【摘要】 鸭儿湖地区在上世纪60—70年代有机氯农药(OCPs)污染严重,为了改善水质1975年鸭儿湖开展了水质污染处理,并于2003年和2004年开展了清淤工作.为了解现阶段鸭儿湖地区有机氯农药污染状况,本文于2009年采集了鸭儿湖5个氧化塘20个表层沉积物,对有机氯农药残留进行了研究.利用气相色谱-质谱联用法(GC-MS)对表层沉积物样品中的六六六(HCHs)、滴滴涕(DDTs)、六氯苯(HCB)进行了分析,测定结果分别为0.73—19.8 ng.g-1、2.2—34.5 n.gg-1和0.13—8.8 n.gg-1(干重),平均值分别为5.0 ng.g-1、8.7 n.gg-1和2.2 n.gg-1(干重).本次有机氯农药分析结果远低于历史数据,表明鸭儿湖地区的有机氯农药污染已经得到了很大的缓解.本文结果与国内其它部分有机氯农药污染区含量相当.沉积物中HCHs和DDTs的分布特征研究表明,沉积物中有机氯农药主要来自于早期的历史残留,近期基本没有新的污染输入.将鸭儿湖地区现在有机氯农药残留与沉积物生态风险评估值相比较,存在一定的生态风险,但风险已较低,不对生态环境构成严重威胁.更多还原

【Abstract】 Ya-Er Lake was heavily polluted by OCPs during the 1960s and 1970s.In 1975,a water disposal program was carried out for the improvement of the water environmental quality,and a sediment dredging project was conducted in 2003 and 2004.In order to assess the contamination of organochlorine pesticides(OCPs) in Ya-Er Lake now,twenty surface sediment samples were collected from five oxidation ponds.HCHs,DDTs and HCB were analyzed by gas chromatograph-mass spectrometery(GC-MS).The concentrations of HCHs,DDTs and HCB were 0.73—19.8,2.2—34.5 and 0.13—8.8 ng·g-1 respectively.The levels of OCPs in Ya-Er Lake had been greatly decreased by comparison with previous data in 1990s.Concentrations of OCPs in Ya-Er Lake were at the same magnitude compared with those of surface sediments collected from other polluted lakes in China.The distribution characters of HCHs and DDTs indicated that the OCPs mainly came from early residues.The risk of OCPs in surface sediments is relatively low when comparing with the ERL and ERM value of risk evaluation.The results indicate that there is no serious threat to the ecological environment.更多还原