Heavy metals contamination in coastal waters of South Vietnam

The study was conducted to estimate the spatial and temporal variations, pollution levels, and potential sources of some heavy metals in the south coastal areas of Vietnam, using data obtained from the national monitoring stations from 2015 to 2021. The concentrations of As, Cr, Cu, Fe, Mn, Pb, and Zn in surface and bottom water samples at seven monitoring sites were analysed using Inductively Coupled Plasma Mass Spectrometry for heavy metal pollution indexing. Results indicated that concentrations of almost all the heavy metals (As, Cr, Cu, Pb, Mn, and Zn) were lower than the threshold limits. In exception, Fe concentrations were 1.0 – 12.8 fold higher than the standard level of seawater quality in Vietnam. The highest concentrations of Fe, Cu, Mn, Pb, and Zn were observed in Dinh An and Rach Gia sites, which may be due to the influence of strong discharges from local rivers. The Contamination Factor (CF) and Contamination Degree (CD) values were far below 1, indicating that the seawater in these sites is at a low contamination level. The principal component analysis indicated that heavy metal concentrations in Ganh Rai, Dinh An, Rach Gia, and Ha Tien sites might be affected by natural factors; while it might also be caused by anthropogenic activities in Nha Trang, Phan Thiet, and Song Doc sites.