福建省海水贝类养殖区表层沉积物及贝类滴滴涕的残留与风险评价

Residue and risk assessment of DDTs in surface sediment and cul-tured shellfish along the Fujian coast,China

为了评估福建省海水贝类养殖区滴滴涕(DDTs)的残留水平和风险,于2005年8月和2006年8月,采集养殖区20个站位的表层沉积物样品20个、养殖贝类样品46个,用气相色谱法测定其中DDTs的残留量,并对其残留水平、分布趋势和组成特征进行分析,以期对该地区污染状况、生态风险及贝类食用安全进行探讨与评价。结果表明,福建省贝类养殖区表层沉积物DDTs含量范围为1.93～56.6μg/kg(干重),平均值15.8μg/kg;40%的样品DDTs的污染指数在0.697～2.83之间,不同程度受到DDTs的污染,提示存在一定的潜在生态风险。养殖贝类DDTs含量范围为2.04～107μg/kg(湿重),平均21.7μg/kg;贝体DDT残留量符合中国无公害水产品质量安全标准,低于欧盟、美国、日本的食品安全限量;以每人50 g/d的摄食量估算,沿海居民食用养殖贝类的DDTs暴露量远低于WHO暂定的TDI值、美国EPA推荐的RfD值,由此引起的健康风险小。与国内邻近海域相比较,福建省贝类养殖区表层沉积物和养殖贝类体中DDTs残留量处于中等水平,与亚太等国外海域相比较,处于较高水平;从DDTs的组成特征推测,调查区部分海域有新的DDTs污染源输入。

We measured the residual levels, distribution, and composition of dichloro-diphenyl-trichloroethane （DDTs） in areas containing cultured shellfish along the Fujian coast, China. In addition, we evaluated the risk posed by exposure to DDTs in this region. We collected 20 samples of surface sediment and 46 samples of cul- tured shellfish from 20 sites in August 2005 and 2006. We measured the residual DDT in each sample using gas chromatography. The residue ranged from 1.93 to 56.6μg/kg （net weight, mean 15.8μg/kg） in the surface sedi- ment. Forty percent of samples＇ pollution indexes for the DDTs was between 0.697 and 2.83, which suggested there was a potential ecological risk for DDTs pollution on some extent. The DDT residues ranged from 2.04 μg/kg to 107μg/kg （net weight, mean： 21.7μg/kg） in the shellfish samples. These levels were below the Maxi- mum Residual Limits published by the European Community, USA, and Japan, and met the sea food safety index set by the Chinese government. Assuming a person ingested a maximum of 50 g/（person.day） cultured shellfish, their intake of DDT would be well below the TDI regulated by WHO and RfD and suggested by US EPA, indi- cating that the health risk arising from exposure to DDTs is low. DDT residues in the surface sediment and shell- fish were within the middle of the range reported in nearby domestic water sources, but were relatively high when compared with those reported in water within the Asia-Pacific region. The relative composition of DDT isomers suggested that there has been input into this area in recent years.