Arsenic(As)contamination poses a significant global environmental and health concern.Crayfish shell biochar(CSBC)has shown considerable potential for remediating As-contaminated soil.However,the effect of CSBC on As m...Arsenic(As)contamination poses a significant global environmental and health concern.Crayfish shell biochar(CSBC)has shown considerable potential for remediating As-contaminated soil.However,the effect of CSBC on As mobility in acid and alkaline aerobic soils,and its underlying mechanism remains unclear.This study investigated the variation in As availability,dissolved organic matter(DOM),microbial community,and As metabolism genes in CSBCamended soil.Results indicated that CSBC application decreased the available As content in alkaline soil(4.5-9.9%),but increased it in acid soil(19.6-26.8%).The increase in soil pH and DOM humification degree,along with the decrease in DOM molecular weight,contributed to enhanced As mobility in CSBC-amended acid soil.Additionally,CSBC application stimulated microbial membrane transport and signal transport function in acid soil.Furthermore,it increased the relative abundance of Bradyrhizobium,Sphingomonas,Streptomyces,and Ktedonobacter,which harbor As(V)reduction(arsC and arrB)and As(III)efflux(ACR3)genes,thereby promoting As mobility in acid soil.In alkaline soil,the CSBC provided additional bonding sites for As to mitigate its environmental risk.This study provides new insights into the critical role of biochar in influencing As fate in aerobic soil.展开更多
Background Cadmium(Cd)pollution in agricultural soils has become a priority environmental concern globally.A reasonable application of passivators is critical to address the problem.In this study,we examined the remed...Background Cadmium(Cd)pollution in agricultural soils has become a priority environmental concern globally.A reasonable application of passivators is critical to address the problem.In this study,we examined the remediation effects of rice husk biochar(r BC)and sepiolite(Sep)as single and combined(r BC+Sep)treatments on Cd pollution in a weakly alkaline soil using three maize cultivars(Liyu 16,Zhengdan 958,and Sanbei 218)as test crops.We also explained the mechanisms involved in the remediation effects.Results The pseudo-second-order kinetic equation and Langmuir model could well describe the adsorption process of r BC+Sep for Cd^(2+).Compared with the control treatment(CK),soil available Cd concentration decreased by 29.51–36.34%under r BC+Sep treatment(p<0.05)and the Cd concentrations in maize grains of Liyu 16,Zhengdan 958,and Sanbei 218 decreased by 38.08–47.85%,37.25–45.61%,and 33.96–46.15%,respectively(p<0.05).Following passivation treatment,soil available Cd concentration decreased and gradually changed from the exchangeable and carbonate binding forms to the Fe/Mn oxide and residual forms.The bioconcentration factors of Liyu 16(0.05–0.09)and Sanbei 218(0.05–0.09)were lower than those of Zhengdan 958(0.07–0.13).In addition,r BC+Sep treatment increased soil p H and soil electrical conductivity,but the differences were not significant(p>0.05).Conclusions The application of 0.2%r BC+0.5%Sep composite passivation material to weakly alkaline Cd-contaminated soil can effectively reduce the Cd concentration of soil and maize.展开更多
基金supported by the National Natural Science Foundation of China(31971525)National Key Research and Development Program of China(2024YFD1701100)Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSGLCA-202302).
文摘Arsenic(As)contamination poses a significant global environmental and health concern.Crayfish shell biochar(CSBC)has shown considerable potential for remediating As-contaminated soil.However,the effect of CSBC on As mobility in acid and alkaline aerobic soils,and its underlying mechanism remains unclear.This study investigated the variation in As availability,dissolved organic matter(DOM),microbial community,and As metabolism genes in CSBCamended soil.Results indicated that CSBC application decreased the available As content in alkaline soil(4.5-9.9%),but increased it in acid soil(19.6-26.8%).The increase in soil pH and DOM humification degree,along with the decrease in DOM molecular weight,contributed to enhanced As mobility in CSBC-amended acid soil.Additionally,CSBC application stimulated microbial membrane transport and signal transport function in acid soil.Furthermore,it increased the relative abundance of Bradyrhizobium,Sphingomonas,Streptomyces,and Ktedonobacter,which harbor As(V)reduction(arsC and arrB)and As(III)efflux(ACR3)genes,thereby promoting As mobility in acid soil.In alkaline soil,the CSBC provided additional bonding sites for As to mitigate its environmental risk.This study provides new insights into the critical role of biochar in influencing As fate in aerobic soil.
基金supported by the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSGLCA-202302)the National Natural Science Foundation of China(31971525)
文摘Background Cadmium(Cd)pollution in agricultural soils has become a priority environmental concern globally.A reasonable application of passivators is critical to address the problem.In this study,we examined the remediation effects of rice husk biochar(r BC)and sepiolite(Sep)as single and combined(r BC+Sep)treatments on Cd pollution in a weakly alkaline soil using three maize cultivars(Liyu 16,Zhengdan 958,and Sanbei 218)as test crops.We also explained the mechanisms involved in the remediation effects.Results The pseudo-second-order kinetic equation and Langmuir model could well describe the adsorption process of r BC+Sep for Cd^(2+).Compared with the control treatment(CK),soil available Cd concentration decreased by 29.51–36.34%under r BC+Sep treatment(p<0.05)and the Cd concentrations in maize grains of Liyu 16,Zhengdan 958,and Sanbei 218 decreased by 38.08–47.85%,37.25–45.61%,and 33.96–46.15%,respectively(p<0.05).Following passivation treatment,soil available Cd concentration decreased and gradually changed from the exchangeable and carbonate binding forms to the Fe/Mn oxide and residual forms.The bioconcentration factors of Liyu 16(0.05–0.09)and Sanbei 218(0.05–0.09)were lower than those of Zhengdan 958(0.07–0.13).In addition,r BC+Sep treatment increased soil p H and soil electrical conductivity,but the differences were not significant(p>0.05).Conclusions The application of 0.2%r BC+0.5%Sep composite passivation material to weakly alkaline Cd-contaminated soil can effectively reduce the Cd concentration of soil and maize.
