Temporal trends of heavy metals in the sediments of Bohai Bay in China

The status and trend of mercury (Hg), cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), zinc (Zn), and arsenic (As) in the sediment of Bohai Bay from 1978 to 2017 were evaluated. The results indicated that the sediment status in 2017 was good. The contents of Hg, Cd, Pb, Cu, Cr, Zn, and As in all the monitoring stations were lower than category I. But, it is worth noting that the contents of Cu, Cr, and As in some stations were between threshold effects levels (TEL) and probable effects levels (PEL) guidelines, which were occasionally correlated to negative ecological effects. Since the reform and opening up of China, only the average content of Cd in 1996 was between category II and category III, but that in other years did not exceed category I. The average contents of Hg, Pb, Cu, Cr, Zn, and As were lower than category I. The Chinese Government should continue to pay high attention to the total quantity control measures of major risk factors Cd, Cu, Cr, and As.

Automated summary

The sediment status of Bohai Bay was evaluated for the presence of several heavy metals from 1978 to 2017. While the overall levels were below category I standards, some stations showed concentrations of copper, chromium, and arsenic that fell between threshold effect levels and probable effect levels, potentially leading to negative ecological effects. The Chinese Government is advised to monitor and control major risk factors such as cadmium, copper, chromium, and arsenic.