北京市场常见水产品中总汞、甲基汞分布特征及食用风险

以甲苯二次萃取-直接测汞的方法对北京市场常见水产品中的甲基汞进行分析测定,并评价了食用人群的暴露风险。分析样品包括大黄鱼（Pseudosciaena crocea）、虾（Penaeus chinensis）等9种常见海产品以及武昌鱼（Megalobrama amblycephala Yih）、鳙鱼（Aristichthys nobilis）2种淡水海产品。测定结果表明：海产品中总汞和甲基汞质量分数要远高于淡水鱼中的总汞和甲基汞质量分数,总汞绝大多数是以甲基汞的形式存在,所占比例从74.7%到96.0%不等;对其中3种鱼类的鱼体甲基汞分布研究表明：肌肉中的甲基汞质量分数最高,肝脏中次之,鱼鳃中质量分数最低。根据我国水产品甲基汞标准,本研究中水产品甲基汞质量分数均低于国家标准,但根据世界卫生组织（WHO）和美国环保署EPA颁布的甲基汞摄入量参考值,食用银鳕鱼等甲基汞质量分数相对较高的水产品仍然存在一定的风险,应注意限量。

Analysis and risk assessment of total mercury and methyimercury in aquatic products in Beijing market

The objective of this paper is to analyze the total mercury and methylmercury concentrations in aquatic products in Beijing market,and evaluate the exposure risk to human beings.Nine seawater species and two fresh water species were sampled from Beijing market.Methylmercury was extracted and concentrated based on the method of toluene extraction and cystein back-extraction.The final extracts were analyzed according to the method of US EPA 7473.The results showed that methylmercury accounted for 74.5%-96.0% of the total mercury in the muscle of the tested samples.The methylmercury concentration in different organs followed the order of musclelivergills.Compared with the China national standard for aquatic products（GB 2762-2005 and GB 2733-2005）,the methylmercury concentration of the measured samples was all below the standard value.However,according to the criteria of the maximum allowable methylmercury intake from WHO and EPA,consumption of the seawater fishes with high methylmercury concentration（such as Anoplopoma fimbria） should be limited.