2004～2013年安徽省县域畜禽养殖环境风险时空特征及调控规划

为掌握安徽省近十年来畜禽养殖业对生态环境的潜在污染影响,本文基于2004～2013年安徽省县域畜禽养殖统计数据及耕地数据,以耕地畜禽粪便氮、磷负荷为评价指标,对安徽省县域畜禽养殖环境风险时空特征进行评估,并对高环境风险县市区进行调控规划研究。结果表明,安徽省各县市区的耕地畜禽粪便氮、磷负荷结果相互之间差异较大; 2004～2013年安徽省大部分区域都属于无环境风险区域,高环境风险区域主要集中在合肥市的市辖区、肥西县、长丰县等县市区,低环境风险区域主要集中在灵璧县、全椒县等县市区;十年间存在环境风险的县市区数量以2005年最多,为28个;其次是2006和2013年,为26个;数量最少的年份是2007年,为11个;安庆市太湖县、合肥市长丰县、宣州市广德县等6个县市区的畜禽粪便能在其所属地级市的范围内进行畜禽养殖产业转移消化,以达到减排的目的。宿州市砀山县、蚌埠市固镇县、六安市寿县等5个县市区的畜禽粪便中的氮也能进行畜禽养殖产业转移实现消化减排,但部分磷无法通过产业转移实现消化减排。研究结果可为该省畜禽养殖业持续健康发展提供科学依据。     

丙烯醛-DNA加合物的研究进展

丙烯醛是一种活泼的a,β不饱和醛,在环境中广泛存在,香烟烟气和厨房油烟是人体丙烯醛暴露的主要环境来源.另一方面机体内丙烯醛可以通过脂质过氧化、氨基酸氧化等多种途径自发生成.进入人体后,丙烯醛和DNA发生加合生成丙烯醛-DNA加合物,目前研究最多的是丙烯醛-dG加合物,包括a-OH-PdG和γ-OH-PdG,其中γ-OH...     

水电站建设中作业安全风险控制方案研究

水电站建设工程涉及的人员多,设备设施多,作业点多,战线长,作业安全风险大,需要系统性的作业安全风险控制方案以解决安全问题.对作业要素安全风险、作业过程安全风险控制进行了研究,提出了系统化的作业安全风险控制方案,为水电站建设的安全管理提供技术支持.     

Natural resources,population aging,and environmental quality: analyzing the role of green technologies

Environmental Science and Pollution Research - Depletion of natural resources and population aging are the two most critical challenges for environmental sustainability. However, the research that...     

基于采空区底板应力分布规律划分自燃“三带”的方法与实践*

针对目前采空区自燃三带实测方法的不便性和局限性,为准确合理地划分采空区自燃三带的范围,构建采空区底板应力分布和自燃危险区域的相互关系,提出以采空区底板应力分布规律直接划分采空区自燃三带的方法并结合实例进行实践验证。以实际工作面为背景,通过运用FLAC3D数值模拟、现场埋管实测和理论分析等方法分析采空区底板应力分布演化规律和自燃危险区域分布特征,得到二者之间的定量关系以及空隙率变化规律。结果表明:采空区底板应力场先后经历应力降低区、应力升高区和应力稳定区,根据走向、倾向应力峰值曲线初步判断采空区自燃三带的范围为:散热带0~89 m,氧化升温带89~190 m,窒息带190 m以外;模拟结果与现场实测划分得到的散热带0~86.4 m,氧化升温带86.4~187 m,窒息带187 m以外有较好的一致性,从而验证了该方法的准确性。     

硫精矿中单质硫提取的实验和工艺过程

针对某些单质硫含量较高的硫精矿中硫磺的提取进行实验和工艺过程研究,得到了硫单质完全分离的时间-温度曲线,确定最适分离温度为300℃—350℃,并比较了不同气氛下（N2气氛和还原性气氛）硫精矿样品热处理前后组分的变化,发现在500℃还原性气氛下可以得到纯度较高的FeS产物.根据实验结果,提出了一种适用于某些单质硫含量较高...     

Environmental Implication of Intensive Farming Practices on North China Plain

1 INTRODUCTION Growing pressure on the land of North China Plain (NCP - a food bowl of the country, has made many of th traditional farming practices increasingly difficult to sustain such as manuring, composting, mulching, legume-based rotations, field levelling and fertilizing with mud from rivers and canals. The pressure on the farmlands has also led to a decrease in farm sizes and shortened fallow periods To cope with this pressure on the land and to maintain its fertility, farmers …     

Removal of cobalt(Ⅱ) ion from aqueous solution by chitosan-montmorillonite

Montmorillonite （MMT） modified with chitosan （CTS, molecular weight = S x 104） was applied to remove heavy metal cations by using Co2＋ as a model ion. An increase in MMT interlayer distance observed from X-ray diffraction indicates the intercalation of CTS into MMT. Together with the results of scanning electron microscopy and Fourier transform infrared spectroscopy, it was concluded that the composite material of CTS and MMT （CTS-- MMT） was prepared successfully. The mass ratio of CTS to MMT had a strong influence on the adsorption performance of CTS-MMT. The highest adsorption value of 150 mg/g was obtained over the composite material with CTS to MMT mass ratio of 0.25, which is much higher than those reported in other studies. The adsorption isotherms and kinetic results indicated that Co2＋ was adsorbed over CTS-MMT in a multilayer model, and the chemical sorption of Co2＋ was determined to be the rate-limiting step.     

Tetrachloro-1,4-benzoquinone induces apoptosis of mouse embryonic stem cells

Pentachlorophenol(PCP) is a widespread,persistent environmental contaminant,and it is enzymatically activated to form a reactive metabolite,tetrachloro-l,4-benzoquinone(TCBQ).To our knowledge,there is no information about TCBQ toxicity on embryonic stem cells.Here,we demonstrated that TCBQ induced significantly apoptosis of mouse embryonic stem cells in a concentration-dependent manner.We also showed that TCBQ elevated genomic5-hydroxymethylcytosine(5hmC) by affecting ten-eleven translocation(Tet) dioxygenases in mouse embryonic stem cells.We further investigated whether Tet dioxygenases were implicated in TCBQ-induced apoptosis.By depleting all three dioxygenases(Tet1-3),we found that Tet dioxygenases slightly inhibited both early and late apoptosis induced by TCBQ at a low concentration(30 μmol/L).Meanwhile,treated by TCBQ at higher concentrations(40and 50 μmol/L),the total percentage of apoptotic cells was not affected by Tet dioxygenases.However,Tet dioxygenases tended to arrest mouse ES cells to be at early apoptotic stage and to reduce the cells to enter later apoptotic stage.These results indicate that Tet dioxygenases play a role in shaping TCBQ-induced apoptosis in mouse embryonic stem cells.Our study provides new insights into the toxicology of PCP and its reactive metabolite TCBQ.     

Keep swimming but stop peeing in the pools

正Swimming is excellent exercise and offers many health benefits.However,the"chlorine smell"in swimming pools may be a turn-off for some people.Although this smell is often thought to be of chlorine,it actually comes from volatile compounds that are produced from unintended reactions between disinfectants(e.g.,chlorine)and organic matter in