To evaluate soil environmental quality of introduced new crops and other traditional crops,and to understand the importance of response of soil microbial community to heavy metal stress,rhizosphere soil samples of dif...To evaluate soil environmental quality of introduced new crops and other traditional crops,and to understand the importance of response of soil microbial community to heavy metal stress,rhizosphere soil samples of different land use types(Sphagnum farming,rice field,grassland and bare land) in Dading Village,Duyun City,Guizhou Province of China were selected as research objects.The differences of soil chemical properties,heavy metal concentration and microbial community among different land use types were compared.The abundance and structural diversity of microbial communities in soil samples were analyzed by 16S rDNA sequencing,the relationship between soil pollution characteristics and microbial community in farmland was studied.The results showed that the different land use types planting different agricultural products under the same growing environment were subject to different heavy metal pollution.Soil chemical properties and heavy metals had significant effects on the soil microbial community.Proteobacteria,Actinobacteriota and Acidobacteriota were the most dominant groups of bacteria.The soil microorganisms responded more actively to the variability of pH,SOM and AK contents,although the variability was not high.With the increase of pH value,the abundance of the dominant species Proteobacteria also increased.Verrucomicrobiota had a better tolerance to the heavy metal Hg.Verrucomicrobiota and Firmicutes had strong resistance to the heavy metal Cd.These results deepen our understanding of the changes and aggregation of microorganisms under different land use patterns in heavy-metal contaminated farmland soils.展开更多
The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determine...The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.展开更多
The pollution characteristics of Cd,Cr,Cu,Zn,Ni and Hg in agricultural soil around coal mining area were studied. After longterm mining activity,the soil around mining area was polluted by 6 elements to different degr...The pollution characteristics of Cd,Cr,Cu,Zn,Ni and Hg in agricultural soil around coal mining area were studied. After longterm mining activity,the soil around mining area was polluted by 6 elements to different degrees. Especially for Cd,its concentration was 3. 2times that of the National Soil Environmental Quality Standard Ⅱ. The values suggest that the contamination degree from strong to weak in soil is in the order of Hg > Cu > Cr > Zn > Ni > Cd. BCR sequential extraction results show that the order of average percentage about weak acid soluble fraction( F1) is that Cd > Ni > Zn > Cu > Hg > Cr,the order of 6 heavy metals available fraction( F1 + F2 + F3) is that Cu( 56. 89) > Cd( 50. 95) > Ni( 41. 52) > Zn( 35. 06) > Hg( 23. 04) > Cr( 4. 88). The RAC results indicate that soils were in a moderate potential ecological risk by pollution of Cd,and at the same time,Cu,Zn,Ni,Hg should be noted.展开更多
In this paper the seven-step continuous extracting method was employed in the studyof chemical forms of the six heavy metals Co, Zn, Pb, Cu, Cr and Mn. The result shows thatthe metals in the laterite are present in th...In this paper the seven-step continuous extracting method was employed in the studyof chemical forms of the six heavy metals Co, Zn, Pb, Cu, Cr and Mn. The result shows thatthe metals in the laterite are present in the chemical form of crystalline iron oxides andresidues, and they are transformed toward organic and exchangeable forms in the surface soil.Linear regression analysis indicates that the above heavy metals have a positive correlation withthe crystalline iron oxide minerals. The crystalline iron oxide minerals have a very importantrole to play in the enrichment of heavy metals, especially the solid components in the laterite.展开更多
Excessive use of agro-chemicals (such as mineral fertilizers) poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmenta...Excessive use of agro-chemicals (such as mineral fertilizers) poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments: 100% chemical fertilizer (CF100), 80% chemical fertilizer (CF80), 60% chemical fertilizer and 20% organic fertilizer (CF60+OM20), and 40% chemical fertilizer and 40% organic fertilizer (CF40+OM40). Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction (CF80) had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer (CF60+OM20, CF40+OM40) significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.展开更多
Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP), were evaluated by means of chemical fractions of heavy metals in soils and concentrati...Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP), were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils (calcareous soil and acidic soil) polluted with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials) for 12 months. Results indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd Cu Zn. The reduction of exchangeable fraction of heavy metals in the soils amended with different mineral materials followed the sequence of CMP, PG AL RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12% for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were 25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44% for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing heavy metals in the polluted urban soils.展开更多
Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and sp...Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and spatiotemporal distributions of lead (Pb), mercury (Hg), cadmium (Cd), chromium (Cr) and arsenic (As) in the topsoil of a coal chemical plant in Ningxia Aulonomous region (Ningxia), China. Topsoil samples (/?= 153) were obtained using the checkerboard method, and the HM concentrations were determined. The soil residual rates of the five HMs were measured with leaching experinients and were applied in a soil environmental capacity model to predict the quarHitiHive variation of the HM concentrations. The predicted results were employed to estimate the HM spatiotemporal distribution within 2() years with the Kriging technique. The number of sampling sites, where all five HM concentratio ns exceed their corresponding background values in Ningxia, would be increased from 0 to 90% within 1() years of the plant operation. In addition, Pb and Cd were distributed along the traffic routes. Mercury and As were distributed near fuel gas emission vents. Chromium was mainly accumulated in slag dumps. The study may provide the theoretical and practical foun d at ion for future HM pollution control in coal chemical plants.展开更多
Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition...Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition in wind and spreading minerals during vehicle transportation,respectively.In each zone,soil samples were collected.Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods.The results indicate that the average contents of Zn,Pb,Cd,Cu and As in soils are 508.6,384.8,7.53,356 and 44.6 mg/kg,respectively.But the contents of heavy metals in different zone have distinct differences.The proportion of oxidizing association with organic substance is small.Difference of the association of heavy metals is small in different polluted zones.展开更多
Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd ...Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd levels to be regulated or reduced,it is necessary to first elucidate the mechanism of Cd uptake and accumulation in the plant,in addition to its detoxification mechanisms.This present study used inductively couple plasma-mass-spectrometry to analyze the subcellular distribution and chemical forms of Cd in different tissues of P.grandiflorum.The experimental results showed that Cd was mainly accumulated in the roots[predominantly in the cell wall(50.96%-61.42%)],and it was found primarily in hypomobile and hypotoxic forms.The proportion of Cd in the soluble fraction increased after Cd exposure,and the proportion of insoluble phosphate Cd and oxalate Cd increased in roots and leaves,with a higher increase in oxalate Cd.Therefore,it is likely that root retention mechanisms,cell wall deposition,vacuole sequestration,and the formation of low mobility and low toxicity forms are tolerance strategies for Cd detoxification used by P.grandiflorum.The results of this study provide a theoretical grounding for the study of Cd accumulation and detoxification mechanisms in P.grandiflorum,and they can be used as a reference for developing Cd limits and standards for other medicine food homology plants.展开更多
High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metal...High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metals along the banks of the Yangtze River in Huangshi. Heavy metal concentrations of 22 topsoil samples were measured using the inductively coupled plasma mass spectrometry instrument and data was analyzed by multivariate statistic approaches. Heavy metal contamination risk assessment was performed using a combination of the Nemerow multi-factor index method, the Hakanson potential ecological risk index method and the Muller index of geo-accumulation method. These methods determined similar results indicating that cadmium(Cd) poses a health risk to residents at the study site while Cr, Cu, Zn, Pb and Ni do not. The Nemerow multi-factor index method demonstrated that 18 samples were heavily polluted, three moderately polluted and one lightly polluted. The Muller index of geo-accumulation method found ten samples were moderately to strongly polluted by Cd, five were moderately polluted, six were lightly to moderately polluted and one was lightly polluted. The Hakanson potential ecological risk index method proved six samples were strongly polluted, seven were moderately polluted and nine were lightly polluted. Since our sampling sites were all in agricultural lands, we recommend the potential ecological risk index method as the most effective given it not only considers the range of pollutants contributing to soil pollution but factors in heavy metals toxicity. We are apt that the source of the high concentrations of Cd found in topsoil is derived from alluvial sediments upstream of the Yangtze River with a high percentage of residual speciation and a low percentage of exchangeable speciation distribution of Cd. This in turns indicates that a high concentration of Cd in soil had little impact on the natural environment. However, 31.9% of the iron-manganese oxides bound speciation indicating that such levels of Cd in soil would be potentially hazardous to the crops, particularly if exposed to a reductive condition.展开更多
From soil contamination and risk assessment perspectives,it is imperative to understand the ecological processes occurring in soils.Certain soil processes greatly affect chemical speciation of potentially toxic metals...From soil contamination and risk assessment perspectives,it is imperative to understand the ecological processes occurring in soils.Certain soil processes greatly affect chemical speciation of potentially toxic metals(PTMs),and thus also influence their biogeochemical activity.The current study analyzed chemical speciation of eight PTMs(Cd,Cr,Fe,Cu,Mn,Ni,Zn,and Pb)in upper and lower soil layers for 15 agronomic fields of Vehari-Pakistan using Visual Minteq software.The divalent forms of most PTMs(PTM^(2+))generally predominated in both soil layers(79.9%overall occurrence).However,chromium revealed a different pattern of chemical speciation(95.8%as CrOH^(+))compared to other PTMs.The mean percentage of all the PTMs2+was slightly higher for the lower soil layer(81.3%)than in the upper layer(78.4%),the trend being same for all the PTMs,except Cr.This higher PTMs^(2+)percentage in lower soil layers than upper layers was due to lower content of organic matter and other anions such as Cl^(−)and HCO_(3)_(−).The mean percentage ages of all the PTMs^(2+)was similar among all the 15 agronomic fields,which was confirmed by strong Pearson correlation values(R^(2)>0.95).The PCA graph grouped all the agronomic fields and PTM^(2+) closely,except Cr^(2+) and Cu^(2+).This grouping confirmed the similar chemical speciation of PTMs,except Cu and Cr in studied fields.展开更多
The soil pH of tea garden was acidic (4.6 - 5.3) with organic contents ranging between 0.91% - 1.09%. Available po- tassium concentration was predominantly found in the range of 167 - 208 mg/kg followed by the nitroge...The soil pH of tea garden was acidic (4.6 - 5.3) with organic contents ranging between 0.91% - 1.09%. Available po- tassium concentration was predominantly found in the range of 167 - 208 mg/kg followed by the nitrogen (150 - 189 mg/ha) and phosphorus (42 - 169 mg/kg). The Fe content was the one of the predominant heavy metal in soil (5494 - 5627 mg/kg) followed by Mn (245 - 435 mg/kg), Zn (30 - 111 mg/kg) and Cu (22 - 51 mg/kg). The concentration of toxic heavy metals Pb, Ni, and Cd in tea leaves, made tea and its infusions were too low. The level of most abundant essential heavy metals in tea infusion was Zn ranging from 0.09 - 0.52 mg/kg followed by Mn 0.10 - 0.42 mg/kg. The level of Fe and Cu was ranging from 0.068 - 0.073 mg/kg and 0.007 - 0.04 mg/kg in tea infusion respectively. The levels of all es- sential and the toxic metals were thus obtained were compared well with the other parts of the world.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
基金the National Natural Science Foundation of China (No.31960044)the Department of Science and Technology Foundation of Guizhou Province, China [DSTFGC (2019)] for financial support。
文摘To evaluate soil environmental quality of introduced new crops and other traditional crops,and to understand the importance of response of soil microbial community to heavy metal stress,rhizosphere soil samples of different land use types(Sphagnum farming,rice field,grassland and bare land) in Dading Village,Duyun City,Guizhou Province of China were selected as research objects.The differences of soil chemical properties,heavy metal concentration and microbial community among different land use types were compared.The abundance and structural diversity of microbial communities in soil samples were analyzed by 16S rDNA sequencing,the relationship between soil pollution characteristics and microbial community in farmland was studied.The results showed that the different land use types planting different agricultural products under the same growing environment were subject to different heavy metal pollution.Soil chemical properties and heavy metals had significant effects on the soil microbial community.Proteobacteria,Actinobacteriota and Acidobacteriota were the most dominant groups of bacteria.The soil microorganisms responded more actively to the variability of pH,SOM and AK contents,although the variability was not high.With the increase of pH value,the abundance of the dominant species Proteobacteria also increased.Verrucomicrobiota had a better tolerance to the heavy metal Hg.Verrucomicrobiota and Firmicutes had strong resistance to the heavy metal Cd.These results deepen our understanding of the changes and aggregation of microorganisms under different land use patterns in heavy-metal contaminated farmland soils.
文摘The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.
基金Supported by Project for Social Development of Guizhou Province(SY20103013)
文摘The pollution characteristics of Cd,Cr,Cu,Zn,Ni and Hg in agricultural soil around coal mining area were studied. After longterm mining activity,the soil around mining area was polluted by 6 elements to different degrees. Especially for Cd,its concentration was 3. 2times that of the National Soil Environmental Quality Standard Ⅱ. The values suggest that the contamination degree from strong to weak in soil is in the order of Hg > Cu > Cr > Zn > Ni > Cd. BCR sequential extraction results show that the order of average percentage about weak acid soluble fraction( F1) is that Cd > Ni > Zn > Cu > Hg > Cr,the order of 6 heavy metals available fraction( F1 + F2 + F3) is that Cu( 56. 89) > Cd( 50. 95) > Ni( 41. 52) > Zn( 35. 06) > Hg( 23. 04) > Cr( 4. 88). The RAC results indicate that soils were in a moderate potential ecological risk by pollution of Cd,and at the same time,Cu,Zn,Ni,Hg should be noted.
文摘In this paper the seven-step continuous extracting method was employed in the studyof chemical forms of the six heavy metals Co, Zn, Pb, Cu, Cr and Mn. The result shows thatthe metals in the laterite are present in the chemical form of crystalline iron oxides andresidues, and they are transformed toward organic and exchangeable forms in the surface soil.Linear regression analysis indicates that the above heavy metals have a positive correlation withthe crystalline iron oxide minerals. The crystalline iron oxide minerals have a very importantrole to play in the enrichment of heavy metals, especially the solid components in the laterite.
基金financially supported by grants of the Key Projects in the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2012BAD14B00)the Guangdong Provincial Science and Technology Plan Key Project,China(2012A020100003,2015A050502043)
文摘Excessive use of agro-chemicals (such as mineral fertilizers) poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments: 100% chemical fertilizer (CF100), 80% chemical fertilizer (CF80), 60% chemical fertilizer and 20% organic fertilizer (CF60+OM20), and 40% chemical fertilizer and 40% organic fertilizer (CF40+OM40). Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction (CF80) had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer (CF60+OM20, CF40+OM40) significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.
基金supported by the National Natural Science Foundation of China(No.40771090,41071145)the National Basic Research Program(973)of China(No.2005CB121104)
文摘Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP), were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils (calcareous soil and acidic soil) polluted with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials) for 12 months. Results indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd Cu Zn. The reduction of exchangeable fraction of heavy metals in the soils amended with different mineral materials followed the sequence of CMP, PG AL RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12% for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were 25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44% for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing heavy metals in the polluted urban soils.
文摘Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and spatiotemporal distributions of lead (Pb), mercury (Hg), cadmium (Cd), chromium (Cr) and arsenic (As) in the topsoil of a coal chemical plant in Ningxia Aulonomous region (Ningxia), China. Topsoil samples (/?= 153) were obtained using the checkerboard method, and the HM concentrations were determined. The soil residual rates of the five HMs were measured with leaching experinients and were applied in a soil environmental capacity model to predict the quarHitiHive variation of the HM concentrations. The predicted results were employed to estimate the HM spatiotemporal distribution within 2() years with the Kriging technique. The number of sampling sites, where all five HM concentratio ns exceed their corresponding background values in Ningxia, would be increased from 0 to 90% within 1() years of the plant operation. In addition, Pb and Cd were distributed along the traffic routes. Mercury and As were distributed near fuel gas emission vents. Chromium was mainly accumulated in slag dumps. The study may provide the theoretical and practical foun d at ion for future HM pollution control in coal chemical plants.
基金Porject(50474050)supported by the Natural Science Foundation of ChinaProject(2006BAK04B01-2)supported by the National Key Technology R&D Program of China
文摘Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition in wind and spreading minerals during vehicle transportation,respectively.In each zone,soil samples were collected.Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods.The results indicate that the average contents of Zn,Pb,Cd,Cu and As in soils are 508.6,384.8,7.53,356 and 44.6 mg/kg,respectively.But the contents of heavy metals in different zone have distinct differences.The proportion of oxidizing association with organic substance is small.Difference of the association of heavy metals is small in different polluted zones.
基金This work was supported by the Major Science and Technology Projects in Inner Mongolia Autonomous Region(No.2019ZD005)the National Natural Science Foundation of China(No.81903751)+1 种基金by the Natural Science Basic Research Project of Shaanxi Science and Technology Department(No.2019JQ-877)by the Scientific Research Project of Shaanxi Administration of Traditional Chinese Medicine(No.2019-ZZ-ZY018).
文摘Although Platycodon grandiflorum(Jacq.)A.DC.is a renowned medicine food homology plant,reports of excessive cadmium(Cd)levels are common,which affects its safety for clinical use and food consumption.To enable its Cd levels to be regulated or reduced,it is necessary to first elucidate the mechanism of Cd uptake and accumulation in the plant,in addition to its detoxification mechanisms.This present study used inductively couple plasma-mass-spectrometry to analyze the subcellular distribution and chemical forms of Cd in different tissues of P.grandiflorum.The experimental results showed that Cd was mainly accumulated in the roots[predominantly in the cell wall(50.96%-61.42%)],and it was found primarily in hypomobile and hypotoxic forms.The proportion of Cd in the soluble fraction increased after Cd exposure,and the proportion of insoluble phosphate Cd and oxalate Cd increased in roots and leaves,with a higher increase in oxalate Cd.Therefore,it is likely that root retention mechanisms,cell wall deposition,vacuole sequestration,and the formation of low mobility and low toxicity forms are tolerance strategies for Cd detoxification used by P.grandiflorum.The results of this study provide a theoretical grounding for the study of Cd accumulation and detoxification mechanisms in P.grandiflorum,and they can be used as a reference for developing Cd limits and standards for other medicine food homology plants.
基金supported by the National Natural Science Foundation of China (40772155)the Opening Fund of Institute of Hydrogeology and Environmental Geology, CAGS (KF201505)
文摘High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metals along the banks of the Yangtze River in Huangshi. Heavy metal concentrations of 22 topsoil samples were measured using the inductively coupled plasma mass spectrometry instrument and data was analyzed by multivariate statistic approaches. Heavy metal contamination risk assessment was performed using a combination of the Nemerow multi-factor index method, the Hakanson potential ecological risk index method and the Muller index of geo-accumulation method. These methods determined similar results indicating that cadmium(Cd) poses a health risk to residents at the study site while Cr, Cu, Zn, Pb and Ni do not. The Nemerow multi-factor index method demonstrated that 18 samples were heavily polluted, three moderately polluted and one lightly polluted. The Muller index of geo-accumulation method found ten samples were moderately to strongly polluted by Cd, five were moderately polluted, six were lightly to moderately polluted and one was lightly polluted. The Hakanson potential ecological risk index method proved six samples were strongly polluted, seven were moderately polluted and nine were lightly polluted. Since our sampling sites were all in agricultural lands, we recommend the potential ecological risk index method as the most effective given it not only considers the range of pollutants contributing to soil pollution but factors in heavy metals toxicity. We are apt that the source of the high concentrations of Cd found in topsoil is derived from alluvial sediments upstream of the Yangtze River with a high percentage of residual speciation and a low percentage of exchangeable speciation distribution of Cd. This in turns indicates that a high concentration of Cd in soil had little impact on the natural environment. However, 31.9% of the iron-manganese oxides bound speciation indicating that such levels of Cd in soil would be potentially hazardous to the crops, particularly if exposed to a reductive condition.
基金Project(2232013A3-08)supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by Shanghai Pujiang Program and DHU Distinguished Young Professor Program,China
基金Dr.Shahid thanks HEC-Pakistan for NTPU-4423 projectsupported by the Distinguished Scientist Fellowship Program(DSFP)at King Saud University,Riyadh,Saudi Arabia.
文摘From soil contamination and risk assessment perspectives,it is imperative to understand the ecological processes occurring in soils.Certain soil processes greatly affect chemical speciation of potentially toxic metals(PTMs),and thus also influence their biogeochemical activity.The current study analyzed chemical speciation of eight PTMs(Cd,Cr,Fe,Cu,Mn,Ni,Zn,and Pb)in upper and lower soil layers for 15 agronomic fields of Vehari-Pakistan using Visual Minteq software.The divalent forms of most PTMs(PTM^(2+))generally predominated in both soil layers(79.9%overall occurrence).However,chromium revealed a different pattern of chemical speciation(95.8%as CrOH^(+))compared to other PTMs.The mean percentage of all the PTMs2+was slightly higher for the lower soil layer(81.3%)than in the upper layer(78.4%),the trend being same for all the PTMs,except Cr.This higher PTMs^(2+)percentage in lower soil layers than upper layers was due to lower content of organic matter and other anions such as Cl^(−)and HCO_(3)_(−).The mean percentage ages of all the PTMs^(2+)was similar among all the 15 agronomic fields,which was confirmed by strong Pearson correlation values(R^(2)>0.95).The PCA graph grouped all the agronomic fields and PTM^(2+) closely,except Cr^(2+) and Cu^(2+).This grouping confirmed the similar chemical speciation of PTMs,except Cu and Cr in studied fields.
文摘The soil pH of tea garden was acidic (4.6 - 5.3) with organic contents ranging between 0.91% - 1.09%. Available po- tassium concentration was predominantly found in the range of 167 - 208 mg/kg followed by the nitrogen (150 - 189 mg/ha) and phosphorus (42 - 169 mg/kg). The Fe content was the one of the predominant heavy metal in soil (5494 - 5627 mg/kg) followed by Mn (245 - 435 mg/kg), Zn (30 - 111 mg/kg) and Cu (22 - 51 mg/kg). The concentration of toxic heavy metals Pb, Ni, and Cd in tea leaves, made tea and its infusions were too low. The level of most abundant essential heavy metals in tea infusion was Zn ranging from 0.09 - 0.52 mg/kg followed by Mn 0.10 - 0.42 mg/kg. The level of Fe and Cu was ranging from 0.068 - 0.073 mg/kg and 0.007 - 0.04 mg/kg in tea infusion respectively. The levels of all es- sential and the toxic metals were thus obtained were compared well with the other parts of the world.
基金Project supported by the Guangdong Environmental Protection Bureau of China (No.2001-27)Guangdong Provincial Department of Science and Technology,China (No.2004A30308002)State Key Laboratory of Environment Geochemistry,Chinese Academy of Sciences
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.