海河干流及河口地区土壤中有机氯农药的分布特征

Distribution of Organochlorine Pesticides in Soils in Haihe River and Haihe Estuary Area,China

以海河干流沿岸及海河河口周边地区为研究区域,采集了31个表层土壤样品,利用加速溶剂萃取(ASE)技术,使用气相色谱-电子捕获检测器(GC-ECD)分析方法测定了样品中的六六六(HCHs)和滴滴涕(DDTs)的含量.结果显示,海河河口地区土壤中HCHs和DDTs的含量范围分别为n.d.～1728μg·kg-1(平均含量为93.9μg·kg-1)和n.d.～288μg·kg-1(平均含量为34.4μg·kg-1).其中HCHs占优势,约占有机氯农药(OCPs)总残留量的72%.从海河干流到河口地区,OCPs的含量分布呈非均一性,受污染点源的分布影响较大,农药化工企业分布的区域土壤中的有机氯农药含量明显高于其它区域,海河干流区域相对高于河口地区.土壤中有机氯农药的成分分析结果表明,该地区土壤中除个别采样点OCPs仍有新的污染源输入外,大部分点位土壤中的OCPs主要来自于工业点源的历史输入和农业面源即有机氯农药的历史施用.与国内外其他地区土壤相比,该地区土壤中OCPs污染处于较高水平.

Levels and distribution of organochlofine pesticides （OCPs） were investigated in soils along Haihe River and in Haihe Estuary area. 31 surface soil samples were collected on August 2007, and they were extracted using accelerated solvent extraction. The HCHs and DDTs contents in soils were determined by gas chromatography with an electron capture detector （GC-ECD）. The results show that the concentrations in soils range from n.d. to 1 728 μg·kg^-1 with a mean value of 93.9 μg·kg^-1 for HCH congeners, and from n.d. to 288 μg·kg^-1 with a mean value of 34.4μg·kg^-1 for the sum of p,p＇-DDT, p,p＇-DDT, DDE, and DDD, respectively. The HCHs is dominant, accounting for 72 percent of total OCPs content. The working hypothesis is that OCPs levels and distribution in the area are dependent on the degree of anthropogenic intervention. Higher concentrations of total OCPs are found in the chemical industrial region, and ones from Haihe River area are higher than Haihe Estuary area, due to impact from chemical industrial emissions. According to the isomers of HCHs and metabolites of DDTs, HCHs and DDTs in soils in this area may be derived from the use of pesticide in agricultural and industrial emissions in history, though having recent inputs of OCPs at a few sites. Compared with those in other national or international regions, the concentrations of HCHs and DDTs in soils from Haihe River area are higher. It can be concluded that soil OCPs levels are relatively high in this area.