Gold mining is now widely acknowledged as one of the significant sources of soil pollution in developed countries. In developing countries, the sources and levels of soil contamination have not been thoroughly address...Gold mining is now widely acknowledged as one of the significant sources of soil pollution in developed countries. In developing countries, the sources and levels of soil contamination have not been thoroughly addressed. Thus, this study was intended to determine the source of soil pollution and the level of contamination in the active and closed gold mining areas. The research paper presents the pollution load of heavy metals (lead-Pb, chromium-Cr, cadmium-Cd, copper-Cu, arsenic-As, manganese-Mn, and nickel-Ni) in 90 soil samples collected from the studied sites. Multivariate statistical analysis, including Principal Component Analysis (PCA) and Cluster Analysis (CA), coupled with correlation coefficient analysis, was performed to determine the possible sources of pollution in the study areas. The results indicated that Pb, Cr, Cu and Mn come from different sources than Cd, As and Ni. The results obtained from the metal pollution assessment using the Pollution Index (PI) and the Geoaccumulation Index (Igeo) confirmed that soils in the mining areas were contaminated in the range from moderately through strongly to highly contaminated soils. This study verified that soil contamination in the gold mining areas results from natural and anthropogenic processes. The current study findings would enhance our knowledge regarding the soil contamination level in the mining areas and the source of contamination. It is recommended to use PCA, CA, PI and Igeo to assess and monitor the heavy metal contaminated soil in gold mining areas.展开更多
The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific obje...The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific objective is to produce the spatial distribution maps showing the spatial distribution of toxic heavy metals in the study area. Inverse Distance Weighting (IDW), a GIS technique was used to produce dotted maps showing the spatial distribution of heavy metals in neem bark for better visualization of contamination zones and non-contamination zones. The map reveals few hotspot areas showing areas of high concentrations of the heavy metals investigated which were identified in red colours, the following concentration ranges were obtained;As (4.71 - 6.43 mg/kg), Cd (13.9 - 16.84 mg/kg), Cr (46.3 - 60.84 mg/kg), Hg (3.70 - 5.05 mg/kg) and Pb (24.02 - 31.34 mg/kg). These hotspot areas were found close to business outlets, fuel filling and service stations, farm sites where the application of fertilizers and pesticides were persistent coupled with heavy traffic of vehicles and other machinery which was associated with As, Hg, Cd, Pb and Cr been released into the environment thus, suggesting anthropogenic activities controlling the concentration of these heavy metals in the study areas. The cumulative effect of these heavy metals into the barks of neem could pose as danger, because this plant is used as herbs in folk medicine.展开更多
Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of thi...Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.展开更多
Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteris...Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteristics of high environmental adaptation and barren resistance. Some varieties of pteridophyta have ability of excessive absorption and accumulation of heavy metals such as arsenic(As) and antimony(Sb). Besides,pteridophyta have excellent performance in absorbing such heavy metals as cadmium(Cd),lead(Pb),copper(Cu),and nickel(Ni),and rare earth elements. In this paper,a review was made for application,mechanism,and advantages of pteridophyta in remediation of heavy metal contaminated environments,and prospect and possible research fields of pteridophyta in phytoremediation were discussed.展开更多
Laser-induced breakdown spectroscopy(LIBS)can be used for the rapid detection of heavy metal contamination of Tegillarca granosa(T.granosa),but an appropriate classification model needs to be constructed.In the one-cl...Laser-induced breakdown spectroscopy(LIBS)can be used for the rapid detection of heavy metal contamination of Tegillarca granosa(T.granosa),but an appropriate classification model needs to be constructed.In the one-class classification method,only target samples are needed in training process to achieve the recognition of abnormal samples,which is suitable for rapid identification of healthy T.granosa from those contaminated with uncertain heavy metals.The construction of a one-class classification model for heavy metal detection in T.granosa by LIBS has faced the problem of high-dimension and small samples.To solve this problem,a novel one-class classification method was proposed in this study.Here,the principal component scores and the intensity of the residual spectrum were combined as extracted features.Then,a one-class classifier based on Mahalanobis distance using the extracted features was constructed and its threshold was set by leave-one-out crossvalidation.The sensitivity,specificity and accuracy of the proposed method were reached to 1,0.9333 and 0.9667 respectively,which are superior to the previously reported methods.展开更多
Through the use of general sampling and measurement by ^(137)Cs dating,problems regarding the absence of monitoring data can easily be resolved.Further,weighted values need to be determined while Environment Quality C...Through the use of general sampling and measurement by ^(137)Cs dating,problems regarding the absence of monitoring data can easily be resolved.Further,weighted values need to be determined while Environment Quality Comprehensive Index(EQCI)is commonly used as applied in environmental quality comprehensive evaluation.In order to overcome the subjectivity in determining weights,the modified Analytical Hierarchy Process(AHP)method was designed.The modified AHP method involved the following key procedures:First,the parameters y_(i1) and y_(i2) were calculated based on the monitoring data;second,the factors were put in order according to the symbol and value of y_(i1) and y_(i2);third,the continuous odd integers,which represented the importance of factors,were given to factors according to their seating order;and,fourth,the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd integers.Therefore,the weights were completely based on the monitoring data.In the present study,the comprehensive quality of sediments in five sections of Lake Dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history.展开更多
Heavy metal(HM)contamination in soils of greenhouse vegetable production(GVP)systems has drawn increasing attention in terms of food safety.In the present study,64 surface soils were sampled,and the concentrations of ...Heavy metal(HM)contamination in soils of greenhouse vegetable production(GVP)systems has drawn increasing attention in terms of food safety.In the present study,64 surface soils were sampled,and the concentrations of select HMs were determined using atomic absorption spectroscopy.The results showed that the concentrations of cadmium(Cd),lead(Pb),zinc(Zn),copper(Cu),nickel(Ni)and chromium(Cr)in the soils were(0.2±0.2)mg/kg,(26.5±8.4)mg/kg,(101.4±43.2)mg/kg,(29.1±8.6)mg/kg,(24.5±3.3)mg/kg,and(56.5±6.3)mg/kg,and the corresponding accumulation index(AI)values were 2.30,1.10,1.43,1.45,1.07,and 0.97,respectively.The spatial distribution of the HMs suggested that Cd pollution displays a fractionation effect,which may be related to the source of Cd and its mobility.The concentration of Zn was significantly correlated with that of other HMs,implying that a comprehensive interactive effect might occur between Zn and other HMs.Furthermore,the values of the potential ecological risk index(RI)ranged from 41.23 to 185.91,meaning that attention should be paid to HM contamination of GVP soils to ensure food quality and safety.展开更多
As the major water catchment in Hobart city, the River Derwent provides water services to Hobart residents; however, water quality of the River Derwent is becoming unreliable. The aims of this paper are to identify th...As the major water catchment in Hobart city, the River Derwent provides water services to Hobart residents; however, water quality of the River Derwent is becoming unreliable. The aims of this paper are to identify the major water issues in the river and to reveal its impacts on Hobart residents and ecosystem. A methodology of secondary data analysis has been involved; which covers a wide range of existing dissertations. Through all the analysis of data, heavy metals, contaminated sediment and overload nitrogen can be regarded as three main causes of the water pollution. Moreover, the impacts of the water pollution are proved to be significant and perennial. On the basis of the analysis result, water pollution tends to be a tough issue that requires a great amount of time and efforts to deal with.展开更多
Remediation via adsorption process has been proven to be one of the best water treatment technologies globally. Many adsorbents, including agricultural wastes, have been considered for the removal of a variety of poll...Remediation via adsorption process has been proven to be one of the best water treatment technologies globally. Many adsorbents, including agricultural wastes, have been considered for the removal of a variety of pollutants from water. However, most of the studies reported in the literature used metal concentrations below 1000 ppm. It is also known that initial metal concentrations in polluted aqueous solutions, as well as metal and adsorbent type, are some of the factors that affect metal removal. Therefore, this project examined the remediation of water contaminated by 1000 ppm of lead, zinc, copper, magnesium, and calcium ions using wood ash, sodium hydrogen phosphate (dibasic), and sodium carbonate (dibasic). Comparative analysis of the results showed the order of order of metal removal by the adsorbents as: dibasic phosphate (Ca > Cu > Pb > Zn > Mg);dibasic Carbonate (Pb ~ Ca > Zn > Cu > Mg);Wood ash (Mg > Cu > Zn > Pb > Ca). These results suggest that metal and adsorbent type as well as the inherent chemical properties of these metal cations may contribute to the varying binding affinity of the metals to the adsorbent ligand(s) and thus, affect the extent of metal removal. It is equally worthy to note that wood ash more effectively removed hardness metals (Mg and Ca) from water than the inorganic phosphate and carbonate ions.展开更多
Introduction:The development of coal power base(CPB)poses a severe challenge to the soil.We conducted a soil survey in Xilinhot CPB,to evaluate and analyze the pollution characteristics,potential ecological risk,and s...Introduction:The development of coal power base(CPB)poses a severe challenge to the soil.We conducted a soil survey in Xilinhot CPB,to evaluate and analyze the pollution characteristics,potential ecological risk,and sources of six heavy metals(As,Pb,Cu,Zn,Mn,and Cd)in soil by using Geo-accumulation index,revised Nemerow integrated pollution index(RNIPI),and potential ecological risk index(RI).Outcomes/other:The results showed that the pollution of Cd and As were dramatic.The mean of Cd and As were 1.11 mg·kg^(-1) and 25.13 mg·kg^(-1),which were 42.55 times and 4.41 times higher than its local background value.The Geo-accumulation indices showed the contamination degree of Cd was strong and As was moderate,and the status of Cu,Pb,Zn,and Mn were uncontaminated.Xilinhot was strongly contaminated based on its RNIPI and RI values.Discussion:The accumulations of As,Pb,and Cd were mainly associated with anthropogenic sources,including coal mining and combustion,and industrial exhaust emissions.Cu,Mn,and Zn were primarily originated from the parent material(natural sources).Conclusion:This study provides scientific basis and effective countermeasures for the prevention and control of soil pollution in surrounding areas of CPB.展开更多
Heavy metals can exist in soil for a long time and seriously affect soil quality.The coexistence of various heavy metal pollutants leads to biotoxicity and alters the activity of microorganisms.Soil microbial metaboli...Heavy metals can exist in soil for a long time and seriously affect soil quality.The coexistence of various heavy metal pollutants leads to biotoxicity and alters the activity of microorganisms.Soil microbial metabolism plays an important role in nutrient cycling and biochemical processes of soil ecosystem.However,the effects of heavy metal contamination on microbial metabolism in soil are still unclear.This study aims to reveal the responses of microbial metabolic limitation to heavy metals using extracellular enzyme stoichiometry,and further to evaluate the potential impacts of heavy metal pollution on soil nutrient cycle.The results showed that soil microbial metabolism reflected by the ecoenzymatic activities had a significant response to soil heavy metals pollution.The metabolism was limited by soil carbon(C)and phosphorus(P)under varied heavy metal levels,and the increase of heavy metal concentration significantly increased the microbial C limitation,while had no effect on microbial P limitation.Microorganisms may increase the energy investment in metabolism to resist heavy metal stress and thus induce C release.The results suggest that energy metabolism selected by microorganisms in response to long-term heavy metal stress could increase soil C release,which is not conducive to the soil C sequestration.Our study emphasizes that ecoenzymatic stoichiometry could be a promising methodology for evaluating the toxicity of heavy metal pollution and its ecological effects on nutrient cycling.展开更多
Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb...Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb(II),a sensitive and selective electrode was developed using disposable screen-printed carbon electrode(SPE)immobilized with a composite film of reduced graphene oxide/carboxylation multi-walled carbon nanotubes/gold nanoparticle hybrid(RGO-MWNT-AuNP)throughπ-πbind.This highly conductive nano-composite layer,“RGO-MWNT-AuNP,”was characterized by scanning electron microscopy,UV-visible spectrometer,cyclic voltammetry,and electrochemical impedance spectroscopy.Square wave stripping voltammetry was applied to RGO-MWNT-AuNP/SPE to electroplate bismuth film and monitor the Cd(II)and Pb(II)simultaneously.To obtain high current responses,the detecting parameters were optimized.Under optimized conditions,the current responses showed a linear relationship with the concentrations of Cd(II)and Pb(II)in the range from 1.0 to 80.0μg/L with a lower detection limit of 0.7μg/L and 0.3μg/L(S/N=3),respectively.Finally,the prepared electrode was further employed to detect Cd(II)and Pb(II)in soil samples with good results.展开更多
Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years.Heavy metal pollutants may enter the human food chain through agricultural prod...Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years.Heavy metal pollutants may enter the human food chain through agricultural products and groundwater from the polluted soils.Progress has been made in the past decade on phytoremediation,a safe and inexpen-sive approach to remove contaminants from soil and water using plants.However,in most cases,agricultural land in China cannot afford to grow phytoremediator plants instead of growing crops due to food supply for the great population.Therefore,new and effective methods to decrease the risk of heavy metal pollution in crops and to clean the contaminated soils are urgently needed.If we can find crop germplasms(including species and varieties)that accumulate heavy metals in their edible parts,such as the leaves of vegetables or grains of cereals,at a level low enough for safe consumption,then we can grow these selected species or varieties in the lands contaminated or potentially contaminated by heavy metals.If we can find crop germplasms that take in low con-centrations of heavy metals in their edible parts and high con-tent of the metals in their inedible parts,then we can use these selected species or varieties for soil remediation.In this study,the feasibility of the method is assessed by analyzing Pb concentrations in edible and inedible parts of 25 varieties of maize(Zea mays)grown in Pb-contaminated soils.The soil concentrations of Pb were 595.55 mg/kg in the high Pb exposed treatment and 195.55 mg/kg in the control.The results showed that the Pb concentrations in different tissues were in the order of root>shoot≌leaf>grain.Com-pared with the control,the Pb concentrations in root,shoot and leaf were greatly increased under the high Pb exposed condition,while the increments of Pb concentration in grain were relatively lower.Under the high Pb exposure,the grain Pb concentrations of 12 varieties exceeded the maximal Pb limitation of the National Food Hygiene Standard of China(NFHSC)and were inedible.This indicates that there is a high Pb pollution risk for maize grown on Pb polluted sites.Although 22 of the 25 tested varieties had harvest loss under the highly Pb stressed condition,ranging from 0.86%-38.7%of the grain biomass acquired at the control,the average harvest loss of all the tested varieties was only 12.6%,which is usually imperceptible in normal farming practices.There-fore the risk of Pb pollution in maize products cannot be promptly noticed and prevented based only on the outcome of the harvest.However,we did find that 13 of the 25 tested varieties had grain Pb concentrations lower than the limita-tion of the NFHSC.It is,therefore,possible to reduce the pollution risk if these favorable varieties are used for maize production in Pb-contaminated or potentially contaminated agricultural lands.Pb concentrations in vegetative tissues(root,stem and leaf)were significantly correlated with each other,while Pb concentrations of each vegetative tissue were not significant-ly correlated with that of grain.Among the 25 tested varieties,some varieties had Pb concentrations in grain lower than(No.1-3 and No.6)or slightly above(No.4)the limitation of the NFHSC,while their Pb concentrations in the vegetative tissues were among the highest.When excluding these variet-ies,correlations between the Pb concentrations of grain and those of vegetative tissues of the rest of the tested varieties became highly significant.In addition,variety No.1 had the lowest harvest loss under high Pb exposed,and the highest Pb accumulation in vegetative tissues(51.69 mg/plant,12 times as much as in the control).Similar features were also observed in varieties No.2,No.3 and No.6,which absorbed Pb for 36-42 mg/plant under high Pb exposed.We recommend these varieties of maize to be used for bioremediation of Pb contaminated soil and crop production at the same time.展开更多
文摘Gold mining is now widely acknowledged as one of the significant sources of soil pollution in developed countries. In developing countries, the sources and levels of soil contamination have not been thoroughly addressed. Thus, this study was intended to determine the source of soil pollution and the level of contamination in the active and closed gold mining areas. The research paper presents the pollution load of heavy metals (lead-Pb, chromium-Cr, cadmium-Cd, copper-Cu, arsenic-As, manganese-Mn, and nickel-Ni) in 90 soil samples collected from the studied sites. Multivariate statistical analysis, including Principal Component Analysis (PCA) and Cluster Analysis (CA), coupled with correlation coefficient analysis, was performed to determine the possible sources of pollution in the study areas. The results indicated that Pb, Cr, Cu and Mn come from different sources than Cd, As and Ni. The results obtained from the metal pollution assessment using the Pollution Index (PI) and the Geoaccumulation Index (Igeo) confirmed that soils in the mining areas were contaminated in the range from moderately through strongly to highly contaminated soils. This study verified that soil contamination in the gold mining areas results from natural and anthropogenic processes. The current study findings would enhance our knowledge regarding the soil contamination level in the mining areas and the source of contamination. It is recommended to use PCA, CA, PI and Igeo to assess and monitor the heavy metal contaminated soil in gold mining areas.
文摘The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific objective is to produce the spatial distribution maps showing the spatial distribution of toxic heavy metals in the study area. Inverse Distance Weighting (IDW), a GIS technique was used to produce dotted maps showing the spatial distribution of heavy metals in neem bark for better visualization of contamination zones and non-contamination zones. The map reveals few hotspot areas showing areas of high concentrations of the heavy metals investigated which were identified in red colours, the following concentration ranges were obtained;As (4.71 - 6.43 mg/kg), Cd (13.9 - 16.84 mg/kg), Cr (46.3 - 60.84 mg/kg), Hg (3.70 - 5.05 mg/kg) and Pb (24.02 - 31.34 mg/kg). These hotspot areas were found close to business outlets, fuel filling and service stations, farm sites where the application of fertilizers and pesticides were persistent coupled with heavy traffic of vehicles and other machinery which was associated with As, Hg, Cd, Pb and Cr been released into the environment thus, suggesting anthropogenic activities controlling the concentration of these heavy metals in the study areas. The cumulative effect of these heavy metals into the barks of neem could pose as danger, because this plant is used as herbs in folk medicine.
文摘Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.
基金Supported by Scientific Research Foundation of Yunnan Provincial Department of Education(2015Y296)Construction Project of Key Superior and Characteristic Disciplines in Colleges and Universities of Yunnan Province
文摘Pteridophyta are vascular plants(plants with xylem and phloem) that reproduce and disperse via spores. In evolution,pteridophyta lie between bryophyta and spermatophyta. Pteridophyta have unique ecological characteristics of high environmental adaptation and barren resistance. Some varieties of pteridophyta have ability of excessive absorption and accumulation of heavy metals such as arsenic(As) and antimony(Sb). Besides,pteridophyta have excellent performance in absorbing such heavy metals as cadmium(Cd),lead(Pb),copper(Cu),and nickel(Ni),and rare earth elements. In this paper,a review was made for application,mechanism,and advantages of pteridophyta in remediation of heavy metal contaminated environments,and prospect and possible research fields of pteridophyta in phytoremediation were discussed.
基金supported by the Zhejiang Natural Science Foundation of China(Grant No.LY21C200001,LY20F030019)National Natural Science Foundation of China(Grant No.62105245,62071386)+1 种基金Wenzhou Major Scientific and Technological Innovation Projects of China(Grant No.ZG2021029,ZY2021027)the Wenzhou Science and Technology Bureau General Project(Grant No.S2020011).
文摘Laser-induced breakdown spectroscopy(LIBS)can be used for the rapid detection of heavy metal contamination of Tegillarca granosa(T.granosa),but an appropriate classification model needs to be constructed.In the one-class classification method,only target samples are needed in training process to achieve the recognition of abnormal samples,which is suitable for rapid identification of healthy T.granosa from those contaminated with uncertain heavy metals.The construction of a one-class classification model for heavy metal detection in T.granosa by LIBS has faced the problem of high-dimension and small samples.To solve this problem,a novel one-class classification method was proposed in this study.Here,the principal component scores and the intensity of the residual spectrum were combined as extracted features.Then,a one-class classifier based on Mahalanobis distance using the extracted features was constructed and its threshold was set by leave-one-out crossvalidation.The sensitivity,specificity and accuracy of the proposed method were reached to 1,0.9333 and 0.9667 respectively,which are superior to the previously reported methods.
基金This work was supported by the State Key Laboratory of Soil sustainable Agriculture,Institute of Soil Sciences,Chinese Academy of Sciences(Grant No.5022505)the National Natural Science Foundation of China(Grant No.40771186)。
文摘Through the use of general sampling and measurement by ^(137)Cs dating,problems regarding the absence of monitoring data can easily be resolved.Further,weighted values need to be determined while Environment Quality Comprehensive Index(EQCI)is commonly used as applied in environmental quality comprehensive evaluation.In order to overcome the subjectivity in determining weights,the modified Analytical Hierarchy Process(AHP)method was designed.The modified AHP method involved the following key procedures:First,the parameters y_(i1) and y_(i2) were calculated based on the monitoring data;second,the factors were put in order according to the symbol and value of y_(i1) and y_(i2);third,the continuous odd integers,which represented the importance of factors,were given to factors according to their seating order;and,fourth,the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd integers.Therefore,the weights were completely based on the monitoring data.In the present study,the comprehensive quality of sediments in five sections of Lake Dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history.
基金This work was supported by the Science and Technology Research Project of Heilongjiang Province,China(GC12C205)the Scientific Foundation of Heilongjiang Academics of Sciences.
文摘Heavy metal(HM)contamination in soils of greenhouse vegetable production(GVP)systems has drawn increasing attention in terms of food safety.In the present study,64 surface soils were sampled,and the concentrations of select HMs were determined using atomic absorption spectroscopy.The results showed that the concentrations of cadmium(Cd),lead(Pb),zinc(Zn),copper(Cu),nickel(Ni)and chromium(Cr)in the soils were(0.2±0.2)mg/kg,(26.5±8.4)mg/kg,(101.4±43.2)mg/kg,(29.1±8.6)mg/kg,(24.5±3.3)mg/kg,and(56.5±6.3)mg/kg,and the corresponding accumulation index(AI)values were 2.30,1.10,1.43,1.45,1.07,and 0.97,respectively.The spatial distribution of the HMs suggested that Cd pollution displays a fractionation effect,which may be related to the source of Cd and its mobility.The concentration of Zn was significantly correlated with that of other HMs,implying that a comprehensive interactive effect might occur between Zn and other HMs.Furthermore,the values of the potential ecological risk index(RI)ranged from 41.23 to 185.91,meaning that attention should be paid to HM contamination of GVP soils to ensure food quality and safety.
文摘As the major water catchment in Hobart city, the River Derwent provides water services to Hobart residents; however, water quality of the River Derwent is becoming unreliable. The aims of this paper are to identify the major water issues in the river and to reveal its impacts on Hobart residents and ecosystem. A methodology of secondary data analysis has been involved; which covers a wide range of existing dissertations. Through all the analysis of data, heavy metals, contaminated sediment and overload nitrogen can be regarded as three main causes of the water pollution. Moreover, the impacts of the water pollution are proved to be significant and perennial. On the basis of the analysis result, water pollution tends to be a tough issue that requires a great amount of time and efforts to deal with.
文摘Remediation via adsorption process has been proven to be one of the best water treatment technologies globally. Many adsorbents, including agricultural wastes, have been considered for the removal of a variety of pollutants from water. However, most of the studies reported in the literature used metal concentrations below 1000 ppm. It is also known that initial metal concentrations in polluted aqueous solutions, as well as metal and adsorbent type, are some of the factors that affect metal removal. Therefore, this project examined the remediation of water contaminated by 1000 ppm of lead, zinc, copper, magnesium, and calcium ions using wood ash, sodium hydrogen phosphate (dibasic), and sodium carbonate (dibasic). Comparative analysis of the results showed the order of order of metal removal by the adsorbents as: dibasic phosphate (Ca > Cu > Pb > Zn > Mg);dibasic Carbonate (Pb ~ Ca > Zn > Cu > Mg);Wood ash (Mg > Cu > Zn > Pb > Ca). These results suggest that metal and adsorbent type as well as the inherent chemical properties of these metal cations may contribute to the varying binding affinity of the metals to the adsorbent ligand(s) and thus, affect the extent of metal removal. It is equally worthy to note that wood ash more effectively removed hardness metals (Mg and Ca) from water than the inorganic phosphate and carbonate ions.
基金This work was supported by the National Key Research and Development Program of China[2016YFC0501101,2016YFC0503603].
文摘Introduction:The development of coal power base(CPB)poses a severe challenge to the soil.We conducted a soil survey in Xilinhot CPB,to evaluate and analyze the pollution characteristics,potential ecological risk,and sources of six heavy metals(As,Pb,Cu,Zn,Mn,and Cd)in soil by using Geo-accumulation index,revised Nemerow integrated pollution index(RNIPI),and potential ecological risk index(RI).Outcomes/other:The results showed that the pollution of Cd and As were dramatic.The mean of Cd and As were 1.11 mg·kg^(-1) and 25.13 mg·kg^(-1),which were 42.55 times and 4.41 times higher than its local background value.The Geo-accumulation indices showed the contamination degree of Cd was strong and As was moderate,and the status of Cu,Pb,Zn,and Mn were uncontaminated.Xilinhot was strongly contaminated based on its RNIPI and RI values.Discussion:The accumulations of As,Pb,and Cd were mainly associated with anthropogenic sources,including coal mining and combustion,and industrial exhaust emissions.Cu,Mn,and Zn were primarily originated from the parent material(natural sources).Conclusion:This study provides scientific basis and effective countermeasures for the prevention and control of soil pollution in surrounding areas of CPB.
基金the Science Foundation for Distinguished Youth of Shaanxi Province(2020JC-31)the National Natural Science Foundation of China(41977031)+1 种基金CAS“Light of West China”Program(XAB2016A03)Program of State Key Laboratory of Loess and Quaternary Geology CAS(SKLLQGZR1803).
文摘Heavy metals can exist in soil for a long time and seriously affect soil quality.The coexistence of various heavy metal pollutants leads to biotoxicity and alters the activity of microorganisms.Soil microbial metabolism plays an important role in nutrient cycling and biochemical processes of soil ecosystem.However,the effects of heavy metal contamination on microbial metabolism in soil are still unclear.This study aims to reveal the responses of microbial metabolic limitation to heavy metals using extracellular enzyme stoichiometry,and further to evaluate the potential impacts of heavy metal pollution on soil nutrient cycle.The results showed that soil microbial metabolism reflected by the ecoenzymatic activities had a significant response to soil heavy metals pollution.The metabolism was limited by soil carbon(C)and phosphorus(P)under varied heavy metal levels,and the increase of heavy metal concentration significantly increased the microbial C limitation,while had no effect on microbial P limitation.Microorganisms may increase the energy investment in metabolism to resist heavy metal stress and thus induce C release.The results suggest that energy metabolism selected by microorganisms in response to long-term heavy metal stress could increase soil C release,which is not conducive to the soil C sequestration.Our study emphasizes that ecoenzymatic stoichiometry could be a promising methodology for evaluating the toxicity of heavy metal pollution and its ecological effects on nutrient cycling.
基金This work was supported by the International Research Exchange Scheme of the Marie Curie Program of the 7th Framework Program(Ref.PIRSES-GA-2013-612659)Chinese National Natural Science Foundation(No.31671578)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2016 XD001)the Shandong Provincial Natural Science Foundation of China(No.ZR2015CM016).
文摘Cadmium(Cd)and lead(Pb)in soil or water environment cause the ecological destruction and environmental deterioration when their contents exceed the natural background values.To trace the concentrations of Cd(II)and Pb(II),a sensitive and selective electrode was developed using disposable screen-printed carbon electrode(SPE)immobilized with a composite film of reduced graphene oxide/carboxylation multi-walled carbon nanotubes/gold nanoparticle hybrid(RGO-MWNT-AuNP)throughπ-πbind.This highly conductive nano-composite layer,“RGO-MWNT-AuNP,”was characterized by scanning electron microscopy,UV-visible spectrometer,cyclic voltammetry,and electrochemical impedance spectroscopy.Square wave stripping voltammetry was applied to RGO-MWNT-AuNP/SPE to electroplate bismuth film and monitor the Cd(II)and Pb(II)simultaneously.To obtain high current responses,the detecting parameters were optimized.Under optimized conditions,the current responses showed a linear relationship with the concentrations of Cd(II)and Pb(II)in the range from 1.0 to 80.0μg/L with a lower detection limit of 0.7μg/L and 0.3μg/L(S/N=3),respectively.Finally,the prepared electrode was further employed to detect Cd(II)and Pb(II)in soil samples with good results.
基金This research was supported by Natural Science Foundation of Guangdong Province,China(No.021686)Research Foundation for Doctoral Programs of Chinese Universities(No.20020558004)Research Foundation for Talented Scientists of Guangdong Universities.
文摘Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years.Heavy metal pollutants may enter the human food chain through agricultural products and groundwater from the polluted soils.Progress has been made in the past decade on phytoremediation,a safe and inexpen-sive approach to remove contaminants from soil and water using plants.However,in most cases,agricultural land in China cannot afford to grow phytoremediator plants instead of growing crops due to food supply for the great population.Therefore,new and effective methods to decrease the risk of heavy metal pollution in crops and to clean the contaminated soils are urgently needed.If we can find crop germplasms(including species and varieties)that accumulate heavy metals in their edible parts,such as the leaves of vegetables or grains of cereals,at a level low enough for safe consumption,then we can grow these selected species or varieties in the lands contaminated or potentially contaminated by heavy metals.If we can find crop germplasms that take in low con-centrations of heavy metals in their edible parts and high con-tent of the metals in their inedible parts,then we can use these selected species or varieties for soil remediation.In this study,the feasibility of the method is assessed by analyzing Pb concentrations in edible and inedible parts of 25 varieties of maize(Zea mays)grown in Pb-contaminated soils.The soil concentrations of Pb were 595.55 mg/kg in the high Pb exposed treatment and 195.55 mg/kg in the control.The results showed that the Pb concentrations in different tissues were in the order of root>shoot≌leaf>grain.Com-pared with the control,the Pb concentrations in root,shoot and leaf were greatly increased under the high Pb exposed condition,while the increments of Pb concentration in grain were relatively lower.Under the high Pb exposure,the grain Pb concentrations of 12 varieties exceeded the maximal Pb limitation of the National Food Hygiene Standard of China(NFHSC)and were inedible.This indicates that there is a high Pb pollution risk for maize grown on Pb polluted sites.Although 22 of the 25 tested varieties had harvest loss under the highly Pb stressed condition,ranging from 0.86%-38.7%of the grain biomass acquired at the control,the average harvest loss of all the tested varieties was only 12.6%,which is usually imperceptible in normal farming practices.There-fore the risk of Pb pollution in maize products cannot be promptly noticed and prevented based only on the outcome of the harvest.However,we did find that 13 of the 25 tested varieties had grain Pb concentrations lower than the limita-tion of the NFHSC.It is,therefore,possible to reduce the pollution risk if these favorable varieties are used for maize production in Pb-contaminated or potentially contaminated agricultural lands.Pb concentrations in vegetative tissues(root,stem and leaf)were significantly correlated with each other,while Pb concentrations of each vegetative tissue were not significant-ly correlated with that of grain.Among the 25 tested varieties,some varieties had Pb concentrations in grain lower than(No.1-3 and No.6)or slightly above(No.4)the limitation of the NFHSC,while their Pb concentrations in the vegetative tissues were among the highest.When excluding these variet-ies,correlations between the Pb concentrations of grain and those of vegetative tissues of the rest of the tested varieties became highly significant.In addition,variety No.1 had the lowest harvest loss under high Pb exposed,and the highest Pb accumulation in vegetative tissues(51.69 mg/plant,12 times as much as in the control).Similar features were also observed in varieties No.2,No.3 and No.6,which absorbed Pb for 36-42 mg/plant under high Pb exposed.We recommend these varieties of maize to be used for bioremediation of Pb contaminated soil and crop production at the same time.
