长江三角洲典型地区农田土壤中多氯联苯残留状况

Residues of PCBs in Agricultural Fields in the Yangtze Delta,China

选择地处长江三角洲的苏南某市为试区,对该市农田土壤中18种PCBs同系物的残留量进行了调研,以揭示非污染区农田土壤中PCBs的残留现状,以及各种同系物在农田土壤中的分布特征.结果表明:PCBs残留总量介于数十至数千ng.kg-1水平,除PCB77未检出外,其它17种PCBs同系物有不同程度地检出,残留量及检出率最高的分别是PCB138和PCB180.土壤的不同利用方式对PCBs残留量有一定影响,水稻土中PCBs残留量最高,传统菜地中PCBs残留量最低.不同利用方式土壤中同系物残留的分布状况具有不同的特征,而同系物的分布特征从一定程度上能反映污染物的来源:稻土中PCBs主要来源于灌溉水,而传统蔬菜地PCBs主要来源为大气降尘,大棚土壤中PCBs则主要来自于农用化学品.

Residues of 18 congeners of PCBs in agricultural fields located at the Yangtze Delta were investigated. The results show that residues of ∑ PCBs ranged from tens to thousands ng· kg^- 1. Except PCB77, all other PCB congeners were detected at different residue level. PCB138 showed the highest residue, and PCB180 had the highest occurrence. Soil utilization had some influence on ∑PCBs. The order of residue level in different utilization listed as follows： paddy soil 〉 vegetable soil 〉 green house soil 〉 traditional kailyard soil. Distribution character of PCB congeners may reflect the source of pollutants, namely PCBs in paddy soil resulted from irrigation water, PCBs in kailyard soil came from atmosphere deposition and PCBs in green house soil originated from agrochemical utilization.