3种海洋贝类重金属污染及食用风险评价研究

Situation of Heavy Metal Pollution and Food Risk Assessment of 3 Kinds of Marine Shellfish

为全面了解常见海产贝类的重金属污染状况,对3个不同养殖区域内水煮加工后的牡蛎、缢蛏和血蚶体内的Cd、Cr、Cu、Pb、甲基Hg和无机As等重金属含量进行分析,利用体外生物可利用度分析贝类中重金属在人体胃肠道中的溶解和转化情况,并采用生物质量指数（Pi）和靶标危害系数（THQs）对贝类食用风险进行评估。结果表明,牡蛎中重金属污染水平较高,且Cu、Cd是牡蛎的主要污染因子。Pb和Cd的单项污染指数平均值分别达到4.6675和1.0601,综合污染指数最大值达7.6552,说明部分贝类达到重度污染。体外生物利用度模型表明,贝类中的重金属在人体胃肠道环境下不能完全溶解,其生物利用度在1.1975%~69.5775%之间。采用THQs值评价贝类中金属元素总量和体外消化模型后的含量,以金属总量进行评价时,77.78%贝类样品的THQs值大于1.0;以体外消化模型后的金属元素含量评价时,3个养殖区的牡蛎和象山缢蛏的THQs值大于1.0,表明长期食用牡蛎对人体存在一定的健康风险,并且各重金属对人体的危害依次为Cd〉无机As〉Cu〉Pb〉甲基Hg〉Cr。本研究结果为评价重金属对人类健康的风险提供了更为可靠的科学依据。

In order to evaluate the status of heavy metal pollution of shellfish, the effects of exposure to Cd, Cr, Cu, Pb, methylmercury（MeHg） and inorganic arsenic via consumption of oysters, razor clams and blood clams after boiling process, pollution index （Pi） and target hazard quotient （THQs） were measured in three marine seashells collected from three primary culturing areas. The concentration of heavy metal pollution in oysters was higher than razor clams and blood clams, and the metal Cu and Cd were the main pollution factors. With the total concentrations, the pollution index for Pb and Cd were 4.6675 and 1.0601, respectively, and the integrated pollution index, reached the maximum value of 7.6552, which means there is severe pollution among seashells. Bioaccessibility of Cd, Cr, Cu, Pb, methylmercury（MeHg） and inorganic arsenic was predicted for edible cooked flesh of marine seashells by use of an in vitro gastrointestinal assay, ranging from 1.1975% to 69.5775%. Based on total concentrations, diets of 77.78% exceeded the reference dose（THQs〉1）, but when bioaccessibility was considered, consumption of oysters in three culturing areas and the razor clams in Xiangshan districts exceeded the reference dose of THQs （THQs〉1）, which suggests that the long-term consumption of oysters exists certain health risks to human being. Furthermore, it can also be concluded that the harm of heavy metals to human body： Cd 〉 inorganic arsenic 〉 Cu 〉 Pb 〉 methylmercury 〉 Cr. The study providing more reliable scientific evaluation of heavy metals on human health.