浙江沿岸海域经济贝类中有机氯农药和多氯联苯的残留分布与污染评价

Residue levels and distribution and evaluation of organochlorine pesticides and polychlorinated biphenyls in shellfish samples of Zhejiang coastal areas

对2006年6月和2007年6月采集于浙江沿岸海域12个站位的5种经济贝类样品,采用气相色谱(GC)方法,进行了有机氯农药(HCHs和DDTs)和多氯联苯(PCBs)残留量的检测,分析了不同种类贝类中HCHs、DDTs和PCBs异构体组分特征,探讨了浙江沿岸海域HCHs、DDTs和PCBs残留分布状况、年际变化趋势和DDTs的来源,并与厦门岛东部等5个主要沿海海域进行了污染物残留量的比较。结果表明:(1)调查区各海域贝类中的HCHs、DDTs和PCBs残留量(湿质量)分别为:(ND^7.86)×10-9,(0.72~281.73)×10-9,(ND^97.95)×10-9;残留量(湿质量)平均值分别为:1.50×10-9,33.65×10-9,19.56×10-9。调查区各海域所有贝类中的HCHs残留量,均符合国家一类生物质量标准,DDTs残留量仅在四角蛤蜊中符合国家一类生物质量标准,在其余4种贝类中仅符合国家二类生物质量标准。DDTs残留量平均值明显高于HCHs和PCBs,因此可以将DDTs视为调查区各海域典型的有机氯污染物。(2)在HCHs和DDTs组分中,分别以-αHCH和P,P-′DDT占优势;在PCBs中,以含4~7个氯原子的PCB占主要优势,调查区部分海域有新的HCHs和DDTs污染源。(3)自2006年6月至2007年6月,HCHs和PCBs残留量总体呈下降趋势,而DDTs残留量则呈上升趋势,不同海域的有机氯残留量有较明显差异。DDTs的污染源与农业生产中三氯杀螨醇的使用有关。(4)与厦门岛东部等5个主要沿海地区相比,浙江沿岸海域经济贝类有机氯污染物中,HCHs残留量仍处于较低水平,DDTs残留量处于中等水平,PCBs残留量则处于较高水平。

To analyze and evaluate the status of organochlorine pesticides and polychlorinated biphenyls（PCBs） pollutants in Zhejiang coastal areas,the concentrations of hexachlorocyclohexane（HCHs）,dichlorodiphenyltrichloroethane（DDTs） and PCBs in shellfish collected in study area from June 2006 to June 2007 were detected by gas chromatography（GC）.The concentration range of HCHs was（ND～7.86） ×10-9（wet weight） and average was 1.50×10-9.The concentration range of DDTs was（0.72～281.73）×10-9（wet weight） and average was 33.65×10-9.The concentration range of PCBs was（ND～97.95） ×10-9（wet weight） and average was 19.56×10-9.The concentration of DDTs in the shellfish was higher than HCHs and PCBs,so DDTs could be considered as typical organochlorine pollutants in the areas.The HCHs in all shellfish conformed to the first level of criterion of the national standard,and those of DDTs in most samples were beyond the first level but conformed to the second level.On average,α-HCH occupied the most part of HCHs and P,P′-DDT occupied the most part of DDTs while PCBs including 4 to 7 chlorine occupied the most part of PCBs.There were new sources of HCHs and DDTs discharged into coastal areas of Zhejiang Province.The pollution source of DDTs associated with the use of dicofo.HCHs and PCBs levels in shellfish degraded slightly from June 2006 to June 2007 while DDTs decreased.The concentration of organochlorine pesticides and PCBs were different in different coastal areas.Level of HCHs was lower.DDTs was at the middle level while PCBs was higher compared with the other coastal areas.