不同参数下植被过滤带对径流中农药的净化效果研究

Experimental Study on the Purification Effects of Vegetative Filter Strips on the Pesticide under the Different Parameters

陕西眉县地区在农业生产时使用的新型农药高效氯氟氰菊酯随着径流流入受纳水体,对河虾和鱼危害极大。植被过滤带作为生物工程措施主要集中在对泥沙、氮、磷、COD等污染物的净化效果研究方面,但是对径流中农药的净化效果研究较少。该研究旨在为西北地区应用植被过滤带控制径流中主要农药残留物提供理论依据与参考。通过野外水流试验,研究了在不同参数条件下,植被过滤带(沙棘灌木(Hippophae rhamnoides L.)、草本植被)对径流中农药的净化效果。结果表明:当流量为0.85 L·s^(-1),质量浓度为0.3 mg·L^(-1),土壤初始含水率分别为20%、50%、70%时,土壤初始含水率越低,浓度削减率越高;当质量浓度为0.3 mg·L^(-1),土壤初始含水率为20%,入流流量分别为0.85、1.5、7.1 L·s^(-1)时,入流流量越小,净化效果越好,当入流流量为0.85 L·s^(-1)时,沙棘过滤带的浓度削减率、负荷削减率高达62%、86.02%,草本过滤带的浓度削减率、负荷削减率高达62.67%、87.69%;当流量为0.85 L·s^(-1),土壤初始含水率为20%,入流污染物质量浓度分别为0.3、0.6、0.9 mg·L^(-1)时,入流浓度越大,净化效果越好,当入流农药质量浓度为0.9 mg·L^(-1)时,沙棘过滤带浓度削减率、负荷削减率分别高达83%、91.38%,草本过滤带的浓度削减率、负荷削减率分别达84.33%、95.43%。此外,通过对比和计算可知,草本植被过滤袋净化效果优于沙棘灌木过滤带。

This study aims to provide the theoretic proof and reference for the application of the vegetation filter strips(VFS)tocontrolling the major pesticide remnants in runoff in Northwestern China.The new style pesticide-high efficiencylambda-cyhalothrin,used in Mei county of Shaanxi province,is extremely harmful to the prawn and fish of the rivers when flowinginto the nearby water recipients along with the runoff during agricultural production.The VFS,as a type of biological measure,concentrates mainly on the purification-effect research on preventing the pollutants such as sediment,nitrogen,phosphorus andCOD.However,less research is focused on the purification effects for pesticide.In this paper,through the field water flowexperiment,we studied the purification effects of VFSs(composed of the seabuckthorn shrub(Hippophae rhamnoides L.)and herbvegetation,respectively)on the pesticide in the runoff under the various parameters.The results showed that:(1)when both theinflow discharge is0.85L?s-1and the pollutant mass concentration is0.3mg?L-1,and the soil initial moisture content is20%,50%,and70%,respectively,the less the soil initial moisture content,the higher the load reduction rate is:(2)when both the pollutant massconcentration is0.3mg?L-1and the soil initial moisture content is20%,and the inflow rate is0.85,1.5,7.1L?s-1,respectively,the lessthe inflow rate,the better the purification effect is.That is to say,when the inflow rate is0.85L?s-1,the concentration reduction rateand the load reduction rate within the seabuckthorn filter strip(SFS)can be up to62%and86.02%,respectively,and theconcentration reduction rate and the load reduction rate within the herb filter strip(HFS)can be up to62.67%and87.69%,respectively.(3)When the inflow rate is0.85L?s-1,the initial moisture content is20%and inflow pollutant mass concentration is0.3,0.6,0.9mg?L-1,respectively,the bigger the inflow pollutant concentration,the better the purification effect is.That is to say,whenthe inflow mass concentration is0.9mg?L-1,the concentration reduction rate and the load reduction rate of the SFS can be up to83%and91.38%,respectively,and the concentration reduction rate and the load reduction rate of the HFS can be up to84.33%and95.43%,respectively.In addition,the purification effect of the HFS is better than that of the SFS by computation comparison.