Spatial distribution, source apportionment and ecological risk assessment of heavy metals in the sediments of Haizhou Bay national ocean park, China

Haizhou Bay National Ocean Park is the first national ocean park in China. Consequently, the investigation of the spatial distribution characteristics, source apportionment, and ecological risks associated with heavy metals in this area is of great significance. Twelve sediment samples were collected in October 2016, and the geoaccumulation index (Igeo) method and the potential ecological risk index (PERI) method were used to assess the ecological risk. The results showed that the concentrations of the heavy metals (except Cr and Cu) in the surface sediments of the study area met the primary standard of marine sediment quality (GB18668-2002). The spatial distribution pattern of heavy metals in the surface sediments of Haizhou Bay National Ocean Park featured high concentrations in the southwestern region and low concentrations in the northeastern region, with a gradual decrease with increasing distance offshore, indicating that anthropogenic activities were the main source of heavy metal pollution. The evaluation results of the Igeo and PERI methods showed that Cd was the element posing the greatest ecological risk and that the ecological risk level in Haizhou Bay National Ocean Park corresponded to moderately contaminated. These findings indicate that effective management strategies should be developed to protect the marine environmental quality.