华南沿海牡蛎重金属含量特征及其风险评估

The variation features of heavy metal contents in oyster samples from the coast of South China Sea and their safety assessment

根据2009年对华南沿海部分海域的近江牡蛎和太平洋牡蛎的监测数据,对产品中重金属元素Cd、Cu、Pb、As、Hg和Zn的含量水平、分布与变化特征进行了分析讨论;采用点评估方法,计算Cd、Cu、Pb、As、Hg和Zn的膳食暴露量,对牡蛎产品的食用安全性进行风险评估。结果表明,调查海域牡蛎样品中Cu、Zn、Cd的含量较高,其值分别为92.0、268、1.32 mg/kg(湿重,下同);Hg、As、Pb的含量低,其值分别为9.21、0.11、0.26 mg/kg。不同海域、不同养殖季节的牡蛎产品中重金属元素的含量具有明显的差异。与无公害水产品质量标准的限量值相比,调查海域牡蛎产品中Cu、Zn、Pb、Hg、As的含量符合产品质量标准,Cd的含量超过产品限量标准值。由于元素间的相互作用,牡蛎产品Zn的含量高、Cd的含量低,Zn的可利用性阻止对Cd的吸收,牡蛎产品中的Cd不会对健康造成危害。风险评估的结果显示,每周食用适量的牡蛎,重金属的膳食摄入量低于世界卫生组织/联合国粮食和农业组织的食品添加剂联合专家委员会(JECFA)推荐的暂定每周耐受摄入量,处于安全范围内。

The contents,distributions and variation features of heavy metal Cd,Cu,Pb,As,Hg and Zn in oyster samples collected from the coast of the South China Sea in 2009 were discussed,and the dietary exposure of heavy metals were calculated using point estimate.It showed that the contents of copper,zinc and cadmium in oyster samples were high and the contents of mercury,arsenic and lead were low,and their contents were 92.0,268,1.32,9.21,0.11 and 0.26 mg/kg（wet weight）,respectively.The statistics results showed that the contents of cadmium,copper,lead,mercury,arsenic and zinc in oyster samples had obvious variation with sampling areas and cultivation seasons.Compared with the limit values of the safety requirements for non-environmental pollution aquatic product,the contents of copper,zinc,lead,mercury and arsenic in oyster samples were lower than the limit values,while the content of cadmium was higher than the limit value.The increased intake of bioavailable zinc reduced excessive cadmium absorption because oysters were rich in zinc with the low ratio of cadmium and zinc content.Therefore the cadmium in oyster samples was not harmful to health.The assessment results showed that the dietary exposures of heavy metals in oysters were lower than the recommended values of the Joint FAO/WHO Expert Committee on Food Additives（JECFA）.