Based on the analysis of the enrichment char- acteristics of Hg and MeHg in bird feathers from Caohai National Nature Reserve in Guizhou, the risks of Hg pol- lution to the birds from Caohai wetland have been evalu- a...Based on the analysis of the enrichment char- acteristics of Hg and MeHg in bird feathers from Caohai National Nature Reserve in Guizhou, the risks of Hg pol- lution to the birds from Caohai wetland have been evalu- ated. The total Hg content of bird feathers ranges from 40 to 5058 ng/g.vyjth an average of 924 ng/g. The content of MeHg is significantly correlated with total Hg （r = 0.68,p 〈 0.01）, and the content are among 0.75 and 113 ng/g. The total Hg content in the birds feathers is significantly dependent on their feeding habits, which is mainly in accordance with the following rule： carnivorous birds 〉 omnivorous birds that are mainly carnivo- rous 〉 omnivorous birds that are mainly herbivorous. There are also differences in the Hg enrichment ability in the different parts of bird feathers, and the total Hg and MeHg content in the wing feathers are significantly higher than that in the other parts of feathers. The bioaccumula- tion coefficients of aqueous Hg and MeHg by bird feathers are 0.9 × 10︿4-112.13× 10︿4 （mean value is 20.47 ×10︿4）and 0.47 × 10︿4-70.4 × 10︿4 （mean value is 9.52 × 10︿4）, respectively. Although the whole Hg level in Caohai bird feathers is not too high, the Hg content in some carnivorous birds exceeds over or approaches the abnormal threshold when birds are breeding （5μg/g）, which indicates that the birds in Caohai wetland are faced with some risks of ecological Hg pollution.展开更多
Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccu...Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.展开更多
Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reduc...Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria（SRB） on mercury（Hg） methylation at sediment–water interfaces. Concentrations of dissolved methyl mercury（DMe Hg） in the overlying water of the control cores with bioactivity maintained（BAC） and cores with only sulfate-reducing bacteria inhibited（SRBI） and bacteria fully inhibited（BACI） were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMe Hg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations（r =- 0.5311 and r =- 0.4977 for BAC and SRBI, respectively）. The water DMe Hg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment–water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster（hgc AB）, besides SRB,causing Hg methylation in the sediment–water system.展开更多
基金supported by the National Natural Science Foundation of China (No. 41363007)
文摘Based on the analysis of the enrichment char- acteristics of Hg and MeHg in bird feathers from Caohai National Nature Reserve in Guizhou, the risks of Hg pol- lution to the birds from Caohai wetland have been evalu- ated. The total Hg content of bird feathers ranges from 40 to 5058 ng/g.vyjth an average of 924 ng/g. The content of MeHg is significantly correlated with total Hg （r = 0.68,p 〈 0.01）, and the content are among 0.75 and 113 ng/g. The total Hg content in the birds feathers is significantly dependent on their feeding habits, which is mainly in accordance with the following rule： carnivorous birds 〉 omnivorous birds that are mainly carnivo- rous 〉 omnivorous birds that are mainly herbivorous. There are also differences in the Hg enrichment ability in the different parts of bird feathers, and the total Hg and MeHg content in the wing feathers are significantly higher than that in the other parts of feathers. The bioaccumula- tion coefficients of aqueous Hg and MeHg by bird feathers are 0.9 × 10︿4-112.13× 10︿4 （mean value is 20.47 ×10︿4）and 0.47 × 10︿4-70.4 × 10︿4 （mean value is 9.52 × 10︿4）, respectively. Although the whole Hg level in Caohai bird feathers is not too high, the Hg content in some carnivorous birds exceeds over or approaches the abnormal threshold when birds are breeding （5μg/g）, which indicates that the birds in Caohai wetland are faced with some risks of ecological Hg pollution.
基金supported by the National Natural Science Foundation of China (No.41763017)the Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV (No.U1612442)+2 种基金the Science and Technology Planning Project of Guizhou Province (No.Qiankehe-[2018]2336)the Key Discipline Construction Project,Guizhou (No.ZDXK [2016]11)the Topclass Discipline Construction Project of Ecology in Guizhou Province (No.GNYL[2017]007)
文摘Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.
基金supported by the National Natural Science Foundation of China(nos.41063006,41363007,and 41273099)the Science and Technology Fund of Guizhou Province(no.[2013]2296)
文摘Sediment cores（containing sediment and overlying water） from Baihua Reservoir（SW China）were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria（SRB） on mercury（Hg） methylation at sediment–water interfaces. Concentrations of dissolved methyl mercury（DMe Hg） in the overlying water of the control cores with bioactivity maintained（BAC） and cores with only sulfate-reducing bacteria inhibited（SRBI） and bacteria fully inhibited（BACI） were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMe Hg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations（r =- 0.5311 and r =- 0.4977 for BAC and SRBI, respectively）. The water DMe Hg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment–water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster（hgc AB）, besides SRB,causing Hg methylation in the sediment–water system.
