Pollution Assessment and Temporal-Spatial Distribution of Heavy Metals in Seawater of Daya Bay During 2009-2018

To study the status of heavy metal pollution in the seawater of Daya Bay, the 10-year changes of Cu, Pb and Zn concentrations and their spatial distributions in the seawater of Daya Bay were investigated, and the severity of heavy metal contamination in the seawater was evaluated with the comprehensive pollution index. The following results were obtained. First, the concentrations of Cu, Pb and Zn in Class I functional area and the concentrations of Pb in Class II functional area exceeded the national standards and the industrial waste water discharged along the coast might be the main source of heavy metals. Second, the average comprehensive pollution index of heavy metals in three functional areas in Daya Bay are ranked as Class I, Class II and Class III, indicating that the seawater in Class I area was contaminated by heavy metals while Class II and III areas haven't been affected yet. Third, during the research period, the levels of Cu, Pb and Zn in the seawater of Daya Bay fluctuated, but concentrations of these metals did not rise significantly with increasing sewage discharge from the petrochemical zone.