Hydro-chemical characteristics of surface water in Cao Bang, Vietnam: A multivariate statistical and GIS approach

Hydro-chemical information on surface waters in Cao Bang Province remains limited, particularly at the provincial scale. This study assessed the hydro-chemical characteristics of surface waters in Cao Bang Province, northeastern Vietnam, using ۱۶۸ samples collected during the dry season and analyzing ۵۵ chemical elements. Descriptive statistics, principal component analysis (PCA), and Geographic Information Systems (GIS) to evaluate spatial patterns and the factors controlling water chemistry. The results show significant change in hydro-chemical composition across the study area. High Ca concentrations are associated with carbonate dissolution in karst terrains, whereas higher K and Si concentrations reflect silicate weathering and water-rock interactions. Increased concentrations of Fe, Ti, Zn, and Pb occur mainly in the Bang Giang River basin and are linked to mineralized formations and mining activities. The calculation result of PCAexplained ۷۰.۹۴% of the total variance in the dataset. The first principal component is dominated by Na, K, Si, Cl, and I, indicating the importance of weathering processes and dissolved constituents derived from water-rock interactions. The second principal component is characterized by Fe, Ti, Zn, Pb, and Ba, reflecting the influence of mineralization and mining related trace metal inputs. A third principal component highlights lithological contrasts between carbonate and silicate terrains, with Ca enrichment associated with carbonate dissolution and Fe-Ti-Si enrichment linked to noncarbonate geological units. Overall, geological factors, including lithology, weathering processes, and mineralization, are the primary controls on surface water chemistry in Cao Bang Province, whereas anthropogenic influences are mainly restricted to mining areas. The generated dataset provides a valuable baseline for future water-quality monitoring and hydro-geochemical studies in the karst regions of the northeastern Vietnam.

کلیدواژه ها:

Hydro-chemical ، geographic information system (GIS) ، Principal component analysis (PCA) ، Surface water ، Tropical Karst Region ، Cao Bang Province