were used to analyze the sources and controlling factors of groundwater chemistry, and evaluate health risks of nitrate and fluoride. The results showed that the evaporation process and water-rock interaction were the main factors influencing groundwater chemistry in the region. Based on the SOM, 239 groundwater samples were divided into six clusters. The main hydrochemical types were Cl-Na, HCO-Na, and SO-Ca. Natural factors such as evaporation, water-rock interaction and cation exchange play important roles in Cluster 1-2 and 4-6, while Cluster 3 is mainly polluted by nitrate. Fluoride pollution, primarily caused by geological processes, and nitrate pollution, caused by human activities, cannot be ignored. Attention should be paid to the high non-carcinogenic risk of fluoride and nitrate exposure through drinking water, especially for children. These results provide a theoretical basis for the rational development and utilization of local water resources and ecological environmental protection. The study suggested that the combined method of the SOM and PMF provides a reliable approach for interpreting nonlinear and high-dimensional hydrochemical data.
新疆和田地区是中国西北部的一个干旱地区，水资源匮乏，地下水是主要的供水水源。本研究采用自组织映射（SOM）、正定矩阵因子分解（PMF）、水化学图和健康风险评估模型，分析了地下水化学的来源和控制因素，并评估了硝酸盐和氟化物的健康风险。结果表明，蒸发过程和水岩相互作用是影响该地区地下水化学的主要因素。基于 SOM，对 239 个地下水样本进行了聚类分析，分为 6 个聚类。主要的水化学类型有 Cl-Na、HCO-Na 和 SO-Ca。蒸发、水岩相互作用和阳离子交换等自然因素在聚类 1-2 和 4-6 中起重要作用，而聚类 3 主要受到硝酸盐的污染。氟化物污染主要由地质过程引起，硝酸盐污染主要由人类活动引起，不容忽视。应注意通过饮用水暴露引起的氟化物和硝酸盐的高非致癌风险，特别是对儿童。这些结果为当地水资源的合理开发利用和生态环境保护提供了理论依据。研究表明，SOM 和 PMF 的组合方法为解释非线性和高维水化学数据提供了可靠的方法。
