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
[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
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
The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simult...The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simultaneously collected from the bank were employed as control.Meanwhile,pollution status and potential ecological risk of Hg were calculated and assessed using index of geoaccumulation ( I geo ) and potential ecological risk assessment method (Er) in this study.The results showed that the T-Hg concentrations in sediments at eight sections of YLZB ranged from 4.23 to 48.1 μg/kg with mean concentration of 25.1 μg/kg,which was higher than background Hg value of soils in Tibet.T-Hg concentrations in sediments at three typical segments of YLZB were all significantly higher than those in soils collected from its bank (P<0.05).The Igeo and E r indexes revealed that the T-Hg pollution levels were slight pollution in two sections and moderate ecological risk in six sections of YLZB.Hg pollution risks also existed in the sediments of partial sections of the Lhasa River and the Niyang River,and slightly moderate Hg contamination with high ecological risk was presented in Lhasa urban district.The level of Hg in sediments of YLZB showed a notable spatial distribution characteristic with a trend of increasing firstly and then declining.Human activities played an important role in increasing Hg content in sediments of the river.展开更多
This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (C...This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (Cu, As, Cd, Zn, Pb, Cr, Ni and Mn) were measured in that soil. To calculate the contamination level, the enrichment factor (EF), geoaccumulation index (I<sub>geo</sub>) and Hakanson potential ecological risk index were done. I<sub>geo</sub> values indicated that the study areas at all stations were suffering from moderate contamination with As. The results of enrichment factor revealed that soils in all stations were in extremely high enrichment condition by As metal. Under Hakanson potential ecological risk index, the contamination coefficient () and potential ecological risk index () were calculated. The degree of contamination at BCMCL area reflects moderate contamination. By considering the ecological risk index of a particular heavy metal, the order is as follows: Cd > As > Cu > Pb > Ni > Cr > Zn and Cd has the highest risk index and poses the greatest damage to the BCMCL area’s soil. EF, I<sub>geo</sub> values and potential ecological risk index indicate that there is considerable As and Cd pollution, mainly caused by coal mine drainage water.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 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.
基金Supported by Investigation on Fishery Resources and Environment in Key Waters of TibetSpecial Scientific Research Projects of Public Welfare Industry(Agriculture)(201503108)
文摘The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simultaneously collected from the bank were employed as control.Meanwhile,pollution status and potential ecological risk of Hg were calculated and assessed using index of geoaccumulation ( I geo ) and potential ecological risk assessment method (Er) in this study.The results showed that the T-Hg concentrations in sediments at eight sections of YLZB ranged from 4.23 to 48.1 μg/kg with mean concentration of 25.1 μg/kg,which was higher than background Hg value of soils in Tibet.T-Hg concentrations in sediments at three typical segments of YLZB were all significantly higher than those in soils collected from its bank (P<0.05).The Igeo and E r indexes revealed that the T-Hg pollution levels were slight pollution in two sections and moderate ecological risk in six sections of YLZB.Hg pollution risks also existed in the sediments of partial sections of the Lhasa River and the Niyang River,and slightly moderate Hg contamination with high ecological risk was presented in Lhasa urban district.The level of Hg in sediments of YLZB showed a notable spatial distribution characteristic with a trend of increasing firstly and then declining.Human activities played an important role in increasing Hg content in sediments of the river.
文摘This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (Cu, As, Cd, Zn, Pb, Cr, Ni and Mn) were measured in that soil. To calculate the contamination level, the enrichment factor (EF), geoaccumulation index (I<sub>geo</sub>) and Hakanson potential ecological risk index were done. I<sub>geo</sub> values indicated that the study areas at all stations were suffering from moderate contamination with As. The results of enrichment factor revealed that soils in all stations were in extremely high enrichment condition by As metal. Under Hakanson potential ecological risk index, the contamination coefficient () and potential ecological risk index () were calculated. The degree of contamination at BCMCL area reflects moderate contamination. By considering the ecological risk index of a particular heavy metal, the order is as follows: Cd > As > Cu > Pb > Ni > Cr > Zn and Cd has the highest risk index and poses the greatest damage to the BCMCL area’s soil. EF, I<sub>geo</sub> values and potential ecological risk index indicate that there is considerable As and Cd pollution, mainly caused by coal mine drainage water.