Abstract:

To systematically and comprehensively understand the residue status of pentachlorophenol（PCP）in major commercial shellfish from Ningbo and to assess the health risk of dietary exposure to PCP via shellfish consumption，shellfish samples were collected from farming areas and markets in Ningbo from 2021 to 2025. The PCP concentrations in the samples were determined. Using the risk assessment model recommended by the US EPA，combined with population structure，body weight，and shellfish consumption，the estimated daily intake（EDI），hazard quotient（HQ）for non-carcinogenic risk，and cancer risk index（R）were calculated for different age groups to conduct exposure assessment. A total of 553 samples were analyzed. The overall mean PCP concentration over the five years was 0.94 μg·kg^-1，with annual concentrations ranging from ND to 38.6 μg·kg^-1，showing a decreasing trend. The mean concentration in razor clams（1.28 μg·kg^-1）was slightly higher than the overall mean，while other species were at relatively low levels. The HQ for all age groups ranged from 7.0×10^-5 to 9.4×10^-5，all far below 1. R ranged from 1.4×10^-7 to 1.9×10^-7，below the lower bound of the US EPA acceptable risk range（10^-6）. Among different shellfish species，razor clams made the highest contribution to HQ（45.4%），followed by oysters（35.5%）. The contamination level of pentachlorophenol in shellfish from Ningbo is generally low，and both non-carcinogenic and carcinogenic health risks from dietary exposure via shellfish consumption are within safe and controllable limits. It is recommended to continuously strengthen the supervision of farming environments and regulate the use of pond-cleaning chemicals to ensure the quality and safety of shellfish products.

Key words: pentachlorophenol, shellfish, dietary exposure, risk assessment