Measurement of Fine Particles in Diesel Emissions Using a Real-Time Aerosol Monitor

Abstract

A real-time monitoring methodology to determine diesel fine particles in diesel emissions has been evaluated. The range of particle size captured by the monitor was ～0.1 μm to 1 μm. DustTrak real-time monitors were connected to the dilution tunnel of the vehicle exhaust to measure the emissions during the vehicle tests under both dynamic and steady-state driving conditions, and concentration data were recorded every 5 sec. Test variation of the real-time monitoring among different test days was similar to that measured by traditional filter-based gravi-metric method, whereas the repeatability of the monitor data within the same-day tests was better than that of gravimetric method. Correlations between the two methods were established for different fuels tested on a single light duty vehicle. When the emissions from the reference fuel was used to convert the monitor’s response to diesel fuels, the levels determined by the real-time monitor were consistent with those measured by gravimetric method among different fuels tested. Use of the real-time monitor could provide information on the levels of fine particles that is more relevant to the public health than the total particles.     

Effects of dimethoate on rotifer Brachionus calyciflorus using multigeneration toxicity tests

As important members of the zooplankton community and sources of food for fish, rotifers are used extensively in ecotoxicological research to assess the health of the environment and safety of compounds. However, most rotifer toxicity tests are only conducted using rotifer neonates derived from unexposed mothers, thus ignoring the potential transfer of contaminants from mother to offspring. To understand better the mother to offspring exposure, a multigenerational study was conducted using three successive generations (F₀, F₁ and F₂) of the common freshwater rotifer Brachionus calyciflorus to investigate the toxic effects of the widely used organophosphate pesticide, dimethoate (O, O-dimethyl S-methylcarbamoylmethyl phosphorodithioate). When the F₀ generation was exposed to five pesticide concentrations, the population growth rate (r) displayed symptoms of hormesis, characterized by the conversion of low-concentration stimulation to high-concentration inhibition. Despite this observation, the exposure to any given concentration of dimethoate reduced the population growth rates of the F₁ and F₂ generation rotifers. Significant differences existed between the F₀, F₁ and F₂ rotifers for the population growth rate under dimethoate stress: F₂ individuals were more sensitive than F₁, whereas the F₁ individuals were more sensitive than F₀. The results indicated that the parental exposure to a given toxic stress could result in increased sensitivity and decreased fitness in the offspring. This study illustrates the utility of multigenerational toxicity tests, which may better reflect and more accurately predict the effects of long-term pesticide exposure to aquatic organisms at the population level.     

Interactive effects of natural and human disturbances on vegetation dynamics across landscapes.

Accurate measures of human effects on landscape processes require consideration of both the direct impacts from human activities and the indirect consequences of the interactions between humans and the landscape. This is particularly evident in systems experiencing regular natural disturbances such as in the mountainous areas of southwestern China, where the remaining population of giant pandas (Ailuropoda melanoleuca) is supported. Here the spatiotemporal patterns of human impacts, forests, and bamboo episodic die-offs combine to determine the distribution of panda habitat. To study the complex interactions of humans and landscapes, we developed an integrated spatiotemporally explicit model of household activities, natural vegetation dynamics, and their impacts on panda habitat. Using this model we examined the direct consequences of local fuelwood collection and household creation on areas of critical giant panda habitat and the indirect impacts when coupled with vegetation dynamics. Through simulations, we found that over the next 30 years household impacts would result in the loss of up to 30% of the habitat relied on by pandas during past bamboo die-offs. The accumulation and spatial distribution of household impacts would also have a considerable indirect influence on the spatial distribution of understory bamboo. While human impacts influence both bamboo die-off and regeneration, over 19% of pre-existing low-elevation bamboo habitat may be lost following an episodic die-off depending on the severity of the impacts and timing of the die-offs. Our study showed not only the importance of the spatial distribution of direct household impacts on habitat, but also the far-reaching effects of the indirect interactions between humans and the landscapes they are modifying.     

好氧-缺氧-闲置运行模式处理生活污水

在3个序批式反应器中,利用好氧-缺氧-闲置的运行模式处理实际生活污水,比较了不同曝气时间（2、3和4h）条件下的处理效果,结果表明,在R2（2 h）反应器中成功实现了单级好氧除磷和内聚物驱动的短程硝化反硝化。采用此反应器运行模式,对实际生活污水进行长期处理,反应器的COD、TN和TP的平均去除率分别为85.29%、74.09%和87.97%。本研究表明,在好氧-缺氧-闲置的运行模式下处理生活污水,能成功地实现单级好氧除磷与内聚物驱动的短程硝化反硝化的结合,并且在长期运行的过程中,能稳定地取得较好的脱氮、除磷效率。     

利用污泥熟肥作为高含水率污泥堆肥调理剂

采用静态强制通风好氧堆肥的方法,以木屑作为对比,考察了利用污泥熟肥作为调理剂对污泥堆肥过程的影响。结果表明,与以木屑作为调理剂的污泥堆体(对照组)相比,以污泥熟肥作为调理剂的污泥堆体(实验组)升温快,高温阶段(>50℃)持续时间长达10 d,满足粪便无害化卫生标准的要求,而对照组仅持续了2 d;实验组腐熟的堆肥含水率从60%降到39%,下降了21%,pH维持在7.5～8.5范围内,微生物活性较强,而对照组含水率仅下降15%,pH始终低于7.5;实验组种子发芽指数(GI)在第14天就回升到80%以上,基本上去除了植物毒性,而对照组GI在第22天才回升到50%。总体而言,污泥熟肥能显著改善堆肥中微生物的微环境,促进有机物的降解,缩短堆肥腐熟时间,是一种优质的调理剂。     

混凝剂品种对混凝-超滤联合工艺膜污染的影响

本实验以工业化学合成聚合硫酸铁混凝剂和自制生物聚合硫酸铁为例,考察了铁系混凝剂品种对地表水浊度、TOC和UV254的去除效果,混凝剂品种对混凝-超滤联合工艺处理地表水过程中超滤膜污染的影响。混凝实验结果表明,在10 mg/L(以Fe3+计)最佳投加量下,两类混凝剂对浊度、TOC和UV254的去除率基本相同。超滤膜污染实验结果表明,生物聚合铁预处理水样通量衰减速度略大于化学聚合铁预处理水样;膜污染阻力分析结果显示,随着循环次数的增加,工业化学合成聚合铁预处理水样造成的不可逆污染阻力逐渐增加,而生物聚合铁预处理水样造成的不可逆污染阻力却略有下降;膜污染机理分析表明,2组过滤过程的膜污染类型基本相似,由最初的膜孔堵塞过渡到最终的滤饼层污染。SEM分析表明,生物聚合铁预处理水样的膜污染较为严重。     

添加氮损失抑制剂对蓝藻泥堆肥质量的影响

对脱水蓝藻进行大型生产性堆肥实验。研究堆肥过程中,氮损失抑制剂过磷酸钙的添加对堆肥物料各类理化性质的影响。研究结果表明,过磷酸钙加入的处理组与未加过磷酸钙的对照组堆制37 d后堆肥物料均可腐熟,且堆肥肥效均符合NY525-2002的相关要求。添加过磷酸钙处理组有机质含量为490 g/kg,全N、全P和全K含量分别为20.75、10.02和11.32 g/kg,总养分含量达到9.77%,堆肥品质明显优于对照处理。同时,在微生物的作用下,对照组中微囊藻毒素MC-RR与微囊藻毒素MC-LR去除率分别达到89.8%与78.3%。值得一提的是,添加过磷酸钙后,MC-RR和MC-LR的去除率得到进一步提高,分别达到了92.96%和100%,较好地保证了蓝藻堆肥农用的安全性,为脱水蓝藻好氧堆肥化提供了可行性依据。     

Determination of Steroid Estrogens in Wastewater Treatment Plant of A Controceptives Producing Factory

Steroid estrogens such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethynylestradiol (EE2) have been suspected to be the main contaminants, which can affect the endocrine system of animals. Many authors have investigated these chemicals in the domestic wastewater treatment plants (WTP). However, wastewater from industries producing steroid contraceptives has not got ample attention. From the environmental point of view, the four steroids are very significant because even very low concentrations (ng/L) can cause reproductive disturbances in human, livestock and wildlife. The main purpose of the present investigation was to develop an analytical method for the determination of the four steroid estrogens present in WTP of a pharmacy factory, mainly producing contraceptive medicine in Beijing, China. Analysis was performed by solid-phase extraction (SPE) system and liquid chromatography combined with tandem mass spectrometry (LC/MS/MS). The average recoveries from effluent samples ranged from 88% to 103% and the precision of the method ranged from 9% to 4%. Based on 0.5-L wastewater samples, the limit of quantification (LOQ) was determined at 0.7 ng/L for E1, 0.8 for E2, 0.9 ng/L for E3, and 0.5 ng/L for EE2 in influent, and 1.0 ng/L for E2 and EE2, and 2.0 ng/L for E1 and E3 in effluent. In the influent samples, average concentrations of 80, 85, 73 and 155 ng/L were determined for E1, E2, E3 and EE2, respectively, showing that they were removed in this WTP to the extent of 79, 73, 85 and 67%, respectively.     

地层塌陷的灾害及其防治研究中的关键问题

针对矿山开采沉陷的研究现状和生产实践的需要，提出了地层塌陷防治研究中拟解决的关键问题：岩体的工程属性、地层塌陷的力源、塌陷特征、防治措施，及解决途径；同时还论述了本学科的发展前景。     

特警战训服面料开发技术研究

本文介绍了以芳纶纤维为主要材料的我国新一代特警战训服面料的技术研发及达到的主要性能指标。通过试验研究,开发了具有高强防撕裂、永久阻燃、耐高温、防静电、防油拒水、防酸碱等具有集成防护功能的特警战训服系列面料。