EGSB反应器处理含氯苯有机废水的试验研究

在间歇条件下,针对未接触和接触过氯苯的颗粒污泥,研究了氯苯对它们产甲烷活性的抑制及恢复;在动态条件下,研究了EGSB反应器处理含氯苯有机废水的情况.结果表明,不同浓度的氯苯均会对未接触氯苯的颗粒污泥的活性产生抑制;而接触过氯苯的颗粒污泥具有一定适应能力,只有氯苯浓度为100mg/L时才有较明显抑制.在动态运行过程中,进水氯苯浓度为10～50mg/L,前65天出水氯苯浓度均低于7mg/L,66d后出水氯苯浓度突增至25mg/L以上,停止投加氯苯后,出水氯苯浓度在3.4～38.32mg/L之间无规律波动,说明反应器内颗粒污泥对氯苯有较强吸附,生物降解作用不明显.     

6种挥发性有机物在甲苯驯化微生物中的好氧生物降解性能

利用振荡摇瓶法测定了6种典型挥发性有机物,甲苯、邻二甲苯、间二甲苯、对二甲苯、苯和氯苯在甲苯驯化微生物中的好氧生物降解性能.结果表明,在本研究的液相浓度范围内(甲苯＜174mg/L,邻二甲苯＜149mg/L,间二甲苯＜129mg/L,对二甲苯＜133mg/L,苯＜234mg/L,氯苯＜146mg/L),3种二甲苯、苯和氯苯的降解速率随其初始浓度的增大而增加,符合一级反应,这5种VOCs未对微生物产生明显的抑制或毒害作用;甲苯的液相浓度大于85mg/L时,其降解速率不随初始浓度的增大而改变,其降解规律符合Monod方程.     

内蒙古草原挥发性有机物排放通量的研究

2002年夏季,利用静态箱方法,对我国内蒙古草原生态系统挥发性有机物的排放进行了首次测量,同时观测了太阳辐射、温湿度等参数.结果表明,异戊二烯是草地挥发性有机物排放中的主要成分.异戊二烯的排放有明显的日变化、逐日变化和季节变化规律.因子分析表明,可见光辐射、温度、水汽含量是影响异戊二烯排放的主要因子,而且可见光辐射是控制其排放过程的最主要因子.根据相关分析,在考虑影响异戊二烯的排放因子时,不仅要考虑通常的影响因子--可见光辐射、温度,还要考虑水汽的作用.箱方法的使用不可避免地造成箱内外太阳辐射、温湿度等的差别,因此,必须考虑修正采样箱对挥发性有机物排放通量带来的影响.2002年夏季,异戊二烯排放通量(C)的最大值为1649.3μg/(m²·h).6、8、9月采样期间异戊二烯排放通量的日平均值分别为886.6、707.0、427.2μg/(m²·h).     

西太湖秋季蓝藻水华过后细胞裂解对溶解性有机碳影响

从2009年7月~2010年3月每月采集西太湖表层水样,分析叶绿素含量﹑蓝藻细胞裂解速率﹑磷酸盐浓度的变化,并通过切向流超滤系统分离得到的高分子量(1kDa~0.5μm)溶解性有机物的碳氮比值和高分子量溶解性有机碳浓度的变化.结果表明,西太湖蓝藻细胞裂解速率在11月达到最大值(0.43d-1),而磷酸盐和高分子量溶解性有机碳浓度分别在12月与9月达到最大值.细胞裂解速率与磷酸盐﹑高分子量溶解性有机碳浓度之间没有相关性,说明水华过后影响磷酸盐浓度﹑高分子量溶解性有机碳的因素很多,蓝藻细胞裂解只是其中重要因素之一.藻类水华的出现可能导致水体中其它磷形态(如有机磷)与磷酸盐之间的迁移转化,而大型浅水湖泊扰动导致的沉积物再悬浮和水华过后频繁的细菌活动都可能是影响高分子量溶解性有机碳的因素.秋季水华过后蓝藻细胞裂解释放的有机碳进入微食物网循环,引起细菌活动频繁,而溶解性有机物中含碳化合物比含氮化合物容易降解,所以碳氮比值逐渐减少.此外细菌通过硝酸盐合成溶解性有机氮也可能是碳氮比值减少的一个重要原因.     

厦门汀溪水库溶解有机氮对有毒藻种的生物有效性及其化学本质

为探究厦门汀溪水库溶解有机氮(DON)对有毒藻种的生物有效性及其化学本质,采用水样分子质量和极性分级技术,进行铜绿微囊藻 (Microcystis aeruginosa)培养实验.结果表明,汀溪水库中DON含量呈季节性差异,在枯水期比较高,而丰水期比较低.汀溪水库DON在不同季节中的主要成分都是疏水组分和>3kDa组分.汀溪水库DON的生物有效性为65.20%.较疏水组分和>3kDa组分而言,亲水组分和￡3kDa组分DON更易被铜绿微囊藻利用.从水环境和水源保护角度出发,应首先考虑消除DON中的亲水性组分和小分子质量组分.     

Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case studies

ATSI Model 3800 aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for single-particle analysis in Shanghai during the World Exposition (EXPO), 2010. Measurements on two extreme cases: polluted day (1st May) and clean day (25th September) were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols. Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods. The ART-2a neural network algorithm was applied to sort the collected particles. Seven major classes of particles were obtained: dust, sea salt, industrial, biomass burning, organic carbon (OC), elementary carbon (EC), and NH₄-rich particles. Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation. The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories. Number fraction of biomass burning particles (43.3%) during polluted episode was much higher than that (21.6%) of clean time. Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically (13.3%). The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission. Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time. Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.     

Effects of repeated pesticide exposure on the peripheral and central nervous systems

This study was designed to compare organic farmers (comparison group) and pesticide-using farmers (pesticide group) in terms of neurobehavioral performance and sensorimotor function. The subjects were recruited in October 2004 from Chungnam Province and the neighboring Jeolla Province in western South Korea. Psychological assessment was carried out using the Wechsler Adult Intelligence Scale, the Mini-Mental State Examination, and the Bender Gestalt test. Neuroselective sensory nerve conduction threshold was measured at both left and right middle fingers by using an electrodiagnostic device to determine current perception thresholds (CPTs). Three independent CPT measurements were obtained from each test site by using sinusoidal stimuli at three frequencies. CPT testing showed no difference between the two groups. No significant differences were found in the large myelinated (2000?Hz stimulation; cutaneous touch, pressure), small myelinated (250?Hz stimulation; mechanoreceptive, pressure, temperature, fast pain) and small unmyelinated (5?Hz stimulation; polymodal nociceptive, temperature, slow pain, postganglionic sympathetic) C-fibers. Furthermore, there was no difference found between the pesticide and comparison groups in psychological variables, including intelligence quotient, orientation, memory, calculation, similarities, visual sensitivity, and psychomotor speed. In conclusion, chronic pesticide exposure has no apparent effect on either the peripheral or central nervous system in Korean farmers.     

Employment of passive sampling in monitoring indoor air quality in selected residences in a Tri-city area in Poland

Time-weighted average concentrations of selected volatile compounds were measured in chosen residences in a Tri-City area of Poland by means of passive sampling. The results were compared to those obtained by dynamic technique – sorption tubes filled with Tenax TA sorbent. Results obtained by employing the two techniques were similar. Total volatile organic compound (TVOC) parameters were also determined. An attempt was also made to evaluate the influence of outdoor air pollutants on indoor air quality.     

Study of sorptive properties of trap systems for selective enrichment of volatile organic compounds from tobacco smoke samples

There is a dearth of data on the consumer product concentrations of iron, lead, and nickel for accurate comparison to be made. The levels of these elements were determined in 85 samples of six different classes of personal care products commonly used in Nigeria using atomic absorption spectrophotometry. The results of the analysis showed that the range of the mean concentrations of Fe was 0.485–1.108 ppm, Pb ND–0.163 ppm, and Ni ND-0.160 ppm. The analytical data have demonstrated that the selected consumer products are possible sources of iron, lead, and nickel exposure. Users can be exposed to these metals directly through dermal contact or inhalation. The regulations relating to cosmetic products give no limit values for heavy metals in cosmetic products, hence, it was difficult to establish if the values obtained in this study are safe or not. Prolonged use of soaps, creams, and detergent containing these elements may pose threat to human health and the environment. This could be responsible for various skin diseases such as allergic skin, follicular and pigmentary disorders, which are common among the users (exposed groups) of these products in Nigeria. A body of evidence has presented a rare example of systemic allergic dermatitis caused by topical application of a mercury-containing cosmetic to the upper lip of a 32-year-old Turkish patient.     

Mutagenicity of diesel engine exhaust in the Ames / Salmonella assay using a direct exposure method

The aim of this study was to investigate the potential mutagenic activity of diesel engine exhaust in the Ames/Salmonella assay using a direct aerosol exposure system. So, TA 98 and TA 100 strains, with or without added S9 mix, were exposed to diesel emissions after varying degrees of filtration. Variants of these two strains, deficient in nitroreductase (TA 98NR and TA 100NR) or over-expressing O-Acetyl Transferase (YG 1024 and YG 1029), were also exposed to total (unfiltered) diesel exhaust to highlight the putative mutagenicity of any nitro-PAHs present in these emissions. Mutagenic activity of the diesel exhaust was demonstrated on Salmonella typhimurium, strains TA 100 and variants TA 100 NR and YG1029. The use of a particle filter did not modify the genotoxicity of the diesel emissions, indicating a major contribution of the gas phase to the mutagenicity of these diesel emissions. The prominent role of the particulate-associated nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) claimed by some authors working on diesel exhaust organic extracts was not confirmed by our results with native diesel exhaust exposure. Our results show that the gas phase is potentially more mutagenic than the particles alone.