Mathematical models for the prediction of temperature distributions resulting from the discharge of heated water into large bodies of water

Mathematical models for heated water outfalls were developed for three flow regions. Near the source, the subsurface discharge into a stratified ambient water issuing from a row of buoyant jets was solved with the jet interference included in the analysis. The analysis of the flow zone close to and at intermediate distances from a surface buoyant jet was developed for the two-dimensional and axisymmetric cases. Far away from the source, a passive dispersion model was solved for a two dimensional situation taking into consideration the effects of shear current and vertical changes in diffusivity. A significant result from the surface buoyant jet analysis is the ability to predict the onset and location of an internal hydraulic jump. Prediction can be made simply from the knowledge of the source Froude number and a dimensionless surface exchange coefficient. Parametric computer programs of the above models are also developed as a part of this study. This report was submitted in fulfillment of Contract No. 14-12-570 under the sponsorship of the Federal Water Quality Administration.

A study of water quality in Baltimore Harbor

Baltimore Harbor is polluted by discharge of sewage and industrial wastes into tributary streams and peripheral waters. The Harbor is used extensively for navigation, industrial water supply, and recreation as well as for waste disposal. The degree of pollution varies from negligible in the principal fairway to severe in the innermost sections. Private industry discharges several hundred tons of acid materials daily and is also the principal source of organic pollution.

Marine pollution and water quality monitoring in Myanmar: assessment and bridging capacity needs

This study looked at improving knowledge base capacity and enhance capacity to address marine pollution and water quality monitoring issues in Myanmar. Significant capacity needs were identified and a follow up plan presented.

Use of PFU protozoan community structural and functional characteristics in assessment of water quality in a large, highly polluted freshwater lake in China

Structural and functional parameters of protozoan communities colonizing on PFU (polyurethane foam unit) artificial substrate were assessed as indicators of water quality in the Chaohu Lake, a large, shallow and highly polluted freshwater lake in China. Protozoan communities were sampled 1, 3, 6, 9 and 14 days after exposure of PFU artificial substrate in the lake during October 2003. Four study stations with the different water quality gradient changes along the lake were distinguishable in terms of differences in the community's structural (species richness, individual abundance, etc.) and functional parameters (protozoan colonization rates on PFU). The concentrations of TP, TN, COD and BOD as the main chemical indicators of pollution at the four sampling sites were also obtained each year during 2002-2003 for comparison with biological parameters. The results showed that the species richness and PFU colonization rate decreased as pollution intensity increased and that the Margalef diversity index values calculated at four sampling sites also related to water quality. The three functional parameters based on the PFU colonization process, that is, S-eq, G and T-90%, were strongly related to the pollution status of the water. The number of protozoan species colonizing on PFU after exposure of 1 to 3 days was found to give a clear comparative indication of the water quality at the four sampling stations. The research provides further evidence that the protozoan community may be utilized effectively in the assessment of water quality and that the PFU method furnishes rapid, cost-effective and reliable information that may be useful for measuring responses to pollution stress in aquatic ecosystems.

Efficiency of constructed wetlands in decontamination of water polluted by heavy metals

A twin-shaped constructed wetland (CW) comprising a vertical flow (inflow) chamber with Cyperus alternifolius followed by a reverse-vertical flow (outflow) chamber with Villarsia exaltata was assessed for decontamination of artificial wastewater polluted by heavy metals. After application of Cd, Cu, Pb, Zn over 150 days, together with Al and Mn during the final 114 days, no heavy metals with the exception of Mn could be detected in either the drainage zone at the bottom, shared by both chambers, or in the effluent. The inflow chamber was, therefore, seen to be predominantly responsible for the decontamination process of more toxic metal species with final concentrations far below WHO drinking-water standards. About one-third of the applied Cu and Mn was absorbed, predominantly by lateral roots of C. alternifolius. Lower accumulation levels were observed for Zn (5%), Cd (6%), Al (13%). and Pb (14%). Contents of Cd, Cu, Mn, and Zn in soil were highest in top layer, while Al and Pb were evenly distributed through the whole soil column. Metal species accumulating mainly in the top layer can be removed mechanically. A vertical flow CW with C. alternifolius is an effective tool in phytoremediation for treatment of water polluted with heavy metals. (C) 2002 Elsevier Science B.V. All rights reserved.

A demonstration of wireless sensing for long-term monitoring of water quality

At a time when technological advances are providing new sensor capabilities, novel network capabilities, long-range communications technologies and data interpreting and delivery formats via the World Wide Web, we never before had such opportunities to sense and analyse the environment around us. However, the challenges exist. While measurement and detection of environmental pollutants can be successful under laboratory-controlled conditions, continuous in-situ monitoring remains one of the most challenging aspects of environmental sensing. This paper describes the development and test of a multi-sensor heterogeneous real-time water monitoring system. A multi-sensor system was deployed in the River Lee, County Cork, Ireland to monitor water quality parameters such as pH, temperature, conductivity, turbidity and dissolved oxygen. The R. Lee comprises of a tidal water system that provides an interesting test site to monitor. The multi-sensor system set-up is described and results of the sensor deployment and the various challenges are discussed.

Mutual Solubilities of Water and Hydrophobic Ionic Liquids

The ionic nature of ionic liquids (ILs) results in a unique combination of intrinsic properties that produces increasing interest in the research of these fluids as environmentally friendly "neoteric" solvents. One of the main research fields is their exploitation as solvents for liquid-liquid extractions, but although ILs cannot vaporize leading to air pollution, they present non-negligible miscibility with water that may be the cause of some environmental aquatic risks. It is thus important to know the mutual solubilities between ILs and water before their industrial applications. In this work, the mutual solubilities of hydrophobic yet hygroscopic imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ILs in combination with the anions bis(trifluoromethylsulfonyl)imide, hexafluorophosphate, and tricyanomethane with water were measured between 288.15 and 318.15 K. The effect of the ILs structural combinations, as well as the influence of several factors, namely cation side alkyl chain length, the number of cation substitutions, the cation family, and the anion identity in these mutual solubilities are analyzed and discussed. The hydrophobicity of the anions increases in the order [C(CN)3] <[PF6] <[Tf2N] while the hydrophobicity of the cations increases from [Cnmim] <[Cnmpy] [Cnmpyr] <[Cnmpip] and with the alkyl chain length increase. From experimental measurements of the temperature dependence of ionic liquid solubilities in water, the thermodynamic molar functions of solution, such as Gibbs energy, enthalpy, and entropy at infinite dilution were determined, showing that the solubility of these ILs in water is entropically driven and that the anion solvation at the IL-rich phase controls their solubilities in water. The COSMO-RS, a predictive method based on unimolecular quantum chemistry calculations, was also evaluated for the description of the water-IL binary systems studied, where it showed to be capable of providing an acceptable qualitative agreement with the experimental data.

Mutual Solubilities of Water and the [Cnmim][Tf2N] Hydrophobic Ionic Liquids

Ionic liquids (ILs) have recently garnered increased attention because of their potential environmental benefits as "green" replacements over conventional volatile organic solvents. While ILs cannot significantly volatilize and contribute to air pollution, even the most hydrophobic ones present some miscibility with water posing environmental risks to the aquatic ecosystems. Thus, the knowledge of ILs toxicity and their water solubility must be assessed before an accurate judgment of their environmental benefits and prior to their industrial applications. In this work, the mutual solubilities for [C2-C8mim][Tf2N] (n-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and water between 288.15 and 318.15 K at atmospheric pressure were measured. Although these are among the most hydrophobic ionic liquids known, the solubility of water in these compounds is surprisingly large, ranging from 0.17 to 0.36 in mole fraction, while the solubility of these ILs in water is much lower ranging from 3.2 × 10-5 to 1.1 × 10-3 in mole fraction, in the temperature and pressure conditions studied. From the experimental data, the molar thermodynamic functions of solution and solvation such as Gibbs energy, enthalpy, and entropy at infinite dilution were estimated, showing that the solubility of these ILs in water is entropically driven. The predictive capability of COSMO-RS, a model based on unimolecular quantum chemistry calculations, was evaluated for the description of the binary systems investigated providing an acceptable agreement between the model predictions and the experimental data both with the temperature dependence and with the ILs structural variations.

Metagenomic characterisation of the viral community of lough neagh, the largest freshwater lake in Ireland

Lough Neagh is the largest and the most economically important lake in Ireland. It is also one of the most nutrient rich amongst the world's major lakes. In this study, 16S rRNA analysis of total metagenomic DNA from the water column of Lough Neagh has revealed a high proportion of Cyanobacteria and low levels of Actinobacteria, Acidobacteria, Chloroflexi, and Firmicutes. The planktonic virome of Lough Neagh has been sequenced and 2,298,791 2×300 bp Illumina reads analysed. Comparison with previously characterised lakes demonstrates that the Lough Neagh viral community has the highest level of sequence diversity. Only about 15% of reads had homologs in the RefSeq database and tailed bacteriophages (Caudovirales) were identified as a major grouping. Within the Caudovirales, the Podoviridae and Siphoviridae were the two most dominant families (34.3% and 32.8% of the reads with sequence homology to the RefSeq database), while ssDNA bacteriophages constituted less than 1% of the virome. Putative cyanophages were found to be abundant. 66,450 viral contigs were assembled with the largest one being 58,805 bp; its existence, and that of another 34,467 bp contig, in the water column was confirmed. Analysis of the contigs confirmed the high abundance of cyanophages in the water column.

Studies on the Nature and Chemistry of Sediments and Water of Periyar and Chalakudy Rivers, Kerala, India

The present study is an attempt to address issues related to sediment properties like texture, mineralogy and geochemistry as well as water quality of two important rivers of central Kerala-the Periyar and the Chalakudy rivers. The main objectives of the study are to investigate the textural and mineralogical characteristics as well as transportation and depositional mechanisms of the sediments of Periyar and Chalakudy rivers, to find out the geochemical variability of organic carbon, phosphorus and certain major (Na,K,Ca and Mg) and minor/trace(Mn,Pb,Ni,Cr, and Zn) elements in the bulk sediments and mud fraction of these rivers, to evaluate the status of heavy metal pollution registered in the sediments of these rivers, to assess the physico-chemical characteristics and water quality of Periyar and Chalakudy rivers and to estimate the dissolved nutrient flux through the Periyar and Chalakudy rivers into the receiving coastal waters. The granulometric characteristics as well as statistical parameters of the sediments of Periyar and Chalakudy rivers depend on the flow pattern controlled by the gradient of the terrain. Compared to Periyar, fluctuations in the dispersal of particles are more in Chalakudy river. In Periyar river, the P and Fe in bulk sediments show a positive correlation with C-org, while in Chalakudy river, both the elements are related to THM concentration. In general, C-org, Fe and P Shows an increasing trend downstream. In Periyar river, the P and Fe in bulk sediments show a positive correlation with C-org, while in Chalakudy river, both the elements are related to THM concentration. Among these two rivers, the pollution of water is several fold higher in Periyar river due to influx due to influx of considerable quantity of liquid and solid wastes of industrial/domestic/urban origin. Nutrient analysis reveals 2-3 times increase in N and P during monsoon season whereas SiO2-Si shows a decreasing trend.

The Mersey Basin: an historical assessment of water quality from an anecdotal perspective

The freshwaters of the Mersey Basin have been seriously polluted for over 200 years. Anecdotal evidence suggests that the water quality was relatively clean before the start of the Industrial Revolution. The development of the cotton and chemical industries increased the pollution load to rivers, and consequently a decline in biota supported by the water was observed. Industrial prosperity led to a rapid population increase and an increase in domestic effluent. Poor treatment of this waste meant that it was a significant pollutant. As industry intensified during the 19th century, the mix of pollutants grew more complex. Eventually, in the 1980s, the government acknowledged the problem and more effort was made to improve the water quality. Knowledge of social and economic history, as well as anecdotal evidence, has been used in this paper to extrapolate the changes in water quality that occurred. (C) 2003 Elsevier Science B.V. All rights reserved.

Genotoxicity assessment of water soluble fractions of biodiesel and its diesel blends using the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cytotoxicity of water-soluble fraction from biodiesel and its diesel blends to human cell lines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)