岩溶区不同水体有机氯农药对比研究

The comparison of organochlorine pesticides between underground water and surface water in karst area

为研究岩溶区地下水、地表水之间有机氯农药的差异,用气相色谱-微池电子捕获检测器(GC-μECD)分析了水中OCPs含量.结果表明:研究区水样中有机氯农药检出率达100%.OCPs浓度范围32.13～319.53ng/L,均值为134.17ng/L.OCPs浓度季节差异明显,枯水期高于丰水期.水井(sj)中OCPs,DDTs、HCHs浓度均大于水池(sc).通过采样点间的对比可知,雨季水池、水井间OCPs含量相当,旱季水池小于水井.水池、水井间DDTs、HCHs对比没有明显的季节性,表现为水池的DDTs含量小于水井,但HCHs含量大于水井.水井中的OCPs、DDTs、HCHs的最小值与水池相比均表现出了滞后性.地表水与地下水有机氯农药表现出的差异,是由于两采样点的环境不同.通过比值法得出HCHs来自于混合源,地表水的比值更能准确的反映出HCHs的来源.DDTs可能来自于混合DDTs,且为历史残留,降解环境为好氧环境.水井中DDTs、HCHs百分比组成由于土壤的影响发生了变化.

In order to study the difference of organochlorine pesticides （OCPs） between underground water and surface water in karst area. The concentrations of OCPs residues in the water samples were measured by gas chromatography equipped with miro-63Ni electron capture detector. The results showed that the total OCPs concentrations in the water ranged from 32.13-319.53ng/L with a mean value of 134.17ng/L. The concentrations of OCPs have obvious seasonal difference and the dry season is higher than the rainy seasons. The concentrations of OCPs, DDTs, HCHs in sj is higher than sc. Through the contrast the concentrations of OCPs in sc was lower than sj during the dry season and fluctuations are small during the rainy season. The concentrations of DDTs, HCHs in the two sits have no seasonal. The concentrations of DDTs mainly for sc were less than sj. The concentrations of HCHs mainly for sc were higher than sj. Compared with sc the minimum value of OCPs, DDTs, HCHs appeared hysteresis. The difference of OCPs between underground water and surface water is due to they are in different environment. The ratio of OCPs isomers implied that using mixture HCH caused HCHs pollution. Relative to the groundwater, surface water can more accurately reflect the source of HCHs. The historical usage of mixture DDTs maybe caused DDTspollution, and DDT was dechlorinated under aerobic conditions. Due to the effect of soil, the percentage composition ofDDTs, HCHs has changed.