养殖贻贝各组织有机氯农药和多氯联苯的污染特征和影响因素

Pollution characteristics and factors of OCPs and PCBs in cultured mussels

  • 摘要: 有机氯农药(organochlorine pesticides,OCPs)和多氯联苯(polychlorinated biphenyls,PCBs)是两类传统的持久性有机污染物,易在环境中富集并对水生态系统造成潜在风险。贝类对水体中的污染物具有很强的积蓄能力,可作为评估环境行为、毒理效应、生态和健康风险的指示生物。本文以花鸟岛养殖贻贝为研究对象,分析各组织中OCPs和PCBs的污染特征。总体来看,OCPs化合物中滴滴涕(DDTs)含量最高,硫丹(ENDs)含量最低,分别为1.1~74 μg/kg和0.0050~0.22 μg/kg(湿重计,下同);PCBs化合物中五氯、六氯和七氯联苯含量较高,分别为(10~220)×10−3 μg/kg、(14~240)×10−3 μg/kg和(7.3~200)×10−3 μg/kg;从组织角度来看,性腺是富集污染物最多的组织,较高的脂含量有利于脂溶性有机物的富集,其中以降解产物和更稳定化合物为主。此外,本研究发现,高毒害化合物在体内传递过程中,会优先被外部组织吸收,贻贝存在自我保护机制。各化合物的致癌风险值范围为(0.0037~14)×10−6,均小于10−4,说明养殖贻贝几乎不会产生致癌风险,可放心食用。

     

    Abstract: Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are two kinds of traditional persistent organic pollutants, they are capable of accumulating in the environment and pose potential risks to aquatic ecosystems. As bioindicators, shellfish exhibit a strong capability to accumulate waterborne pollutants that can be used to assess environmental behaviors, toxicological effects and ecological health risks. In this study, cultivated mussels were collected from Huaniao Island and analyzed for OCPs and PCBs with the objective of examining their pollution characteristics. In general, among OCPs compounds, dichlorodiphenyltrichloroethane (DDTs) exhibited the highest content, while endosulfan (ENDs) displayed the lowest, they ranged from 1.1 to 74 μg/kg and 0.0050 to 0.22 μg/kg, respectively (wet weight, the same below). Among PCBs compounds, pentachloro, hexachloro and heptachloro biphenyls showed higher contents, ranging from 10 to 220 (×10−3 μg/kg), 14 to 240 (×10−3 μg/kg) and 7.3 to 200 (×10−3 μg/kg) respectively. The gonads are the most enriched tissue for pollutants, with their elevated lipid content facilitating the accumulation of lipophilic organic compounds, which own more degradation products and stable compounds. In addition, the research found highly toxic compounds are preferentially absorbed by external tissues during the transformation, mussels have self-protection mechanism. The carcinogenic risk index of each compound ranged from 0.0037 to 14 (×10−6), all lower than 10−4, indicating that cultivated mussels hardly produced carcinogenic risk and could be safely consumed.

     

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