基于三次样条插值法的土壤中有机氯污染研究

OCPs CONTAMINATION OF SOILS AROUND GUANTING RESERVOIR BASED ON CARDINAL-SPLINE-INTERPOLATION METHOD

根据2003年、2007年以及2009年的北京官厅水库地区表层土壤中有机氯农药(OCPs)残留实验数据,应用三次样条插值法对缺失年份的数据进行了补充,并预测了2010年的数据。在此基础上,分析了各采样点OCPs浓度时间变化规律及原因,探讨了影响有机氯农药降解的因素,并且参照国家土壤环境质量评价标准,对区域表层土壤中有机氯的污染现状进行了评价。结果显示:部分样点OCPs含量随着时间的变化存在反弹,判断存在OCPs的外源性输入;土壤质地对OCPs降解速率有很大程度上的影响,立地植被的影响不显著;对比国家土壤质量一级标准来看,2003年至2009年均未检出总六六六(∑HCH)超标样点,采样点的总滴滴涕(∑DDT)浓度至2009年也均下降至国家土壤环境质量标准一级限值内;预计到2010年,采样点总六六六浓度基本保持恒定,总滴滴涕仍维持良好的降解趋势。

Based on determinations of organochlorine pesticide （OCPs） residuals in surface soils around the Guanting Reservoir, Beijing in 2003, 2007 and 2009, the Cardinal-spline interpolation method was used to make up the data of the missing years for prediction of data on OCP residual in 2010. On such a basis, analysis was done for temporal variation of OCPs concentrations at the sampling points and affecting factors of the degradation of OCPs. By referencing the National Standard for Soil Environment Quality, surface soils in the region were evaluated for OCPs pollution. Results show that 1 ） OCPs concentrations at some sample sites have rebounded, which suggests existence of exogenous inputs ; 2） soil texture is a major factor affecting OCPs degradation rate while vegetation on-site is not ; 3 ） ∑HCH was found below the bottom limit of Grade I criteria of the national standard at all sample sites from 2003 to 2009, and ∑DDT was declining and fell within Grade I criteria of the national standard in 2009; and 4） it is predicted that in 2010, ∑HCH will basically remain stable and ∑DDT go on declining.