Analysis of four common heavy metals in animal seafood sold in Tianjin City and risk assessment of dietary exposure

ObjectiveTo evaluate the pollution levels of lead， cadmium， mercury， arsenic in animal seafood sold in Tianjin City and dietary exposure risk of people in Tianjin.MethodsAccording to the requirements of the national food contaminants and harmful factors risk monitoring manual， 384 representative samples of commercial animal seafood were collected in supermarkets and farmers’ markets in 16 administrative regions of Tianjin City in 2023. The contents of lead， cadmium， mercury， and arsenic were detected according to the national standard detection method， and the pollution degree was evaluated by the single factor pollution evaluation index （Pi） and metal pollution index （MPI）. Combined with residents dietary intake， the dietary exposure risk of 4 kinds of heavy metals were assessed by point assessment method.ResultsThe median content of the four heavy metals （P50） was cadmium （0.061 mg/kg）， lead （0.022 mg/kg）， methylmercury （0.008 mg/kg）， and inorganic arsenic （0.005 mg/kg）， the difference is statistically significant （P<0.05）. Only cadmium exceeded the standard， with the exceeding rate of 2.08% （8/384）， and the sample varieties exceeding the standard were bivalve shellfish and sea crab. The pollution levels of different aquatic products were different. Pi evaluation results showed that sea crabs had lead and cadmium pollution， and cadmium pollution in bivalve shellfish， while the other varieties were at the normal background level； MPI evaluation results showed that the overall pollution degree of 4 kinds of heavy metals was sea crabs>bivalve shellfish>sea shrimp>sea fish. Point assessment results showed that the average exposure （Exp） of the four heavy metals ranged from 0.19-12.36 μg/（kg·BW）， with the highest cadmium and the lowest inorganic arsenic； The hazard quotients （HQ） for cadmium and methylmercury were 0.49 and 0.04， both less than 1. The margins of exposure （MOE） for lead and inorganic arsenic were 25.83 and 473.68， both greater than 1， all less than 1.ConclusionThere is a certain degree of lead and cadmium pollution in the municipal animal seafood sold in Tianjin， but the total dietary exposure level was low， and the edible safety was in the acceptable range.