The community structures of phytoplankton are important factors and indicators of lake water quality. Harmful algal blooms severely impact water supply, recreational activities and wildlife habitat. This study aimed t...The community structures of phytoplankton are important factors and indicators of lake water quality. Harmful algal blooms severely impact water supply, recreational activities and wildlife habitat. This study aimed to examine the phytoplankton composition and variations using microscopy, and identify harmful Cyanobacteria in weekly samples taken from four sites at Harsha Lake in southwest Ohio. Over the course of the summer in 2015, the phytoplankton of Harsha Lake consisted mainly of 13 taxa belonging to Bacillariophyta, Chlorophyta, Cryptophyta, Cyanobacteria, Dinophyta and Euglenophyta. Their significant successions started with Bacillariophyta and/or Chlorophyta, then bloomed with Cyanobacteria and ended with Chlorophyta and/or Dinophyta. Cyanobacteria members: Microcystis, Planktothrix, Dolichospermum, Aphanizomenon, Cylindrospermopsis, and Oscillatoria from the Cyanophyceae were identified to be dominant genera. These organisms varied spatially and temporally in similar patterns along with the variations of nutrients and formed the summer bloom with the total biomasses ranging from 0.01 to 114.89 mg L-1 with mean of 22.88 mg L-1. M. aeruginosa and P. rubescens were revealed as the microcystin producers, while A. circinalis and Aphanizomenon sp. were identified as a saxitoxin producer through cloning and sequencing PCR products of mcyA, mcyE and sxtA genes. The biomasses of phytoplankton, Cyanobacteria and Microcystis were positively correlated to nutrients, especially to total nitrogen. The total ELISA measurement for microcystin positively correlated with Cyanobacteria (R2 = 0.66, P Microcystis (R2 = 0.64, P 2 = 0.59, P < 0.0001). The basic information on the occurrence and biomasses of Cyanobacteria and total phytoplankton, and the analysis for toxic species, which were the first report for the inland water in Ohio, USA, will document the succession patterns of phytoplankton and toxin production over a season and provide data to predict risk occurrence to both human and ecological factors.展开更多
To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed-system pyrolyses were performed at temperatures of 250°C to 65...To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed-system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values(Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ^(13)C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media.展开更多
Continuous measurements of speciated atmospheric mercury(Hg), including gaseous elemental mercury(GEM), particulate mercury(PHg), and reactive gaseous mercury(RGM) were conducted in Guizhou Province, southwestern Chin...Continuous measurements of speciated atmospheric mercury(Hg), including gaseous elemental mercury(GEM), particulate mercury(PHg), and reactive gaseous mercury(RGM) were conducted in Guizhou Province, southwestern China. Guiyang Power Plant(GPP),Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant(GAP), and Guiyang Forest Park(GFP) in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers(Tekran 2537A) were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/impactor, KCl-coated annular denuder, and a ?lter holder.Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ± 28.3 ngám^(-3)and the lowest 6.1 ± 3.9 ngám^(-3),from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pgám^(-3)and the minimum average 55.9 pgám^(-3), also from GPP and GAP,respectively. Similarly, the highest average RGM of 68.8pgám^(-3)was measured at GPP, and the lowest level of20.5 pgám^(-3)was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM;traf?c contributes signi?cantly to PHg; and domestic pollution dominates RGM.展开更多
Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum-fed counterparts....Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum-fed counterparts.Many of the effects of dietary restriction on laboratory animals have been suggested to be related to a deceleration of the aging process.The inhibition of age-related changes in xenobiotic metabolizing enzyme activities by dietary restriction has previously been reported.Alterations of these enzyme activities may cause changes in metabolic activation of carcinogens and ,therefore,carcinogen-DNA binding.DNA-repair capability has also been reported to be enhanced in diet-restricted rats.Using AFB1 as a model carcinogen,we have studied in vivo and in vitro hepatic AFB1-DNA binding, demonstration that dietary restriction(60% of ad libitum consumption) may decrease the metabolic activation of AFB1 ,and subsequently reduce AFB1-DNA binding .Our preliminary results obtained from the AFB1-DNA binding experiments in isolated hepatocytes suggest that the observed age-dependent reduction in AFB1-DNA binding which may be attributed to a loss of metabolic activation capability was delayed in the diet-restricted rats.展开更多
运用连续颗粒物采样仪（URG Model 2000-01J）对贵阳市城区大气颗粒物PM2.5进行了连续3个月（9-11月）的采集与分析,探讨了PM2.5的浓度分布特征、气象条件的影响。结果显示,贵阳市大气颗粒物PM2.5的平均质量浓度为53±27μg/m^3,变...运用连续颗粒物采样仪（URG Model 2000-01J）对贵阳市城区大气颗粒物PM2.5进行了连续3个月（9-11月）的采集与分析,探讨了PM2.5的浓度分布特征、气象条件的影响。结果显示,贵阳市大气颗粒物PM2.5的平均质量浓度为53±27μg/m^3,变化范围为3.7-186μg/m^3;初步推断大气颗粒物PM2.5的污染来源主要是燃料燃烧、生物质燃烧、汽车尾气等人为源;相对湿度、风速、风向、温度等气象条件是影响大气颗粒物浓度及分布的重要因素。展开更多
利用连续颗粒物采样仪（URG Model 2000-01 J）和黑碳仪（Aethalometer）对贵阳市城区2008年9—11月大气黑碳浓度进行了连续观测,结果表明,贵阳市城区秋冬季大气24h黑碳浓度变化范围为1.6~12μg.m-3,平均值为4.1μg.m-3;12 h黑碳浓度观...利用连续颗粒物采样仪（URG Model 2000-01 J）和黑碳仪（Aethalometer）对贵阳市城区2008年9—11月大气黑碳浓度进行了连续观测,结果表明,贵阳市城区秋冬季大气24h黑碳浓度变化范围为1.6~12μg.m-3,平均值为4.1μg.m-3;12 h黑碳浓度观测值主要分布在2~5μg.m-3,白昼黑碳浓度变化范围介于1.9~9.2μg.m-3,平均值3.9μg.m-3,夜间黑碳浓度变化范围0.48~15μg.m-3,平均值4.3μg.m-3;黑碳浓度与大气PM2.5浓度变化一致,呈正相关关系（r=0.84,P〈0.0001,n=178）,大气黑碳浓度的变化趋势还明显受相对湿度、温度和风速的影响。展开更多
We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PR.D) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury e...We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PR.D) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed.展开更多
文摘The community structures of phytoplankton are important factors and indicators of lake water quality. Harmful algal blooms severely impact water supply, recreational activities and wildlife habitat. This study aimed to examine the phytoplankton composition and variations using microscopy, and identify harmful Cyanobacteria in weekly samples taken from four sites at Harsha Lake in southwest Ohio. Over the course of the summer in 2015, the phytoplankton of Harsha Lake consisted mainly of 13 taxa belonging to Bacillariophyta, Chlorophyta, Cryptophyta, Cyanobacteria, Dinophyta and Euglenophyta. Their significant successions started with Bacillariophyta and/or Chlorophyta, then bloomed with Cyanobacteria and ended with Chlorophyta and/or Dinophyta. Cyanobacteria members: Microcystis, Planktothrix, Dolichospermum, Aphanizomenon, Cylindrospermopsis, and Oscillatoria from the Cyanophyceae were identified to be dominant genera. These organisms varied spatially and temporally in similar patterns along with the variations of nutrients and formed the summer bloom with the total biomasses ranging from 0.01 to 114.89 mg L-1 with mean of 22.88 mg L-1. M. aeruginosa and P. rubescens were revealed as the microcystin producers, while A. circinalis and Aphanizomenon sp. were identified as a saxitoxin producer through cloning and sequencing PCR products of mcyA, mcyE and sxtA genes. The biomasses of phytoplankton, Cyanobacteria and Microcystis were positively correlated to nutrients, especially to total nitrogen. The total ELISA measurement for microcystin positively correlated with Cyanobacteria (R2 = 0.66, P Microcystis (R2 = 0.64, P 2 = 0.59, P < 0.0001). The basic information on the occurrence and biomasses of Cyanobacteria and total phytoplankton, and the analysis for toxic species, which were the first report for the inland water in Ohio, USA, will document the succession patterns of phytoplankton and toxin production over a season and provide data to predict risk occurrence to both human and ecological factors.
基金supported by the National Natural Science Foundation of China(Grant nos.41772108 and 41472121)
文摘To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed-system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values(Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ^(13)C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media.
基金support was provided by the National Natural Science Foundation of China(No.40773067)
文摘Continuous measurements of speciated atmospheric mercury(Hg), including gaseous elemental mercury(GEM), particulate mercury(PHg), and reactive gaseous mercury(RGM) were conducted in Guizhou Province, southwestern China. Guiyang Power Plant(GPP),Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant(GAP), and Guiyang Forest Park(GFP) in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers(Tekran 2537A) were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/impactor, KCl-coated annular denuder, and a ?lter holder.Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ± 28.3 ngám^(-3)and the lowest 6.1 ± 3.9 ngám^(-3),from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pgám^(-3)and the minimum average 55.9 pgám^(-3), also from GPP and GAP,respectively. Similarly, the highest average RGM of 68.8pgám^(-3)was measured at GPP, and the lowest level of20.5 pgám^(-3)was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM;traf?c contributes signi?cantly to PHg; and domestic pollution dominates RGM.
文摘Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum-fed counterparts.Many of the effects of dietary restriction on laboratory animals have been suggested to be related to a deceleration of the aging process.The inhibition of age-related changes in xenobiotic metabolizing enzyme activities by dietary restriction has previously been reported.Alterations of these enzyme activities may cause changes in metabolic activation of carcinogens and ,therefore,carcinogen-DNA binding.DNA-repair capability has also been reported to be enhanced in diet-restricted rats.Using AFB1 as a model carcinogen,we have studied in vivo and in vitro hepatic AFB1-DNA binding, demonstration that dietary restriction(60% of ad libitum consumption) may decrease the metabolic activation of AFB1 ,and subsequently reduce AFB1-DNA binding .Our preliminary results obtained from the AFB1-DNA binding experiments in isolated hepatocytes suggest that the observed age-dependent reduction in AFB1-DNA binding which may be attributed to a loss of metabolic activation capability was delayed in the diet-restricted rats.
文摘运用连续颗粒物采样仪（URG Model 2000-01J）对贵阳市城区大气颗粒物PM2.5进行了连续3个月（9-11月）的采集与分析,探讨了PM2.5的浓度分布特征、气象条件的影响。结果显示,贵阳市大气颗粒物PM2.5的平均质量浓度为53±27μg/m^3,变化范围为3.7-186μg/m^3;初步推断大气颗粒物PM2.5的污染来源主要是燃料燃烧、生物质燃烧、汽车尾气等人为源;相对湿度、风速、风向、温度等气象条件是影响大气颗粒物浓度及分布的重要因素。
文摘利用连续颗粒物采样仪（URG Model 2000-01 J）和黑碳仪（Aethalometer）对贵阳市城区2008年9—11月大气黑碳浓度进行了连续观测,结果表明,贵阳市城区秋冬季大气24h黑碳浓度变化范围为1.6~12μg.m-3,平均值为4.1μg.m-3;12 h黑碳浓度观测值主要分布在2~5μg.m-3,白昼黑碳浓度变化范围介于1.9~9.2μg.m-3,平均值3.9μg.m-3,夜间黑碳浓度变化范围0.48~15μg.m-3,平均值4.3μg.m-3;黑碳浓度与大气PM2.5浓度变化一致,呈正相关关系（r=0.84,P〈0.0001,n=178）,大气黑碳浓度的变化趋势还明显受相对湿度、温度和风速的影响。
文摘We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PR.D) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed.
