定量的発生源アロケーションによる地下水中のセレン濃縮における水理地質学的および人為的寄与の解明とセレン欠乏の文脈

To clarify the mechanisms of selenium (Se) enrichment and/or contamination in groundwater under combined hydrogeological and anthropogenic influences, a representative catchment (Handan, central North China) was selected to systematically explore the factors controlling groundwater Se concentrations. The results revealed a moderate enrichment level (0.078-19.61 μg/L) and significant spatial heterogeneity of Se. The Durov diagram and self-organizing map (SOM) indicated that the hydrochemical facies, reflected by major ions, exerted a limited effect on the Se enrichment. Leveraging the principal component analysis-absolute principal component score-multiple linear regression (PCA-APCS-MLR) model, we quantitatively identified the contributions of six potential sources of Se in the groundwater. The oxidative dissolution of Se-bearing pyrite was the primary contributor (38.08%), followed by heavy industrial contamination (23.21%), surface water infiltration (ca. 22.14%), and hydrogeochemical processes (13.43%). Agricultural non-point source input (2.63%) and rural domestic sewage-related pollution (0.51%) were minor sources. Additionally, the presence of SO₄^2-, Cl^-, and NO₃^- promoted Se enrichment through competitive adsorption. Our findings, grounded in quantitative source apportionment, offer a scientific framework and conceptual insights for developing precise strategies to manage Se in groundwater under complex hydrogeological and anthropogenic influences, supporting both pollution mitigation and resource utilization.