老化生物炭对小白菜积累重金属的影响
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摘要
[目的]生物炭对土壤中的重金属具有较强的吸附固定能力,能够降低重金属的植物可累积性。生物炭进入土壤后,在各种生物及非生物氧化作用下发生老化,而老化后的生物炭对土壤重金属的有效性以及对植物累积重金属的影响等方面的研究较少。[方法]本研究以氧化剂-干湿-冻融交替循环的方法对新鲜制备的生物炭(原始炭)进行老化,比较生物炭老化前后的阳离子交换量(CEC)、元素含量和表面官能团等参数的变化,并通过盆栽实验,探究生物炭老化前后对小白菜积累重金属(Pb、Cu、Cd)的影响。[结果]结果显示:与原始炭相比,老化作用能够增加生物炭的CEC、O/C值以及生物炭表面羟基和羰基的数量。相比未添加炭处理(对照组),老化炭的施用显著增加了土壤pH值和有机质含量(P<0.05)。而老化炭对土壤重金属有效态含量表现为显著降低,且施加量越大,效果越明显。即相比对照,5%老化炭处理下土壤中Pb、Cu、Cd的减少率分别为12.42%、11.67%、11.21%。相应地,老化炭的添加显著降低了小白菜体内重金属累积量(P<0.05),即未添加炭处理中小白菜体内Pb、Cu、Cd的含量分别为24.33 mg·kg~(-1)、28.8mg·kg~(-1)、0.2mg·kg~(-1),而在5%老化炭处理下小白菜体内Pb、Cu、Cd的含量各减少至3.33 mg·kg~(-1)、7.23mg·kg~(-1)、0.03mg·kg~(-1)。[结论]因此,老化生物炭依然能有效降低土壤重金属的生物有效性,说明生物炭对重金属污染土壤的修复具有一定的长期稳定性。
[Objective]Biochar has strong adsorption and fixation capacity to heavy metals in soil,which can reduce the accumulation of heavy metals by plants.Biochar undergoes oxidizing process under various biological and abiotic factors once it is introduced into soil.The oxidizing process makes the biochar aging which changes the physicochemical properties of biochar and thus influence the heavy metals availability in soil and the accumulation of heavy metals in plants,however,the research on this filed was much limited.[Methods]In the present study,the pristine biochar was aged by oxidant-drying/wetting-freeze/thaw alternating cycle method.The cation exchange capacity(CEC),element content and surface functional groups before and after biochar aging was compared.And pot experiment was set to investigate the aging effects on the accumulation of heavy metal(Pb,Cu and Cd)in pakchoi(Brassica chinensis L.).[Results]The results showed that aging increased the CEC,O/C value and the number of hydroxyl and carbonyl groups on the surface of biochar.Compared with the treatment without biochar addition(control group),the application of aged biochar significantly increased soil pH and the organic matter content(P<0.05).However,the bioavailable concentration of heavy metals in soil was significantly reduced by adding aged biochar.And the reducing effect was more obvious with the increasing of biochar application rate,that is,the concentration of Pb,Cu and Cd in soil decreased by 12.42%,11.67%,11.21%for aged biochar with 5% application,respectively,compared to the control.Accordingly,the accumulation of heavy metals in the pakchoi was also significantly reduced by addition of aged biochar(P<0.05).Consequently,the contents of Pb,Cu and Cd in pakchoi without biochar treatment were 24.33 mg·kg~(-1),28.8 mg·kg~(-1),and 0.2 mg·kg~(-1),respectively,whereas those were markedly decreased to 3.33 mg·kg~(-1),7.23 mg·kg~(-1),and 0.03 mg·kg~(-1) under 5%aged biochar treatment.[Conclusion]Therefore,the aged biochar still effectively reduced the bioavailability of heavy metals to plants which is important to evaluate the long-term application of biochar in remediation of heavy metal polluted soil.
[Objective]Biochar has strong adsorption and fixation capacity to heavy metals in soil,which can reduce the accumulation of heavy metals by plants.Biochar undergoes oxidizing process under various biological and abiotic factors once it is introduced into soil.The oxidizing process makes the biochar aging which changes the physicochemical properties of biochar and thus influence the heavy metals availability in soil and the accumulation of heavy metals in plants,however,the research on this filed was much limited.[Methods]In the present study,the pristine biochar was aged by oxidant-drying/wetting-freeze/thaw alternating cycle method.The cation exchange capacity(CEC),element content and surface functional groups before and after biochar aging was compared.And pot experiment was set to investigate the aging effects on the accumulation of heavy metal(Pb,Cu and Cd)in pakchoi(Brassica chinensis L.).[Results]The results showed that aging increased the CEC,O/C value and the number of hydroxyl and carbonyl groups on the surface of biochar.Compared with the treatment without biochar addition(control group),the application of aged biochar significantly increased soil pH and the organic matter content(P<0.05).However,the bioavailable concentration of heavy metals in soil was significantly reduced by adding aged biochar.And the reducing effect was more obvious with the increasing of biochar application rate,that is,the concentration of Pb,Cu and Cd in soil decreased by 12.42%,11.67%,11.21%for aged biochar with 5% application,respectively,compared to the control.Accordingly,the accumulation of heavy metals in the pakchoi was also significantly reduced by addition of aged biochar(P<0.05).Consequently,the contents of Pb,Cu and Cd in pakchoi without biochar treatment were 24.33 mg·kg~(-1),28.8 mg·kg~(-1),and 0.2 mg·kg~(-1),respectively,whereas those were markedly decreased to 3.33 mg·kg~(-1),7.23 mg·kg~(-1),and 0.03 mg·kg~(-1) under 5%aged biochar treatment.[Conclusion]Therefore,the aged biochar still effectively reduced the bioavailability of heavy metals to plants which is important to evaluate the long-term application of biochar in remediation of heavy metal polluted soil.
引文
[1]Chibuike G U,Obiora S C.Heavy metal polluted soils:effect on plants and bioremediation methods[J].Applied and Environmental Soil Science,2014:1-12.
[2]Rehman Z U,Khan S,Shah M T,et al.Transfer of heavy metals from soils to vegetables and associated human health risks at selected sites in pakistan[J].Pedosphere,2018,28(4):666-679.
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[4]Lian F,Xing B.Black carbon(biochar)in water/soil environments:molecular structure,sorption,stability,and potential risk[J].Environmental Science and Technology,2017,51(23):13517-13532.
[5]Uchimiya M,Lima I M,Klasson K T,et al.Contaminant immobilization and nutrient release by biochar soil amendment:roles of natural organic matter[J].Chemosphere,2010,80(8):935-940.
[6]Awad Y M,Blagodatskaya E,Ok Y S,et al.Effects of polyacrylamide,biopolymer,and biochar on decomposition of soil organic matter and plant residues as determined by 14Cand enzyme activities[J].European Journal of Soil Biology,2012,48:1-10.
[7]王玲,贾俊香,张毅,等.生物炭对山西雨养旱地土壤肥力与酶活性的影响[J].山西农业大学学报(自然科学版),2017,37(12):884-889.
[8]Kim H S,Kim K R,Kim H J,et al.Effect of biochar on heavy metal immobilization and uptake by lettuce(Lactuca sativa L.)in agricultural soil[J].Environmental Earth Sciences,2015,74(2):1249-1259.
[9]Paz-Ferreiro J,Lu H,Fu S,et al.Use of phytoremediation and biochar to remediate heavy metal polluted soils:a review[J].Solid Earth,2014,5(1):65-75.
[10]Gonzaga M I S,Mackowiak C,Quintao de Almeida A,et al.Assessing biochar applications and repeated Brassica juncea L.production cycles to remediate Cu contaminated soil[J].Chemosphere,2018,201:278-285.
[11]张艺腾,范禹博,徐笑天,等.鸡粪生物炭对土壤铜和锌形态及植物吸收的影响[J].农业环境科学学报,2018,37(11):2514-2521.
[12]Cheng C H,Lehmann J,Engelhard M H.Natural oxidation of black carbon in soils:changes in molecular form and surface charge along a climosequence[J].Geochimica et Cosmochimica Acta,2008,72(6):1598-1610.
[13]Fang G,Gao J,Liu C,et al.Key role of persistent free radicals in hydrogen peroxide activation by biochar:implications to organic contaminant degradation[J].Environmental Science and Technology,2014,48(3):1902-1910.
[14]Wan S,Hua Z,Sun L,et al.Biosorption of nitroimidazole antibiotics onto chemically modified porous biochar prepared by experimental design:kinetics,thermodynamics,and equilibrium analysis[J].Process Safety and Environmental Protection,2016,104:422-435.
[15]Kumar A,Joseph S,Tsechansky L,et al.Biochar aging in contaminated soil promotes Zn immobilization due to changes in biochar surface structural and chemical properties[J].Science of the Total Environment,2018,626:953-961.
[16]Huff M D,Lee J W.Biochar-surface oxygenation with hydrogen peroxide[J].Journal of Environmental Economics and Management,2016,165:17-21.
[17]Naisse C,Girardin C,Lefevre R,et al.Effect of physical weathering on the carbon sequestration potential of biochars and hydrochars in soil[J].Global Change Biology Bioenergy,2015,7(3):488-496.
[18]Khan S,Waqas M,Ding F,et al.The influence of various biochars on the bioaccessibility and bioaccumulation of PAHs and potentially toxic elements to turnips(Brassica rapaL.)[J].Journal of Hazardous Materials,2015,300:243-253.
[19]Gul S,Whalen J K,Thomas B W,et al.Physico-chemical properties and microbial responses in biochar-amended soils:mechanisms and future directions[J].Agriculture,Ecosystems and Environment,2015,206:46-59.
[20]Roosa S,Wattiez R,Prygiel E,et al.Bacterial metal resistance genes and metal bioavailability in contaminated sediments[J].Environmental Pollution,2014,189:143-151.
[21]Zhao R,Coles N,Kong Z,et al.Effects of aged and fresh biochars on soil acidity under different incubation conditions[J].Soil and Tillage Research,2015,146:133-138.
[22]Rajapaksha A U,Vithanage M,Lim J E,et al.Invasive plant-derived biochar inhibits sulfamethazine uptake by lettuce in soil[J].Chemosphere,2014,111:500-504.
[23]Xu Z,Xu X,Tsang D C W,et al.Contrasting impacts of pre-and post-application aging of biochar on the immobilization of Cd in contaminated soils[J].Environmental Pollution,2018,242:1362-1370.
[24]Uchimiya M,Chang S,Klasson K T.Screening biochars for heavy metal retention in soil:role of oxygen functional groups[J].Journal of Hazardous Materials,2011,190(1-3):432-441.
[25]文方园,陈建,田路萍,等.过氧化氢氧化对生物炭表面性质的改变及其对双酚A吸附的影响[J].生态毒理学报,2016,11(2):628-635.
[26]Ren X,Yuan X,Sun H.Dynamic changes in atrazine and phenanthrene sorption behaviors during the aging of biochar in soils[J].Environmental Science and Pollution Research,2018,25(1):81-90.
[27]唐伟,郭悦,沈小明,等.模拟生物质炭老化前后对菲吸持作用的影响[J].环境化学,2014,33(6):923-929.
[28]Lucchini P,Quilliam R S,DeLuca T H,et al.Does biochar application alter heavy metal dynamics in agricultural soil?[J].Agriculture,Ecosystems and Environment,2014,184:149-157.
[29]Park J H,Choppala G K,Bolan N S,et al.Biochar reduces the bioavailability and phytotoxicity of heavy metals[J].Plant Soil,2011,348(1-2):439-451.
[30]Igalavithana A D,Lee S E,Lee Y H,et al.Heavy metal immobilization and microbial community abundance by vegetable waste and pine cone biochar of agricultural soils[J].Chemosphere,2017,174:593-603.
[31]Zeng G,Wu H,Liang J,et al.Efficiency of biochar and compost(or composting)combined amendments for reducing Cd,Cu,Zn and Pb bioavailability,mobility and ecological risk in wetland soil[J].Royal Society of Chemistry,2015,5(44):34541-34548.
[32]Namgay T,Singh B,Pal Singh B P.Influence of biochar application to soil on the availability of As,Cd,Cu,Pb,and Zn to maize(Zea mays L.)[J].Australian Journal of Soil Research,2010,48(7):638-647.
[33]Mohamed B A,Ellis N,Kim C S,et al.The role of tailored biochar in increasing plant growth,and reducing bioavailability,phytotoxicity,and uptake of heavy metals in contaminated soil[J].Environmental Pollution,2017,230:329-338.
[2]Rehman Z U,Khan S,Shah M T,et al.Transfer of heavy metals from soils to vegetables and associated human health risks at selected sites in pakistan[J].Pedosphere,2018,28(4):666-679.
[3]Chang C Y,Yu H Y,Chen J J,et al.Accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the Pearl River Delta,South China[J].Environmental Monitoring and Assessment,2014,186(3):1547-1560.
[4]Lian F,Xing B.Black carbon(biochar)in water/soil environments:molecular structure,sorption,stability,and potential risk[J].Environmental Science and Technology,2017,51(23):13517-13532.
[5]Uchimiya M,Lima I M,Klasson K T,et al.Contaminant immobilization and nutrient release by biochar soil amendment:roles of natural organic matter[J].Chemosphere,2010,80(8):935-940.
[6]Awad Y M,Blagodatskaya E,Ok Y S,et al.Effects of polyacrylamide,biopolymer,and biochar on decomposition of soil organic matter and plant residues as determined by 14Cand enzyme activities[J].European Journal of Soil Biology,2012,48:1-10.
[7]王玲,贾俊香,张毅,等.生物炭对山西雨养旱地土壤肥力与酶活性的影响[J].山西农业大学学报(自然科学版),2017,37(12):884-889.
[8]Kim H S,Kim K R,Kim H J,et al.Effect of biochar on heavy metal immobilization and uptake by lettuce(Lactuca sativa L.)in agricultural soil[J].Environmental Earth Sciences,2015,74(2):1249-1259.
[9]Paz-Ferreiro J,Lu H,Fu S,et al.Use of phytoremediation and biochar to remediate heavy metal polluted soils:a review[J].Solid Earth,2014,5(1):65-75.
[10]Gonzaga M I S,Mackowiak C,Quintao de Almeida A,et al.Assessing biochar applications and repeated Brassica juncea L.production cycles to remediate Cu contaminated soil[J].Chemosphere,2018,201:278-285.
[11]张艺腾,范禹博,徐笑天,等.鸡粪生物炭对土壤铜和锌形态及植物吸收的影响[J].农业环境科学学报,2018,37(11):2514-2521.
[12]Cheng C H,Lehmann J,Engelhard M H.Natural oxidation of black carbon in soils:changes in molecular form and surface charge along a climosequence[J].Geochimica et Cosmochimica Acta,2008,72(6):1598-1610.
[13]Fang G,Gao J,Liu C,et al.Key role of persistent free radicals in hydrogen peroxide activation by biochar:implications to organic contaminant degradation[J].Environmental Science and Technology,2014,48(3):1902-1910.
[14]Wan S,Hua Z,Sun L,et al.Biosorption of nitroimidazole antibiotics onto chemically modified porous biochar prepared by experimental design:kinetics,thermodynamics,and equilibrium analysis[J].Process Safety and Environmental Protection,2016,104:422-435.
[15]Kumar A,Joseph S,Tsechansky L,et al.Biochar aging in contaminated soil promotes Zn immobilization due to changes in biochar surface structural and chemical properties[J].Science of the Total Environment,2018,626:953-961.
[16]Huff M D,Lee J W.Biochar-surface oxygenation with hydrogen peroxide[J].Journal of Environmental Economics and Management,2016,165:17-21.
[17]Naisse C,Girardin C,Lefevre R,et al.Effect of physical weathering on the carbon sequestration potential of biochars and hydrochars in soil[J].Global Change Biology Bioenergy,2015,7(3):488-496.
[18]Khan S,Waqas M,Ding F,et al.The influence of various biochars on the bioaccessibility and bioaccumulation of PAHs and potentially toxic elements to turnips(Brassica rapaL.)[J].Journal of Hazardous Materials,2015,300:243-253.
[19]Gul S,Whalen J K,Thomas B W,et al.Physico-chemical properties and microbial responses in biochar-amended soils:mechanisms and future directions[J].Agriculture,Ecosystems and Environment,2015,206:46-59.
[20]Roosa S,Wattiez R,Prygiel E,et al.Bacterial metal resistance genes and metal bioavailability in contaminated sediments[J].Environmental Pollution,2014,189:143-151.
[21]Zhao R,Coles N,Kong Z,et al.Effects of aged and fresh biochars on soil acidity under different incubation conditions[J].Soil and Tillage Research,2015,146:133-138.
[22]Rajapaksha A U,Vithanage M,Lim J E,et al.Invasive plant-derived biochar inhibits sulfamethazine uptake by lettuce in soil[J].Chemosphere,2014,111:500-504.
[23]Xu Z,Xu X,Tsang D C W,et al.Contrasting impacts of pre-and post-application aging of biochar on the immobilization of Cd in contaminated soils[J].Environmental Pollution,2018,242:1362-1370.
[24]Uchimiya M,Chang S,Klasson K T.Screening biochars for heavy metal retention in soil:role of oxygen functional groups[J].Journal of Hazardous Materials,2011,190(1-3):432-441.
[25]文方园,陈建,田路萍,等.过氧化氢氧化对生物炭表面性质的改变及其对双酚A吸附的影响[J].生态毒理学报,2016,11(2):628-635.
[26]Ren X,Yuan X,Sun H.Dynamic changes in atrazine and phenanthrene sorption behaviors during the aging of biochar in soils[J].Environmental Science and Pollution Research,2018,25(1):81-90.
[27]唐伟,郭悦,沈小明,等.模拟生物质炭老化前后对菲吸持作用的影响[J].环境化学,2014,33(6):923-929.
[28]Lucchini P,Quilliam R S,DeLuca T H,et al.Does biochar application alter heavy metal dynamics in agricultural soil?[J].Agriculture,Ecosystems and Environment,2014,184:149-157.
[29]Park J H,Choppala G K,Bolan N S,et al.Biochar reduces the bioavailability and phytotoxicity of heavy metals[J].Plant Soil,2011,348(1-2):439-451.
[30]Igalavithana A D,Lee S E,Lee Y H,et al.Heavy metal immobilization and microbial community abundance by vegetable waste and pine cone biochar of agricultural soils[J].Chemosphere,2017,174:593-603.
[31]Zeng G,Wu H,Liang J,et al.Efficiency of biochar and compost(or composting)combined amendments for reducing Cd,Cu,Zn and Pb bioavailability,mobility and ecological risk in wetland soil[J].Royal Society of Chemistry,2015,5(44):34541-34548.
[32]Namgay T,Singh B,Pal Singh B P.Influence of biochar application to soil on the availability of As,Cd,Cu,Pb,and Zn to maize(Zea mays L.)[J].Australian Journal of Soil Research,2010,48(7):638-647.
[33]Mohamed B A,Ellis N,Kim C S,et al.The role of tailored biochar in increasing plant growth,and reducing bioavailability,phytotoxicity,and uptake of heavy metals in contaminated soil[J].Environmental Pollution,2017,230:329-338.