Heavy metal distribution, contamination and analysis of sources - Intertidal zones of Sandu Bay, Ningde, China

Highlights: • Main contaminants in the sediments and seawater are As, Cr, Cu, Hg, Ni, Pb, and Zn. • The contamination with heavy metals is of anthropogenic origin. • Fish, cage bred in the bay, exceed Chinese food safety standards for As, Cr and Zn. • Processes of heavy industry and maritime ship traffic can be considered as sources. - Abstract: Concentrations of heavy metals in sediments and seawaters from the intertidal zone are analyzed along with cage-bred fish in the Sandu Bay of Fujian Province in China. Elements measured are As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. The concentrations of Cu and Ni found in the sediments do not meet the first standard of the Chinese National Criteria for Marine Sediment Quality. The results of I_geo, EF, and CF index calculations for the sediment samples clearly prove anthropogenic causes of contamination. The water quality standard for fisheries was exceeded by As, Hg, and Cu. Cage-bred fish show increased levels of As, Cr, and Zn. Significant associations are found for AsCu and NiZn. These findings can be related to coal and crude oil combustion and processes associated with the production of batteries, steel, and alloys. The results point to industrial source locations along discharging rivers north and northwest of the Sandu Bay.