Environmental effects of nano remediation engineering of arsenic(As)pollution need to be considered.In this study,the roles of Fe_(2)O_(3)and TiO_(2)nanoparticles(NPs)on the microbial mediated As mobilization from As ...Environmental effects of nano remediation engineering of arsenic(As)pollution need to be considered.In this study,the roles of Fe_(2)O_(3)and TiO_(2)nanoparticles(NPs)on the microbial mediated As mobilization from As contaminated soil were investigated.The addition of Fe_(2)O_(3)and TiO_(2)NPs restrained As(V)release,and stimulated As(Ⅲ)release.As(V)concentration decreased by 94% and 93% after Fe_(2)O_(3)addition,and decreased by 89% and 45% after Ti O_(2)addition compared to the Biotic and Biotic+Acetate(amended with sodium acetate)controls,respectively.The maximum values of As(Ⅲ)were 20.5 and 27.1μg/L at 48 d after Fe_(2)O_(3)and TiO_(2)NPs addition,respectively,and were higher than that in Biotic+Acetate control(12.9μg/L).The released As co-precipitated with Fe in soils in the presence of Fe_(2)O_(3)NPs,but adsorbed on TiO_(2)NPs in the presence of TiO_(2)NPs.Moreover,the addition of NPs amended with sodium acetate as the electron donor clearly promoted As(V)reduction induced by microbes.The NPs addition changed the relative abundance of soil bacterial community,while Proteobacteria(42.8%-70.4%),Planctomycetes(2.6%-14.3%),and Firmicutes(3.5%-25.4%)were the dominant microorganisms in soils.Several potential As/Fe reducing bacteria were related to Pseudomonas,Geobacter,Desulfuromonas,and Thiobacillus.The addition of Fe_(2)O_(3)and TiO_(2)NPs induced to the decrease of arr A gene.The results indicated that the addition of NPs had a negative impact on soil microbial population in a long term.The findings offer a relatively comprehensive assessment of Fe_(2)O_(3)and TiO_(2)NPs effects on As mobilization and soil bacterial communities.展开更多
Iron and nitrate(NO_(3)^(-))are dominant physiologically required nutrients for phytoplankton growth,and iron may also play a key role in the marine nitrogen cycle.In this study,we investigated the temporal and spatia...Iron and nitrate(NO_(3)^(-))are dominant physiologically required nutrients for phytoplankton growth,and iron may also play a key role in the marine nitrogen cycle.In this study,we investigated the temporal and spatial distributions of dissolved iron(DFe)and Fe(Ⅱ)in the surface waters of Jiaozhou Bay(JZB)from April 2 to July 26,2017.High concentrations of DFe and Fe(Ⅱ)predominantly occurred in nearshore and estuarine stations and concentrations were generally higher in April and May.The highest DFe concentration was observed along the coast of Hongdao(51.55 nmol/L)in May,while the lowest concentration was observed in the western coastal region(2.88 nmol/L)in April.The highest and lowest Fe(Ⅱ)concentrations were observed in the Licun estuary(22.42 nmol/L)and outer bay(0.50 nmol/L)in May,respectively.We calculated the proportions of nitrate,nitrite,and ammonium in dissolved inorganic nitrogen(DIN)as well as the ratio of Fe(Ⅱ)to DFe in all four months.The mean Fe(Ⅱ)/DFe ratio was 0.48 in April,0.43 in May,0.69 in June,and 0.32 in July.The mean ratio of NO_(3)^(-)to DIN was 0.78 in April,0.54 in May,0.20 in June,and 0.62 in July.NO_(3)^(-)/DIN continuously decreased in the first three months,while Fe(Ⅱ)/DFe remained high,which suggests that the reduction of iron and nitrate occurred simultaneously in the surface waters of JZB.展开更多
基金supported by the National Natural Science Foundation of China(No.41977283)the Qing Lan Project of Jiangsu Province of China。
文摘Environmental effects of nano remediation engineering of arsenic(As)pollution need to be considered.In this study,the roles of Fe_(2)O_(3)and TiO_(2)nanoparticles(NPs)on the microbial mediated As mobilization from As contaminated soil were investigated.The addition of Fe_(2)O_(3)and TiO_(2)NPs restrained As(V)release,and stimulated As(Ⅲ)release.As(V)concentration decreased by 94% and 93% after Fe_(2)O_(3)addition,and decreased by 89% and 45% after Ti O_(2)addition compared to the Biotic and Biotic+Acetate(amended with sodium acetate)controls,respectively.The maximum values of As(Ⅲ)were 20.5 and 27.1μg/L at 48 d after Fe_(2)O_(3)and TiO_(2)NPs addition,respectively,and were higher than that in Biotic+Acetate control(12.9μg/L).The released As co-precipitated with Fe in soils in the presence of Fe_(2)O_(3)NPs,but adsorbed on TiO_(2)NPs in the presence of TiO_(2)NPs.Moreover,the addition of NPs amended with sodium acetate as the electron donor clearly promoted As(V)reduction induced by microbes.The NPs addition changed the relative abundance of soil bacterial community,while Proteobacteria(42.8%-70.4%),Planctomycetes(2.6%-14.3%),and Firmicutes(3.5%-25.4%)were the dominant microorganisms in soils.Several potential As/Fe reducing bacteria were related to Pseudomonas,Geobacter,Desulfuromonas,and Thiobacillus.The addition of Fe_(2)O_(3)and TiO_(2)NPs induced to the decrease of arr A gene.The results indicated that the addition of NPs had a negative impact on soil microbial population in a long term.The findings offer a relatively comprehensive assessment of Fe_(2)O_(3)and TiO_(2)NPs effects on As mobilization and soil bacterial communities.
基金supported by the National Natural Science Foundation of China(No.41876079)the Open Fund of Key Laboratory of Science and Engineering for Marine Ecology and Environment of State Oceanic Administration(No.MESE-2018-05)。
文摘Iron and nitrate(NO_(3)^(-))are dominant physiologically required nutrients for phytoplankton growth,and iron may also play a key role in the marine nitrogen cycle.In this study,we investigated the temporal and spatial distributions of dissolved iron(DFe)and Fe(Ⅱ)in the surface waters of Jiaozhou Bay(JZB)from April 2 to July 26,2017.High concentrations of DFe and Fe(Ⅱ)predominantly occurred in nearshore and estuarine stations and concentrations were generally higher in April and May.The highest DFe concentration was observed along the coast of Hongdao(51.55 nmol/L)in May,while the lowest concentration was observed in the western coastal region(2.88 nmol/L)in April.The highest and lowest Fe(Ⅱ)concentrations were observed in the Licun estuary(22.42 nmol/L)and outer bay(0.50 nmol/L)in May,respectively.We calculated the proportions of nitrate,nitrite,and ammonium in dissolved inorganic nitrogen(DIN)as well as the ratio of Fe(Ⅱ)to DFe in all four months.The mean Fe(Ⅱ)/DFe ratio was 0.48 in April,0.43 in May,0.69 in June,and 0.32 in July.The mean ratio of NO_(3)^(-)to DIN was 0.78 in April,0.54 in May,0.20 in June,and 0.62 in July.NO_(3)^(-)/DIN continuously decreased in the first three months,while Fe(Ⅱ)/DFe remained high,which suggests that the reduction of iron and nitrate occurred simultaneously in the surface waters of JZB.
