A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extracta...A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry （CVAAS）. Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2＋on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2＋ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2＋ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit （30） for Hg^2＋ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2＋ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD （n = 5） of 2.9%-3.5%.展开更多
Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest o...Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest on a global scale. Natural emissions of mercury form two-thirds of the input; man-made releases form about one-third. Significant amounts of mercury may be added to agricultural land with sludge, fertilizers, lime and manures. Total mercury levels were determined in six breeds of quality protein maize using cold vapor atomic absorption spectrometry （CVAAS）. The breeds analyzed were Aziga, Abeleehi, Akposoe, Golden Jubilee, Etubi and Obaatanpa. Proximate composition of these breeds was also determined. The objective of this study was therefore to assess the effect of mercury on the proximate composition of quality protein maize. The proximate composition of the maize varieties analyzed showed that the moisture content ranged from 11.57% ± 0.205% to 12.76%± 0.042%, ash from 1.11% ±0.064% to 1.58% ±0.021%, protein, 6.51%± 0.307% to 10.39% ±0.306%, fiber 1.44% ±0.071% to 1.87% ± 0.057%, fat 1.84% ± 0.078% to 2.75% ± 0.092% and carbohydrate 71.77% ± 0.035% to 76.54% ± 0.216%. The total mercury levels in the maize breeds analyzed ranged from 0.0010 ＋ 1.17E-05μg/g to 0.0079 ＋ 1.00E-05μg/g. The mercury levels detected were lower than the WHO limit for mercury in food of 0.5 μg/g in all the maize breeds. The low levels of mercury in the maize samples show they are safe for consumption.展开更多
The World Health Organization (WHO), Environmental Protection Agency (EPA), and International Atomic Energy Agency (IAEA) have recommended the use of hair for worldwide environmental monitoring. Mercury exposure to th...The World Health Organization (WHO), Environmental Protection Agency (EPA), and International Atomic Energy Agency (IAEA) have recommended the use of hair for worldwide environmental monitoring. Mercury exposure to the inhabitants of Karachi was assessed by using hair as bioindicator. Hair samples of 200 residents of Karachi were collected and analyzed through cold vapor atomic absorption spectroscopy (CVAA) technique for mercury concentration. The effects of age, gender, working status, location, food and smoking habit were investigated. Control region showed a positive correlation between HHg and age of donor while no such correlation was observed for polluted regions. Mercury exposure through cosmetic usage in female was only pronounced in control region. These results indicate that environmental pollution dominates other potential factors. Age and smoking habit were not found to be the influencing factors while an elevated mean level of mercury was noticed for regular fish consumers than rarely fish consumers. 95.33% of the samples contained HHg greater than the permissible level of 2 μg?g?1 set by WHO. An apparently healthy male donor had HHg concentration (28.24 μg?g?1) closer to the high risk concentration of 30 μg?g?1 based on WHO criteria. Whereas, two female donors of the age group of 41-50 years had HHg concentrations (10.82 and 11.84 μg?g?1) higher than the NOAEL (no observed adverse affects level) value (10 μg?g?1) for females which is associated with fetus neurotoxicity. However, no symptoms of mercury toxicity were visible. The results indicate the alarming condition of pollution in the city which should be taken into further consideration.展开更多
基金the Natural Science Foundation of the Department of Education, Guangdong Province, China (No. 02025).
文摘A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2） as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry （CVAAS）. Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2＋on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2＋ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2＋ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit （30） for Hg^2＋ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2＋ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD （n = 5） of 2.9%-3.5%.
文摘Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest on a global scale. Natural emissions of mercury form two-thirds of the input; man-made releases form about one-third. Significant amounts of mercury may be added to agricultural land with sludge, fertilizers, lime and manures. Total mercury levels were determined in six breeds of quality protein maize using cold vapor atomic absorption spectrometry （CVAAS）. The breeds analyzed were Aziga, Abeleehi, Akposoe, Golden Jubilee, Etubi and Obaatanpa. Proximate composition of these breeds was also determined. The objective of this study was therefore to assess the effect of mercury on the proximate composition of quality protein maize. The proximate composition of the maize varieties analyzed showed that the moisture content ranged from 11.57% ± 0.205% to 12.76%± 0.042%, ash from 1.11% ±0.064% to 1.58% ±0.021%, protein, 6.51%± 0.307% to 10.39% ±0.306%, fiber 1.44% ±0.071% to 1.87% ± 0.057%, fat 1.84% ± 0.078% to 2.75% ± 0.092% and carbohydrate 71.77% ± 0.035% to 76.54% ± 0.216%. The total mercury levels in the maize breeds analyzed ranged from 0.0010 ＋ 1.17E-05μg/g to 0.0079 ＋ 1.00E-05μg/g. The mercury levels detected were lower than the WHO limit for mercury in food of 0.5 μg/g in all the maize breeds. The low levels of mercury in the maize samples show they are safe for consumption.
文摘The World Health Organization (WHO), Environmental Protection Agency (EPA), and International Atomic Energy Agency (IAEA) have recommended the use of hair for worldwide environmental monitoring. Mercury exposure to the inhabitants of Karachi was assessed by using hair as bioindicator. Hair samples of 200 residents of Karachi were collected and analyzed through cold vapor atomic absorption spectroscopy (CVAA) technique for mercury concentration. The effects of age, gender, working status, location, food and smoking habit were investigated. Control region showed a positive correlation between HHg and age of donor while no such correlation was observed for polluted regions. Mercury exposure through cosmetic usage in female was only pronounced in control region. These results indicate that environmental pollution dominates other potential factors. Age and smoking habit were not found to be the influencing factors while an elevated mean level of mercury was noticed for regular fish consumers than rarely fish consumers. 95.33% of the samples contained HHg greater than the permissible level of 2 μg?g?1 set by WHO. An apparently healthy male donor had HHg concentration (28.24 μg?g?1) closer to the high risk concentration of 30 μg?g?1 based on WHO criteria. Whereas, two female donors of the age group of 41-50 years had HHg concentrations (10.82 and 11.84 μg?g?1) higher than the NOAEL (no observed adverse affects level) value (10 μg?g?1) for females which is associated with fetus neurotoxicity. However, no symptoms of mercury toxicity were visible. The results indicate the alarming condition of pollution in the city which should be taken into further consideration.
