Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-te...Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-term effects on economy,environment,and society.This study collected soil samples from 16 sample points including a control point to examine the pollution degrees and spatial distribution of heavy metals,as well as ecological and health risks associated with heavy metal pollution in the Ijero-Ekiti mining site,Nigeria.Geographical Information System(GIS)and remote sensing technologies were used to identify regions with high concentrations of heavy metals and assess the environmental impact of gold mining activities.The results show that the mean heavy metal concentrations of 16 soil pointa are 8.94(±5.97)mg/kg for As,0.18(±0.54)mg/kg for Cd,0.11(±1.06)mg/kg for Co,14.32(±3.43)mg/kg for Cr,6.89(±0.64)mg/kg for Cu,48.92(±11.77)mg/kg for Fe,135.81(±30.75)mg/kg for Mn,5.92(±0.96)mg/kg for Ni,5.72(±1.66)mg/kg for Pb,and 13.94(±1.38)mg/kg for Zn.The study reveals that heavy metal concentration in soils follows the order of Mn>Fe>Cr>Zn>As>Cu>Ni>Pb>Co>Cd.An analysis of soil samples indicates that 3 principal components(PCs)account for 70.008%of the total variance and there are strong positive correlations between various pairs of heavy metals.The total potential ecological risk index(309.599)in the study area is high.Non-carcinogenic risk suggests that there may be long-term health impacts on people who work in the mining areas due to chronic exposure to the environment.Based on the study,the hazard index of carcinogenic health risks associated with heavy metals through ingestion is 520.00×10^(–4).Dermal contact from As and Cr also increases the risk of cancer,with the highest hazard index value of 18.40×10^(–4).The lowest exposure pathway,with the hazard index value of 0.68×10^(–4),indicates that the inhalation of heavy metals has a comparatively low risk of cancer.This study recommends the formulation of policies to monitor the Ijero-Ekiti mining site and other regions in Nigeria where indiscriminate artisanal gold mining activities exist.展开更多
In order to determine the environmental quality condition of reclaimed soils inHuainan mining area, soil samples were collected from three representative mines, suchas Panyi Mine, Xinzhuangzi Mine and Datong Mine.The ...In order to determine the environmental quality condition of reclaimed soils inHuainan mining area, soil samples were collected from three representative mines, suchas Panyi Mine, Xinzhuangzi Mine and Datong Mine.The total concentration of Cd, Hg, Cu,Pb and As in the samples were analyzed.The potential ecological risk was used to evaluatethe heavy metals pollution.The investigation reveals that the reclaimed soils are contaminatedto a certain degree and the trace elements in coal gangue transferred to thesurface soil.The order of potential ecological risk is Cd>Hg>Cu>Pb>As; the pollution degreeof each sampling site is arranged in the following order: Xinzhuangzi Mine>DatongMine>Panyi Mine, and the multiform of heavy metals of potential ecological risk index is at357.35~484.62.展开更多
Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollutio...Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollution of wetland are becoming more and more serious. To evaluate the pollution of heavy metals in the sediments of Longjiang Wetland in Binzhou City, chromium(Cr), copper(Cu), zinc(Zn), cadmium(Cd) and lead(Pb) were measured by inductively coupled plasma mass spectrometry. Concentrations of Cr, Cu, Zn, Cd and Pb in the sediments were 5.3–13.6, 5.6–15.0, 16.6–33.0, 0.1–0.4 and 7.9–24.9 mg/kg dry weight, respectively. The concentrations of heavy metals in Longjiang Wetland was lower than soil background values of Shandong Province and in lower level compared with those reported in sediments/soils of wetlands in some other locations. Based on geo-accumulation index(Igeo), Cr, Cu, Zn and Pb showed low levels of contamination at all stations, while Cd was observed at a moderate pollution degree. Potential ecological risk factor(E_r^i) and risk index(RI) values showed low ecological risk of heavy metals in sediments of the wetland.展开更多
The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great sign...The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution.Taking the Taowanbeigou River Basin in the mine concentration area as the research object,the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method,potential ecological risk assessment method and geoaccumulation index method.On this basis,the cumulative exceeding years of specific heavy metals were predicted by using the early warning model.The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate,and the single element Cd is the main ecological risk factor,with a contribution rate of 53.6%.The overall cumulative degrees of Cu and Pb in the soil are“none-moderate”,Zn and Cd are moderate,Mo has reached an extremely strong cumulative level,Hg,As and Cr risks are not obvious,and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg.According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard,the locations over standard rates of Cu,Zn and Cd will exceed 78%in 90years,and the over standard rate of Pb will reach approximately 57%in 200 years.The cumulative exceeding standard periods of As,Cr and Hg are generally long,which basically indicates that these elements do not pose a significant potential threat to the ecological environment.Mining activities will accelerate the accumulation of heavy metals in soil.With the continuous development of mining activities,the potential pollution risk of heavy metals in the soil of mining areas will also increase.展开更多
Soil,crop and residents'hair over Xiaoqinling gold mining region,China,which was selected as a case study,were sampled and analyzed for Hg,Cd,Pb,Cu,Cr,As and Zn concentrations.The concentrations of heavy metals in...Soil,crop and residents'hair over Xiaoqinling gold mining region,China,which was selected as a case study,were sampled and analyzed for Hg,Cd,Pb,Cu,Cr,As and Zn concentrations.The concentrations of heavy metals in soil or crop and hair samples were used to assess their potential ecological risks,or to find the responses to these metals as evidences to prove the potential risk was coming down to observed harm,respectively.The results showed that,these metals in soil were ranked by severity of ecological risk as Hg>Cd>Pb>Cu>Cr>As>Zn,based on their single-element indexes.In the view of the potential ecological risk indexes,of all soil samples,about half had significantly high or high potential ecological risk,which covered more than 74%of the studied region.Most of the risks were 97.41%from Hg,Pb and Cd,especially,84.37%from Hg.Both the single-element and potential ecological risk indexes indicated that,the ecological risk grades had a special spatial characteristic,and increased from northwest to southeast generally.This was agreed with the spatial distribution of the strength in gold mining activities over the studied region.The concentrations of Hg and Pb were higher than their relative backgrounds in the corps,and were even 9.48 and 25.09 times higher than their relative backgrounds in residents'hair,respectively.All these showed that the heavy metals in the soil had a high potential ecological risk,especially,had been affecting these crops'growing and yield,and even the residents'health through food strains.Obviously,these metals'potential ecological harm had been coming down to observed harm to the ecology.展开更多
[Objective] The aim was to analyze the content of heavy metals in surface sediment in Weishan Lake and further assess its ecological risk.[Method] Heavy metal pollution in surface sediment in Weishan Lake was studied,...[Objective] The aim was to analyze the content of heavy metals in surface sediment in Weishan Lake and further assess its ecological risk.[Method] Heavy metal pollution in surface sediment in Weishan Lake was studied,and the pollution indices and potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were calculated to assess the potential ecological risk of heavy metal pollution.[Result] In surface sediment in Weishan Lake,the average contents of Cu,Zn,Pb,Cd,Cr and Ni were 64.78,185.05,78.76,0.17,37.76 and 46.84mg/kg respectively.Cr and Cd weren’t beyond standards in all stations,while Cu and Pb exceeded standards in all stations,with average super-standard multiple of 0.85 and 0.31,respectively,and Zn content wasn’t beyond standard in S2 station,with average super-standard multiple of 0.24.The average pollution indices of Cu,Zn,Pb,Cd and Cr were 1.85,1.23,1.31,0.34 and 0.47 respectively,with average comprehensive pollution index of 5.21,which showed that heavy metal pollution was light.In addition,heavy metal pollution in entryway portion and sea-route portion were more serious than that of breeding portion.Potential ecological risk assessment showed that the average potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were 9.25,1.23,6.56,10.34 and 0.94 respectively,with average comprehensive potential ecological risk index of 28.33,and it revealed that potential ecological risk of heavy metals was slight.Besides,the potential ecological risk order of heavy metal pollution was sea-route portion>entryway portion>breeding portion.[Conclusion] The study could provide references for the regulation and improvement of ecological environment in Weishan Lake in the east route of south-to-north water transfer project.展开更多
The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil wer...The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu,Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form(31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions(27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions(90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code(RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd(45.6 and 54.4 %), medium risk of Zn(100 %), low and medium risk of Cu(41.2 and 58.8 %), largely no risk of Hg(97.1 %), and mainly low risk of As and Pb(92.6and 91.8 %). The range of the potential ecological risk of soil was 58.2–1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk.展开更多
The concentrations of five metals(Cu, Pb, Zn, Cd and Hg) were measured in sediments obtained before and after the establishment of Techeng Island Special Marine Reserves(TCISMR) in Zhanjiang Bay to evaluate the ecolog...The concentrations of five metals(Cu, Pb, Zn, Cd and Hg) were measured in sediments obtained before and after the establishment of Techeng Island Special Marine Reserves(TCISMR) in Zhanjiang Bay to evaluate the ecological risk of heavy metals. The results showed that average values of potential ecological risk indexes of heavy metals at all stations increased slightly from 32.09 to 30.54 after establishment of TCISMR. Optimal semivariance simulation showed that the contents of five heavy metals have strong spatial correlations in August 2010(before), while this correlations weakened in April 2013(after establishment of TCISMR), suggesting that the main sources of heavy metals changed. The Hakanson Risk Index(HRI) values in Donghai levee, central and southern parts of Zhanjiang harbor were high up to 60.13 and 46.46, respectively. And Zhanjiang Bay Channel, the areas around special marine reserves, the artificial reef areas and mangrove areas at south of Techeng Island are the areas with low ecological risk and high ecological value, which should be treated as the prior ecological protection areas. Our study provided a priority control pattern of heavy metal pollution in TCISMR, which greatly benefits the sustainable development and resource protection in Zhanjiang Bay.展开更多
At present, the methods widely applied to assess ecological risk of heavy metals are essentially single-point estimates in which exposure and toxicity data cannot be fully used and probabilities of adverse biological ...At present, the methods widely applied to assess ecological risk of heavy metals are essentially single-point estimates in which exposure and toxicity data cannot be fully used and probabilities of adverse biological effects cannot be achieved. In this study, based on investigation of concentrations of six heavy metals(As, Hg, Pb, Cd, Cu, and Zn) in the surface seawater and sediment near the outlet of a zinc factory, located in Huludao City, Liaoning Province, China, a tiered approach consisting of several probabilistic options was used to refi ne ecological risk assessment for the individuals. A mixture of various heavy metals was detected in the surface seawater, and potential ecological risk index(PERI) was adopted to assess the potential ecological risk of heavy metals in the surface sediment. The results from all levels of aquatic ecological risk assessment in the tiered framework, ranging from comparison of single effects and exposure values to the use of distribution-based Hazard Quotient obtained through Monte Carlo simulation, are consistent with each other. Briefl y, aquatic Zn and Cu posed a clear ecological risk, while Cd, Pb, Hg, and As in the water column posed potential risk. As expected, combined ecological risk of heavy metal mixture in the surface seawater was proved signifi cantly higher than the risk caused by any individual heavy metal, calculated using the concept of total equivalent concentration. According to PERI, the severity of pollution by the six heavy metals in the surface sediment decreased in the following sequence: Cd>Hg>As>Pb>Cu>Zn, and the total heavy metals in the sediment posed a very high risk to the marine environment. This study provides a useful mathematical framework for ecological risk assessment of heavy metals.展开更多
A protected semi-enclosed embayment,the Eastern Harbor(EH),is situated in the central sector of the Mediterranean coast of Alexandria,Egypt.It is a famous fishing dock and water-sport center and its importance arose a...A protected semi-enclosed embayment,the Eastern Harbor(EH),is situated in the central sector of the Mediterranean coast of Alexandria,Egypt.It is a famous fishing dock and water-sport center and its importance arose after the discovery of the Ptolemaic royal quarter of ancient Alexandria.To protect this national treasure and improve its environmental health,the untreated anthropogenic effluents,which continued for decades into the EH since 1992,must be totally stopped.Accordingly,it is an important issue to continually monitor and asses the environmental status of the EH.The sediment texture,total organic carbon,and the accumulation,distribution,and ecological risks of Cd,Cr,Pb,As,Hg and A1 were determined with a total of 14 surficial sediments samples collected in the EH during 2010.Metal contents were compared to the literature data to assess the pollution status of sediments.Enrichment factors,Degree of contamination(mCd)and potential ecological risk were calculated as a criterion of possible contamination.Since mCd calculation produces an overall average value for a range of pollutants,in the present study the contamination factor that provides a measure of the degree of overall contamination in the surface layers in a particular sampling site may provide a better indication of the state of pollution in the EH sediments than other indicators.展开更多
Identifying and monitoring the spatiotemporal patterns of potentially contaminated land(PCL) in China is a key concern of ecological governance. However, the dynamics of PCL’s expansion remain unclear nationwide. Int...Identifying and monitoring the spatiotemporal patterns of potentially contaminated land(PCL) in China is a key concern of ecological governance. However, the dynamics of PCL’s expansion remain unclear nationwide. Integrating high-resolution remote sensing images, a land-use/cover change database, crawler data from websites, and other multisource data, we produced a new dataset of China’s PCL in 1990, 2000, 2010, and 2020 using data fusion technology. Then we analyzed the spatiotemporal patterns of China’s PCL from 1990 to 2020. Our study shows that the acquired vector dataset of China’s PCL is of high quality and reliability, with an overall accuracy of 93.21%. The area of China’s PCL has kept growing for the past 30 years, and the growth rate was especially rapid during2000–2010, 2.32 and 6.13 times as rapid as that during 1990–2000 and 2010–2020, respectively. PCL has also been trending toward higher aggregation over markedly enlarged areas and has transferred progressively from north and southeast of China to northwest and southwest of China and Qinghai-Tibet Plateau. The patterns of China’s PCL have been driven by the joint factors of policies, mineral resources, economy, and others, among which policies and the economy have contributed more prominently to the long-term transition.Our study promotes the access to high-quality spatial data of PCL to facilitate environmental governance of mine wastes, pollution and land management.展开更多
文摘Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-term effects on economy,environment,and society.This study collected soil samples from 16 sample points including a control point to examine the pollution degrees and spatial distribution of heavy metals,as well as ecological and health risks associated with heavy metal pollution in the Ijero-Ekiti mining site,Nigeria.Geographical Information System(GIS)and remote sensing technologies were used to identify regions with high concentrations of heavy metals and assess the environmental impact of gold mining activities.The results show that the mean heavy metal concentrations of 16 soil pointa are 8.94(±5.97)mg/kg for As,0.18(±0.54)mg/kg for Cd,0.11(±1.06)mg/kg for Co,14.32(±3.43)mg/kg for Cr,6.89(±0.64)mg/kg for Cu,48.92(±11.77)mg/kg for Fe,135.81(±30.75)mg/kg for Mn,5.92(±0.96)mg/kg for Ni,5.72(±1.66)mg/kg for Pb,and 13.94(±1.38)mg/kg for Zn.The study reveals that heavy metal concentration in soils follows the order of Mn>Fe>Cr>Zn>As>Cu>Ni>Pb>Co>Cd.An analysis of soil samples indicates that 3 principal components(PCs)account for 70.008%of the total variance and there are strong positive correlations between various pairs of heavy metals.The total potential ecological risk index(309.599)in the study area is high.Non-carcinogenic risk suggests that there may be long-term health impacts on people who work in the mining areas due to chronic exposure to the environment.Based on the study,the hazard index of carcinogenic health risks associated with heavy metals through ingestion is 520.00×10^(–4).Dermal contact from As and Cr also increases the risk of cancer,with the highest hazard index value of 18.40×10^(–4).The lowest exposure pathway,with the hazard index value of 0.68×10^(–4),indicates that the inhalation of heavy metals has a comparatively low risk of cancer.This study recommends the formulation of policies to monitor the Ijero-Ekiti mining site and other regions in Nigeria where indiscriminate artisanal gold mining activities exist.
基金Supported by the Natural Science Foundation of China of Anhui Education to Research(KJ2009A088)
文摘In order to determine the environmental quality condition of reclaimed soils inHuainan mining area, soil samples were collected from three representative mines, suchas Panyi Mine, Xinzhuangzi Mine and Datong Mine.The total concentration of Cd, Hg, Cu,Pb and As in the samples were analyzed.The potential ecological risk was used to evaluatethe heavy metals pollution.The investigation reveals that the reclaimed soils are contaminatedto a certain degree and the trace elements in coal gangue transferred to thesurface soil.The order of potential ecological risk is Cd>Hg>Cu>Pb>As; the pollution degreeof each sampling site is arranged in the following order: Xinzhuangzi Mine>DatongMine>Panyi Mine, and the multiform of heavy metals of potential ecological risk index is at357.35~484.62.
基金Sponsored by the Natural Science Foundation of Shandong Province(ZR2018PD002)
文摘Wetland is a unique habitat with great biodiversity and important ecological functions between land and water on the earth. With the irrational utilization of wetland resources, the ecological destruction and pollution of wetland are becoming more and more serious. To evaluate the pollution of heavy metals in the sediments of Longjiang Wetland in Binzhou City, chromium(Cr), copper(Cu), zinc(Zn), cadmium(Cd) and lead(Pb) were measured by inductively coupled plasma mass spectrometry. Concentrations of Cr, Cu, Zn, Cd and Pb in the sediments were 5.3–13.6, 5.6–15.0, 16.6–33.0, 0.1–0.4 and 7.9–24.9 mg/kg dry weight, respectively. The concentrations of heavy metals in Longjiang Wetland was lower than soil background values of Shandong Province and in lower level compared with those reported in sediments/soils of wetlands in some other locations. Based on geo-accumulation index(Igeo), Cr, Cu, Zn and Pb showed low levels of contamination at all stations, while Cd was observed at a moderate pollution degree. Potential ecological risk factor(E_r^i) and risk index(RI) values showed low ecological risk of heavy metals in sediments of the wetland.
基金supported by the Science and Technology Research Project to Henan Provincial Department of Natural Resources(Henan Natural Resources Letter[2019]373–10)。
文摘The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution.Taking the Taowanbeigou River Basin in the mine concentration area as the research object,the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method,potential ecological risk assessment method and geoaccumulation index method.On this basis,the cumulative exceeding years of specific heavy metals were predicted by using the early warning model.The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate,and the single element Cd is the main ecological risk factor,with a contribution rate of 53.6%.The overall cumulative degrees of Cu and Pb in the soil are“none-moderate”,Zn and Cd are moderate,Mo has reached an extremely strong cumulative level,Hg,As and Cr risks are not obvious,and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg.According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard,the locations over standard rates of Cu,Zn and Cd will exceed 78%in 90years,and the over standard rate of Pb will reach approximately 57%in 200 years.The cumulative exceeding standard periods of As,Cr and Hg are generally long,which basically indicates that these elements do not pose a significant potential threat to the ecological environment.Mining activities will accelerate the accumulation of heavy metals in soil.With the continuous development of mining activities,the potential pollution risk of heavy metals in the soil of mining areas will also increase.
基金Project(1212010741003)supported by the Ministry of Land and Resources of ChinaProject(SJ08-ZT08)supported by the Natural Science Foundation of Shaanxi Province,ChinaProject(NCET-07-0694)supported by Program for University Talents in the NewCentury,China
文摘Soil,crop and residents'hair over Xiaoqinling gold mining region,China,which was selected as a case study,were sampled and analyzed for Hg,Cd,Pb,Cu,Cr,As and Zn concentrations.The concentrations of heavy metals in soil or crop and hair samples were used to assess their potential ecological risks,or to find the responses to these metals as evidences to prove the potential risk was coming down to observed harm,respectively.The results showed that,these metals in soil were ranked by severity of ecological risk as Hg>Cd>Pb>Cu>Cr>As>Zn,based on their single-element indexes.In the view of the potential ecological risk indexes,of all soil samples,about half had significantly high or high potential ecological risk,which covered more than 74%of the studied region.Most of the risks were 97.41%from Hg,Pb and Cd,especially,84.37%from Hg.Both the single-element and potential ecological risk indexes indicated that,the ecological risk grades had a special spatial characteristic,and increased from northwest to southeast generally.This was agreed with the spatial distribution of the strength in gold mining activities over the studied region.The concentrations of Hg and Pb were higher than their relative backgrounds in the corps,and were even 9.48 and 25.09 times higher than their relative backgrounds in residents'hair,respectively.All these showed that the heavy metals in the soil had a high potential ecological risk,especially,had been affecting these crops'growing and yield,and even the residents'health through food strains.Obviously,these metals'potential ecological harm had been coming down to observed harm to the ecology.
基金Supported by Natural Science Foundation of Shandong Province (ZR2010CL004)Doctoral Research Foundation of Zaozhuang University+2 种基金Key Program of Zaozhuang UniversityYouth Foundation of Zaozhuang UniversityKey Discipline Construction Project of Hydrobiology of Zaozhuang University
文摘[Objective] The aim was to analyze the content of heavy metals in surface sediment in Weishan Lake and further assess its ecological risk.[Method] Heavy metal pollution in surface sediment in Weishan Lake was studied,and the pollution indices and potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were calculated to assess the potential ecological risk of heavy metal pollution.[Result] In surface sediment in Weishan Lake,the average contents of Cu,Zn,Pb,Cd,Cr and Ni were 64.78,185.05,78.76,0.17,37.76 and 46.84mg/kg respectively.Cr and Cd weren’t beyond standards in all stations,while Cu and Pb exceeded standards in all stations,with average super-standard multiple of 0.85 and 0.31,respectively,and Zn content wasn’t beyond standard in S2 station,with average super-standard multiple of 0.24.The average pollution indices of Cu,Zn,Pb,Cd and Cr were 1.85,1.23,1.31,0.34 and 0.47 respectively,with average comprehensive pollution index of 5.21,which showed that heavy metal pollution was light.In addition,heavy metal pollution in entryway portion and sea-route portion were more serious than that of breeding portion.Potential ecological risk assessment showed that the average potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were 9.25,1.23,6.56,10.34 and 0.94 respectively,with average comprehensive potential ecological risk index of 28.33,and it revealed that potential ecological risk of heavy metals was slight.Besides,the potential ecological risk order of heavy metal pollution was sea-route portion>entryway portion>breeding portion.[Conclusion] The study could provide references for the regulation and improvement of ecological environment in Weishan Lake in the east route of south-to-north water transfer project.
基金funded by National Natural Science Foundation of China (No. 41303069)
文摘The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu,Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form(31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions(27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions(90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code(RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd(45.6 and 54.4 %), medium risk of Zn(100 %), low and medium risk of Cu(41.2 and 58.8 %), largely no risk of Hg(97.1 %), and mainly low risk of As and Pb(92.6and 91.8 %). The range of the potential ecological risk of soil was 58.2–1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk.
基金jointly funded by the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (No.2013K0011)the State Oceanic Administration Key Laboratory of Sea area Management Technology Fund (No.201711)+2 种基金the Guangdong MEPP Fund (No.GDOE [2019]A46)the GDNRC (No.[2020]067)the South China Sea Branch Secretary fund (No.1673)。
文摘The concentrations of five metals(Cu, Pb, Zn, Cd and Hg) were measured in sediments obtained before and after the establishment of Techeng Island Special Marine Reserves(TCISMR) in Zhanjiang Bay to evaluate the ecological risk of heavy metals. The results showed that average values of potential ecological risk indexes of heavy metals at all stations increased slightly from 32.09 to 30.54 after establishment of TCISMR. Optimal semivariance simulation showed that the contents of five heavy metals have strong spatial correlations in August 2010(before), while this correlations weakened in April 2013(after establishment of TCISMR), suggesting that the main sources of heavy metals changed. The Hakanson Risk Index(HRI) values in Donghai levee, central and southern parts of Zhanjiang harbor were high up to 60.13 and 46.46, respectively. And Zhanjiang Bay Channel, the areas around special marine reserves, the artificial reef areas and mangrove areas at south of Techeng Island are the areas with low ecological risk and high ecological value, which should be treated as the prior ecological protection areas. Our study provided a priority control pattern of heavy metal pollution in TCISMR, which greatly benefits the sustainable development and resource protection in Zhanjiang Bay.
基金Supported by the Science and Technology Project of North China Sea Branch of State Oceanic Administration(No.2014B02)
文摘At present, the methods widely applied to assess ecological risk of heavy metals are essentially single-point estimates in which exposure and toxicity data cannot be fully used and probabilities of adverse biological effects cannot be achieved. In this study, based on investigation of concentrations of six heavy metals(As, Hg, Pb, Cd, Cu, and Zn) in the surface seawater and sediment near the outlet of a zinc factory, located in Huludao City, Liaoning Province, China, a tiered approach consisting of several probabilistic options was used to refi ne ecological risk assessment for the individuals. A mixture of various heavy metals was detected in the surface seawater, and potential ecological risk index(PERI) was adopted to assess the potential ecological risk of heavy metals in the surface sediment. The results from all levels of aquatic ecological risk assessment in the tiered framework, ranging from comparison of single effects and exposure values to the use of distribution-based Hazard Quotient obtained through Monte Carlo simulation, are consistent with each other. Briefl y, aquatic Zn and Cu posed a clear ecological risk, while Cd, Pb, Hg, and As in the water column posed potential risk. As expected, combined ecological risk of heavy metal mixture in the surface seawater was proved signifi cantly higher than the risk caused by any individual heavy metal, calculated using the concept of total equivalent concentration. According to PERI, the severity of pollution by the six heavy metals in the surface sediment decreased in the following sequence: Cd>Hg>As>Pb>Cu>Zn, and the total heavy metals in the sediment posed a very high risk to the marine environment. This study provides a useful mathematical framework for ecological risk assessment of heavy metals.
文摘A protected semi-enclosed embayment,the Eastern Harbor(EH),is situated in the central sector of the Mediterranean coast of Alexandria,Egypt.It is a famous fishing dock and water-sport center and its importance arose after the discovery of the Ptolemaic royal quarter of ancient Alexandria.To protect this national treasure and improve its environmental health,the untreated anthropogenic effluents,which continued for decades into the EH since 1992,must be totally stopped.Accordingly,it is an important issue to continually monitor and asses the environmental status of the EH.The sediment texture,total organic carbon,and the accumulation,distribution,and ecological risks of Cd,Cr,Pb,As,Hg and A1 were determined with a total of 14 surficial sediments samples collected in the EH during 2010.Metal contents were compared to the literature data to assess the pollution status of sediments.Enrichment factors,Degree of contamination(mCd)and potential ecological risk were calculated as a criterion of possible contamination.Since mCd calculation produces an overall average value for a range of pollutants,in the present study the contamination factor that provides a measure of the degree of overall contamination in the surface layers in a particular sampling site may provide a better indication of the state of pollution in the EH sediments than other indicators.
基金Under the auspices of the National Key Research and Development Program (No. 2018YFC1800103, 2018YFC1800106)。
文摘Identifying and monitoring the spatiotemporal patterns of potentially contaminated land(PCL) in China is a key concern of ecological governance. However, the dynamics of PCL’s expansion remain unclear nationwide. Integrating high-resolution remote sensing images, a land-use/cover change database, crawler data from websites, and other multisource data, we produced a new dataset of China’s PCL in 1990, 2000, 2010, and 2020 using data fusion technology. Then we analyzed the spatiotemporal patterns of China’s PCL from 1990 to 2020. Our study shows that the acquired vector dataset of China’s PCL is of high quality and reliability, with an overall accuracy of 93.21%. The area of China’s PCL has kept growing for the past 30 years, and the growth rate was especially rapid during2000–2010, 2.32 and 6.13 times as rapid as that during 1990–2000 and 2010–2020, respectively. PCL has also been trending toward higher aggregation over markedly enlarged areas and has transferred progressively from north and southeast of China to northwest and southwest of China and Qinghai-Tibet Plateau. The patterns of China’s PCL have been driven by the joint factors of policies, mineral resources, economy, and others, among which policies and the economy have contributed more prominently to the long-term transition.Our study promotes the access to high-quality spatial data of PCL to facilitate environmental governance of mine wastes, pollution and land management.