The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for...The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.展开更多
基于高分辨率图像对比法,利用同一卫星平台上空间分辨率19.5m的CCD相机图像对CBERS-02B卫星上空间分辨率为258m的WFI成像仪图像进行在轨MTF(modulate transfer function)测量,获得WFI(wide field imager)相机沿轨、跨轨与45o方向的MTF曲...基于高分辨率图像对比法,利用同一卫星平台上空间分辨率19.5m的CCD相机图像对CBERS-02B卫星上空间分辨率为258m的WFI成像仪图像进行在轨MTF(modulate transfer function)测量,获得WFI(wide field imager)相机沿轨、跨轨与45o方向的MTF曲线,并计算出3个方向的线扩展函数LSF(line spread function),获得3个方向的有效半带宽。结果表明WFI相机红波段跨轨、沿轨与45o方向的有效半带宽,即有效瞬时视场,分别为1.188,1.165与1.281个像元,近红外波段为1.258,1.195与1.326个像元。基于获得的MTF,利用维纳滤波法对WFI图像进行补偿,部分恢复了WFI图像的细部信息。展开更多
In the department of Zouan-Hounien, gold mining is booming. This activity, marked by the excavation of rocks and the use of chemicals such as mercury, is likely to contaminate the region’s groundwater resources and e...In the department of Zouan-Hounien, gold mining is booming. This activity, marked by the excavation of rocks and the use of chemicals such as mercury, is likely to contaminate the region’s groundwater resources and expose populations to serious diseases. This study aims to assess the health risks associated with the consumption of this water by the population. To this end, 72 groundwater samples were taken in eight (08) villages of the department at the rate of forty-six (46) well water samples and twenty-six (26) borehole water samples. A total of twenty-twenty-three wells and thirteen boreholes were sampled during two campaigns. An atomic absorption spectrometer (AAS) was used to determine the concentrations of metallic trace elements (MTEs), such as mercury (Hg), lead (Pb), cadmium (Cd), Arsenic (As), and iron (Fe) in the different samples. The daily exposure doses for oral ingestion (CDIing) and skin contact (Expderm) were calculated. The non-carcinogenic (HQ) and carcinogenic risks (CR) were estimated. The results show that the mean concentrations of Fe, Pb, Hg, As and Cd are respectively 2233.48 > 3.10 > 0.60 > 1.18 > 0.08 μg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>L<sup>-1</sup> in the wells and 2427.94 > 4.08 > 1.27 > 1.76 > 0.08 μg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>L<sup>-1</sup> in boreholes. Evaluating the risks to human health reveals that the mean values of hazard quotient (HQ) and cancer risk (CR) for all the elements in the wells and boreholes are lower than 1 and 10<sup>-4</sup> respectively in children and adults for oral and dermal exposure. However, at the oral exposure level, 9 wells and 6 boreholes recorded HQ and CR above the define<span>d critical limits. These values indicate that the occurrence of non-cancero</span>us and cancerous diseases in populations consuming these waters by contamination with mercury and arsenic is not excluded. Dermal exposure to MTEs also poses no potential health risk to the population.展开更多
In Tunisia,water scarcity is only adding pressure on water demand in agriculture.In the context of sustainable development goals,Tunisia has been reusing treated wastewater(TWW)as a renewable and inexpensive source fo...In Tunisia,water scarcity is only adding pressure on water demand in agriculture.In the context of sustainable development goals,Tunisia has been reusing treated wastewater(TWW)as a renewable and inexpensive source for soil fertigation and groundwater(GW)recharge.However,major risks can be expected when the irrigation water is of poor quality.This study aims for evaluating the potential risk of TWW and GW irrigation on soil parameters.Accordingly,we evaluated the suitability of water quality through the analysis of major and minor cations and anions,metallic trace elements(MTEs),and the sodium hazard by using the sodium adsorption ratio(SAR)and the soluble sodium percentage(SSP).The risk of soil sodicity was further assessed by SAR and the exchangeable sodium percentage(ESP).The degree of soil pollution caused by MTEs accumulation was evaluated using geoaccumulation index(Igeo)and pollution load index(PLI).Soil maps were generated using inverse spline interpolation in ArcGIS software.The results show that both water samples(i.e.,TWW and GW)are suitable for soil irrigation in terms of salinity(electrical conductivity<7000μS/cm)and sodicity(SAR<10.00;SSP<60.00%).However,the contents of PO_(4)^(3-),Cu^(2+),and Cd^(2+)exceed the maximum threshold values set by the national and other standards.Concerning the soil samples,the average levels of SAR and ESP are within the standards(SAR<13.00;ESP<15.00%).On the other hand,PLI results reveal moderate pollution in the plot irrigated with TWW and no to moderate pollution in the plot irrigated with GW.Igeo results indicate that Cu^(2+)is the metallic trace element(MTE)with the highest risk of soil pollution in both plots(Igeo>5.00),followed by Ni^(2+)and Pb^(2+).Nevertheless,Cd^(2+)presents the lowest risk of soil pollution(Igeo<0.00).Statistical data indicates that Ca^(2+),Na+,Ni^(2+),and Pb^(2+)are highly distributed in both plots(coefficient of variation>50.0%).This study shows that the use of imagery tools,such as ArcGIS,can provide important information for evaluating the current status of soil fertility or pollution and for better managing soil irrigation with TWW.展开更多
A large size CH3SiO3/2-SiO2 self sustained film with the thickness ranging from 50 to 1000 μm was prepared through sol-gel method by adopting CH3Si(OC2H5)3 and Si(OC2H5) as precursors.In this paper, the preparation p...A large size CH3SiO3/2-SiO2 self sustained film with the thickness ranging from 50 to 1000 μm was prepared through sol-gel method by adopting CH3Si(OC2H5)3 and Si(OC2H5) as precursors.In this paper, the preparation processes of this thick film are discussed in detail and XRD technique was adopted for the identification of oligomer solution. Also, IR and AFM techniques were used to investigate the film structure and surface morphology展开更多
文摘The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.
文摘基于高分辨率图像对比法,利用同一卫星平台上空间分辨率19.5m的CCD相机图像对CBERS-02B卫星上空间分辨率为258m的WFI成像仪图像进行在轨MTF(modulate transfer function)测量,获得WFI(wide field imager)相机沿轨、跨轨与45o方向的MTF曲线,并计算出3个方向的线扩展函数LSF(line spread function),获得3个方向的有效半带宽。结果表明WFI相机红波段跨轨、沿轨与45o方向的有效半带宽,即有效瞬时视场,分别为1.188,1.165与1.281个像元,近红外波段为1.258,1.195与1.326个像元。基于获得的MTF,利用维纳滤波法对WFI图像进行补偿,部分恢复了WFI图像的细部信息。
文摘In the department of Zouan-Hounien, gold mining is booming. This activity, marked by the excavation of rocks and the use of chemicals such as mercury, is likely to contaminate the region’s groundwater resources and expose populations to serious diseases. This study aims to assess the health risks associated with the consumption of this water by the population. To this end, 72 groundwater samples were taken in eight (08) villages of the department at the rate of forty-six (46) well water samples and twenty-six (26) borehole water samples. A total of twenty-twenty-three wells and thirteen boreholes were sampled during two campaigns. An atomic absorption spectrometer (AAS) was used to determine the concentrations of metallic trace elements (MTEs), such as mercury (Hg), lead (Pb), cadmium (Cd), Arsenic (As), and iron (Fe) in the different samples. The daily exposure doses for oral ingestion (CDIing) and skin contact (Expderm) were calculated. The non-carcinogenic (HQ) and carcinogenic risks (CR) were estimated. The results show that the mean concentrations of Fe, Pb, Hg, As and Cd are respectively 2233.48 > 3.10 > 0.60 > 1.18 > 0.08 μg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>L<sup>-1</sup> in the wells and 2427.94 > 4.08 > 1.27 > 1.76 > 0.08 μg<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>L<sup>-1</sup> in boreholes. Evaluating the risks to human health reveals that the mean values of hazard quotient (HQ) and cancer risk (CR) for all the elements in the wells and boreholes are lower than 1 and 10<sup>-4</sup> respectively in children and adults for oral and dermal exposure. However, at the oral exposure level, 9 wells and 6 boreholes recorded HQ and CR above the define<span>d critical limits. These values indicate that the occurrence of non-cancero</span>us and cancerous diseases in populations consuming these waters by contamination with mercury and arsenic is not excluded. Dermal exposure to MTEs also poses no potential health risk to the population.
文摘In Tunisia,water scarcity is only adding pressure on water demand in agriculture.In the context of sustainable development goals,Tunisia has been reusing treated wastewater(TWW)as a renewable and inexpensive source for soil fertigation and groundwater(GW)recharge.However,major risks can be expected when the irrigation water is of poor quality.This study aims for evaluating the potential risk of TWW and GW irrigation on soil parameters.Accordingly,we evaluated the suitability of water quality through the analysis of major and minor cations and anions,metallic trace elements(MTEs),and the sodium hazard by using the sodium adsorption ratio(SAR)and the soluble sodium percentage(SSP).The risk of soil sodicity was further assessed by SAR and the exchangeable sodium percentage(ESP).The degree of soil pollution caused by MTEs accumulation was evaluated using geoaccumulation index(Igeo)and pollution load index(PLI).Soil maps were generated using inverse spline interpolation in ArcGIS software.The results show that both water samples(i.e.,TWW and GW)are suitable for soil irrigation in terms of salinity(electrical conductivity<7000μS/cm)and sodicity(SAR<10.00;SSP<60.00%).However,the contents of PO_(4)^(3-),Cu^(2+),and Cd^(2+)exceed the maximum threshold values set by the national and other standards.Concerning the soil samples,the average levels of SAR and ESP are within the standards(SAR<13.00;ESP<15.00%).On the other hand,PLI results reveal moderate pollution in the plot irrigated with TWW and no to moderate pollution in the plot irrigated with GW.Igeo results indicate that Cu^(2+)is the metallic trace element(MTE)with the highest risk of soil pollution in both plots(Igeo>5.00),followed by Ni^(2+)and Pb^(2+).Nevertheless,Cd^(2+)presents the lowest risk of soil pollution(Igeo<0.00).Statistical data indicates that Ca^(2+),Na+,Ni^(2+),and Pb^(2+)are highly distributed in both plots(coefficient of variation>50.0%).This study shows that the use of imagery tools,such as ArcGIS,can provide important information for evaluating the current status of soil fertility or pollution and for better managing soil irrigation with TWW.
文摘A large size CH3SiO3/2-SiO2 self sustained film with the thickness ranging from 50 to 1000 μm was prepared through sol-gel method by adopting CH3Si(OC2H5)3 and Si(OC2H5) as precursors.In this paper, the preparation processes of this thick film are discussed in detail and XRD technique was adopted for the identification of oligomer solution. Also, IR and AFM techniques were used to investigate the film structure and surface morphology
