This study investigated heavy metal bioaccumulation, pollution sources, and human health risks in the Wujiang and Zhenjiang rivers, the major headwaters of the Beijiang River in southern China. Concentrations of 11 heavy metals (Fe, Mn, Ba, Zn, As, Cu, Ni, Cr, Co, Cd, Pb) in surface water, sediments, and the soft tissues of four bivalve species (Corbicula fluminea, Limnoperna fortunei, Unio douglasiae, and Anodonta woodiana) were determined. Results showed that surface water remained below pollution thresholds, whereas sediments in the Wujiang River exhibited moderate-to-heavy Cd, As, Pb, and Zn contamination linked to historical Pb-Zn mining. Among the two better-represented species, C. fluminea showed relatively high As and Zn concentrations, whereas L. fortunei showed relatively high Cu accumulation. Data for U. douglasiae and A. woodiana were treated as preliminary observations because of their limited sample sizes. Biota-sediment accumulation factor (BSAF) values indicated that Mn, Cu, Cd, Zn, Ni, and Cr were actively accumulated beyond sediment concentrations, whereas As and Pb showed limited sediment-to-biota transfer. Multivariate analysis of the two better-represented species indicated species-related differences in tissue metal profiles, with patterns consistent with both natural geogenic inputs and historical Pb-Zn mining activities. All four species posed potential non-carcinogenic health risks to consumers, with As and Mn as the dominant risk contributors. These findings underscore the necessity of multi-species biomonitoring and consumption advisories in mining-impacted watersheds.
Huang et al. (Thu,) studied this question.