In situ stabilization remediation of cadmium contaminated soils of wastewater irrigation region using sepiolite

The effects of immobilization remediation of Cd-contaminated soils using sepiolite on soil pH,enzyme activities and microbial communities,TCLP-Cd(toxicity characteristic leaching procedure-Cd) concentration,and spinach(Spinacia oleracea) growth and Cd uptake and accumulation were investigated.Results showed that the addition of sepiolite could increase soil pH,while the TCLP-Cd concentration in soil was decreased with increasing sepiolite.The changes of soil enzyme activities and bacteria number indicated that a certain metabolic recovery occurred after the sepiolite treatments,and spinach shoot biomass increased by 58.5%-65.5% in comparison with the control group when the concentration of sepiolite was 10 g/kg.However,the Cd concentrations in the shoots and roots of spinach decreased with an increase in the rate of sepiolite,experiencing 38.4%-59.1% and 12.6%-43.6% reduction,respectively,in contrast to the control.The results indicated that sepiolite has the potential for success on a field scale in reducing Cd entry into the food chain.