Environ Geochem Health. 2026 Jul 12;48(10):448. doi: 10.1007/s10653-026-03326-1.
ABSTRACT
Samples were taken from 16 surface sediments (0-10 cm) and 12 core sediments from the drinking-water reservoir, the Wan’an Reservoir, which is located near small-scale and historical tungsten occurrences. The total concentrations and chemical speciation of As, Cd, Cr, Cu, Pb, Zn and W were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and the BCR sequential extraction procedure. Spatial distribution analysis indicated that toxic metal pollution exhibited significant downstream enrichment characteristics, among which Cd, W, and Cu were particularly prominent. The geo-accumulation and ecological risk analyses indicated that Cd was the dominant risk contributor. As a result, 87.5% of the surface sampling points were classified as having extremely high potential ecological risk. The Risk Assessment Code further indicated that the proportion of the acid-soluble/exchangeable fraction of Cd was relatively high, indicating strong mobility risk. Core sediment analysis indicated abrupt historical Cd enrichment peaks in the midstream area, while Zn and Cu exhibited surface enrichment over the past decade. Multivariate statistical analysis, along with geographical data on mining areas, revealed that mining activities were the primary anthropogenic source of complex pollution from Cu, Pb, Zn, W, and Cd in the downstream regions. In contrast, the middle and upper reaches are primarily influenced by natural geology and agricultural non-point sources. Comprehensive assessment suggests prioritizing the control of Cd migration in the downstream areas. In the middle and upstream regions, efforts should focus on preventing agricultural non-point source pollution to safeguard the reservoir’s water quality.
PMID:42437432 | DOI:10.1007/s10653-026-03326-1
