It is of great significance to study the degree and source of soil heavy metal pollution in geological high background value area for remediation of local contaminated soil. The 0 - 20 cm topsoil was taken around the ...It is of great significance to study the degree and source of soil heavy metal pollution in geological high background value area for remediation of local contaminated soil. The 0 - 20 cm topsoil was taken around the mining area, and the contents of Pb, Zn, Ni, Cd, Hg, Cu and As in the soil were measured. Single-factor pollution index, Nemeiro comprehensive pollution index and potential ecological risk index were used to evaluate the degree of heavy metal pollution and ecological risk. Finally, multivariate statistical analysis was used to analyze the sources of soil heavy metals. The results show that the measured elements are polluted to different degrees, mainly due to the ecological environment problems caused by extensive mining development methods and inefficient utilization of resources. The key link is the release of pollutants at the source. Effectively blocking the release at the source can cut off the possibility of pollutants entering the food chain and the circulation of materials in the ecosystem. The results of potential ecological risk index showed that the potential ecological damage of seven heavy metals was ranked as follows: Cd (97.67) > Hg (68.97) > As (14.29) > Pb (11.55) > Ni (4.62) > Zn (1.61) > Cu (1.45) had a high ecological risk coefficient, and the potential comprehensive ecological risk index was 200.16 and the degree was medium. Principal component analysis shows that the sources of heavy metals are divided into Pb, Cd, As, Zn and Hg mainly from human activities such As mining, while Ni and Cu mainly come from soil parent materials, mining and agricultural activities.展开更多
The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the ...The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the theory of groundwater circulation and solid-liquid equilibrium,a simple and easy-touse flux model of soil heavy metals migrating to groundwater is constructed.Based on groundwater environmental capacity,an innovative method for evaluating the harm of heavy metals in soil to groundwater is proposed,which has been applied in Hunchun Basin,Jilin Province,China.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn,Cu,As,Pb,Cd,Ni,and Hg in descending order.The content of heavy metals in groundwater(As,Hg,Cu,Pb,Zn,Ni,and Cd)in most areas has not risen to the threshold of environmental capacity within 10 years.The harm levels of soil heavy metals to groundwater in the most townships soils are at the moderate level or below.This evaluation method can quantify the flux of soil heavy metals into groundwater simply and quickly,determine the residual capacity of groundwater to heavy metals,evaluate the harm level of soil heavy metals to groundwater,provide support for relevant departments to carry out environmental protection of soil and groundwater,and provide a reference to carry out similar studies for related scholars.展开更多
The soil heavy metals(Hg and As)in Duanzhou District of Zhaoqing City were determined by AFS200 T atomic fluorescence spectropho-tometer,and the soil environment in Duanzhou District was evaluated by several evaluatio...The soil heavy metals(Hg and As)in Duanzhou District of Zhaoqing City were determined by AFS200 T atomic fluorescence spectropho-tometer,and the soil environment in Duanzhou District was evaluated by several evaluation methods of soil heavy metal pollution,such as single factor index method,pollution load index method and Nemerow comprehensive pollution index method.Finally,according to the data and conclu-sions,the soil pollution situation in Duanzhou District of Zhaoqing was analyzed.The results will let more people pay attention to the changes of the environment and realize the harm of the environment,and the government can formulate a new plan conducive to the coordinated development of the environment and economy.展开更多
With the continuous development of human society and economy and the continuous progress of industrial technology,more and more pollutants are discharged into the natural environment,and soil environment is also affec...With the continuous development of human society and economy and the continuous progress of industrial technology,more and more pollutants are discharged into the natural environment,and soil environment is also affected at the same time. Among pollutants leading to soil pollution,heavy metals have resulted in most serious soil pollution. Here,many control and restoration approaches to soil pollution from heavy metals are proposed,and characteristics and applicable conditions of various methods are compared,so as to provide theoretical references for the control and restoration of soil pollution from heavy metals in future.展开更多
[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the co...[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the content of nutrients and heavy metals in aeolian sandy soil were ana- lyzed. [ Result] After the simulated leaching with sewage sludge, the contents of total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and available phosphorus (AP) in each layer of aeolian sandy soil increased significantly, and the increase in 0 -20 cm soil was more signifi- cant than that in 20 -40 and 40 -60 cm soil. Meanwhile, the content of each heavy metal in 0 -20 cm soil rose significantly, while the increase was small in 40 -60 cm soil. In addition, after the application of sewage sludge, the Nemrew Index of aeolian sandy soil was 0.67, lower than the na- tional soil quality standard of forestland (0.70), and the short-time application of sewage sludge to sandy soil did not cause serious pollution. How- ever, if sewage sludge has been applied to aeolian sandy soil for a long term, the potential hazard of heavy metals (especially Cd) caused by loneterm accumulation should be paid more attention to.展开更多
Soil amendment with fly ash(FA) and combined supplementation with N_2-fixing cyanobacteria masses as biofertilizer were done in field experiments with rice. Amendments with FA levels, 0, 0.5, 1.0, 2.0, 4.0, 8.0 and ...Soil amendment with fly ash(FA) and combined supplementation with N_2-fixing cyanobacteria masses as biofertilizer were done in field experiments with rice. Amendments with FA levels, 0, 0.5, 1.0, 2.0, 4.0, 8.0 and 10.0 kg/m2, caused increase in growth and yield of rice up to 8.0 kg/m2, monitored with several parameters. Pigment contents and enzyme activities of leaves were enhanced by FA, with the maximum level of FA at 10.0 kg/m2. Protein content of rice seeds was the highest in plants grown at FA level 4.0 kg/m2. Basic soil properties, p H value, percentage of silt, percentage of clay, water-holding capacity, electrical conductivity, cation exchange capacity, and organic carbon content increased due to the FA amendment. Parallel supplementation of FA amended plots with 1.0 kg/m2 N_2-fixing cyanobacteria mass caused further significant increments of the most soil properties, and rice growth and yield parameters. 1000-grain weight of rice plants grown at FA level 4.0 kg/m2 along with cyanobacteria supplementation was the maximum. Cyanobacteria supplementation caused increase of important basic properties of soil including the total N-content. Estimations of elemental content in soils and plant parts(root and seed) were done by the atomic absorption spectrophotometry. Accumulations of K, P, Fe and several plant micronutrients(Mn, Ni, Co, Zn and Cu) and toxic elements(Pb, Cr and Cd) increased in soils and plant parts as a function of the FA gradation, but Na content remained almost unchanged in soils and seeds. Supplementation of cyanobacteria had ameliorating effect on toxic metal contents of soils and plant parts. The FA level 4.0 kg/m2, with 1.0 kg/m2 cyanobacteria mass supplementation, could be taken ideal, since there would be recharging of the soil with essential micronutrients as well as toxic chemicals in comparative lesser proportions, and cyanobacteria mass would cause lessening toxic metal loads with usual N_2-fixation.展开更多
Using visible and near-infrared (Vis-NIR) spectroscopy combined with partial least squares (PLS) regression, the rapid reagent-free analysis model for chromium (Cr) content in tideland reclamation soil in the Pearl Ri...Using visible and near-infrared (Vis-NIR) spectroscopy combined with partial least squares (PLS) regression, the rapid reagent-free analysis model for chromium (Cr) content in tideland reclamation soil in the Pearl River Delta, China was established. Based on Savitzky-Golay (SG) smoothing and PLS regression, a multi-parameters optimization platform (SG-PLS) covering 264 modes was constructed to select the appropriately spectral preprocessing mode. The optimal SG-PLS model was determined according to the prediction effect. The selected optimal parameters <em>d, p, m</em> and LV were 2, 6, 23 and 8, respectively. Using the validation samples that were not involved in modeling, the root mean square error (SEP<sub>V</sub>), relative root mean square error (R-SEP<sub>V</sub>) and correlation coefficients (R<sub>P, V</sub>) of prediction were 11.66 mg<span style="white-space:nowrap;">·</span>kg<sup>-1</sup>, 10.7% and 0.722, respectively. The results indicated that the feasibility of using Vis-NIR spectroscopy combined with SG-PLS method to analyze soil Cr content. The constructed multi-parameters optimization platform with SG-PLS is expected to be applied to a wider field of analysis. The rapid detection method has important application values to large-scale agricultural production.展开更多
Lead (Pb) in the urban environment can have a negative effect on human health, especially children’s health. Reducing elevated Pb exposure in the home landscape is essential. The purpose of this study was to determin...Lead (Pb) in the urban environment can have a negative effect on human health, especially children’s health. Reducing elevated Pb exposure in the home landscape is essential. The purpose of this study was to determine which ornamental groundcover landscape plants uptake Pb from contaminated soil. Plants for both shade and sun were selected. Plants for shade [Brake fern (</span><i><span>Pteris</span></i><span> <i>vittata</i></span><span>), Asian Jasmine (</span><i><span>Trachelospermum</span></i><span> <i>asiaticum</i></span><span>), “Big Blue” Liriope </span></span></span><span><span><span><span>(</span><i><span>Liriope</span></i><span> <i>muscari</i></span><span>), and St. Augustinegrass (</span><i><span>Stenotaphrum</span></i><span> <i><span>secundatum</span></i><span>)</span></span><span>] and sun [Variegated Liriope (</span><i><span>Liriope</span></i><span> <i><span>muscari</span></i><span> “</span><i><span>Variegata</span></i><span>”</span></span><span>), Asian Jasmine </span><span><span>(</span><i><span>Trachelospermum</span></i> <i><span>asiaticum</span></i></span><span>), Asparagus Fern (</span><i><span>Asparagus</span></i><span> <i>setaceus</i></span><span>), </span><span>a</span><span>nd Bermudagrass (</span><i><span>Cynodon</span></i><span> <i>dactylon</i></span><span>)] adapted landscape groundcover plants successfully assimilated Pb grown in soil containing 250 ppm and 500 ppm Pb concentrations. Additionally, soil movement at both 25 mph and 50 mph wind speed was significantly different, with increased soil movement at 50 mph. Therefore, it was determined that landscape plants adapted to both sun and shade can help remove Pb from contaminated soils and stabilize soil particles reducing the movement of soil and be aesthetically pleasing.展开更多
Soil enzyme activities have been suggested as suitable indicators for the evaluation of metal contamination because they are susceptible to microbial changes caused by heavy metal stress and are strictly related to so...Soil enzyme activities have been suggested as suitable indicators for the evaluation of metal contamination because they are susceptible to microbial changes caused by heavy metal stress and are strictly related to soil nutrient cycles.However,there is a growing lack of recognition and summary of the historic advancements that use soil enzymology as the proposal of evaluation methods.Here,we review the most common methods of heavy metal pollution evaluation based on enzyme activities,which include single enzyme index,combined enzyme index,enzyme-based functional diversity index,microbiological stress index,and ecoenzymatic stoichiometry models.This review critically examines the advantages and disadvantages of these methods based on their execution complexity,performance,and ecological implications and gets a glimpse of avenues to come to improved future evaluation systems.Indices based on a single enzyme are variable and have no consistent response to soil heavy metals,and the following three composite indices are characterized by the loss of many critical microbial processes,which thus not conducive to reflect the effects of heavy metals on soil ecosystems.Considering the dexterity of ecoenzymatic stoichiometry methods in reflecting changes in soil functions under heavy metal stress,we propose that microbial metabolic limitations quantified by ecoenzymatic stoichiometry models could be promising indicators for enhancing the reality and acceptance of results and further improving the potential for actual utility in environmental decision-making.展开更多
Batch experiments were conducted with a heavy metals and arsenic co-contaminated soil from an abandoned mine to evaluate the feasibility of a remediation technology that combines sieving with soil washing.Leaching of ...Batch experiments were conducted with a heavy metals and arsenic co-contaminated soil from an abandoned mine to evaluate the feasibility of a remediation technology that combines sieving with soil washing.Leaching of the arsenic and heavy metals from the different particle size fractions was found to decrease in the order:〈 0.1,2–0.1,and 〉 2 mm.With increased contact time,the concentration of heavy metals in the leachate was significantly decreased for small particles,probably because of adsorption by the clay soil component.For the different particle sizes,the removal efficiencies for Pb and Cd were75%–87%,and 61%–77% for Zn and Cu,although the extent of removal was decreased for As and Cr at 〈 45%.The highest efficiency by washing for Pb,Cd,Zn,and As was from the soil particles 〉 2 mm,although good metal removal efficiencies were also achieved in the small particle size fractions.Through SEM-EDS observations and correlation analysis,the leaching regularity of the heavy metals and arsenic was found to be closely related to Fe,Mn,and Ca contents of the soil fractions.The remediation of heavy metal-contaminated soil by sieving combined with soil washing was proven to be efficient,and practical remediation parameters were also recommended.展开更多
In this study, effects of water conditions (flooded, wet, or dry) and eggshell dosages (0, 0.1, 1.0, and 10.0 g/kg soil, respectively) on pH variation, content of unavailable state of heavy metals, form of heavy m...In this study, effects of water conditions (flooded, wet, or dry) and eggshell dosages (0, 0.1, 1.0, and 10.0 g/kg soil, respectively) on pH variation, content of unavailable state of heavy metals, form of heavy metals, and available nutritious element calcium (Ca) in acid soils contaminated with heavy metals were investigated, respectively. The soil samples were continuously cultivated indoors and analyzed by toxicity characteristic leaching procedure and community bureau of reference (BCR) sequential extraction procedure. The results showed that the addition of eggshell could effectively improve the pH of acid soil and increase it to neutral level. Moreover, the contents of unavailable state of heavy metals Cu, Zn, and Cd increased significantly. Furthermore, when the soil was cultivated under the flooded condition with 1.0 g/kg eggshell, the unavailable state ofCu, Zn, and Cd increased the most, and these heavy metals were transformed into residual state. On the other hand, the amount of available state of Ca increased to 432.19 from 73.34 mg/kg with the addition of 1.0 g/kg eggshell, which indicated that the addition of eggshell dramatically improved the available state of Ca. Therefore, eggshell could ameliorate the soil environment as it led to the decrease of available heavy metals and improvement of fertilization effectively. In a word, this study indicates that the addition of eggshell would be a new potential method for remediation of acid field soils contaminated with heavy metals.展开更多
Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8....Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8.67 mg/kg dry weight,respectively.Factors that influence the dynamics of these metals in soils around the watersheds of Beijing reservoirs were examined.The influence of atmospheric deposition,land use,soil texture,soil type and soil chemical parameters on metal contents in soils was investigated.Atmospheric deposition,land use and soil texture were the important factors affecting heavy metal residues.Soil type and soil chemical parameters were also involved in heavy metal retention in soils.The data provided in this study are considered crucial for reservoir remediation,especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.展开更多
Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The effects of clay minerals on availability, chemical distribution, and biotoxicity of...Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The effects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment, the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An 8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the control red soil. Acid exchangeable Cu decreased with increasing effect reached at a dose of 8%. Results also showed that the Cu amounts of attapulgite and montmorillonite, with best remediation poisoning effect on earthworms was reduced with the addition of attapulgite and montmorillonite. Montmorillonite showed the best effect, with the addition of a 2% dose the mortality of earthworms decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more effectively with the application of montmorillonite than attapulgite.展开更多
The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied d...The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity,and higher Ca and Mg levels in biomass ashes,which made them particularly good at ameliorating effects on soil acidity. However,heavy metal contents,such as Cr,Cu,and Zn in the ashes,were relatively high. The incorporation of all ashes increased soil p H,exchangeable base cations,and available phosphorus,but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore,the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments.展开更多
Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effec...Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application.Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives,which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.展开更多
The current study investigated the effect of biochars derived from cinnamomum woodchip,garden waste and mulberry woodchip on soil phytoavailable lead(Pb),cadmium(Cd)pools,and their uptake by Chinese cabbage(Brassica c...The current study investigated the effect of biochars derived from cinnamomum woodchip,garden waste and mulberry woodchip on soil phytoavailable lead(Pb),cadmium(Cd)pools,and their uptake by Chinese cabbage(Brassica chinensis L.).The biochars were produced at 450℃of pyrolysis temperature.The contaminated soils were collected from Yunfu(clas-sified as Udept),Jiyuan(Ustalf)and Shaoguan(Udult)cities in China at the depth of 0-20 cm and amended with biochars at the rate of 3%w/w.After mixing the soil with biochar for 14 days,the Chinese cabbage was planted in the amended soils.Then,it was harvested on the 48th day after sowing period.In Udult soil,Chinese cabbage died 18 days after sowing period in control and soils amended with cinnamomum and mulberry biochars.Although only plants grown with the garden waste biochar treatment survived in Udult soil,amendment of garden waste or mulberry biochars at 3%w/w(450℃)to Udult soil significantly increased(4.95-6.25)soil pH compared to other biochar treatments.In Udept and Ustalf soils,the application of garden waste and mulberry biochars significantly improved plant biomass compared to control,albeit it was dependent on both biochar and soil properties.Garden waste biochar significantly decreased soil Cd phytoavailable concentration by 26%in the Udult soil,while a decrease of soil Cd phytoavailable concentration by 16%and 9%was observed in Ustalf and Udept soils,respectively.The available phosphorus in biochar and soil pH were important factors controlling toxic metal phytouptake by the plant.Thus,the amendment of soil with biochar at 3%can effectively reduce the mobility of Cd and Pb in soil and plant uptake.However,biochar and soil properties should be well-known before being used for soil toxic metal immobilization.展开更多
Soil contamination with tetrabromobisphenol A(TBBPA) has caused great concerns;however, the presence of heavy metals and soil organic matter on the biodegradation of TBBPA is still unclear. We isolated Pseudomonas s...Soil contamination with tetrabromobisphenol A(TBBPA) has caused great concerns;however, the presence of heavy metals and soil organic matter on the biodegradation of TBBPA is still unclear. We isolated Pseudomonas sp. strain CDT, a TBBPA-degrading bacterium, from activated sludge and incubated it with ^(14)C-labeled TBBPA for 87 days in the absence and presence of Cu^(2+)and humic acids(HA). TBBPA was degraded to organic-solvent extractable(59.4% ± 2.2%) and non-extractable(25.1% ± 1.3%) metabolites,mineralized to CO_2(4.8% ± 0.8%), and assimilated into cells(10.6% ± 0.9%) at the end of incubation. When Cu^(2+)was present, the transformation of extractable metabolites into non-extractable metabolites and mineralization were inhibited, possibly due to the toxicity of Cu^(2+)to cells. HA significantly inhibited both dissipation and mineralization of TBBPA and altered the fate of TBBPA in the culture by formation of HA-bound residues that amounted to 22.1% ± 3.7% of the transformed TBBPA. The inhibition from HA was attributed to adsorption of TBBPA and formation of bound residues with HA via reaction of reactive metabolites with HA molecules, which decreased bioavailability of TBBPA and metabolites in the culture. When Cu^(2+)and HA were both present, Cu^(2+)significantly promoted the HA inhibition on TBBPA dissipation but not on metabolite degradation. The results provide insights into individual and interactive effects of Cu^(2+)and soil organic matter on the biotransformation of TBBPA and indicate that soil organic matter plays an essential role in determining the fate of organic pollutants in soil and mitigating heavy metal toxicity.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It is of great significance to study the degree and source of soil heavy metal pollution in geological high background value area for remediation of local contaminated soil. The 0 - 20 cm topsoil was taken around the mining area, and the contents of Pb, Zn, Ni, Cd, Hg, Cu and As in the soil were measured. Single-factor pollution index, Nemeiro comprehensive pollution index and potential ecological risk index were used to evaluate the degree of heavy metal pollution and ecological risk. Finally, multivariate statistical analysis was used to analyze the sources of soil heavy metals. The results show that the measured elements are polluted to different degrees, mainly due to the ecological environment problems caused by extensive mining development methods and inefficient utilization of resources. The key link is the release of pollutants at the source. Effectively blocking the release at the source can cut off the possibility of pollutants entering the food chain and the circulation of materials in the ecosystem. The results of potential ecological risk index showed that the potential ecological damage of seven heavy metals was ranked as follows: Cd (97.67) > Hg (68.97) > As (14.29) > Pb (11.55) > Ni (4.62) > Zn (1.61) > Cu (1.45) had a high ecological risk coefficient, and the potential comprehensive ecological risk index was 200.16 and the degree was medium. Principal component analysis shows that the sources of heavy metals are divided into Pb, Cd, As, Zn and Hg mainly from human activities such As mining, while Ni and Cu mainly come from soil parent materials, mining and agricultural activities.
基金supported by the project of China Geology Survey(12120115032801,DD20190340)。
文摘The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the theory of groundwater circulation and solid-liquid equilibrium,a simple and easy-touse flux model of soil heavy metals migrating to groundwater is constructed.Based on groundwater environmental capacity,an innovative method for evaluating the harm of heavy metals in soil to groundwater is proposed,which has been applied in Hunchun Basin,Jilin Province,China.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn,Cu,As,Pb,Cd,Ni,and Hg in descending order.The content of heavy metals in groundwater(As,Hg,Cu,Pb,Zn,Ni,and Cd)in most areas has not risen to the threshold of environmental capacity within 10 years.The harm levels of soil heavy metals to groundwater in the most townships soils are at the moderate level or below.This evaluation method can quantify the flux of soil heavy metals into groundwater simply and quickly,determine the residual capacity of groundwater to heavy metals,evaluate the harm level of soil heavy metals to groundwater,provide support for relevant departments to carry out environmental protection of soil and groundwater,and provide a reference to carry out similar studies for related scholars.
基金Supported by Special Projects in Key Fields of Universities and Colleges in Guangdong Province(2021ZDZX4023)Special Fund Project for Enterprise Science and Technology Commissioners of Guangdong Province in 2020(GDKTP2020059100)+1 种基金Quality Engineering and Educational Reform Project of Zhaoqing University(zlgc 201931)Guangdong Provincial Key Laboratory of Environmental Health and Land Resource(2020B121201014)
文摘The soil heavy metals(Hg and As)in Duanzhou District of Zhaoqing City were determined by AFS200 T atomic fluorescence spectropho-tometer,and the soil environment in Duanzhou District was evaluated by several evaluation methods of soil heavy metal pollution,such as single factor index method,pollution load index method and Nemerow comprehensive pollution index method.Finally,according to the data and conclu-sions,the soil pollution situation in Duanzhou District of Zhaoqing was analyzed.The results will let more people pay attention to the changes of the environment and realize the harm of the environment,and the government can formulate a new plan conducive to the coordinated development of the environment and economy.
基金Supported by the Research and Demonstration of Restoration Technology of Typical Degraded Ecosystems in Tibet Plateau
文摘With the continuous development of human society and economy and the continuous progress of industrial technology,more and more pollutants are discharged into the natural environment,and soil environment is also affected at the same time. Among pollutants leading to soil pollution,heavy metals have resulted in most serious soil pollution. Here,many control and restoration approaches to soil pollution from heavy metals are proposed,and characteristics and applicable conditions of various methods are compared,so as to provide theoretical references for the control and restoration of soil pollution from heavy metals in future.
文摘[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the content of nutrients and heavy metals in aeolian sandy soil were ana- lyzed. [ Result] After the simulated leaching with sewage sludge, the contents of total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and available phosphorus (AP) in each layer of aeolian sandy soil increased significantly, and the increase in 0 -20 cm soil was more signifi- cant than that in 20 -40 and 40 -60 cm soil. Meanwhile, the content of each heavy metal in 0 -20 cm soil rose significantly, while the increase was small in 40 -60 cm soil. In addition, after the application of sewage sludge, the Nemrew Index of aeolian sandy soil was 0.67, lower than the na- tional soil quality standard of forestland (0.70), and the short-time application of sewage sludge to sandy soil did not cause serious pollution. How- ever, if sewage sludge has been applied to aeolian sandy soil for a long term, the potential hazard of heavy metals (especially Cd) caused by loneterm accumulation should be paid more attention to.
基金supported by the project from Council of Scientific and Industrial Research,New Delhi,India (Grant No.21 (0859)/11/EMR-Ⅱ)
文摘Soil amendment with fly ash(FA) and combined supplementation with N_2-fixing cyanobacteria masses as biofertilizer were done in field experiments with rice. Amendments with FA levels, 0, 0.5, 1.0, 2.0, 4.0, 8.0 and 10.0 kg/m2, caused increase in growth and yield of rice up to 8.0 kg/m2, monitored with several parameters. Pigment contents and enzyme activities of leaves were enhanced by FA, with the maximum level of FA at 10.0 kg/m2. Protein content of rice seeds was the highest in plants grown at FA level 4.0 kg/m2. Basic soil properties, p H value, percentage of silt, percentage of clay, water-holding capacity, electrical conductivity, cation exchange capacity, and organic carbon content increased due to the FA amendment. Parallel supplementation of FA amended plots with 1.0 kg/m2 N_2-fixing cyanobacteria mass caused further significant increments of the most soil properties, and rice growth and yield parameters. 1000-grain weight of rice plants grown at FA level 4.0 kg/m2 along with cyanobacteria supplementation was the maximum. Cyanobacteria supplementation caused increase of important basic properties of soil including the total N-content. Estimations of elemental content in soils and plant parts(root and seed) were done by the atomic absorption spectrophotometry. Accumulations of K, P, Fe and several plant micronutrients(Mn, Ni, Co, Zn and Cu) and toxic elements(Pb, Cr and Cd) increased in soils and plant parts as a function of the FA gradation, but Na content remained almost unchanged in soils and seeds. Supplementation of cyanobacteria had ameliorating effect on toxic metal contents of soils and plant parts. The FA level 4.0 kg/m2, with 1.0 kg/m2 cyanobacteria mass supplementation, could be taken ideal, since there would be recharging of the soil with essential micronutrients as well as toxic chemicals in comparative lesser proportions, and cyanobacteria mass would cause lessening toxic metal loads with usual N_2-fixation.
文摘Using visible and near-infrared (Vis-NIR) spectroscopy combined with partial least squares (PLS) regression, the rapid reagent-free analysis model for chromium (Cr) content in tideland reclamation soil in the Pearl River Delta, China was established. Based on Savitzky-Golay (SG) smoothing and PLS regression, a multi-parameters optimization platform (SG-PLS) covering 264 modes was constructed to select the appropriately spectral preprocessing mode. The optimal SG-PLS model was determined according to the prediction effect. The selected optimal parameters <em>d, p, m</em> and LV were 2, 6, 23 and 8, respectively. Using the validation samples that were not involved in modeling, the root mean square error (SEP<sub>V</sub>), relative root mean square error (R-SEP<sub>V</sub>) and correlation coefficients (R<sub>P, V</sub>) of prediction were 11.66 mg<span style="white-space:nowrap;">·</span>kg<sup>-1</sup>, 10.7% and 0.722, respectively. The results indicated that the feasibility of using Vis-NIR spectroscopy combined with SG-PLS method to analyze soil Cr content. The constructed multi-parameters optimization platform with SG-PLS is expected to be applied to a wider field of analysis. The rapid detection method has important application values to large-scale agricultural production.
文摘Lead (Pb) in the urban environment can have a negative effect on human health, especially children’s health. Reducing elevated Pb exposure in the home landscape is essential. The purpose of this study was to determine which ornamental groundcover landscape plants uptake Pb from contaminated soil. Plants for both shade and sun were selected. Plants for shade [Brake fern (</span><i><span>Pteris</span></i><span> <i>vittata</i></span><span>), Asian Jasmine (</span><i><span>Trachelospermum</span></i><span> <i>asiaticum</i></span><span>), “Big Blue” Liriope </span></span></span><span><span><span><span>(</span><i><span>Liriope</span></i><span> <i>muscari</i></span><span>), and St. Augustinegrass (</span><i><span>Stenotaphrum</span></i><span> <i><span>secundatum</span></i><span>)</span></span><span>] and sun [Variegated Liriope (</span><i><span>Liriope</span></i><span> <i><span>muscari</span></i><span> “</span><i><span>Variegata</span></i><span>”</span></span><span>), Asian Jasmine </span><span><span>(</span><i><span>Trachelospermum</span></i> <i><span>asiaticum</span></i></span><span>), Asparagus Fern (</span><i><span>Asparagus</span></i><span> <i>setaceus</i></span><span>), </span><span>a</span><span>nd Bermudagrass (</span><i><span>Cynodon</span></i><span> <i>dactylon</i></span><span>)] adapted landscape groundcover plants successfully assimilated Pb grown in soil containing 250 ppm and 500 ppm Pb concentrations. Additionally, soil movement at both 25 mph and 50 mph wind speed was significantly different, with increased soil movement at 50 mph. Therefore, it was determined that landscape plants adapted to both sun and shade can help remove Pb from contaminated soils and stabilize soil particles reducing the movement of soil and be aesthetically pleasing.
基金the National Natural Science Foundation of China(41977031)the Science Foundation for Distinguished Youth of Shaanxi Province(2020JC-31).
文摘Soil enzyme activities have been suggested as suitable indicators for the evaluation of metal contamination because they are susceptible to microbial changes caused by heavy metal stress and are strictly related to soil nutrient cycles.However,there is a growing lack of recognition and summary of the historic advancements that use soil enzymology as the proposal of evaluation methods.Here,we review the most common methods of heavy metal pollution evaluation based on enzyme activities,which include single enzyme index,combined enzyme index,enzyme-based functional diversity index,microbiological stress index,and ecoenzymatic stoichiometry models.This review critically examines the advantages and disadvantages of these methods based on their execution complexity,performance,and ecological implications and gets a glimpse of avenues to come to improved future evaluation systems.Indices based on a single enzyme are variable and have no consistent response to soil heavy metals,and the following three composite indices are characterized by the loss of many critical microbial processes,which thus not conducive to reflect the effects of heavy metals on soil ecosystems.Considering the dexterity of ecoenzymatic stoichiometry methods in reflecting changes in soil functions under heavy metal stress,we propose that microbial metabolic limitations quantified by ecoenzymatic stoichiometry models could be promising indicators for enhancing the reality and acceptance of results and further improving the potential for actual utility in environmental decision-making.
基金supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA06A201)the Science and Technology Project of Beijing(No.Z141100000914011)
文摘Batch experiments were conducted with a heavy metals and arsenic co-contaminated soil from an abandoned mine to evaluate the feasibility of a remediation technology that combines sieving with soil washing.Leaching of the arsenic and heavy metals from the different particle size fractions was found to decrease in the order:〈 0.1,2–0.1,and 〉 2 mm.With increased contact time,the concentration of heavy metals in the leachate was significantly decreased for small particles,probably because of adsorption by the clay soil component.For the different particle sizes,the removal efficiencies for Pb and Cd were75%–87%,and 61%–77% for Zn and Cu,although the extent of removal was decreased for As and Cr at 〈 45%.The highest efficiency by washing for Pb,Cd,Zn,and As was from the soil particles 〉 2 mm,although good metal removal efficiencies were also achieved in the small particle size fractions.Through SEM-EDS observations and correlation analysis,the leaching regularity of the heavy metals and arsenic was found to be closely related to Fe,Mn,and Ca contents of the soil fractions.The remediation of heavy metal-contaminated soil by sieving combined with soil washing was proven to be efficient,and practical remediation parameters were also recommended.
文摘In this study, effects of water conditions (flooded, wet, or dry) and eggshell dosages (0, 0.1, 1.0, and 10.0 g/kg soil, respectively) on pH variation, content of unavailable state of heavy metals, form of heavy metals, and available nutritious element calcium (Ca) in acid soils contaminated with heavy metals were investigated, respectively. The soil samples were continuously cultivated indoors and analyzed by toxicity characteristic leaching procedure and community bureau of reference (BCR) sequential extraction procedure. The results showed that the addition of eggshell could effectively improve the pH of acid soil and increase it to neutral level. Moreover, the contents of unavailable state of heavy metals Cu, Zn, and Cd increased significantly. Furthermore, when the soil was cultivated under the flooded condition with 1.0 g/kg eggshell, the unavailable state ofCu, Zn, and Cd increased the most, and these heavy metals were transformed into residual state. On the other hand, the amount of available state of Ca increased to 432.19 from 73.34 mg/kg with the addition of 1.0 g/kg eggshell, which indicated that the addition of eggshell dramatically improved the available state of Ca. Therefore, eggshell could ameliorate the soil environment as it led to the decrease of available heavy metals and improvement of fertilization effectively. In a word, this study indicates that the addition of eggshell would be a new potential method for remediation of acid field soils contaminated with heavy metals.
基金supported by the National Natural Science Foundation of China(No.41071355,41171394)the Environmental Protection Welfare Program(No.201009032)International S&T Cooperation Project(No.2012DFA91150)
文摘Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8.67 mg/kg dry weight,respectively.Factors that influence the dynamics of these metals in soils around the watersheds of Beijing reservoirs were examined.The influence of atmospheric deposition,land use,soil texture,soil type and soil chemical parameters on metal contents in soils was investigated.Atmospheric deposition,land use and soil texture were the important factors affecting heavy metal residues.Soil type and soil chemical parameters were also involved in heavy metal retention in soils.The data provided in this study are considered crucial for reservoir remediation,especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.
基金supported by the National Basic Research and Development (973) Program of China (No.2007CB936604)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KSCX2-YW-N-038)
文摘Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The effects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment, the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An 8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the control red soil. Acid exchangeable Cu decreased with increasing effect reached at a dose of 8%. Results also showed that the Cu amounts of attapulgite and montmorillonite, with best remediation poisoning effect on earthworms was reduced with the addition of attapulgite and montmorillonite. Montmorillonite showed the best effect, with the addition of a 2% dose the mortality of earthworms decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more effectively with the application of montmorillonite than attapulgite.
基金supported by the National Key Basic Research Program of China(No.2014CB441003)the National Key Research and Development of China(No.2016YFD0200302)
文摘The chemical characteristics,element contents,mineral compositions,and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity,and higher Ca and Mg levels in biomass ashes,which made them particularly good at ameliorating effects on soil acidity. However,heavy metal contents,such as Cr,Cu,and Zn in the ashes,were relatively high. The incorporation of all ashes increased soil p H,exchangeable base cations,and available phosphorus,but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore,the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments.
基金supported by the Fellowship Program of National Science Information and Communication Technology (NSICT) under Ministry of Science Information and Communication Technology, Bangladesh (code no.- 3-2605-3965-5901)
文摘Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application.Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives,which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.
基金The financial supports from Special fund for Agricultural competitive industry discipline team building project of Guangdong Academy of Agricultural Sciences(202120TD)Guangdong Academy of Agricultural Sciences Dean Fund,China(BZ201903,BZ202001)+3 种基金Natural Science Foundation of China(41571313,21876027)Department of Science and Technology of Guangdong Province,China(2019B121201003)The National Project for Agricultural Technology System(CARS-18)Guangdong Provincial Special Fund For Modern Agriculture Industry Technology Innovation Teams(2019KJ109,2019KJ148)are gratefully acknowledged.
文摘The current study investigated the effect of biochars derived from cinnamomum woodchip,garden waste and mulberry woodchip on soil phytoavailable lead(Pb),cadmium(Cd)pools,and their uptake by Chinese cabbage(Brassica chinensis L.).The biochars were produced at 450℃of pyrolysis temperature.The contaminated soils were collected from Yunfu(clas-sified as Udept),Jiyuan(Ustalf)and Shaoguan(Udult)cities in China at the depth of 0-20 cm and amended with biochars at the rate of 3%w/w.After mixing the soil with biochar for 14 days,the Chinese cabbage was planted in the amended soils.Then,it was harvested on the 48th day after sowing period.In Udult soil,Chinese cabbage died 18 days after sowing period in control and soils amended with cinnamomum and mulberry biochars.Although only plants grown with the garden waste biochar treatment survived in Udult soil,amendment of garden waste or mulberry biochars at 3%w/w(450℃)to Udult soil significantly increased(4.95-6.25)soil pH compared to other biochar treatments.In Udept and Ustalf soils,the application of garden waste and mulberry biochars significantly improved plant biomass compared to control,albeit it was dependent on both biochar and soil properties.Garden waste biochar significantly decreased soil Cd phytoavailable concentration by 26%in the Udult soil,while a decrease of soil Cd phytoavailable concentration by 16%and 9%was observed in Ustalf and Udept soils,respectively.The available phosphorus in biochar and soil pH were important factors controlling toxic metal phytouptake by the plant.Thus,the amendment of soil with biochar at 3%can effectively reduce the mobility of Cd and Pb in soil and plant uptake.However,biochar and soil properties should be well-known before being used for soil toxic metal immobilization.
基金supported by the National Science Foundation of China(NSFC)(Nos.21237001,21477052)the National Key Research and Development Program of China(No.2016YFD0800207,2016YFD0800700)
文摘Soil contamination with tetrabromobisphenol A(TBBPA) has caused great concerns;however, the presence of heavy metals and soil organic matter on the biodegradation of TBBPA is still unclear. We isolated Pseudomonas sp. strain CDT, a TBBPA-degrading bacterium, from activated sludge and incubated it with ^(14)C-labeled TBBPA for 87 days in the absence and presence of Cu^(2+)and humic acids(HA). TBBPA was degraded to organic-solvent extractable(59.4% ± 2.2%) and non-extractable(25.1% ± 1.3%) metabolites,mineralized to CO_2(4.8% ± 0.8%), and assimilated into cells(10.6% ± 0.9%) at the end of incubation. When Cu^(2+)was present, the transformation of extractable metabolites into non-extractable metabolites and mineralization were inhibited, possibly due to the toxicity of Cu^(2+)to cells. HA significantly inhibited both dissipation and mineralization of TBBPA and altered the fate of TBBPA in the culture by formation of HA-bound residues that amounted to 22.1% ± 3.7% of the transformed TBBPA. The inhibition from HA was attributed to adsorption of TBBPA and formation of bound residues with HA via reaction of reactive metabolites with HA molecules, which decreased bioavailability of TBBPA and metabolites in the culture. When Cu^(2+)and HA were both present, Cu^(2+)significantly promoted the HA inhibition on TBBPA dissipation but not on metabolite degradation. The results provide insights into individual and interactive effects of Cu^(2+)and soil organic matter on the biotransformation of TBBPA and indicate that soil organic matter plays an essential role in determining the fate of organic pollutants in soil and mitigating heavy metal toxicity.
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.