Quantitative identification of anthropogenic sources of metal(loid)s in river sediments from a small watershed based...

Sediment contamination by metal(loid)s poses significant ecological risks. This study employed an integrated approach, including the enrichment factor method (EF), principal component analysis (PCA), absolute principal component score-multiple linear regression (APCS-MLR), and mixing stable isotope analysis in R (MixSIAR), to investigate the spatiotemporal distribution and anthropogenic sources of six metal(loid)s (Cu, Zn, Cr, Pb, Cd, As) in a small river watershed sediment. The findings revealed varying degrees of anthropogenic influence across the watershed. Surface sediments exhibited high anthropogenic enrichment of Cd (82.3 ± 13.1 %) and Cu (60.8 ± 26.1 %). Sediment core analysis revealed a pronounced historical increase in Cd and Zn accumulation since the 1930s, consistent with regional industrialization. PCA and APCS-MLR quantification identified industrial activities as the dominant anthropogenic sources for Cd (96.5 %) and Zn (92.0 %), whereas a mixed source associated with atmospheric deposition from vehicle exhaust emission and coal combustion contributed to As, Cu, Cr, and Pb accumulation. Independent varication using Pb stable isotope ratios via MixSIAR model confirmed the anthropogenic source for Pb. The strong consistency between the APCS-MLR and MixSIAR results in apportioning anthropogenic Pb sources cross-validates the APCS-MLR approach, thereby supporting its application to the other metal(loid)s. This study presents a robust integrated framework for apportioning anthropogenic metal(loid) sources in aquatic sediments.