Distribution and pollution assessment of heavy metals in seawater, surface sediments and marine organisms in Lianyungang offshore, China

The heavy metal pollution due to human activities has attracted considerable attention and may lead to serious environmental problems. Multiple indices were used to analyze the spatial distribution and pollution status of heavy metals in surface sediments, seawater and marine organisms in Lianyungang offshore. The results showed that the quality of all heavy metals in seawater and sediments complied with the first-class water quality standard (GB 3097-1997) and marine sediment quality standard (GB 18668-2002). Heavy metals in the seawater were in a clean state and at a low potential ecological risk. Spatial distribution of heavy metals in the sediments was mainly controlled by mean grain size and most of the stations were at a low potential ecological risk. The presence of mercury and cadmium represents a significant ecological risk due to their strong biological toxicity. Although the concentration of heavy metals in seawater is often very low, but the pollutants in the seawater can be concentrated step by step in the higher level of organisms through the food chain. The majority of heavy metals exhibited a BWAF value exceeding 1, indicating that the organisms possess a notable capacity for enrichment from seawater. Therefore, it's necessary to safeguard the quality of seawater, particularly in light of its potential impact on seafood consumption.