Effect Of Chemical Activators On Arsenic Bioaccumulation From As-Contaminated Soil By Pteris Vittata L.

In recent years,with the rapid development of industry and agriculture,a large area of soil arsenic pollution has been caused.Arsenic pollution in soil causes crop reduction,human food poisoning and cancer risk.Therefore,it is urgent to remedy the As-contaminated soil.In this study,the effects of the activators on the changes of available arsenic and arsenic geochemical forms in soil were studied by soil screening experiments,which were reduced glutathione(GSH),sodium tripolyphosphate,Span 80,sodium dodecyl sulfate(SDS),citric acid and their mixtures.The effect of compound activators on the extraction efficiency of arsenic from As-contaminated soil by Pteris vittata L.was studied by pot experiment.The main results were as follows:1.Compound activators Span 80+SDS,GSH+Span 80+SDS,GSH+sodium tripolyphosphate+Span 80,sodium tripolyphosphate+citric acid,Span 80+citric acid can significantly increase the content of available arsenic of As-contaminated soil in Jingmen,Hubei Province and in Foshan,Guangdong Province.And these compound activators can promote the conversion of arsenic that is difficult to use into available arsenic in soil.2.In the pot experiment,compared with the control,all compound chemical activators(Span 80+SDS,GSH+Span 80+SDS,GSH+sodium tripolyphosphate+Span 80,sodium tripolyphosphate+citric acid,Span 80+citric acid)can improve the content of total arsenic in aboveground of Pteris vittata L.and the activator GSH+Span 80+SDS has the most significant effect,which can significantly increase by more than 62.0%.The activator GSH+sodium tripolyphosphate +Span 80 had the best effect on the increase of the pinnae biomass,which can significantly increas by more than 39.0%.Compared with the first harvest,the bioconcentration factors of As in the aboveground of Pteris vittata L.in the second harvest increased.The addition of compound activators did not significantly affect the diversity of soil microflora.3.An increase in the dosage of Span 80 in compound activator GSH+sodium tripolyphosphate+Span 80(ACD)can significantly increase the content of available arsenic in As-contaminated soil in Foshan,Guangdong Province and increase the arsenic concentration and bioconcentration factors of As in the aboveground of Pteris vittata L.With the increase of the dosage of Span 80,SOD and CAT enzyme activities and the content of GSH increased first and then decreased,while the content of MDA decreased first and then increased,indicating that the optimal dosage of activators were 0.25 g of GSH,0.25 g of sodium tripolyphosphate and 0.375 g of Span 80.An appropriate increase of Span 80 could promote the biomass of the pinnae and petiole.Hence,an appropriate increased of Span 80 in the compound activator ACD is useful to improve the efficiency of phytoremediation by Pteris vittata L.This study found that the compound chemical activators has a significant strengthening effect on improving the efficiency of phytoremediation of As-contaminated soil by Pteris vittata L.,and it has a certain application prospects.