东营市北部海域文蛤重金属污染特征与食用风险评价

2016年10月在东营市北部海域采集文蛤，测定其体内7种重金属含量，分析其污染特征，从而探究文蛤（Meretrix meretrix）对沉积物中重金属的生物富集能力及其影响因素，并采用单因子污染指数（P_i）和总目标危险系数（THQ_s）评价文蛤食用风险.结果表明，该海域文蛤体内Hg、As、Pb、Cd、Cr、Cu和Zn含量分别为0.009~0.019，0.51~0.80，0.25~0.76，0.45~0.76，0.43~2.46，1.83~3.78，14.33~17.75mg/kg.与国内外其它区域文蛤体内重金属含量对比发现，该海域文蛤体内重金属含量处于中等水平.基于综合污染指数（MPI），S5站位文蛤受重金属污染最严重.文蛤对Cd的富集能力最强（生物-沉积物积累因子（BSAF）平均为455.13%）.7种重金属中，只有Pb的生物蓄积与其在沉积物中的含量呈显著正相关，而Hg、Cu的蓄积分别与沉积物中细颗粒物（粒径< 63 μm，FGS）、有机质（OM）含量呈显著正相关和负相关.通过分析各站位的THQ_s值可知，长期食用该海域文蛤对人体有害，且食用风险主要来源于As.因此，为降低食用该海域文蛤给消费者带来的健康风险，必须采取有效措施控制重金属（特别是As）在海产品中的积累.

Contamination characteristics of heavy metal and risk assessment of seafood safety for bivalves Meretrix meretrix collected from the northern coastal area of Dongying City

Concentrations of seven heavy metals were determined in the clams Meretrix meretrix collected from the northern coastal area of Dongying City in October, 2016, to explore the contamination characteristic of these metals. Bioaccumulation and its influence factors of the heavy metals by M. meretrix from sediment environment were discovered. Consumption risk for these clams was also evaluated using the single factor pollution index (P_i) and the target hazard quotients (THQ_s) models. Results demonstrated that the concentrations of Hg, As, Pb, Cd, Cr, Cu, and Zn varied as 0.009~0.019, 0.51~0.80, 0.25~0.76, 0.45~0.76, 0.43~2.46, 1.83~3.78, and 14.33~17.75mg/kg, respectively. Comparing with other coastal areas, the contamination of heavy metals was at medium level in the clams M. meretrix investigated in this study. The contamination of heavy metals was the worst in the clams from the sampling site S5 based on the metal pollution index (MPI) model. The highest bioaccumulation capacity in M. meretrix occurred for Cd, and the average biota-sediment accumulation factor (BSAF) was calculated as 455.13%. Among these heavy metals, only Pb presented a significant positive correlation between its BSAF value and total content in sediment, while the bioaccumulation of Hg and Cu were positively and negatively correlated with the fine grain size (particle size <63μm, FGS) and organic matter (OM) contents in the sediments, respectively. The THQ_s values indicated that a potential health risk will be mainly caused by the heavy metal As through a long-term clam consumption. Therefore, some effective measures should be taken to reduce the accumulation of heavy metals, especially the element As, in clams in order to protect consumer health.