Distribution and contamination assessment of trace metals in surface sediments of the South China Sea, Vietnam

Highlights: • Trace metals in sediment from the Vietnam Shelf, South China Sea were assessed. • Ecotoxicological indexes in sediments show low to moderate contamination. • Dominant sources of elements were natural, except Cd. The distribution and enrichment of trace metals in sediments of the South China Sea along the entire coast of Vietnam were described. The concentrations of Cr, Ni, Zn, and Pb in the sediments showed a significant positive correlation with fine-sized fractions and TOC. In contrast, the concentration of As was not positively correlated with particle size and other metals. The relatively positive correlations of Cd with Fe, Al, Ti, Sc, TOC, P, Cr, Ni, Zn, and Pb indicated that it comes from different sources. Ecotoxicological indexes of all elements showed low values, except for Cd in the southwestern part of the South China Sea area, which is likely related to the influx of suspended matter from the Mekong River.