Toxicity and subcellular distribution of cadmium in wheat as affected by dissolved organic acids

We aim to investigate the effects of humic acid (HA) and citric acid (CA) on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. The EC₅₀ values of Cd increased from 3.36 μmol/L to 4.96 and 7.33 μmol/L at 50 and 250 mg/L HA, respectively, but decreased to 1.39 μmol/L in the presence of CA based on free ion activity model (FIAM). HA decreased the relative subcellular distribution of Cd in the heat-denatured proteins (decreased from 54% to 33%) but increased Cd in the heat-stable proteins in root (from 25% to 50%) at 7.61 μmol/L {Cd²⁺} (free Cd activity), which resulted in decreasing Cd toxicity. However, CA increased Cd toxicity due to the increased internalization of Cd although the relative subcellular distributions of Cd exhibited a decrease in the heat-denatured proteins and increase in the granule fraction compared to the control at high-level Cd. The FIAM could not predict the toxicity of Cd in the presence of organic acids. Alternatively, the internal Cd accumulation and subcellular Cd concentration were better to describe the toxicity of Cd to wheat.     

石化行业的VOCs排放控制管理

概述了我国挥发性有机化合物（VOCs）的排放情况。介绍了国内外VOCs的管理现状。分析了国内石化行业VOCs排放控制管理中存在的主要问题以及污染物排放过程的类别。提出了明确定义、制定相关标准、完善分类管理体系、研究最佳的可行性控制技术等加强VOCs排放控制管理的对策和建议。     

UASB反应器厌氧氨氧化菌的脱氮特性研究

研究UASB厌氧氨氧化（ANAMMOX）反应器运行情况,采用普通城市污水厂活性污泥接种,人工合成废水,pH值在7.4～7.8之间,温度控制在(32±1)℃。在反应器稳定运行270～450 d之间的180 d中,对NH⁺₄-N和NO^-₂-N去除率均达到99.9％以上,总氮去除率保持在90％以上,NO^-₃-N产生量在20～30 mg/L之间波动。研究表明,UASB厌氧氨氧化反应器处理废水效果明显,对NH⁺₄-N、NO^-₂-N和TN去除率高,NO^-₂-N和NH⁺₄-N比值可以指示厌氧氨氧化反应器性能的演变。UASB反应器稳定运行阶段容积负荷的影响较小,ANAMMOX菌对合成废水适应性强,反应器抗冲击能力较强,受冲击后恢复迅速。出水pH值稳定在8.5附近,pH值变化情况可作为反应器运行状况的指示。关键词硝化厌氧氨氧化上流式厌氧污泥床生物脱氮     

基于唐南渗析原理阳离子交换膜对Cu~(2+)、Mn~(2+)、Zn~(2+)去除能力的研究

基于唐南渗析原理,采用阳离子交换膜去除原水中Cu2+、Mn2+、Zn2+等重金属离子,研究影响阳离子交换膜去除各重金属离子能力大小的机制以及2种重金属离子共存时互相干扰的机制.结果表明,阳离子交换膜可有效去除原水中Cu2+、Mn2+、Zn2+等重金属离子,去除率为75%～85%;在浓度相同下且重金属离子带相同电荷数时,其水化离子半径越小,离子扩散速度就越快,阳离子交换膜对其去除能力就越强;当重金属水化离子半径基本相同时,膜对原子序数小的重金属离子的去除能力更强;相同浓度且相同电荷数的重金属离子共存时,各离子同步被去除,但各离子之间存在干扰,越易于被离子交换的离子与其它离子共存时,其竞争能力越强,使其他离子的去除率降低越多;当待去除离子的总浓度远低于膜的交换容量时,离子共存时各离子的去除率相比离子单独存在时各离子的去除率下降幅度不大.     

Single and joint effects of acetochlor and urea on earthworm Esisenia foelide populations in phaiozem

Much attention is paid to soil health and environmental safety. Earthworms are an important indicator of soil ecosystem health and safety. Ecological toxicity of acetochlor and excessive urea, in both their single and joint effects, on earthworm Esisenia foelide was thus studied using the soil-culture method. Acetochlor had an enhanced toxicity from low concentration to high concentration. The mortality of earthworms after a 6-day exposure was changed from 0 to 86.7%, and the weight change rate ranged from 7.86 to -30.43%, when the concentration of acetochlor was increased from 164 to 730 mg kg(-1). Urea expressed its positive and beneficial effects on earthworms when its concentration was lower than 500 mg kg(-1). Strongly toxic effects took place when the concentration of urea was higher than 1000 mg kg(-1). The mortality of earthworms exposed to urea reached 100% when its concentration was more than 1500 mg kg(-1). When the concentration of urea was lower than 500 mg kg(-1), there were antagonistic effects between the two agrochemicals on earthworms; when the concentration of urea was higher than 500 mg kg(-1), joint toxic effects of acetochlor and excessive urea on earthworms were synergic. In any case, excessive urea application is very harmful to the health of soil ecosystems.     

高等学校职业指导的实践与思考

分析了目前大学毕业生就业难的原因．阐述了职业指导的概念，内容重要提及其基本要求，探讨了职业指导的成功做法和当前职业指导中存在的问题，并由此首次提出高等学校职业指导应贯穿于大学教育的全过程的观点，并对学生在校期间应如何进行职业规划，职业设计提出了建设性的意见．     

论我国环境侵权救济法律制度的完善

环境侵权是随着工业化和城市化的发展而出现的新型侵权行为之一。随着中国经济的迅速发展，由环境污染和生态破坏造成的环境污染侵权现象及其救济已成为中国的一大社会问题。中国目前尚缺乏对环境侵权救济法律制度的全面深入研究，有关立法也不完善，而西方发达国家有关环境侵权救济法的理论和实践已经较为成熟。拟借鉴西方国家的环境侵权救济法律制度，并立足中国国情，提出了完善中国环境侵权救济法律制度的若干建议。     

Experimental study on the removal of PAHs using in-duct activated carbon injection

This paper presents the incineration tests of municipal solid waste (MSW) in a fluidized bed and the adsorption of activated carbon (AC) on polycyclic aromatic hydrocarbons (PAHs). An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 US EPA specified PAHs contained in raw MSW, flue gas, fly ash, and bottom ash. The aim of this work was to decide the influence of AC on the distribution of PAHs during the incineration of MSW. Experimental researches show that there were a few PAHs in MSW and bottom ash. With the increase of AC feeding rate, the concentrations of three- to six-ring PAHs in fly ash increased, and the concentration of two-ring PAH decreased. The total-PAHs in flue gas were dominated by three-, and four-ring PAHs, but a few two-, five-ring PAHs and no six-ring PAHs were found. PAHs could be removed effectively from flue gas by using in-duct AC injection and the removal efficiencies of PAHs were about 76-91%. In addition, the total toxic equivalent (TEQ) concentrations of PAH in raw MSW, bottom ash, fly ash, and flue gas were 1.24 mg TEQ kg-1, 0.25 mg TEQ kg-1, 6.89-9.67 mg TEQ kg-1, and 0.36-1.50 microg TEQ Nm-3, respectively.     

污染土壤修复效果评定方法的研究

在实施污染土壤修复的环境工程后,需要通过灵敏和有效的评定方法对污染土壤修复的效果进行评定.然而,单纯依靠化学方法进行污染土壤修复效果的评定,不能揭示土壤的整体质量特征,因此需要生态毒理方法作为相互补充的手段.本文概述了植物毒性评定法、陆生无脊椎动物评定法和土壤微生物评定法及其在污染土壤修复效果评定中的应用,并对污染土壤修复效果评定方法的发展前景进行展望.     

UV/Fenton法处理间-甲酚废水

利用UV/Fenton工艺对模拟间-甲苯酚废水进行了处理,研究了H2O2加入量、FeSO4加入量、pH、原水初始COD值、环境温度、反应时间等因素对COD去除率的影响.实验表明:间-甲苯酚浓度为100mg/L、初始COD值251 mg/L的废水,在30℃下,pH为4.Q,[H2O2]/[Fe2 ]=15(质量浓度比),紫外灯照射3 h后,COD去除率达86.3%,若再经Ca(OH)2絮凝沉降,则COD去除率提高到92.6%.同时,对Fenton及UV/Fenton的处理效果进行了比较,实验表明:UV/Fenton的处理效果明显优于Fenton法.