Investigation of groundwater pollution has been carried out on multiple typical karst underground river systems in recent years in order to reveal the characteristics and mechanism of underground river pollution. Thro...Investigation of groundwater pollution has been carried out on multiple typical karst underground river systems in recent years in order to reveal the characteristics and mechanism of underground river pollution. Through the summary of the survey results, five characteristics of underground river pollution have been revealed, including directionality, weak hysteresis, easier for reversibility, linear and intermittent(or seasonal); combining with karst geomorphic types, pollution sources(primordial, secondary pollution and compound), pollution ways and pollution receptors, three basic pollution patterns of the underground river were depicted: Recharge area pollution, runoff area pollution and discharge area pollution. At the same time, the study discloses the reality of the underground river pollution is the three basic patterns and their subgenera in combination with super imposition on the space and time. And from the angle of the hydrogeological model, the study expounds the process of underground river pollution. Finally, the study gives naming rules of pollution pattern of the underground river and sets up PISAB method of pattern recognition. The results provide scientific basis for pollution repair and management of underground river in the southwest karst region.展开更多
In the storage of Radix Ophiopogonis, browning often happens to cause potential risk with regard to safety. Previously few reports investigate the browning of Radix Ophiopogonis. In this research, the causes and mecha...In the storage of Radix Ophiopogonis, browning often happens to cause potential risk with regard to safety. Previously few reports investigate the browning of Radix Ophiopogonis. In this research, the causes and mechanisms of the browning of Radix Ophiopogonis were preliminarily elucidated. Content determination by high-performance liquid chromatogra- phy （HPLC） and spectrophotometry, enzyme activity determination by colorimetry, and morphological observation by electron mi- croscopy were performed in the present study. Uniform design and three-dimensional response surfaces were applied to investigate the relationship between browning and storage factors. The cortex cell wall of browned Radix Ophiopogonis was ruptured. Compared with the normal Radix Ophiopogonis, cellulase and polyphenol oxidase enzymes were activated, the levels of 5-hydroxymethylfurfural （5-HMF）, total sugars, and reducing sugars were increased, while the levels of polysaccharides and methylophiopogonanone A were de- creased in browned Radix Ophiopogonis. The relationship between the storage factors and degree of browning （Y） could be described by following correlation equation： Y= - 0.625 4 ＋ 0.020 84 × X3 ＋ 0.001 514×X1×x X2 - 0.000 964 4 × X2 × X3. Accompanied with browning under storage conditions, the chemical composition of Radix Ophiopogonis was altered. Following the activation of cellulase, the rupture of the cortex cell wall and the outflow of cell substances flowed out, which caused the Radix Ophiopogonis tissue to become soft and sticky. The main causes of the browning were the production of 5-HMF, the activation of polyphenol oxidase, Maillard reactions and enzymatic browning. Browning could be effectively prevented when the air relative humidity （HR）, temperature, and moisture content were under 25% RH, 12 ℃ and 18%, respectively.展开更多
基金supported by National Special Research and Development Fund Project(2017YFC0406104)Geological Investigation Project of Ministry of Land and Resources (DD20160300 and DD20160302)+1 种基金Guangxi Natural Science Fund Project (2016JJA150091)Special Fund for Charity Industry of Ministry of Environmental Protection (2016A101)
文摘Investigation of groundwater pollution has been carried out on multiple typical karst underground river systems in recent years in order to reveal the characteristics and mechanism of underground river pollution. Through the summary of the survey results, five characteristics of underground river pollution have been revealed, including directionality, weak hysteresis, easier for reversibility, linear and intermittent(or seasonal); combining with karst geomorphic types, pollution sources(primordial, secondary pollution and compound), pollution ways and pollution receptors, three basic pollution patterns of the underground river were depicted: Recharge area pollution, runoff area pollution and discharge area pollution. At the same time, the study discloses the reality of the underground river pollution is the three basic patterns and their subgenera in combination with super imposition on the space and time. And from the angle of the hydrogeological model, the study expounds the process of underground river pollution. Finally, the study gives naming rules of pollution pattern of the underground river and sets up PISAB method of pattern recognition. The results provide scientific basis for pollution repair and management of underground river in the southwest karst region.
基金supported by the National Natural Science Foundation of China(Nos.30672603&30901956)the "111 Project" from the Ministry of Education of China and the State Administration of Foreign Expert Affairs of China(No.11-2-07)+1 种基金Key Projects in the National Science&Technology Pillar Program during the Eleventh Five-Year Plan Period(2006BAI-09B05-6)Program for Changjiang Scholars and Innovative Research Team in University(IRT0973)
文摘In the storage of Radix Ophiopogonis, browning often happens to cause potential risk with regard to safety. Previously few reports investigate the browning of Radix Ophiopogonis. In this research, the causes and mechanisms of the browning of Radix Ophiopogonis were preliminarily elucidated. Content determination by high-performance liquid chromatogra- phy （HPLC） and spectrophotometry, enzyme activity determination by colorimetry, and morphological observation by electron mi- croscopy were performed in the present study. Uniform design and three-dimensional response surfaces were applied to investigate the relationship between browning and storage factors. The cortex cell wall of browned Radix Ophiopogonis was ruptured. Compared with the normal Radix Ophiopogonis, cellulase and polyphenol oxidase enzymes were activated, the levels of 5-hydroxymethylfurfural （5-HMF）, total sugars, and reducing sugars were increased, while the levels of polysaccharides and methylophiopogonanone A were de- creased in browned Radix Ophiopogonis. The relationship between the storage factors and degree of browning （Y） could be described by following correlation equation： Y= - 0.625 4 ＋ 0.020 84 × X3 ＋ 0.001 514×X1×x X2 - 0.000 964 4 × X2 × X3. Accompanied with browning under storage conditions, the chemical composition of Radix Ophiopogonis was altered. Following the activation of cellulase, the rupture of the cortex cell wall and the outflow of cell substances flowed out, which caused the Radix Ophiopogonis tissue to become soft and sticky. The main causes of the browning were the production of 5-HMF, the activation of polyphenol oxidase, Maillard reactions and enzymatic browning. Browning could be effectively prevented when the air relative humidity （HR）, temperature, and moisture content were under 25% RH, 12 ℃ and 18%, respectively.
