Spatiotemporal distribution and potential risks of metals and total petroleum hydrocarbons (TPHs) in seawater from the Zhifu Bay and its surrounding areas, Yellow Sea, China (2015–2019)

Abstract

To investigate the concentrations, spatiotemporal distribution, correlation with environmental factors, and potential risks of four metals (Hg, Cu, Pb, and Cd) and total petroleum hydrocarbons (TPHs) in seawater from the Zhifu Bay and its surrounding areas, surface seawater samples were collected from 10 stations in spring, summer, and autumn of 2015–2019. Compared with values from other regions, the average concentrations of metals and TPHs were in the low and medium levels, respectively. Concentrations of all the study pollutants decreased in the offshore direction, suggesting that most of these pollutants are from land and nearshore sources. Annual variation patterns indicated decreasing trends of Cu and TPHs, and due to the seasonal differences in river discharges, rainfalls, and human activities, wet seasons (summer and/or autumn) exhibited higher concentrations of Hg, Cu, and TPHs than dry season (spring). The potential ecological risk of Cu and carcinogenic health risk of Cd suggest that the discharge of metals from the sea should be more strictly controlled.