Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific samp...Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10<sup>-4</sup> mg/L;2.2 × 10<sup>-1</sup> mg/L;1.2 × 10<sup>-4</sup> mg/L;2 × 10<sup>-4</sup> mg/L), Cadmium (4.4 × 10<sup>-5</sup> mg/L;1.1 × 10<sup>-2</sup> mg/L;10<sup>-4</sup> mg/L;4 × 10<sup>-4</sup> mg/L). Then Copper (7 × 10<sup>-4</sup> mg/L;3 × 10<sup>-3</sup> mg/L;7 × 10<sup>-4</sup> mg/L;1 × 10<sup>-4</sup> mg/L), Iron (1.51 mg/L;6.4 × 10<sup>-1</sup> mg/L;2.0012 mg/L;2.9 × 10<sup>-1</sup> mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10<sup>-3</sup> mg/L;1.5 × 10<sup>-3</sup> mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.展开更多
The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geoche...The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants con- centrations of effluents from the mine tunnels were dependent on pH and SO_4^(2-) which were con- trolled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate. ^(238)U and ^(226)Ra abnormities in stream sediments and soil were 40-90 cm deep and 790-800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5-13 km from the discharge of effluents of the site mainly depending on mechanical and chemical proc- esses. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.展开更多
The concentrations of natural radionuclides, radium-226, radium-228, and potassium-40, and the artificial radionuclide caesium-137, in river bottom sediments and suspended matter were monitored in the Czech Republic b...The concentrations of natural radionuclides, radium-226, radium-228, and potassium-40, and the artificial radionuclide caesium-137, in river bottom sediments and suspended matter were monitored in the Czech Republic by the Czech Hydrometeorological Institute during the period 2000-2010 and 2001-2010 respectively. The data were used to evaluate the natural background levels of these radionuclides and the impact of human activities on the water environment. For potassium-40 in sediments, the natural background level was estimated to be 570 Bq/kg. To evaluate the background level for radium-226, the river sites affected by human activities (mining and processing uranium ore, coal) were eliminated from the assessment. The average natural background values were 47.8 Bq/kg for radium-226 and 47.2 Bq/kg for radium-228 in sediments and 86.5 Bq/kg for radium-226 and 87.9 Bq/kg for radium-228 in suspended matter. The river sediments were identified as good indicators of radioactive contamination, especially radium-226, which recorded historic contamination due to former uranium mining and milling. The radium-226 contamination rate was assessed using the ratio of radium-226 to radium-228. This ratio was used to classify sediment according to the relative contamination from the uranium industry. The residual contamination of caesium-137 due to the Chernobyl accident in 1986 was also assessed. Average values of caesium-137 were 14.0 Bq/kg in sediments and 25.0 Bq/kg in suspended matter.展开更多
The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geoche...The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants con- centrations of effluents from the mine tunnels were dependent on pH and SO_4^(2-) which were con- trolled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate. ^(238)U and ^(226)Ra abnormities in stream sediments and soil were 40-90 cm deep and 790-800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5-13 km from the discharge of effluents of the site mainly depending on mechanical and chemical proc- esses. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.展开更多
文摘Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10<sup>-4</sup> mg/L;2.2 × 10<sup>-1</sup> mg/L;1.2 × 10<sup>-4</sup> mg/L;2 × 10<sup>-4</sup> mg/L), Cadmium (4.4 × 10<sup>-5</sup> mg/L;1.1 × 10<sup>-2</sup> mg/L;10<sup>-4</sup> mg/L;4 × 10<sup>-4</sup> mg/L). Then Copper (7 × 10<sup>-4</sup> mg/L;3 × 10<sup>-3</sup> mg/L;7 × 10<sup>-4</sup> mg/L;1 × 10<sup>-4</sup> mg/L), Iron (1.51 mg/L;6.4 × 10<sup>-1</sup> mg/L;2.0012 mg/L;2.9 × 10<sup>-1</sup> mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10<sup>-3</sup> mg/L;1.5 × 10<sup>-3</sup> mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.
基金supported by the National Natural Science Foundation of China(Grant No.49832005)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of Ministry of Education,China.
文摘The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants con- centrations of effluents from the mine tunnels were dependent on pH and SO_4^(2-) which were con- trolled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate. ^(238)U and ^(226)Ra abnormities in stream sediments and soil were 40-90 cm deep and 790-800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5-13 km from the discharge of effluents of the site mainly depending on mechanical and chemical proc- esses. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.
文摘The concentrations of natural radionuclides, radium-226, radium-228, and potassium-40, and the artificial radionuclide caesium-137, in river bottom sediments and suspended matter were monitored in the Czech Republic by the Czech Hydrometeorological Institute during the period 2000-2010 and 2001-2010 respectively. The data were used to evaluate the natural background levels of these radionuclides and the impact of human activities on the water environment. For potassium-40 in sediments, the natural background level was estimated to be 570 Bq/kg. To evaluate the background level for radium-226, the river sites affected by human activities (mining and processing uranium ore, coal) were eliminated from the assessment. The average natural background values were 47.8 Bq/kg for radium-226 and 47.2 Bq/kg for radium-228 in sediments and 86.5 Bq/kg for radium-226 and 87.9 Bq/kg for radium-228 in suspended matter. The river sediments were identified as good indicators of radioactive contamination, especially radium-226, which recorded historic contamination due to former uranium mining and milling. The radium-226 contamination rate was assessed using the ratio of radium-226 to radium-228. This ratio was used to classify sediment according to the relative contamination from the uranium industry. The residual contamination of caesium-137 due to the Chernobyl accident in 1986 was also assessed. Average values of caesium-137 were 14.0 Bq/kg in sediments and 25.0 Bq/kg in suspended matter.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 30170866)
文摘The distribution of radioactive pollutants, such as ^(222)Rn, U, Th and ^(226)Ra in the air, sur- face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants con- centrations of effluents from the mine tunnels were dependent on pH and SO_4^(2-) which were con- trolled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate. ^(238)U and ^(226)Ra abnormities in stream sediments and soil were 40-90 cm deep and 790-800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5-13 km from the discharge of effluents of the site mainly depending on mechanical and chemical proc- esses. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.
