Prediction Model And Application Of Bioavailability Of Organic Contaminants In Soils Driven By Surfactants

Based on the investigation of farmland organic pollution in the Yangtze River Delta,this paper analyzes the characteristic distribution and pollution level of organic pollutants in this area.The way of cationic surfactant to alleviate the resistance control was adopted in agriculutral soils with organic contamintation.The micro mechanism of mitigation uesd by cationic surfactant was studied in depth,and the mathematical model was established to quantitatively predict the accumulation of organic pollutants in plants.Based on the combination of agronomic process,the integrated technology of mitigation and remediation with mixed surfactants was developed,and the effect of mixed surfactants on the bioavailability of organic pollutants was discussed.It can provide theoretical basis and technical support for the safe production of agricultural products and the remediation of organic polluted farmland.The following valuable results are obtained in this paper:?1?The effects of typhoon“Lekima”on the distribution of PAHs,PAEs and OCPs in farmland soil of Yangtze River Delta were discussed.For PAHs and PAEs with high air/soil partition coefficient,affected by wet settlement and soil disturbance,after typhoon,the PAEs concentration that of 96.5%points increased by 6.9-32.1%.The PAHs concentration of 68.4%points increased by 11.9-363.0%,that of 31.6%points decreased by 14.7-48.4%;For OCP with low air/soil partition coefficient,typhoon could change the soil aerobic anaerobic environment and promote the anaerobic degradation of OCPs.The concentration of OCPs in all sites decreased by 16.5%-84.5%.?2?The relationship between the degradation rate constant of typical organic pollutants in common plants and the pollutant K_ow was quantified,and the limited allocation model of plant absorption and accumulation of organic pollutants was further revised.The prediction error was reduced from 14.8 to 6.7%.A prediction model for the inhibition of plant uptake of organic pollutants by cationic surfactants was established.The prediction error of 28 kinds of organic pollutants is less than 36.8%.?3?Based on the regulation of bioavailiablity,the integrated technology of mixed surfactant to alleviate the resistance and enhance the efficiency of remediation of organic polluted agricultural soils was developed.In the period of farming,the application of 400 mg/kg CTMAB-Tween80 surfactants with a mass ratio of 4:1 can significantly reduce the content of pollutants in soils and crops.During the fallow period,the application of 100 mg/kg SDBS-Tween80 surfactant with a mass ratio of1:1 and the planting of remediated plants significantly increased the bioavailability of pollutants in soils,enhanced the relative abundance of degradation bacteria and the number of related functional genes,effectively promoting the removal of organic pollutants.The results showed that the PAH contents in cabbage and lettuce decreased by 20.4%and 43.8%respectively.The PAHs removal rate in soil was 69.1%,which realized"production and restoration"in contaminated farmlands.