Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environm...Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.展开更多
The method of principal component analysis was applied to systematical research on the soil multi-media environment, including soil, surface water, ground water, waterbody sediment and agricultural crops, as well as p...The method of principal component analysis was applied to systematical research on the soil multi-media environment, including soil, surface water, ground water, waterbody sediment and agricultural crops, as well as pollution-inducing wastewater, mullock (or waste ore) and slag in the periphery of a large-sized Pb-Zn mining and smelting plant in a karst area of Guangxi Zhuang Autonomous Region. The results revealed that soils in the area studied have been heavily polluted by Cd, Zn, Pb and Hg, and the levels of these metals in the samples of agricultural crop greatly exceed the standards. The above-mentioned pollutants exist in all soil-multi-media environments. The mullock, slag, wastewater, surface water, ground water, soil, and agricultural crops constitute a composite ecological chain. Therefore, the improper disposal of mullock and slag, and the use of polluted wastewater for agricultural irrigation are the main causes of soil pollution. Heavy metals in the soil have three transition progresses: point (improved soil with slag, ground water inflow plot), linear (river transition) and non-point transition (regional pollution by slag) patterns, and the tailing yard is the most important locus for heavy metals to release into the environment.展开更多
Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were meas...Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the Chinese Loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 24.2% of the soil variations.The roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement 】 increase of bio-active substance 】 stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.展开更多
文摘Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.
基金support by Guangxi Scientific and Technological Brainstorm Project (Guikegong 0779011)
文摘The method of principal component analysis was applied to systematical research on the soil multi-media environment, including soil, surface water, ground water, waterbody sediment and agricultural crops, as well as pollution-inducing wastewater, mullock (or waste ore) and slag in the periphery of a large-sized Pb-Zn mining and smelting plant in a karst area of Guangxi Zhuang Autonomous Region. The results revealed that soils in the area studied have been heavily polluted by Cd, Zn, Pb and Hg, and the levels of these metals in the samples of agricultural crop greatly exceed the standards. The above-mentioned pollutants exist in all soil-multi-media environments. The mullock, slag, wastewater, surface water, ground water, soil, and agricultural crops constitute a composite ecological chain. Therefore, the improper disposal of mullock and slag, and the use of polluted wastewater for agricultural irrigation are the main causes of soil pollution. Heavy metals in the soil have three transition progresses: point (improved soil with slag, ground water inflow plot), linear (river transition) and non-point transition (regional pollution by slag) patterns, and the tailing yard is the most important locus for heavy metals to release into the environment.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.90202005 and 40071054)China Postdoctoral Science Foundation.
文摘Plant roots have potential impacts on soil mineral weathering and leaching.Our objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the Chinese Loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 24.2% of the soil variations.The roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement 】 increase of bio-active substance 】 stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.
