Thermal fluorescence quenching properties of dissolved organic matter

The fluorescence excitation-emission matrices of dissolved organic matter (DOM) are investigated between 10 and 45 degrees C for river and waste waters and organic matter standards. With increased temperature, fluorescence intensity is quenched. It is demonstrated that for a range of river and wastewater samples, that tryptophan-like fluorescence exhibits a greater range of quenching (between 20+/-4% and 35+/-5%) than fulvic-like fluorescence (19+/-4 to 26+/-3%) over this temperature range. Humic substance standards exhibit similar fulvic-like (23+/-4%) fluorescence thermal quenching properties to river water samples (23+/-3%); however none of the samples exhibit quenching of tryptophan-like fluorescence to the same extent as the tryptophan standards (approximately 50%). Thermal fluorescence quenching is related to the exposure of the fluorophores to the heat source; our findings suggest that the tryptophan-like groups within DOM is more exposed in untreated wastewaters than in treated wastewaters riverine DOM. Thermal fluorescence properties have the potential to be used to source DOM, to provide additional chemical structural information, to temperature correct laser-induced remotely sensed DOM fluorescence, and to characterise DOM through the wastewater treatment process.     

Water Resources and Management in the Republic of Ireland

Ireland is well-endowed with water resources and has one of the higher rates of water availability in Europe. However, regional variations in rainfall and population distribution give much less favourable conditions in the east of the country compared to other areas. Pollution of waters to date has been generally localized and moderate in intensity, although there is a trend towards eutrophication of the river systems. Piped water supplies, either from public or private schemes, are now available to nearly all dwellings in the state, both urban and rural. The same position holds for sewerage facilities in the urban areas, but nearly 25% of the rural population is still unserviced in this regard. Future development of services will place more emphasis on sewerage facilities, as outlined in the recently issued national action programme on the environment.     

Fluorescence properties of some farm wastes: implications for water quality monitoring.

Some farm wastes have been analysed for their fluorescence properties using fluorescence excitation-matrix (EEM) spectroscopy. Farm wastes investigated were silage liquor, pig and cattle slurry, and sheep barn waste. All farm wastes exhibited high intensities of fluorescence that can be attributed to the protein tryptophan. Silage liquor was characterised by a very high fluorescence intensity and an initial tryptophan: fulvic-like fluorescence intensity ratio of >20. Cattle and pig slurries exhibited a lower tryptophan : fulvic-like fluorescence intensity ratio (approximately 2-5) and lower tryptophan fluorescence intensity, and tyrosine fluorescence was also observed. Sheep barn wastes had the lowest tryptophan: fulvic-like fluorescence intensity ratios (approximately 0.5-4.0). Farm waste samples were reanalysed under controlled temperature conditions over a period of 50 days after sampling, to investigate the stability of their fluorescence properties. For silage liquor. tryptophan: fulvic-like fluorescence intensity ratios were observed to decrease with time, and were associated with a decrease in tryptophan fluorescence intensity, suggestive of clostridia breakdown of protein. For slurry samples. tryptophan: fulvic-like fluorescence intensity exhibited a more variable time-evolution, and tryptophan fluorescence intensity increased through time; the more complex fluorescence signal is due to the relatively heterogeneous nature of the slurry. Sheep barn waste samples exhibited more stable tryptophan: fulvic-like fluorescence intensity ratio and tryptophan intensities, suggesting these samples were more stable due to their greater age and decomposition. The ratios of tryptophan: fulvic-like fluorescence intensity observed from the farm wastes investigated are significantly higher than those observed in the majority of river waters, suggesting that farm waste pollution events could leave a signature in river waters due to their distinctively high protein fluorescence intensity.     

Can fluorescence spectrometry be used as a surrogate for the Biochemical Oxygen Demand (BOD) test in water quality assessment? An example from South West England

The fluorescence intensities of tryptophan-like, tyrosine-like and humic-like materials were determined using excitation-emission-matrices (EEMs) for a wide range of samples including natural surface waters, sewage and industrial effluents and waters that have experienced known pollution events from the South West of England (n=469). Fluorescence intensities reported in arbitrary fluorescence units (AFU) were correlated with standard five day Biochemical Oxygen Demand (BOD(5)) values which were used as an indicator of the amount of biodegradable organic material present. Tryptophan-like fluorescence, which has been found to relate to the activity of the biological community, showed the strongest correlation with BOD(5). Fluorescence analysis of the tryptophan-like peak (excitation/emission wavelength region 275/340 nm) is found to provide an accurate indication of the presence, and relative proportions of bioavailable organic material present (natural or anthropogenic). It therefore provides an insight relating to its oxygen depleting potential. Thus fluorescence spectroscopy is recommended as a portable or laboratory tool for the determination of the presence of biodegradable organic matter with intrinsic oxidising potential in natural waters. The novel application of Geographically Weighted Regression (GWR) to the data illustrates that strong local relationships exist between the two parameters and that site specific character may be a strong factor in the strength of the tryptophan-like fluorescence/BOD(5) relationship.     

中国都市排水系统功能的变革

在当今水环境劣化趋势日益严峻,水资源日益短缺的态势下,在污水深度处理、超深度处理和回收利用已经实用化了的今天,排水系统不应仅仅是排除雨水、污水及保护城市环境和公共水域水质的基础设施,更应升华为维系城市健康水循环和良好水环境,实现水资源可持续利用的人类社会的生命线工程。在城市污水作为可贵的淡水资源之新理念下,阐述了排水系统功能、规划和设计方面的新构想和新特点。     

Characterisation of the fluorescence from freshwater, planktonic bacteria

Amino acid-like fluorescence has been used as an indicator of biological activity in wastewater effluent and in natural waters, and can be detected using fluorescence spectroscopy. Little or no work has been able to state conclusively that these so called 'amino acid-like' fluorophores are associated with proteins present as a result of bacterial activity. This work aims to ascertain whether bacteria are one possible cause of these 'amino acid-like' peaks observed in natural waters. In addition, fluorescence derived solely from one bacterial source was determined as a function of the growth time and temperature. The bacterium Pseudomonas aeruginosa was isolated from the urban River Tame, Birmingham, UK, and planktonic bacteria were grown in sterile, sealed glass jars, in 100 ml growth media. Bacteria were grown at 11, 25 and 37 degrees C, over a maximum of 10 days. A 3D Excitation-Emission Matrix (EEM) plot was generated from fluorescence analysis of the samples. Both tryptophan and tyrosine-like fluorescence, resembling that observed in natural and waste waters, was observed in these samples, indicating that observed fluorescence signals from aquatic systems in the literature were of biotic origin. Significant differences in fluorescence signals were obtained from planktonic cells grown at different temperatures. At 25 and 37 degrees C, cells were found to produce predominantly tryptophan-like fluorescence, with some tyrosine-like fluorescence also detected. A further unknown fluorophore was also detected (emission wavelength of approximately 460 nm, with three excitation centres at 225, 260 and 390 nm), likely to be a bacterially produced metabolite. At 11 degrees C, a more environmentally realistic temperature in temperate environments, quantitative and qualitative differences were observed in fluorescence signals when compared with the higher temperatures, indicating that laboratory observations conducted at higher temperatures may not be easily used to interpret environmental processes.     

Comparison of river and canal water dissolved organic matter fluorescence within an urbanised catchment

Recently, growing interest has been shown in the study of canal water quality, yet no research using continuous fluorescence monitoring to characterise dissolved organic matter (DOM) has been performed. This paper evaluated DOM characteristics at hourly resolution. A comparison was made between canal and nearby urban river fluorescence spectra, to emphasise the specific nature of canal water DOM. Results showed that canal water had a significant proportion of microbially derived DOM, while the urban river had a greater proportion of terrestrially derived fractions. The microbial character of canal water DOM originated from the low flow of water, the nutrients predominance and continuous DOM processing. Hence, DOM fluorescence is invariant over a timescale of days, and recreational navigation and precipitation events have no major influence on DOM characteristics. Our results are expected to be applicable to future research on highly regulated freshwater systems for DOM quantity estimation or for water quality models.     

Production of lipophilic volatile organohalogen materials during laboratory chlorination of some waste water and polluted river water samples from Yugoslavia

Water chlorination leads to the generation of various halogenated products of natural and waste water organic mater. In natural surface water humic matter usually makes the greatest part of the total organic matter. However, in the river water polluted with various organic wastes, other organic matter is also present in significant concentrations. The investigation of the relationship between the concentration of organic matter in the samples of waste water and heavily polluted river waters in Yugoslavia on one side, and the production of the lipophilic volatile organohalogen materials during the process of their chlorination on the other side is described. The production of the halomethanes and other ECD response materials during the chlorination of water samples in laboratory conditions is compared with the concentrations of organic materials in water samples. From the obtained linear correlation coefficients, possibilities of predicting amounts of organohalides during the chlorination process by using several very simple methods for the organic materials estimation in the investigated water samples are discussed and compared.     

Upgrading of Sewerage Assets to Comply with New Legislation: A Lothian Regional Viewpoint

The EC bathing water Directive and the recent EC urban waste water treatment Directive have provided, and will continue to provide, a strong stimulus for the provision of environmental improvement through the upgrading of sewerage assets. The positive response by Lothian Regional Council to necessary improvements in the last fifteen years, and the proposed improvements in the next fifteen years, are reviewed against the background of financial constraints. It is suggested that parts of the urban waste water treatment Directive relating to estuarial and coastal discharges are not appropriate or necessary in the context of conditions in Lothian Region.     

Impact in Scotland of UK and EC Sewage Legislation

The EC Directive (91/271/EEC) concerning urban waste water treatment has far-reaching financial and technological implications for local authorities in Scotland which are responsible for sewerage. Increased capital consent limits and additional financial assistance from central government are essential if the requirements of the legislation are to be met.
Although the Directive is welcomed in general terms, the sections of the legislation dealing with the identification of sensitive waters and the provision of primary treatment for coastal discharges to less sensitive waters are of limited environmental significance in Scotland.
The elimination of sewage sludge disposal at sea will create severe difficulties for Scottish authorities as a high percentage of sewage sludge is currently disposed of at sea. Each of the main alternative disposal options presents environmental, financial and technical problems and, in the case of incineration, the certainty of widespread unpopularity with the public.     

论《园冶》中的植物造景原则

以《园冶》为研究主体,首先从中国古典园林花木造园的基本思想、相地择木、景因木显、花木续景、情景交融五个方面,分别研究了《园冶》一书中植物搭配的基本原则、思想与运用。而后以扬州影园为案例,具体分析了计成在实际园林中运用的植物配置理念,同时在影园的一花一木的种植中印证《园冶》中提及的植物造景手法,最后概述了其哲学思想和造园技艺对中国古典园林与现代园林的意义。     

Linking catchment characteristics and water chemistry with the ecological status of Irish rivers

Requirements of the EU Water Framework Directive for the introduction of ecological quality objectives for surface waters and the stipulation that all surface waters in the EU must be of 'good' ecological status by 2015 necessitate a quantitative understanding of the linkages among catchment attributes, water chemistry and the ecological status of aquatic ecosystems. Analysis of lotic ecological status, as indicated by an established biotic index based primarily on benthic macroinvertebrate community structure, of 797 hydrologically independent river sites located throughout Ireland showed highly significant inverse associations between the ecological status of rivers and measures of catchment urbanisation and agricultural intensity, densities of humans and cattle and chemical indicators of water quality. Stepwise logistic regression suggested that urbanisation, arable farming and extent of pasturelands are the principal factors impacting on the ecological status of streams and rivers in Ireland and that the likelihood of a river site complying with the demands of the EU Water Framework Directive, and be of 'good' ecological status, can be predicted with reasonable accuracy using simple models that utilise either widely available landcover data or chemical monitoring data. Non-linear landcover and chemical 'thresholds' derived from these models provide a useful tool in the management of risk in catchments, and suggest strongly that more careful planning of land use in Ireland is essential in order to restore and maintain water quality as required by the Directive.     

Rapid and direct determination of tryptophan in water using synchronous fluorescence spectroscopy

Water samples from lakes situated in and around the area of Tsukuba Science City, Ibaraki Prefecture, Japan, were analysed using synchronous fluorescence spectroscopy and HPLC. The spectra revealed a major emission peak (lambda emm) at 340 nm corresponding to an excitation wavelength (lambda exc) position of 280 nm and a Stoke's shift, delta lambda = 60 nm. The fluorescence intensities at these wavelengths were normalised with respect to the water Raman peak, where the lambda exc was 397 nm and the lambda emm was 453 nm, and corrections were introduced to take into account absorption/re-absorption effects of the fluorescing signals caused by the sample matrix. Normalised fluorescence values correlate well with levels of tryptophan present in the samples determined by HPLC analysis (R2 = 0.99). The relationship of the observed tryptophan-like fluorescence in the water samples to the presence of free tryptophan is discussed.     

Characteristics of humic substances in the Kuji River waters as determined by high-performance size exclusion chromatography with fluorescence detection

Direct measurement by high-performance size exclusion chromatography with fluorescence detection was applied to the characterization of humic substances in river waters from the Kuji River system, which runs through forest hills and an agricultural plain in Japan. The monitoring wavelength of excitation 320 nm and emission 430 nm corresponds to the fluorescence maxima for aquatic fulvic acid. Chromatograms of the river waters showed four peaks; each peak position was in good agreement among these samples. Peak height ratios for the samples from the upstream Kuji River and its tributaries were different from those of the midstream and downstream sections of the Kuji River, which may reflect differences in the characteristics of humic substances and other organic materials supplied from soil to river.     

Indicator compounds for assessment of wastewater effluent contributions to flow and water quality

Numerous studies have reported the presence of trace (i.e., ng/L) organic chemicals in municipal wastewater effluents, but it is unclear which compounds will be useful to evaluate the contribution of effluent to overall river flow or the attenuation processes that occur in receiving streams. This paper presents a new approach that uses a suite of common trace organic chemicals as indicators to assess the degree of impact and attenuation of trace organic chemicals in receiving streams. The utility of the approach was validated by effluent monitoring at ten wastewater treatment plants and two effluent-impacted rivers with short retention times (<17 h). A total of 56 compounds were particularly well suited as potential indicators, occurring frequently in effluent samples at concentrations that were at least five times higher than their limit of quantification. Monitoring data from two effluent-impacted rivers indicated that biotransformation was not important for these two river stretches, whereas photolysis attenuation was possibly important for the shallow river. The application of this approach to receiving waters and water reclamation and reuse systems will allow for more effective allocation of resources in future monitoring programs.     

农家乐污水中溶解性有机质的三维荧光特性研究

采用三维荧光光谱(3DEEM)技术考察了农家乐污水中溶解性有机质的三维荧光特性.结果表明,农家乐污水中的有机污染物荧光峰以类蛋白质荧光峰为主,其中高激发波长类色氨酸荧光峰Peak T最强,其次是低激发波长类色氨酸荧光峰Peak S和低激发波长类酪氨酸荧光峰Peak D;综合性农家乐污水的Peak S和Peak D荧光强度比以餐饮为主的农家乐污水的要强.农家乐污水经受纳水体稀释和净化后,类蛋白质荧光强度仍远高于地表水的.其对受纳水体的污染不容忽视.     

H市河道水环境评价及综合治理工程设计

河北省H市由于市政基础设施久未更新,且排水管网存在污水直排、雨污混接等现象,城区内河水质基本为劣Ⅴ类。为有效控制和改善当地城区内河污染情况,对H市城区内的河渠进行了水环境调研与评价,并以“控源截污、内源治理、生态修复、统筹兼顾”的整体思路提出治理方案,旨在实现水环境改善与生态协调的双重目标。     

Acclimation to and biodegradation of nitrilotriacetate (NTA) at trace concentrations in natural waters

Acclimation to and biodegradation of nitrilotriacetic acid (NTA), an organic builder used in synthetic laundry detergents as the sodium salt, was studied at trace concentrations (ppb) in several river waters. The river waters tested ranged from those where extensive NTA exposure via detergents had not occurred, to those where NTA exposure had been continuous for several years. In rivers not previously exposed to NTA, acclimation and degradation were observed at the lowest initial concentration tested, 5 μg 1⁻¹. Degradation of NTA after acclimation followed apparent first order kinetics, and half lives for NTA removal ranged from 7 to 138 h at initial NTA concentrations of 50 and 5 μg 1⁻¹, respectively. Degradation of NTA in water samples where prior NTA exposure had already occurred required no acclimation and was less variable than in unexposed rivers. First order rate constants varied only slightly over a 1000-fold initial concentration range (1–1000 μg 1⁻¹) and NTA half lives ranged from 7 to 17 h. In general, our results indicate that microflora present in natural waters can acclimate to and degrade NTA, even if exposed to only trace levels in laboratory experiments. However, rates of NTA biodegradation are more rapid and less variable in river waters where natural NTA exposure has already occurred.     

Determination of volatile organic compounds in surface waters and treated wastewater in Greece

The occurrence of volatile organic compounds (VOCs) was studied in river water, lake water, seawater and treated wastewater in Greece from October 1998 to September 1999. The determination of 41 VOCs was performed with a Purge and Trap-Gas Chromatography-Mass Spectrometry method. Samples were collected seasonally from 10 rivers, seven lakes, three gulfs and four wastewater treatment plants. In surface water samples, 15 VOCs were detected. In wastewater samples, occurrence of 31 VOCs was observed. The results suggest that not only agricultural and industrial activity within the Greek territory, but also transboundary pollution deriving from neighbouring countries consist important sources of VOCs in surface waters of Greece. However, the measured concentrations did not in any case exceed the guideline values proposed by the EC.     

The genetic diversity of human noroviruses detected in river water in Korea

We studied the genetic diversity of human noroviruses in river waters by RT-nested PCR and phylogenetic analysis. During 2002-2003, water samples were collected from four rivers in Gyeonggi Province, South Korea. Among the 58 samples, 32 (55.2%) and 26 (44.8%) showed positive results with noroviruses belonging to genogroups I (GI) and II (GII), respectively. The phylogenetic analysis grouped 8 and 7 genotypes in GI and GII, respectively. The major types were GI/1, GI/13, and GII/15, and GI/1 and GI/3 were temporarily distributed. Most GI- and GII-grouped strains were closely related to the reference strains from neighboring countries, China and Japan, and GII/4-related strains had similar sequences to strains recognized as worldwide epidemic outbreaks. The strains circulating between countries are of particular concern to the outbreaks of noroviral diseases in Korea and must be periodically monitored in the natural environments.