为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference,BCR)形态。...为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference,BCR)形态。结果表明:稻米Cd质量比为0.01~0.51 mg/kg,土壤Cd质量比为0.17~3.15 mg/kg,稻米Cd富集系数为0.04~1.42;土壤Cd主要以弱酸态(40.5%)和还原态(37.1%)存在,二乙烯三胺五乙酸(diethylenetriaminepentaacetic acid,DTPA)浸提土壤Cd能力最强(15.6%);基于w(CaCl_(2)-Cd)构建的三次函数建立的回归模型可解释稻米Cd 57.4%方差,w(CaCl_(2)-Cd)可以作为表征水稻土壤Cd生物有效性的指标,基于水稻土壤Cd生物有效性可提高污染风险评价的科学性。展开更多
Graphene oxide(GO),a carbon nanomaterial that is widely used in the environment and other industries,may pose potential risks to ecosystems,especially the soil ecosystem.Some soils in Northeast China are frequently po...Graphene oxide(GO),a carbon nanomaterial that is widely used in the environment and other industries,may pose potential risks to ecosystems,especially the soil ecosystem.Some soils in Northeast China are frequently polluted with cadmium(Cd) metal.However,there is no study on the influence of GO on the Cd-contaminated soil microbial community and soil chemical properties.In this study,Cd(100 mg kg^(-1))-polluted soils were treated with different concentrations of GO(0,25,50,150,250,and 500 mg L^(-1),expressed as T1,T2,T3,T4,T5,and T6,respectively) for 40 days.The treatment without Cd pollution and GO served as the control(CK).Then,we investigated the influence of the GO concentrations on the bacterial community and chemical properties of Cd-polluted Haplic Cambisols,the zonal soil in Northeast China.After GO addition,the richness and diversity indexes of the bacterial community in Cd-contaminated Haplic Cambisols initially increased by 0.05-33.92% at 25 mg L^(-1),then decreased by0.07-2.37% at 50 mg L^(-1),and then increased by 0.01-24.37%within 500 mg L^(-1) again.The species and abundance of bacteria varied with GO concentration,and GO significantly increased bacterial growth at 25 and 250 mg L^(-1).GO treatments influenced the bacterial community structure,and the order of similarity of the bacterial community structure was as follows:T4=T5> T1=T6> T2> T3> CK.Proteobacteria and Acidobacteria were the dominant bacteria,accounting for 36.0% and 26.2%,respectively,of soil bacteria.Different GO treatments also significantly affected the metabolic function of bacteria and further influenced the diversity of the bacterial community structure by affecting several key soil chemical properties:soil pH,organic matter and available potassium,phosphorus,and cadmium.Our results provide a theoretical basis for scientific and comprehensive evaluation of the environmental impacts of GO on the zonal forest soils of Northeast China.展开更多
Clay minerals,phosphates,alkaline materials,organic materials are common improvers in the management of Cd polluted soil. This paper systematically summarized types of common soil improvers and their passivation mecha...Clay minerals,phosphates,alkaline materials,organic materials are common improvers in the management of Cd polluted soil. This paper systematically summarized types of common soil improvers and their passivation mechanism of Cd in soil. It reviewed advances in researches of soil improvers. Besides,it introduced major problems in four common passivating agents for management of Cd polluted soil. Finally,according to different mechanism characteristics of passivating agents,it came up with some recommendations.展开更多
There is limited information on the release behavior of heavy metals from natural soils by organic acids. Thus,cadmium release,due to two organic acids (tartrate and citrate) that are common in the rhizosphere,from so...There is limited information on the release behavior of heavy metals from natural soils by organic acids. Thus,cadmium release,due to two organic acids (tartrate and citrate) that are common in the rhizosphere,from soils polluted by metal smelters or tailings and soils artificially contaminated by adding Cd were analyzed. The presence of tartrate or citrate at a low concentration (≤6mmol L-1 for tartrate and ≤0.5 mmol L-1 for citrate) inhibited Cd release,whereas the presence of organic acids in high concentrations (≥2 mmol L-1 for citrate and ≥15 mmol L-1 for tartrate)apparently promoted Cd release. Under the same conditions,the Cd release in naturally polluted soils was less than that of artificially contaminated soils. Additionally,as the initial pH rose from 2 to 8 in the presence of citrate,a sequential valley and then peak appeared in the Cd release curve,while in the presence of tartrate the Cd release steadily decreased.In addition,Cd release was clearly enhanced as the electrolyte concentration of KNO3 or KC1 increased in the presence of 2 mmol L-1 tartrate. Moreover,a higher desorption of Cd was shown with the KC1 electrolyte compared to KNO3 for the same concentration levels. This implied that the bioavailability of heavy metals could be promoted with the addition of suitable types and concentrations of organic acids as well as reasonable field conditions.展开更多
A pot experiment was carried out to study the effects of two amendments, lime and calcium magnesium phosphate, on the growth and Cd, Pb, Zn, Cu, Mn, Fe, N, P and K uptake of pakchoi (Brassica chinensis)in a Cd, Pb and...A pot experiment was carried out to study the effects of two amendments, lime and calcium magnesium phosphate, on the growth and Cd, Pb, Zn, Cu, Mn, Fe, N, P and K uptake of pakchoi (Brassica chinensis)in a Cd, Pb and Zn polluted acid soil in the southern part of China. The growth of pakchoi was apparently improved by lime and calcium magnesium phosphate application, the uptake of Cd, Pb, Cu and Zn by pakchoi was significantly depressed and the symptom caused by heavy metals pollution was eliminated.Meanwhile, the absorption of N, K and Mn was also inhibited by these amendments. Soil pH was the main factor controlling the uptake of the heavy metals by pakchoi. This suggests that lime and calcium magnesium phosphate could be used as effective amendments for eliminating the toxicity of heavy metals to the vegetable and inhibiting their absorption by the crop.展开更多
Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils...Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils,vegetables and paddy rice were investigated,and potential non-carcinogenic and carcinogenic health risks exposure to Cd were estimated at six villages around the Dabaoshan Mine,South China.A total of 87 soil samples were found to exceed the China's maximum permission level(MPL)for Cd,while the highest value of 4.42 mg/kg was found near irrigation ditch associated with Hengshi River in Xinyi(XY)Village.Cd contents in vegetables and rice exceeded the maximum permissible concentration by more than five times in every village.Cadmium accumulation in plants is in the order of celery>lactuca sativa L>Chinese cabbage>Romaine lettuce>asparagus lettuce>mustard>cabbage mustard>cabbage.The mean hazard quotient(HQ)of all villages is in the range of [5.29,25.75],and the mean values of cancer risk for investigated areas are more than 10 times greater than the USEPA(2009)threshold limit value of 10-4.Moreover,human non-carcinogenic and carcinogenic risks are mainly attributable to paddy rice intake,followed by vegetables intake,soil ingestion,inhalation,and dermal contact.The results indicate that Cd has a huge potential risk on human health for the local residents.展开更多
Effects of cadmium(Cd) on microbial biomass,activity and community diversity were assessed in a representative variable charge soil(Typic Aquult) using an incubation study.Cadmium was added as Cd(NO3)2 to reach a conc...Effects of cadmium(Cd) on microbial biomass,activity and community diversity were assessed in a representative variable charge soil(Typic Aquult) using an incubation study.Cadmium was added as Cd(NO3)2 to reach a concentration range of 0~16 mg Cd/kg soil.Soil extractable Cd generally increased with Cd loading rate,but decreased with incubation time.Soil microbial biomass was enhanced at low Cd levels(0.5~1 mg/kg),but was inhibited consistently with increasing Cd rate.The ratio of microbial biomass C/N varied with Cd treatment levels,decreasing at low Cd rate(<0.7 mg/kg available Cd),but increasing progressively with Cd loading.Soil respiration was restrained at low Cd loading(<1 mg/kg),and enhanced at higher Cd levels.Soil microbial metabolic quotient(MMQ) was generally greater at high Cd loading(1~16 mg/kg).However,the MMQ is also affected by other factors.Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates.Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids(PLFAs) for Gram-negative bacteria and actinomycetes,while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination.展开更多
One purpose of this research is to present accumulation of cadmium (Cd) and copper (Cu) by female Oxya chinensis (Orthopera: Acridoidea) in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar...One purpose of this research is to present accumulation of cadmium (Cd) and copper (Cu) by female Oxya chinensis (Orthopera: Acridoidea) in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar nymphs of O. chinensis had been fed on wheat (Triticurn aestivum) seedlings contaminated with Cd and Cu for one month. In the ecosystem, the Cd concentration in wheat seedlings rose greatly with the increasing of Cd in the soil, but the Cu concentration in wheat seedlings was not found elevated. There was a highly significant difference(P〈0.05) in Cd concentrations of wheat seedlings and not any significant difference(P〉0.05) in Cu concentrations of wheat seedlings. The Cd and Cu concentration in different body part-head, thorax, abdomen, and hind femur, varied under different Cd concentrations in soil. There were significant differences (P〈0.05) in the four parts of Cd and Cu accumulations with all treatments. The order of Cd accumulation was thorax 〉abdomen 〉head 〉hind femur and the Cu was abdomen 〉thorax 〉 head〉hind femur. The results indicated that Cd and Cu were accumulated from the soil to grasshoppers through the plant; that is to say, Cd and Cu in environment could be transported to animal or human via food chain.展开更多
Heavy metal contamination of soils,derived from sewage irrigation,mining and inappropriate utilization of various agrochemicals and pesticides,and so on,has been of wide concern in the last several decades.The Shenyan...Heavy metal contamination of soils,derived from sewage irrigation,mining and inappropriate utilization of various agrochemicals and pesticides,and so on,has been of wide concern in the last several decades.The Shenyang Zhangshi Irrigation Area(SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years.This study investigated the spatial distribution and temporal variation of soil cadmium(Cd) and copper(Cu) contamination in the SZIA.The soil samples were collected from the SZIA in 1990 and 2004;Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods.The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils.The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil(LSGSS) in China,and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990.The contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in 1992.The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil,but obviously decresed in subsoil.The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation.The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils.展开更多
The DNA sequence diversities for microbial communities in soils contaminated by heavy metal (HM) Cadmium (Cd) and polycyclic aromatic hydrocarbon (PAH) phenanthrene were evaluated by Random Amplified Polymorphic DNA (...The DNA sequence diversities for microbial communities in soils contaminated by heavy metal (HM) Cadmium (Cd) and polycyclic aromatic hydrocarbon (PAH) phenanthrene were evaluated by Random Amplified Polymorphic DNA (RAPD) analysis in pot and laboratory experiments. Fourteen random primers were used to amplify RAPDs from microbial community DNAs in four soils contaminated by HM or/and PAH. The products of 14 primers were separated in gel and generated 212 reliable fragments, of which 203 were polymorphic. The numbers of microorganisms (fungi, bacteria and actinomycetes) were also analyzed. The results showed that the total number of microorganisms in the soil polluted by Cd was lowest among the soils, about 67.4 % lower than the soil without pollution, especially the number of bacterial, about 73.8 %. In contrast, there was the highest number of microorganisms in the soil polluted by phenanthrene, about 180 % more than those in the control without pollution, especially the number of actinomycete, about 19 times of control. The number of microorganism of soil polluted by Cd + phenanthrene was fallen between Cd and phenanthrene, about 19.5 % lower than control. The number of fungi showed no significant differences among soils. However, increases in DNA sequence diversity were observed in all contaminated soil samples. The effects were stronger in the case of soil contaminated with PAH and HM than those in soils amended with HM or PAH, separately. The soil with Cd and phenanthrene had the highest richness, modified richness and Shannon-Weaver index. These results showed that HM or/and PAH might result in some changes for soil microbe’s DNA itself, such as sequence breakage or insertion and genomic rearrangement. The RAPD marker technique combined with traditional methods appears to be an effective approach for studying the combined effects of HM and PAH on DNA sequence diversity of soil microbial community.展开更多
文摘为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference,BCR)形态。结果表明:稻米Cd质量比为0.01~0.51 mg/kg,土壤Cd质量比为0.17~3.15 mg/kg,稻米Cd富集系数为0.04~1.42;土壤Cd主要以弱酸态(40.5%)和还原态(37.1%)存在,二乙烯三胺五乙酸(diethylenetriaminepentaacetic acid,DTPA)浸提土壤Cd能力最强(15.6%);基于w(CaCl_(2)-Cd)构建的三次函数建立的回归模型可解释稻米Cd 57.4%方差,w(CaCl_(2)-Cd)可以作为表征水稻土壤Cd生物有效性的指标,基于水稻土壤Cd生物有效性可提高污染风险评价的科学性。
基金supported financially by the National Natural Science Foundation of China (31370613)the Fundamental Research Funds for the Central Universities(2572019CP15)。
文摘Graphene oxide(GO),a carbon nanomaterial that is widely used in the environment and other industries,may pose potential risks to ecosystems,especially the soil ecosystem.Some soils in Northeast China are frequently polluted with cadmium(Cd) metal.However,there is no study on the influence of GO on the Cd-contaminated soil microbial community and soil chemical properties.In this study,Cd(100 mg kg^(-1))-polluted soils were treated with different concentrations of GO(0,25,50,150,250,and 500 mg L^(-1),expressed as T1,T2,T3,T4,T5,and T6,respectively) for 40 days.The treatment without Cd pollution and GO served as the control(CK).Then,we investigated the influence of the GO concentrations on the bacterial community and chemical properties of Cd-polluted Haplic Cambisols,the zonal soil in Northeast China.After GO addition,the richness and diversity indexes of the bacterial community in Cd-contaminated Haplic Cambisols initially increased by 0.05-33.92% at 25 mg L^(-1),then decreased by0.07-2.37% at 50 mg L^(-1),and then increased by 0.01-24.37%within 500 mg L^(-1) again.The species and abundance of bacteria varied with GO concentration,and GO significantly increased bacterial growth at 25 and 250 mg L^(-1).GO treatments influenced the bacterial community structure,and the order of similarity of the bacterial community structure was as follows:T4=T5> T1=T6> T2> T3> CK.Proteobacteria and Acidobacteria were the dominant bacteria,accounting for 36.0% and 26.2%,respectively,of soil bacteria.Different GO treatments also significantly affected the metabolic function of bacteria and further influenced the diversity of the bacterial community structure by affecting several key soil chemical properties:soil pH,organic matter and available potassium,phosphorus,and cadmium.Our results provide a theoretical basis for scientific and comprehensive evaluation of the environmental impacts of GO on the zonal forest soils of Northeast China.
基金Supported by National Key Research and Development Program(2016YED0800705-01)Key Research and Development Program of Guangxi(Gui Ke AB16380084)+2 种基金Key Agricultural Science and Technology Program of Guangxi(201528,201604)Scientific Research and Technological Development Program Project of Nanning City(20162105)Scientific Development Fund Project of Guangxi Academy of Agricultural Sciences(Gui Nong Ke2017JM06,2017JM07)
文摘Clay minerals,phosphates,alkaline materials,organic materials are common improvers in the management of Cd polluted soil. This paper systematically summarized types of common soil improvers and their passivation mechanism of Cd in soil. It reviewed advances in researches of soil improvers. Besides,it introduced major problems in four common passivating agents for management of Cd polluted soil. Finally,according to different mechanism characteristics of passivating agents,it came up with some recommendations.
基金Project supported by the National Key Basic Research Support Foundation of China (No. 2002CB410804) and the National Natural Science Foundation (No. 40201026).
文摘There is limited information on the release behavior of heavy metals from natural soils by organic acids. Thus,cadmium release,due to two organic acids (tartrate and citrate) that are common in the rhizosphere,from soils polluted by metal smelters or tailings and soils artificially contaminated by adding Cd were analyzed. The presence of tartrate or citrate at a low concentration (≤6mmol L-1 for tartrate and ≤0.5 mmol L-1 for citrate) inhibited Cd release,whereas the presence of organic acids in high concentrations (≥2 mmol L-1 for citrate and ≥15 mmol L-1 for tartrate)apparently promoted Cd release. Under the same conditions,the Cd release in naturally polluted soils was less than that of artificially contaminated soils. Additionally,as the initial pH rose from 2 to 8 in the presence of citrate,a sequential valley and then peak appeared in the Cd release curve,while in the presence of tartrate the Cd release steadily decreased.In addition,Cd release was clearly enhanced as the electrolyte concentration of KNO3 or KC1 increased in the presence of 2 mmol L-1 tartrate. Moreover,a higher desorption of Cd was shown with the KC1 electrolyte compared to KNO3 for the same concentration levels. This implied that the bioavailability of heavy metals could be promoted with the addition of suitable types and concentrations of organic acids as well as reasonable field conditions.
基金the National Natural Science Foundation of China(No.49671048) the Education Department of Fujian Province,China(No.K98025).
文摘A pot experiment was carried out to study the effects of two amendments, lime and calcium magnesium phosphate, on the growth and Cd, Pb, Zn, Cu, Mn, Fe, N, P and K uptake of pakchoi (Brassica chinensis)in a Cd, Pb and Zn polluted acid soil in the southern part of China. The growth of pakchoi was apparently improved by lime and calcium magnesium phosphate application, the uptake of Cd, Pb, Cu and Zn by pakchoi was significantly depressed and the symptom caused by heavy metals pollution was eliminated.Meanwhile, the absorption of N, K and Mn was also inhibited by these amendments. Soil pH was the main factor controlling the uptake of the heavy metals by pakchoi. This suggests that lime and calcium magnesium phosphate could be used as effective amendments for eliminating the toxicity of heavy metals to the vegetable and inhibiting their absorption by the crop.
基金Project(51204074)supported by the National Natural Science Foundation of ChinaProjects(2010009017,201209048,ZX021-201106-031)supported by the National Environmental Protection Public Welfare Industry Targeted Research Fund,China
文摘Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils,vegetables and paddy rice were investigated,and potential non-carcinogenic and carcinogenic health risks exposure to Cd were estimated at six villages around the Dabaoshan Mine,South China.A total of 87 soil samples were found to exceed the China's maximum permission level(MPL)for Cd,while the highest value of 4.42 mg/kg was found near irrigation ditch associated with Hengshi River in Xinyi(XY)Village.Cd contents in vegetables and rice exceeded the maximum permissible concentration by more than five times in every village.Cadmium accumulation in plants is in the order of celery>lactuca sativa L>Chinese cabbage>Romaine lettuce>asparagus lettuce>mustard>cabbage mustard>cabbage.The mean hazard quotient(HQ)of all villages is in the range of [5.29,25.75],and the mean values of cancer risk for investigated areas are more than 10 times greater than the USEPA(2009)threshold limit value of 10-4.Moreover,human non-carcinogenic and carcinogenic risks are mainly attributable to paddy rice intake,followed by vegetables intake,soil ingestion,inhalation,and dermal contact.The results indicate that Cd has a huge potential risk on human health for the local residents.
基金Project supported by the National Basic Research Program (973) of China (No. 2002CB410804)the National Natural Science Founda-tion of China (No. 20577044)the Program for Changjiang Scholars and Innovative Research Team in Higher Education,China
文摘Effects of cadmium(Cd) on microbial biomass,activity and community diversity were assessed in a representative variable charge soil(Typic Aquult) using an incubation study.Cadmium was added as Cd(NO3)2 to reach a concentration range of 0~16 mg Cd/kg soil.Soil extractable Cd generally increased with Cd loading rate,but decreased with incubation time.Soil microbial biomass was enhanced at low Cd levels(0.5~1 mg/kg),but was inhibited consistently with increasing Cd rate.The ratio of microbial biomass C/N varied with Cd treatment levels,decreasing at low Cd rate(<0.7 mg/kg available Cd),but increasing progressively with Cd loading.Soil respiration was restrained at low Cd loading(<1 mg/kg),and enhanced at higher Cd levels.Soil microbial metabolic quotient(MMQ) was generally greater at high Cd loading(1~16 mg/kg).However,the MMQ is also affected by other factors.Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates.Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids(PLFAs) for Gram-negative bacteria and actinomycetes,while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination.
文摘One purpose of this research is to present accumulation of cadmium (Cd) and copper (Cu) by female Oxya chinensis (Orthopera: Acridoidea) in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar nymphs of O. chinensis had been fed on wheat (Triticurn aestivum) seedlings contaminated with Cd and Cu for one month. In the ecosystem, the Cd concentration in wheat seedlings rose greatly with the increasing of Cd in the soil, but the Cu concentration in wheat seedlings was not found elevated. There was a highly significant difference(P〈0.05) in Cd concentrations of wheat seedlings and not any significant difference(P〉0.05) in Cu concentrations of wheat seedlings. The Cd and Cu concentration in different body part-head, thorax, abdomen, and hind femur, varied under different Cd concentrations in soil. There were significant differences (P〈0.05) in the four parts of Cd and Cu accumulations with all treatments. The order of Cd accumulation was thorax 〉abdomen 〉head 〉hind femur and the Cu was abdomen 〉thorax 〉 head〉hind femur. The results indicated that Cd and Cu were accumulated from the soil to grasshoppers through the plant; that is to say, Cd and Cu in environment could be transported to animal or human via food chain.
基金Project supported by the Item of Shenyang Xi River Geochemistry Evaluation,China
文摘Heavy metal contamination of soils,derived from sewage irrigation,mining and inappropriate utilization of various agrochemicals and pesticides,and so on,has been of wide concern in the last several decades.The Shenyang Zhangshi Irrigation Area(SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years.This study investigated the spatial distribution and temporal variation of soil cadmium(Cd) and copper(Cu) contamination in the SZIA.The soil samples were collected from the SZIA in 1990 and 2004;Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods.The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils.The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil(LSGSS) in China,and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990.The contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in 1992.The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil,but obviously decresed in subsoil.The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation.The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils.
基金Item supported by major state basic re-search development program ( 973 ) of China ( No.2004CB18503)national natural science foundation of China(No. 20337010) key program of basic research of Shanghai(No.04JC14051)
文摘The DNA sequence diversities for microbial communities in soils contaminated by heavy metal (HM) Cadmium (Cd) and polycyclic aromatic hydrocarbon (PAH) phenanthrene were evaluated by Random Amplified Polymorphic DNA (RAPD) analysis in pot and laboratory experiments. Fourteen random primers were used to amplify RAPDs from microbial community DNAs in four soils contaminated by HM or/and PAH. The products of 14 primers were separated in gel and generated 212 reliable fragments, of which 203 were polymorphic. The numbers of microorganisms (fungi, bacteria and actinomycetes) were also analyzed. The results showed that the total number of microorganisms in the soil polluted by Cd was lowest among the soils, about 67.4 % lower than the soil without pollution, especially the number of bacterial, about 73.8 %. In contrast, there was the highest number of microorganisms in the soil polluted by phenanthrene, about 180 % more than those in the control without pollution, especially the number of actinomycete, about 19 times of control. The number of microorganism of soil polluted by Cd + phenanthrene was fallen between Cd and phenanthrene, about 19.5 % lower than control. The number of fungi showed no significant differences among soils. However, increases in DNA sequence diversity were observed in all contaminated soil samples. The effects were stronger in the case of soil contaminated with PAH and HM than those in soils amended with HM or PAH, separately. The soil with Cd and phenanthrene had the highest richness, modified richness and Shannon-Weaver index. These results showed that HM or/and PAH might result in some changes for soil microbe’s DNA itself, such as sequence breakage or insertion and genomic rearrangement. The RAPD marker technique combined with traditional methods appears to be an effective approach for studying the combined effects of HM and PAH on DNA sequence diversity of soil microbial community.