UV与UV/H2O2降解水中马拉硫磷的机理及毒性变化

本文以马拉硫磷作为研究对象,利用高效液相色谱串联飞行时间质谱仪(HPLC-TOF/MS)鉴别出其在单独UV和UV/H_2O_2降解过程中主要产物的分子结构,进而结合产物生成量的变化推导出可能的降解路径.同时,利用发光细菌发光抑制法和AChE活性抑制法对降解产物综合生物毒性进行了评估.结果表明,利用单独UV降解马拉硫磷,其去除率达到90%时发光抑制率从23.5%降低至15.4%,AChE抑制率未见显著变化;而经UV/H_2O_2工艺处理后,在相同马拉硫磷去除率(90%)条件下,发光抑制率从23.5%升高至93.7%,AChE抑制率由22.1%升高至88.1%.由此可见,不同氧化过程会对马拉硫磷溶液的生物毒性产生显著影响,且目标污染物的去除率不能指示溶液毒性的变化.     

Characteristics and sources of heavy metal pollution in desert steppe soil related to transportation and industrial activities

Environmental Science and Pollution Research - A study area was selected from the industrial region of Gaoshawo Town, Yanchi County, Ningxia, to explore the level of heavy metal pollution in desert...     

Improved selective extraction of 3,3′-dichlorobenzidine by molecularly imprinted polysiloxane microspheres

This report shows an improved selective extraction of the 3,3??-dichlorobenzidine pollutant using molecularly imprinted polysiloxane microspheres (MIPS). 3,3??-Dichlorobenzidine and degradation products are of environmental concern due to their carcinogenic nature. Environmental samples containing 3,3??-dichlorobenzidine are very complex, and the concentration of 3,3??-dichlorobenzidine is usually very low. Current analysis of 3,3??-dichlorobenzidine in environmental matrices often requires cleanup and preconcentration steps that are complex and time-consuming. Therefore, we designed an improved analytical technique. MIPS were synthesized by covalent imprinting. MIPS were characterized by Fourier-transform infrared spectroscopy, nuclear magnetic resonance and transmission electron microscopy. MIPS size ranges from 150 to 250?nm. Adsorption capacity and recognition selectivity toward 3,3??-dichlorobenzidine were studied using ultraviolet spectroscopy and high-performance liquid chromatography. Compared with non-imprinted polysiloxane microspheres, results show that the amount of 3,3??-dichlorobenzidine adsorbed by MIPS is greater by a factor of ten. The binding capacity of MIPS for 3,3??-dichlorobenzidine is seven times larger than diphenylamine. MIPS exhibits high affinity to 3,3??-dichlorobenzidine and can be used for the selective extraction of 3,3??-dichlorobenzidine.     

Enhanced mixing state of black carbon with nitrate in single particles during haze periods in Zhengzhou, China

Black carbon（BC） plays an important role in air quality and climate change, which is closely associated with its mixing state and chemical compositions. In this work the mixing state of BC-containing single particles was investigated to explore the evolution process of ambient BC particles using a single particle aerosol mass spectrometer（SPAMS） in March 2018 in Zhengzhou, China. The BC-containing particles accounted for 61.4% of total detected ambient single particles and were classified into f...     

中国农业植被净初级生产力模拟(I)——模型的建立与灵敏度分析

以业已建成的稻麦作物净初级生产力模型为基本框架,建立了一个具有普适性的中国农业植被净初级生产力模型(CropC-)。CropC-的模拟对象为占我国农作物总播种面积2/3的水稻、小麦、玉米、棉花、油菜和大豆。该模型包括2个主要功能模块:光合作用和呼吸作用;土壤-作物系统氮素运移。前者综合考虑了环境因子和氮素的影响,后者包括了作物氮素吸收、土壤氮矿化和化肥氮释放。灵敏度分析表明,在输入参数变化±10%时,CropC-对6个主要输入参数响应的敏感性依次为温度>光合有效辐射>大气CO2浓度>土壤全氮含量>施氮量>降水。模型分析表明,气候变暖将降低作物净初级生产力。     

Vinasse-based biochar magnetic composites: adsorptive removal of tetracycline in aqueous solutions

Environmental Science and Pollution Research - Highly efficient and cost-effective adsorbents for antibiotic removal are the key to mitigate pollution by industrial wastewaters. Pyrolyzing low-cost...     

Anaerobic ammonium oxidation coupled to ferric iron reduction in the sediment of a eutrophic lake

Environmental Science and Pollution Research - Anaerobic ammonium oxidation coupled to ferric iron reduction (Feammox) has been assumed to play an important role in nitrogen removal from...     

Nonferrous metal (loid) s mediate bacterial diversity in an abandoned mine tailing impoundment

Environmental Science and Pollution Research - Migration and transformation of toxic metal (loid) s in tailing sites inevitably lead to ecological disturbances and serious threats to the...     

Gas/particle partitioning of polycyclic aromatic hydrocarbons in coastal atmosphere of the north Yellow Sea, China

Samples of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected at three sampling stations (Xiaomai Island, Laohutan, and Zhangzi Island) in the north Yellow Sea, China during November 2008 and September 2009 to study their atmospheric transport potential and the gas/particle distributions. The composition of PAHs was dominated by gaseous compounds. The percentages of the particle-phase PAHs to the total concentrations were found to be higher during the heating period than the non-heating period. The ratios of naphthalene and acenaphthene to phenanthrene, chrysene and dibenzo(a,h)anthracene showed an increasing trend from Xiaomai Island to Zhangzi Island, which can be called as the local atmospheric distillation of PAHs. Gas/particle partitioning coefficients (K _p) and their relationship with the sub-cooled liquid vapor pressures (pº_L) of PAHs were investigated. The regressions of logK _p versus logpº_L gave significant correlations for all samples of the three sites with r ² values in the range 0.56–0.66 (p?<?0.01). Both Junge–Pankow adsorption model and octanol–air partition coefficient absorption model tended to underestimate the sorption for most PAHs, but the absorption model appeared to be more suitable for predicting the particle fraction of PAHs than the Junge–Pankow model.     

网络论坛与机构网站对西藏旅游形象传播的差异性

互联网是旅游地形象传播诸多媒介中的一个重要组成部分.采用内容分析和对应分析的方法,对国际互联网上传播的西藏旅游形象进行了研究.结果表明,网络传播的西藏旅游形象可归纳为6个主题:自然景观、社区生活、宗教文化、地域名称、旅游服务、旅游体验,而不同网站对西藏旅游形象的传播主题存在差异.与其他机构网站相比,旅游论坛网站更加关注宗教文化、旅游体验、旅游服务主题.同时,不同网站在传播西藏旅游形象的有效性方面存在差异,网络上的文字内容成为潜在游客获取信息和形成引致形象的影响因素.