The contamination of heavy metals due to human activities has attracted great attention and may lead to serious environmental problems. This research was performed on seawater, sediments, and organisms in Jieshi Bay, China. The level of Cu, Pb, Zn, Cd, Hg, and As, respectively, was measured in each environment to acquire a comprehensive understanding of their sources and distribution and to accomplish a risk assessment. The results showed that the concentration of heavy metals in autumn was higher than those in spring, and surface water has a higher heavy metal content than bottom water. The main sources of these heavy metals could be surface runoff and industrial wastewater discharge in the said bay. Hg was the main pollutant in the seawater. Hg, Cu, Zn, and Cd could easily accumulate in organisms than other heavy metal contents. In addition, even though the concentration of Pb did not exceed the Seawater Quality Standard, decision-makers should still be attentive to the Pb content in fish because of bioaccumulation from seafood product consumption.

We investigated the distribution, sources, and ecological risks of heavy metals (As, Hg, Zn, Cd, Pb, Cu, and Cr) in seawater, sediments, and shellfish in the inner and outer waters of Daya Bay. 42 seawater quality survey sites, 21 sediment survey sites and 21 biological survey sites were set up in the study area. Our results showed that Daya Bay’s seawater is both clean and has a high Cu exceedance factor. The sediment heavy metal potential ecological hazard indices are all less than 40, which indicates a minimal degree of risk. ERI in the bay (mean value of ERIis 25.43) and that outside the bay (mean value of 23.56) is lower than 150, so the potential impact on the ecosystem is relatively low. In the Bay, Hg and Zn are primarily from fossil fuel and coal combustion, which enter the ocean via dry and wet deposition or surface runoff. Outside the Bay, Cr, Cu, Zn and Pb are derived the combustion waste gases of ships that enter the ocean via atmospheric deposition. Concerningly, arsenic and lead level in shellfish organisms appear to be above the standard values.However, because THQ and TTHQ are less than 1, there is no potential risk to human health. The weekly assessed intakes (EWIs) of Hg, AS, Pb, and Cd in shellfish inside and outside Daya Bay were 0.093 (0.058 outside the Bay), 0.594 (0.534), 1.115 (1.489), and 0.201 (0.190), respectively, all of these values were lower than the provisional PTWI for humans established by WHO. This indicates that the probability of carcinogenic risk to the population from heavy metals in shellfish are all below unacceptable levels.