The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is...The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is still unclear.Based on the DGT(Diffusive Gradients in Thin-films)technology,this study sets up three moisture control scenarios:continuous wet,wet-dry alternating,and continuous dry,and carries out a 6-month soil moisture control experiment.In the experiment,the DGT device collected the diffusion gradient data of soil selenium under different scenarios,and analyzed the migration characteristics of selenium in combination with the adsorption isotherm.Meanwhile,the release rate,migration coefficient,and bioavailability parameters of selenium are calculated by fitting the first-order kinetic model,further verifying the reliability and applicability of the DGT data.The experimental results demonstrate that under continuous wet conditions,the release rate of soil selenium reaches 1.85µg·cm^(-2)·h^(-1),with a migration coefficient of 0.012 cm^(2)·h^(-1)and a bioavailability parameter of 0.74;under wet-dry alternating conditions,they are 1.42µg·cm^(-2)·h^(-1),0.01 cm^(2)·h^(-1),and 0.68,respectively;under continuous dry conditions,the release rate of soil selenium is the smallest,at 0.88µg·cm^(-2)·h^(-1),with a migration coefficient of 0.004 cm^(-2)·h^(-1)and a bioavailability parameter of 0.5.The results of this experiment reveal the dynamic behavior of soil selenium under different moisture conditions and reflect the high efficiency of DGT technology in dynamic monitoring and quantitative analysis of soil selenium behavior,providing a scientific basis for the optimal management of rhizosphere soil selenium.展开更多
The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg an...The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg and the contents of selenium vary from 0.06 to 1.29 mg/kg in soils developed on the basement rocks, which are controlled by the basement rocks themselves.展开更多
Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy r...Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy rice, and vegetables from the north of Xuzhou City, and determined their selenium contents. The background level of selenium in the soil profile was 0.08 mg/kg. The selenium concentrations in agricultural soils and irrigation water were in the range of 0.21-4.08 mg/kg and 0.002-0.29 mg/L, respectively. Soils with high selenium content were located closely to coalmines and power plants. The average selenium concentrations in coal and coal fly ash were 5.46 and 2.81 mg/kg, respectively. In contrast, the concentrations of selenium in bedrock and in the soil profile were very low. These results imply that the high selenium level in agricultural soils is mainly caused by anthropogenic activities, rather than by parent material. The arithmetic mean of selenium concentration in paddy rice was 0.116 mg/kg, and in cabbage was 0.05 mg/kg. The selenium concentration in rice was positively correlated with total selenium concentration in soil, suggesting that selenium in soil is readily transferred into the crops. Furthermore, the estimated dietary intake （88.8 μg） of selenium from paddy rice and cabbage exceeds the recommended dietary allowance （55 μg）. Therefore, there is a potential health risk from consumption of local staple food in the study area.展开更多
To provide reference for selenium resource exploitation of soil,many selenium-tolerant strains were isolated from selenium-rich soil in Guangxi. The dilution spread plate method and selenium-added culture method were ...To provide reference for selenium resource exploitation of soil,many selenium-tolerant strains were isolated from selenium-rich soil in Guangxi. The dilution spread plate method and selenium-added culture method were used to screen the selenium-tolerant strains from the soils which were sampled from the main Selenium-rich areas such as Yongfu,Bama,Yulin Hanshan,Guiping and Tengxian. The results showed that 8 strains with high selenium tolerance were obtained,which could tolerate the selenium concentration above 10 000 μg/m L in solid medium. Among the 8 strains,YLB1-33 showed the highest selenium tolerance,and it could still grow weakly in the solid medium with selenium concentration of 29 000 μg/m L. The sequencing of 16 S rD NA and phylogenetic analysis showed that YLB1-6 was identified as Bacillus cereus,BMB2-1 and TXB1-8 were identified as Bacillus pumilus,GPB2-5 was identified as Bacillus thuringiensis,YLB1-26 and YLB1-33 were identified as Bacillus licheniformis,and YLB1-2 and YFB1-8 were identified as Serratia marcescens. The finding of selenium-tolerance strains had potential application value on promoting the utilization of selenium soil resources and the development of selenium-rich agricultural products in Guangxi.展开更多
In order to to provide scientific reference for the management and development of selenium resources in Enshi,four soil samples and four relevant rice samples were collected from four regions of Enshi,and then seleniu...In order to to provide scientific reference for the management and development of selenium resources in Enshi,four soil samples and four relevant rice samples were collected from four regions of Enshi,and then selenium content in the soil and rice samples were measured by ICP-MS. Afterwards,the occurrence forms of selenium in the soil samples were detected by continuous extraction. At last,the bioavailability of selenium in rice was studied by the in vitro gastrointestinal model. The results showed that selenium content in soil was 0. 15-5. 42 mg/kg in Enshi. The proportion of water-soluble selenium in soil was the lowest,ranging from 1. 41% to 3. 80%; the proportion of residual selenium was the highest,reaching 36. 1%-41. 7%. Besides,selenium content in rice was 0. 07-1. 61 mg/kg,and the bioconcentration factor of selenium in rice was 0. 22-0. 48. The bioaccessibility of selenium in rice ranged from 45. 7% to 56. 4% in the stomach and from 58. 4% to68. 5% in the small intestine. In addition,the daily intake of selenium per capita( PDI) in Yutangba,Changping,Shadi,and Taiyanghe was490,26,132 and 57 μg/d,indicating that people in Yutangba had the risk of chronic selenium poisoning,and people's diet was rich in selenium in Shadi and Taiyanghe,while people's diet was deficient in selenium in Changping.展开更多
Daba Mountain area is one of the two endemic selenosis areas in China,which may relate with the environmental behaviors of selenium (Se) in soil.This study focuses on the concentraion and distribution of Se and its re...Daba Mountain area is one of the two endemic selenosis areas in China,which may relate with the environmental behaviors of selenium (Se) in soil.This study focuses on the concentraion and distribution of Se and its relationships with some other elements in natural soil in the area.The average concentration of Se in Daba Mountain soils was 14.3 times higher than the value cited for natural soil background worldwide,suggesting that soils in the region were contaminated by the element.The finding was confirmed...展开更多
In recent years,production and processing of natural selenium-rich agricultural products has become a research hotspot. The main factor affecting the selenium content in plant is the content of effective selenium in s...In recent years,production and processing of natural selenium-rich agricultural products has become a research hotspot. The main factor affecting the selenium content in plant is the content of effective selenium in soil. So it is important to understand the form and conversion relationship of selenium in soil and find ways to improve selenium effectiveness. By summarizing the researches on selenium at home and abroad,we analyze the classification of soil selenium form,the transformation among different selenium forms and the improving factors of selenium effectiveness. We understand the relationship between chemical form and extraction form of selenium,analyze the driving factors of conversion among different forms,and discuss the ways to improve selenium effectiveness of soil in high selenium-rich area. By combining characteristics of soil and crop in different selenium-rich regions,different selenium activation methods are used,which could provide more scientific evidence for further selenium research.展开更多
Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant ...Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant growth directly and then bring about further influence to the health of human and animals by food-chain.So it is significant to study the transport and transformation of the selenium in the soil profile.展开更多
文摘The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is still unclear.Based on the DGT(Diffusive Gradients in Thin-films)technology,this study sets up three moisture control scenarios:continuous wet,wet-dry alternating,and continuous dry,and carries out a 6-month soil moisture control experiment.In the experiment,the DGT device collected the diffusion gradient data of soil selenium under different scenarios,and analyzed the migration characteristics of selenium in combination with the adsorption isotherm.Meanwhile,the release rate,migration coefficient,and bioavailability parameters of selenium are calculated by fitting the first-order kinetic model,further verifying the reliability and applicability of the DGT data.The experimental results demonstrate that under continuous wet conditions,the release rate of soil selenium reaches 1.85µg·cm^(-2)·h^(-1),with a migration coefficient of 0.012 cm^(2)·h^(-1)and a bioavailability parameter of 0.74;under wet-dry alternating conditions,they are 1.42µg·cm^(-2)·h^(-1),0.01 cm^(2)·h^(-1),and 0.68,respectively;under continuous dry conditions,the release rate of soil selenium is the smallest,at 0.88µg·cm^(-2)·h^(-1),with a migration coefficient of 0.004 cm^(-2)·h^(-1)and a bioavailability parameter of 0.5.The results of this experiment reveal the dynamic behavior of soil selenium under different moisture conditions and reflect the high efficiency of DGT technology in dynamic monitoring and quantitative analysis of soil selenium behavior,providing a scientific basis for the optimal management of rhizosphere soil selenium.
文摘The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg and the contents of selenium vary from 0.06 to 1.29 mg/kg in soils developed on the basement rocks, which are controlled by the basement rocks themselves.
基金supported by the Geological Survey of China and the Jiangsu Province Program "Multipurpose Geochemical Survey of Jiangsu Province" (No.200312300008)
文摘Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy rice, and vegetables from the north of Xuzhou City, and determined their selenium contents. The background level of selenium in the soil profile was 0.08 mg/kg. The selenium concentrations in agricultural soils and irrigation water were in the range of 0.21-4.08 mg/kg and 0.002-0.29 mg/L, respectively. Soils with high selenium content were located closely to coalmines and power plants. The average selenium concentrations in coal and coal fly ash were 5.46 and 2.81 mg/kg, respectively. In contrast, the concentrations of selenium in bedrock and in the soil profile were very low. These results imply that the high selenium level in agricultural soils is mainly caused by anthropogenic activities, rather than by parent material. The arithmetic mean of selenium concentration in paddy rice was 0.116 mg/kg, and in cabbage was 0.05 mg/kg. The selenium concentration in rice was positively correlated with total selenium concentration in soil, suggesting that selenium in soil is readily transferred into the crops. Furthermore, the estimated dietary intake （88.8 μg） of selenium from paddy rice and cabbage exceeds the recommended dietary allowance （55 μg）. Therefore, there is a potential health risk from consumption of local staple food in the study area.
基金Supported by the Program for the Scientific Research and Technology Development in Guangxi(Guikehe 415104001-22)the Science and Technology Planning Project of Guangxi(Guikegong 1598006-5-13)+2 种基金the Experiment Station for Selenium Featured Crops in Guangxi(Gui TS2016011)the Fund for Science and Technology Development and Scientific Research of Guangxi Academy of Agricultural Sciences(Guinongke 2015JM23,2017JM01,2017JM03)the Innovation-Driven Development Special Fund Project of Guangxi(Guike AA17202019-1&Guike AA17202019-4)
文摘To provide reference for selenium resource exploitation of soil,many selenium-tolerant strains were isolated from selenium-rich soil in Guangxi. The dilution spread plate method and selenium-added culture method were used to screen the selenium-tolerant strains from the soils which were sampled from the main Selenium-rich areas such as Yongfu,Bama,Yulin Hanshan,Guiping and Tengxian. The results showed that 8 strains with high selenium tolerance were obtained,which could tolerate the selenium concentration above 10 000 μg/m L in solid medium. Among the 8 strains,YLB1-33 showed the highest selenium tolerance,and it could still grow weakly in the solid medium with selenium concentration of 29 000 μg/m L. The sequencing of 16 S rD NA and phylogenetic analysis showed that YLB1-6 was identified as Bacillus cereus,BMB2-1 and TXB1-8 were identified as Bacillus pumilus,GPB2-5 was identified as Bacillus thuringiensis,YLB1-26 and YLB1-33 were identified as Bacillus licheniformis,and YLB1-2 and YFB1-8 were identified as Serratia marcescens. The finding of selenium-tolerance strains had potential application value on promoting the utilization of selenium soil resources and the development of selenium-rich agricultural products in Guangxi.
基金Supported by National High Technology Research and Development Program of China(863 Program)(2012AA06A204)
文摘In order to to provide scientific reference for the management and development of selenium resources in Enshi,four soil samples and four relevant rice samples were collected from four regions of Enshi,and then selenium content in the soil and rice samples were measured by ICP-MS. Afterwards,the occurrence forms of selenium in the soil samples were detected by continuous extraction. At last,the bioavailability of selenium in rice was studied by the in vitro gastrointestinal model. The results showed that selenium content in soil was 0. 15-5. 42 mg/kg in Enshi. The proportion of water-soluble selenium in soil was the lowest,ranging from 1. 41% to 3. 80%; the proportion of residual selenium was the highest,reaching 36. 1%-41. 7%. Besides,selenium content in rice was 0. 07-1. 61 mg/kg,and the bioconcentration factor of selenium in rice was 0. 22-0. 48. The bioaccessibility of selenium in rice ranged from 45. 7% to 56. 4% in the stomach and from 58. 4% to68. 5% in the small intestine. In addition,the daily intake of selenium per capita( PDI) in Yutangba,Changping,Shadi,and Taiyanghe was490,26,132 and 57 μg/d,indicating that people in Yutangba had the risk of chronic selenium poisoning,and people's diet was rich in selenium in Shadi and Taiyanghe,while people's diet was deficient in selenium in Changping.
文摘Daba Mountain area is one of the two endemic selenosis areas in China,which may relate with the environmental behaviors of selenium (Se) in soil.This study focuses on the concentraion and distribution of Se and its relationships with some other elements in natural soil in the area.The average concentration of Se in Daba Mountain soils was 14.3 times higher than the value cited for natural soil background worldwide,suggesting that soils in the region were contaminated by the element.The finding was confirmed...
基金Supported by Guangxi Science Research and Technology Development Plan Program(Guikehe 415104001-22)the National Natural Science Foundation of China(41761052)+2 种基金Major Project of Guangxi Innovation Driven(Guike AA17202019-1,Guike AA17202019-2,Guike AA17202026-2)Guangxi Youth Foundation Project(2016GXNSFBA380131)Science and Technology Development Fund Project of Guangxi Academy of Agricultural Sciences(Guinongke 2017JM01,Guinongke 2017JM03,Guinongke 2015JM23)
文摘In recent years,production and processing of natural selenium-rich agricultural products has become a research hotspot. The main factor affecting the selenium content in plant is the content of effective selenium in soil. So it is important to understand the form and conversion relationship of selenium in soil and find ways to improve selenium effectiveness. By summarizing the researches on selenium at home and abroad,we analyze the classification of soil selenium form,the transformation among different selenium forms and the improving factors of selenium effectiveness. We understand the relationship between chemical form and extraction form of selenium,analyze the driving factors of conversion among different forms,and discuss the ways to improve selenium effectiveness of soil in high selenium-rich area. By combining characteristics of soil and crop in different selenium-rich regions,different selenium activation methods are used,which could provide more scientific evidence for further selenium research.
文摘Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant growth directly and then bring about further influence to the health of human and animals by food-chain.So it is significant to study the transport and transformation of the selenium in the soil profile.
