Effectiveness of multiplate invertebrate samplers,periphytometers, and electrofishing for biomonitoring in streams

Electrofishing, multiplate invertebrate samplers, and periphytometers were used to collect biological samples from 10 sites in two southeastern coastal plain streams. The objectives were to evaluate two factors that affect the quality of biomonitoring data: inter-replicate variability and sensitivity to habitat effects that could be confounded with environmental impacts. Abundance related estimates (density, catch-per-unit-effort, biomass, chlorophyll a) exhibited high inter-replicate variability necessitating the collection of large numbers of samples (25) to detect small (40%) differences among sites. Species number estimates exhibited much lower inter-replicate variability and sample number requirements (6 samples to detect a 40% difference). Electrofishing generally required fewer samples and less time than the other methods to obtain comparable levels of precision. Species composition and abundance estimates produced by all methods were affected by longitudinal changes in habitat that caused differences between control and impact sites that could be mistaken for impacts. Biomonitoring programs can be improved by assessing the relationship between statistical power and replicate number, collecting as many replicates as is feasible, collecting pre-impact and post-impact data when possible, matching control and impact sites on habitat, comparing the ecological characteristics (e.g. pollution tolerance) of organisms at control and impact sites, and using comparisons based on species number rather than abundance.     

Linear regression analyses of ozone and sulphur dioxide in ambient air

Linear regression analyses were performed on ozone and sulphur dioxide concentrations measured in real time. The predicted values of O₃ and SO₂ from these regression equations were close to the observed values. The relationship between O₃ and SO₂ is explained on theoretical considerations: sulphur dioxide absorbs light and forms an excited electronic state of molecular oxygen which readily combines with O-atoms.     

Aromatic hydrocarbon and methyl tert-butyl ether measurements in ambient air of Helsinki (Finland) using diffusive samplers

The diffusive sampling method was evaluated for measuring benzene, toluene, ethylbenzene, xylenes, styrene, propylbenzene, ethyltoluenes, trimethylbenzenes and methyl tert-butyl ether (MTBE) in the urban air of Helsinki, Finland. Concentrations were measured in 2-week periods at four different sites during the year 2000. Tube type adsorbent tubes were pre-packed with Carbopack-B (60/80). Analysis was conducted using thermal desorption and gas chromatograph coupled to a mass spectrometer. In different seasons, during five diffusive sampling periods, parallel measurements were conducted using pumped and online sampling. The compared techniques agreed reasonably well for other compounds than trimethylbenzenes. Based on comparisons, diffusive uptake rates for ethyltoluenes, styrene, propylbenzene and MTBE were determined, and for trimethylbenzenes, uptake rates were revised. The concentrations of aromatic compounds in Helsinki metropolitan area were also compared to the concentrations of a rural, forested site in Central Finland.     

Using silicone passive samplers to detect polycyclic aromatic hydrocarbons from wildfires in streams and potential acute effects for invertebrate communities

Silicone rubber passive samplers spiked with 4 deuterated performance reference compounds were deployed for 29-33 days to estimate the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in 9 streams in Victoria, Australia, following a wildfire. Silicone rubber strips of 2 thicknesses were used to obtain information on the status of uptake of the chemicals of interest at retrieval. In addition, we monitored the stream macroinvertebrate community for potential effects of PAHs or other fire organics. All selected PAHs were detected in the passive samplers and the sampling rates ranged from 0.5 to 50 L/day significantly varying between sites but not compounds, presumably due to differences in current velocity. The estimated water concentrations were 0.1-10 ng/L for total PAHs with phenanthrene, pyrene and fluoranthene accounting for 91% of the total concentration. All PAHs were a factor of 1000 or more below the reported 48-h median lethal concentrations (48-h LC50) for Daphnia magna. Two sites located closest to the fires exhibited elevated concentrations compared to the other sites and the passive samplers in these sites remained in the integrative uptake regime for all compounds, suggesting precipitation-associated PAH input. No acute toxic effects of PAHs or other fire organics on the invertebrate community were detected using a biotic index for organic toxicants (SPEAR), whereas a non-specific biotic index (SIGNAL) decreased in two sites indicating impacts from changes in other environmental parameters. We conclude (1) that silicone-based passive samplers with two different area-to-volume ratios represent a promising tool for determining organic toxicants and (2) that PAHs from wildfires are unlikely to be a common main cause for fire-related ecological effects in streams adjacent to burnt regions.     

Evolving trend and self-similarity of ozone pollution in central Hong Kong ambient during 1984-2002

The evolving pattern of ozone level in Hong Kong urban air has undergone various changes and corresponds to the regional urban and economic development. We assess such changes by reviewing and analyzing the original ozone pollutant database monitored in central Hong Kong downtown area during the period of 1984-2002. Both fractal analysis and traditional statistical methods are adopted to estimate the ozone evolving characteristics during the studied period. It is found that the ozone evolving pattern has strong self-similarity and the ozone pollution presents increasing trend in Hong Kong region in recent years based on the analysis. The typical fractal dimensions for total time series are D = 0.894 for available data set (N = 5760) and D = 0.859 for complete data set with interpolation (N = 6935), respectively. The fractal analysis can be used to assess the pollution trend in urban environment and may provide an alternative method for environmental study.     

消防部队灭火救援战斗力综合评估

在有关文献提出的消防部队灭火救援战斗力综合评估指标体系基础上,运用层次分析法和相邻指标比较法确定20个三级指标在多人多准则下的指标综合权重,并确定灭火救援战斗力综合评估的12个重要指标.根据三级指标的分级标准,构建了基于单指标等级和数目双约束的综合评估模型.以某支队为例进行了评估计算,并对其战斗力建设提出了改进意见和具体措施.     

基于Energyplus的附加阳光间式太阳房节能分析

本文将内蒙地区的站区公寓改造为附加阳光间式太阳房,通过动态模拟软件的计算,对模拟结果进行评价,同时对附加阳光间的经济性进行计算。结果表明附加阳光间式太阳房仅需15.93 W/m2的热量就能满足房间的采暖需求。在太阳能丰富的北方地区,对房屋进行附加阳光间节能改造是完全可行的。     

Degradation of MCPA by ozone and light

The degradation of dilute aqueous solutions of the herbicide, MCPA (4-chloro-2-methyl-phenoxyacetic acid), by ozone has been examined in the presence and absence of very low energy u.v. light (> 300 nm) to identify early benzenoid intermediates. In the dark, ozonolysis proceeded rapidly, and few aromatic products were detected; under irradiation, MCPA loss occurred even more rapidly, and a series of benzenoid intermediates could be isolated, including 4-chloro-2-methyl-phenol, its formate ester, 5-chlorosalicylaldehyde and 5-chlorosalicyclic acid. Isolation of 5-chloro-3-methylbenzene-1,2-diol from dark ozonolysis suggests the operation of two distinct ozonolysis pathways: ring-hydroxylation and cleavage by molecular ozone in the dark, and side-chain oxidation by hydroxyl radicals under irradiation.     

On an empirical relationship between SO2 concentration and distance from a highway using passive samplers: a case study in Shanghai, China

In this paper, field measurements were performed to determine SO(2) concentration gradients from a highway in Shanghai using passive samplers. It was demonstrated that passive sampling method is a cost-effective and convenient way to monitor specific gaseous pollutants at small scales over long sampling periods in air quality studies. Using function fit analysis for the measured results, a shifted power-law relationship had been found between SO(2) concentration and the distance from a highway. Accordingly, an empirical shifted power-law model was developed for describing and predicting the SO(2) gradients near a highway, in which k is the only parameter and named as diffusion attenuation coefficient. There was a surprisingly significant negative correlation between known SO(2) concentration at reference point (C(0)) and diffusion attenuation coefficient (k). By the correlation equation of C(0) and k, appropriate value of k could be calculated with measured C(0). Therefore, the empirical shifted power-law model developed in this study could be practically and conveniently applied for predicting the SO(2) distributions near a highway with known C(0).     

Pilot-scale evaluation of ozone and biological activated carbon for trace organic contaminant mitigation and disinfection

In an effort to validate the use of ozone for contaminant oxidation and disinfection in water reclamation, extensive pilot testing was performed with ozone/H₂O₂ and biological activated carbon (BAC) at the Reno-Stead Water Reclamation Facility in Reno, Nevada. Three sets of samples were collected over a five-month period of continuous operation, and these samples were analyzed for a suite of trace organic contaminants (TOrCs), total estrogenicity, and several microbial surrogates, including the bacteriophage MS2, total and fecal coliforms, and Bacillus spores. Based on the high degree of microbial inactivation and contaminant destruction, this treatment train appears to be a viable alternative to the standard indirect potable reuse (IPR) configuration (i.e., membrane filtration, reverse osmosis, UV/H₂O₂, and aquifer injection), particularly for inland applications where brine disposal is an issue. Several issues, including regrowth of coliform bacteria in the BAC process, must be addressed prior to full-scale implementation.     

Integrated ozone and biotreatment of pulp mill effluent and changes in biodegradability and molecular weight distribution of organic compounds

The overall effectiveness of integrating ozonation with biological treatment on the biodegradability enhancement and recalcitrant organic matter (ROM) removal from pulp mill alkaline bleach plant effluent was investigated. Ozonation was performed in a semi-batch bubble column reactor at pH of 11 and 4.5. Batch biological treatment was conducted in shake flasks. Samples obtained during the treatments were monitored for BOD₅, COD, TOC, and molecular weight distribution. At an ozone dosage of 0.7-0.8 mg O₃/mL wastewater, integrated treatment showed about 30% higher TOC mineralization compared to individual ozonation or biotreatment. Ozone treatment enhanced the biodegradability of the effluent (monitored as 21% COD reduction and 13% BOD₅ enhancement), allowing for a higher removal of pollutants. The conversion of high molecular weight (HMW) to low molecular weight (LMW) compounds was an important factor in the overall biodegradability enhancement of the alkaline effluent. The overall biodegradability of the LMW compounds did not change over the course of ozonation, but it increased from 5% to 50% (measured as COD removal) for the HMW portion. Ozonation at pH of 11 was more effective than that at pH of 4.5 in terms of generating more biodegradable compounds.     

Photocatalytic destruction of anionic SAS by ozone and oxygen

The article has investigated photocatalytic destruction of anionic SAS—sodium alkylbenzene sulfate (ABS) in the aqueous medium by ozone on TiO₂ Degussa P-25 at UV radiation by a DB-15 low-pressure mercury-quartz lamp. The paper has determined the parameters of photocatalytic ozonization securing complete ABS destruction (100% in terms of organic carbon). We have assessed advantages of photocatalytic ozonization of ABS solutions compared with photocatalytic oxidation by oxygen and O₃/UV treatment.     

Inactivation of enteric adenovirus and feline calicivirus by ozone

Little information is available regarding the effectiveness of ozone on the inactivation of caliciviruses and enteric adenoviruses. Inactivation experiments were conducted with feline calicivirus (FCV), closely related to the human caliciviruses based on nucleic acid organization and capsid architecture, and adenovirus type 40 (AD40). Experiments were carried out in buffered disinfectant demand free water at pH 7 and 5 degrees C. Ct values; concentration of ozone multiplied by contact time with virus; were determined from application of the efficiency factor hom (EFH) model. Ct values for 4-log (99.99%) ozone inactivation at 5 degrees C and pH 7 ranged from 0.07 to 0.60 mg/l min for AD40 and <0.01 to 0.03 mg/l min for FCV. Ct values listed in the US environmental protection agency "Guidance Manual for Compliance with Filtration and Disinfection Requirements for Public Water Systems Using Surface Water Sources" were higher than Ct values generated by this study. Very low ozone residuals (<0.01(mg/l) substantially inactivated FCV and AD40 under the studied conditions.     

Kinetic of benzotriazole oxidation by ozone and hydroxyl radical

Ozonation experiments were performed in batch reactors in order to determine the rate constants for the reaction of molecular ozone and OH radicals with benzotriazole (BT) at different pHs. The first group of ozonation experiments was carried out for the determination of the rate constant for the direct reactions between ozone and BT. Two different kinetic models were used for the determination of kinetic rate constants: (i) the log-reduction of BT with ozone in excess, (ii) the competition kinetic model. The second-order rate constants for BT with molecular ozone were determined to be 36.4 ± 3.8 M⁻¹ s⁻¹ and 18.4 ± 0.8 M⁻¹ s⁻¹ at pH 2 from the two methods respectively. With the competition method, the value at pH 5 was found to be 22.0 ± 2.0 M⁻¹ s⁻¹. In a following stage, the reaction of BT with OH radicals was investigated at pH values ranging from 2 to 10.2. Using a method involving two probe compounds during the ozonation, the second-order rate constants of the BT reaction with hydroxyl radicals were determined. The rate constants were found to vary from 6.2 × 10⁹ M⁻¹ s⁻¹ at pH 10.2 to 1.7 × 10¹⁰ M⁻¹ s⁻¹ at pH 2.     

Photocatalytic destruction of fulvic acids by ozone and oxygen

We have studied destruction of river fulvic acids in water environment with ozone and oxygen. We have also determined advantages of catalytic and photocatalytic ozonization of their solutions compared with ozonization and O₃/UV treatment. Photocatalytic ozonization secures the highest degree of destruction of fulvic acids (93% in terms of total organic carbon) at a shorter time and specific consumption of ozone compare with other methods of oxidation.     

Oxidation of phenolic compounds by ozone and ozone + u.v. radiation: A comparative study

This study was designed to investigate the reaction mechanisms of oxidation of various phenolic compounds by ozone and ozone + u.v. radiation at pH 2.5, 7.0 and 9.0. Experimental results indicated that the molecular ozone is the predominant oxidant only at acidic pH; at neutral and basic pH, in the absence or presence of u.v. radiation, free radical reaction is the major pathway in the oxidation of phenolic compounds. The overall removal of phenols and the removal of TOC increase with increasing pH during ozonation with or without u.v. light. For a specific pH, the removal rates of phenol and TOC are highest for ozone + u.v. light followed by ozone and then u.v. light alone.     

青海藏区农牧民被动太阳能房莫拟分析与评价

结合青海藏区的实际情况,借助动态模拟软件对该地区常见的被动太阳能房设计方案进行了评价分析.结果表明,附加阳光间式被动太阳能房在青海藏区的应用效果最好,采取适当的保温措施后,基本能够满足藏区农牧民冬季的采暖需求.     

军事工程建设项目投资方案综合评价研究

从影响拟定军事工程建设项目投资方案的主要因素出发,建立了比较全面的评价指标体系,引入了灰色关联分析方法,经实例分析,该评价模型和体系合理、有效,以推广灰色关联分析方法的应用。     

中空玻璃承载特性及环境变化对其影响

本文针对中空玻璃在使用过程中受风荷载及环境压、温差影响中空玻璃使用安全问题,直接根据中空玻璃内外片玻璃两面承受的气体压差导致的变形求出中空层体积变化,并结合中空层气体理想状态方程,精确地计算了上述因素影响下中空玻璃内外片变形及应力分布大小,解决了环境温、压差给中空玻璃带来的附加应力和变形理论定量计算这一问题。同时,对目前使用的自动调压式中空玻璃的承载特性及存在的问题进行了分析并提出了相关见解。通过本文研究,详细而定量地分析了中空玻璃在特殊环境下的承载特性及其影响因素,指导中空玻璃生产,设计与工程应用。     

Kinetics and mechanisms of polyethyleneglycol fragmentation by ozone in aqueous solution

The oxidative fragmentation of Polyethyleneglycol by ozone is investigated by means of batch and semibatch ozonation experiments in the pH range 4.0–9.0. Chemical mechanisms and reaction kinetics of the ozonation processes are determined by also exploiting chemical information from experiments on Diethyleneglycol and Ethyleneglycol ozonation. A kinetic model is proposed capable of describing the fragmentation process due to the direct polymer oxidation by ozone.