Differences and risk assessment of heavy metals in seafood and freshwater products

In order to understand the pollution status and ingestion risk of heavy metals in seafood and fresh water products in eastern coastal areas, 12 kinds of seafood and 8 kinds of fresh water products on the market were analyzed in this study. Microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) method was used to determine five kinds of common heavy metals, including lead, cadmium, mercury, arsenic and chromium. The pollution degree was evaluated according to single factor pollution index (P_i) and metal pollution index (MPI), the content difference of heavy metals in different aquatic products and pollution status were compared, and the health risk was evaluated by target hazard quotients (THQS). The test results show that the lead content in seafood and freshwater products was in the range of ND-1.100 mg/kg, the lead exceeding rate was 1.4%, and the average lead content of each species had no significant difference (P>0.05); the range of cadmium content was ND-1.600 mg/kg, the cadmium exceeding rate was 2.8%, and the average content of cadmium in Crassostrea gigas and Argopecten irradians was higher than other varieties (P<0.05); the mercury content range was ND-1.900 mg/kg, the average total mercury content of Thunnus maccoyii was higher than other species (P<0.05), and there was no significant difference in the average total mercury content of other species (P>0.05); the range of total arsenic content was 0.004-4.100 mg/kg, and the average total arsenic content of freshwater fish (except Channa argus) was lower than other species (P<0.05); the chromium content range was 0.010-32.000 mg/kg, the chromium exceeding rate was 2.3% and the average chromium content of Aristichthys nobilis was higher than other species (P<0.05). The single-factor pollution index showed that: different types of aquatic products have certain pollution; the heavy metal pollution index shows the trend of seawater shrimp and crab>seawater shell>freshwater shrimp and crab>sea fish>freshwater fish. The health risk assessment showed that except for T. maccoyii, the health risk values of marine products and freshwater products were less than 1.0, and the risk when eating was relatively small. The results of this study show that seafood and freshwater products in the eastern coastal areas have a certain degree of heavy metal pollution, but the pollution is lighter and the intake risk is relatively small.