River water Research Papers - Academia.edu (original) (raw)

Using a simple conceptual dynamic river water quality model, the effects of different basin-wide water quality management options on downstream water quality improvements in a semi-arid river, the Crocodile River (South Africa) were investigated. When a river is impacted by high rates of freshwater withdrawal (in its upstream reaches), and receives polluted side-stream inflows and wastewater effluent discharges (in the middle reaches), river water quality can deteriorate seriously over time. This study focused on two water quality problems: Progressive increases in the concentrations of total dissolved solids (TDS) as a measure of salinity, and the concentrations of nitrate-plus-nitrite and ammonia (as inorganic nitrogen) as a measure of eutrophication. Based on a lowflow analysis for the period prior to construction of the Kwena Dam (1960 to 1979), the 7d low flows that could be expected to occur every 10 years (7Q10) are generally very low (< 0.5 m 3 •s-1), both in the upstream (Montrose Weir) and the downstream (Kruger National Park) sections of the Crocodile River. During such critical periods of low river flow, very low effluent standard limits would be required to prevent adverse river water quality. However, these options are not economically feasible. Furthermore, inflows from the highly polluted tributary stream, the Kaap River, which drains an area where considerable gold mining takes place, govern water quality in the Crocodile River downstream of the Crocodile-Kaap confluence. Subsequently, two additional water quality control options (setting limits for maximum water withdrawal and low-flow augmentation) were analysed. The results show that a decrease in maximum water withdrawal could reduce the TDS concentration. Furthermore, controlling water release patterns from a dam at the Montrose Weir can have a remarkably positive effect on the downstream river water quality. On the basis of the 1989/90 monitoring data, a minimum flow of 5 m 3 •s-1 at the Montrose Weir can reduce concentrations of TDS and ammonia nitrogen by about 20% and 60%, respectively, in the Kruger National Park (at the downstream point of the considered river). However, this management option does not reduce nitrate nitrogen concentrations. The proposed model used in this study is relatively simple and can be used as a tool for the evaluation of short-term (monthly) basin-wide water quality management options.

- by
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- Engineering, Earth Sciences, Case Studies, Mining

In this work, two toxic compound, sulfide and thiocyanate were determined simultaneously using kinetic spectrophotometry. These anions have shown the catalytic effects on the reaction between iodine and azide. Since the system was nonlinear, a nonlinear model, principal componentwavelet neural network (PC-WNN) was used as the multivariate calibration method. The principal component analysis was used to decrease the dimension of the original matrix. In other words, the scores of the PCs, 5, instead of the original variables, 301, were used as the input for the model. Two methods were used to select the most relevant principal components: eigenvalue ranking and correlation ranking. In this work, eigenvalue and correlation ranking methods have shown better results for thiocyanate and sulfide, respectively, and it can be concluded that these methods are complementary. The WNN has several advantages relative to other types of neural network such as better convergence ability. The data set was divided to calibration, prediction and validation sets. Each set was selected so that the concentrations of the analytes were approximately covered the entire ranges of the analytes. Mean relative error for thiocyanate and sulfide in validation set were 8.5 and 10.6, respectively. Thiocyanate and sulfide can be determined in the range of 60-700 ng ml −1 and 20-400 ng ml −1 , respectively. The proposed method was applied for the determination of sulfide and thiocyanate in real samples such as tap, waste and river waters with satisfactory results.

- by Ali A. Ensafi
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- Analytical Chemistry, Kinetics, Principal Component Analysis, Neural Network

A new chelating resin incorporating imidazolyl azo groups into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury(II), silver(I) and lead(II) as a function of pH has been determined. The resin exhibits no affinity to alkali, or alkaline earth metals. It is highly selective for only mercury(II) and silver(I). In column operation it has been observed that mercury(II) in trace quantities is very effectively removed from river water spiked with mercury(II) at the usual pH of natural waters.

- by Pabitra Chattopadhyay
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- Chemistry, Water, River water, Sorption

In order to evaluate the metal contamination from kaolin industry discharges into rivers in the State of Minas Gerais, Brazil, samples of river water and fluvial sediment were collected up- and down-river from the industries and analysed todetect metal inputs. The metal examined included zinc, iron, andaluminium among others, being selected due to their toxicity andoccurence in waste waters. Metal inputs in the samples analysed appeared to be related to effluent discharges into the rivers. The river water showed high concentrations (in μg mL-1) of Zn (355), Fe (354) and Al (303). Sediment investigations indicated heavy enrichment (SEF = 9.4) for Zn. The Geoaccumulation Index for this element accounted for 3 (moderately to heavy polluted). River water pH of the sample collected near the effluent discharge site reached 3.7, suggesting inadequate treatment.

- by Joana Pereira
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- Multidisciplinary, River water, Minas Gerais, Zinc
- by Praveen Kumar
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- Water quality, Carbon, Water Purification, Environmental Management

Bachmann et al.(1999) postulated that wind energy initiated, and has maintained, high turbidity in hypertrophic (mean chlorophyll a= 92 µg l-1) Lake Apopka, Florida (mean depth= 1.6 m; area= 12? 500 ha). They asserted that the turbid... more

- by Claire Schelske and +1
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- Earth Sciences, Wind Energy, Biological Sciences, Phosphorus
- by Tuula Tuhkanen
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- Environmental Science, Performance, Filtration, Water Pollution

We studied changes in the epilimnetic bacterial community composition (BCC), bacterial biomass and production, and protistan succession and bacterivory along the longitudinal axis of the canyonshaped, highly eutrophic Sau Reservoir (NE Spain) during two sampling campaigns, in April and July 1997. Longitudinal changes in BCC from the river inflow to the dam area of the reservoir were detected by using oligonucleotide probes targeted to the kingdom Bacteria, to the alpha, beta, and gamma subclasses (ALFA, BETA, and GAMA) of the class Proteobacteria, and to the Cytophaga/ Flavobacterium (CF) cluster. In general, the inflow of the organically loaded Ter river, with highly abundant allochthonous bacterial populations, induced a clearly distinguishable longitudinal succession of the structure of the microbial food web. The most dynamic changes in microbial parameters occurred at the plunge point, the mixing area of river water and the reservoir epilimnion. Changes within members of BETA and CF were the most important in determining changes in BCC, bacterial abundance and biomass. Much less relevant changes occurred within the less abundant ALFA and GAMA bacteria. From the plunge point downstream, we described a significant shift in BCC in the form of decreased proportions of BETA and CF. This shift spatially coincided with the highest values of heterotrophic nanoflagellate bacterivory (roughly doubled the bacterial production). CF numerically dominated throughout the reservoir without any marked longitudinal changes in their mean cell volume. In contrast, very large cells affiliated to BETA clearly dominated in the allochthonous bacterial biomass brought by the river. BETA showed a marked downstream trend of decreasing mean cell volume. We conclude that the observed BCC shift and the longitudinal shift in food web structure (bacteria-heterotrophic nanoflagellates-ciliates) resulted from Correspondence highly complex interactions brought about by several major factors: varying hydrology, the high localized allochthonous input of organic matter brought by the river, downstream changing substrate availability, and selective protistan bacterivory.

- by Josef Hejzlar
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- Microbiology, Microbial Ecology, Ecology, River water

Senegal river water has positive alkalinity (0.55 meq l À 1 ) and positive calcite-residual alkalinity (0.30 meq l À 1 ). Without leaching, this water presents a possible alkalinization and sodication hazard for the soil. The effect of flooding on soil solution chemistry in an irrigated nondrained vertisol under rice was monitored during 3 years in northern Senegal. During flooding, soil solution redox potential dropped to about À 0.15 V, and alkalinity increased to 15 meq l À 1 . Mg content increased as well, from about 1 to 5 meq l À 1 , whereas Cl and SO 4 contents decreased to very low levels at the end of the growing season (0.05 meq l À 1 ). After the fallow, nonflooded period between two crop cycles, the soil solution composition returned to its initial neutral sulfate and chloride composition. The observed cycle in soil solution chemistry could not be explained by water and solute transfer because infiltration rates were very low, due to air entrapment in the soil profile. Geochemical control by calcite and gypsum was excluded during irrigation. Mössbauer spectroscopy showed that iron oxides were both well-and poorly crystallized goethite. Goethite dissolution was assessed by pH -Eh stability diagrams.

- by Jean-luc Maeght and +1
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- Geochemistry, Clay Minerals, Senegal, Biological Sciences

The aim of this study was to investigate the seasonal and spatial variations in surface water quality at the mid-Black Sea coast of Turkey. The samples were collected from ten monitoring stations including rivers and sea water during the years from 2007 to 2008. The samples were analyzed for 25 parameters: total carbon, total inorganic carbon, total organic carbon, chromium, cadmium, copper, lead, iron, nickel, manganese, phenol, surfactants, ammonium, nitrite and nitrate-nitrogen, total phosphorus, adsorbable organic halogen, sulfate, hardness, dissolved oxygen, pH, temperature, total dissolved solids, electrical conductivity, and salinity. Multivariate statistical techniques, cluster analysis (CA) and factor analysis/principal component analysis (FA/PCA), were applied to analyze the similarities among the sampling sites to identify the source apportionment of pollution parameters in surface waters. The results indicate that seven factors for river water explained 82.24% of the variance. In seawater, seven factors account for 89.65% of the total variance. Varifactors obtained from factor analysis indicate that the parameters responsible for water quality variations are mainly related to organic pollution (municipal effluents), inorganic pollution (industrial effluents and waste disposal areas), nutrients (agricultural runoff), and dissolved salts (soil leaching and runoff process).

Evoluzione della fauna macrobentonica e qualità delle acque in ambito alpino-torrente THURAS nell'alta Valle di Susa-Premessa La qualità delle acque può essere valutata con diversi criteri : il metodo degli indici biotici, sui popolamenti di macroinvertebrati bentonici tramite l'Extended Biotic Index : E.B.I. o Indice Biotico Esteso : I.B.E. modif. Ghetti, 1986 , rappresenta, allo stato attuale, un criterio di alto valore scientifico.

- by Giacomo Olivero
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- Entomology, River Ecology, Benthic macroinvertebrates, Alps

Fouling is a major obstacle for maintaining efficient membrane-based drinking water treatment processes. Natural organic matter (NOM) components such as humic substances (HS)-and protein-like matter as well as colloidal/particulate matter are known to be the major membrane foulants in ultrafiltration-based drinking water processes. In this study, a fluorescence excitation-emission matrix (EEM) approach was used for characterization of these major membrane foulants. Unlike most NOM and colloidal/particulate matter characterization techniques, this method can provide fast and consistent analyses with high instrumental sensitivity. Principal component analysis (PCA) of fluorescence EEM measurements collected during cross-flow ultrafiltration of river water was used to extract principal components (PCs) that contained information relevant to membrane fouling. These PCs were related to the major membrane foulants, HS, protein-like and colloidal/particulate matter present in natural water. PC score analysis revealed that colloidal/particulate matter mostly contributed to reversible fouling. HSand protein-like matter were largely responsible for irreversible fouling behaviour. Fluorescence EEMs of the foulants extracted from the membranes also revealed different rejection characteristics for two different membranes, 60 kDa and 20 kDa. The proposed method proved suitable for identifying the major foulant components and their contribution to reversible and irreversible membrane fouling, illustrating its potential for monitoring and controlling membrane fouling in drinking water treatment applications.

A multi-class method for the simultaneous quantification and confirmation of 47 pharmaceuticals in environmental and wastewater samples has been developed. The target list of analytes included analgesic and anti-inflammatories, cholesterol lowering statin drugs and lipid regulators, antidepressants, antiulcer agents, psychiatric drugs, ansiolitics, cardiovasculars and a high number (26) of antibiotics from different chemical groups. A common pre-concentration step based on solid-phase extraction with Oasis HLB cartridges was applied, followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) measurement. All compounds were satisfactorily determined in just one single injection, with a chromatographic run time of only 10 min. The process efficiency (combination of the matrix effect and the extraction process recovery) for the 47 selected compounds was evaluated in nine effluent wastewater (EWW) samples, and the use of different isotope-labelled internal standards (ILIS) was investigated to correct unsatisfactory values. Up to 12 ILIS were evaluated in EWW and surface water (SW). As expected, the ILIS provided satisfactory correction for their own analytes. However, the use of these ILIS for the rest of pharmaceuticals was problematic in some cases. Despite this fact, the correction with analogues ILIS was found useful for most of analytes in EWW, while was not strictly required in the SW tested. The method was successfully validated in SW and EWW at low concentration levels, as expected for pharmaceuticals in these matrices (0.025, 0.1 and 0.5 g/L in SW; 0.1 and 0.5 g/L in EWW). With only a few exceptions, the instrumental limits of detection varied between 0.1 and 8 pg. The limits of quantification were estimated from sample chromatograms at the lowest spiked levels tested and normally were below 20 ng/L for SW and below 50 ng/L for EWW. The developed method was applied to the analysis of around forty water samples (river waters and effluent wastewaters) from the Spanish Mediterranean region. Almost all the pharmaceuticals selected in this work were detected, mainly in effluent wastewater. In both matrices, analgesics and anti-inflammatories, lipid regulators and quinolone antibiotics were the most detected groups.

- by Félix Hernández and +1
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- Engineering, Technology, Rivers, Pharmaceuticals

A method for the simultaneous determination of 10 sulfonyl-and phenylurea herbicides (chlorsulfuron, triasulfuron, fenuron, monuron, fluometuron, chlorotoluron, isoproturon, diuron, metobromuron, linuron) and one of their most common degradation products (3-chloro-4-methylphenyl urea) has been developed. Liquid chromatography with diode array UV detection (LC-DAD UV) and positive ion electrospray mass spectrometry (LC-ESI-MS) were used for the separation, identification and quantification of these analytes. In the LC-DAD UV method, chromatographic separation was achieved in about 27 min; however, analysis time can be reduced to less than 13 min when LC-MS is applied, since no complete separation of the chromatographic peaks was required.

ABSTRACT River water cleaning from microorganisms using electrohydraulic discharges and ozonation was investigated. The processed water was highly polluted with the total number of microorganisms (70 400 cfu/mL) and total Escherichia coli bacteria (280 cfu/mL). The processing was conducted in a tube reactor with a hollow needle-rod electrode configuration. A 400-mL sample of river water was treated at different flow rates. Ozonation was performed in a washing bottle with an ozone concentration of 20 g/m3. The corona discharge treatment showed a steady decrease of bacteria and microorganisms but did not kill them completely. Spark discharge killed the bacteria and microorganisms completely; however, its energy efficiency was much lower than that of ozonation. The ozone treatment decreased the concentration of microorganisms and coli bacteria down to 785 and 10 cfu/mL, respectively, in 45 s which resulted in higher energy efficiency than processing using corona and spark discharges. The NPOC analysis of the treated samples showed its concentration of 5 ± 0, 4 ppm in all samples.

- by Jerzy Mizeraczyk
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- Water Treatment, Energy efficiency, River water, Microorganisms

The Aznalco´llar tailings dam at Boliden Apirsa's Aznalco´llar/Los Frailes Ag-Cu-Pb-Zn mine 45 km west of Seville, Spain, was breached on 25 April 1998, flooding approximately 4600 hectares of land along the Rı´os Agrio and Guadiamar with approximately 5.5 million m 3 of acidic water and 1.3Â10 6 m 3 of heavy metal-bearing tailings. Most of the deposited tailings and approximately 4.7Â10 6 m 3 of contaminated soils were removed to the Aznalco´llar open pit during clean-up work undertaken immediately after the spill until January 1999. Detailed geomorphological and geochemical surveys of the post-clean-up channel, floodplain and valley floor, and sediment and water sampling, were carried out in January and May 1999 at 6 reaches representative of the types of river channel and floodplain environments in the Rı´o Guadiamar catchment affected by the spill. The collected data show that the clean-up operations removed enough spill-deposited sediment to achieve pre-spill metal (Ag, As, Cd, Cu, Pb, Sb, Tl, Zn) concentrations in surface sediment. These concentrations, however, are still elevated above pre-mining concentrations, and emphasise that mining continues to contaminate the Agrio-Guadiamar river system. Dilution by relatively uncontaminated sediment appears to reduce metal concentrations downstream but increases in metal and As concentrations occur downstream, presumably as a result of factors such as sewage and agriculture. River water samples collected in May 1999 have significantly greater dissolved concentrations of metals and As than those from January 1999, probably due to greater sulphide oxidation from residual tailings with concomitant release of metals in the warmer early summer months. These concentrations are reduced downstream, probably by a combination of dilution and removal of metals by mineral precipitation. Single chemical extractions (de-ionised water, CaCl 2 0.01 mol l À1 , CH 3 COONH 4 1 M, CH 3 COONa 1 M and ammonium oxalate 0.2 M) on alluvial samples from reaches 1 and 6, the tailings, pre-spill alluvium and marl have shown that the order of sediment-borne contaminant mobility is generally Zn> Cd >Cu > Pb >As. Pb and As are relatively immobile except possibly under reducing conditions. Much of the highly contaminated sediment remaining in the floodplain and channel still contains a large proportion of tailings-related sulphide minerals which are potentially reactive and may continue to release contaminants to the Agrio-Guadiamar river system. Our work emphasises the need for pre-mining geomorphological and geochemical data, and an assessment of potential contributions of contaminants to river systems from other, non-mining sources. #

- by Mark Macklin and +1
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- Geochemistry, Water quality, Applied Geochemistry, River water

The retention of suspended particles transported by river flow on surfaces of freshwater plants is a potentially important process in the contamination of aquatic biota. Field experiments have been performed to test the role of Ž . benthic algae periphyton in trapping inorganic suspended solids transported by the river water and to discriminate between the caesium content of periphyton caused by the adherence of inorganic solids and by the active uptake inside the organisms. The contribution of caesium of suspended solids adhering to biotic surfaces was estimated by Ž . determining the scandium content scandium method . The scandium method was used because this element is geologically ubiquitous in soils and it is not taken up actively by plants and other organisms. The mass of suspended particles retained on the surfaces of microorganisms growing on submerged substrates were determined by comparing the scandium content of suspended material with that in algal communities. Neutron activation analysis was used as the analytical method for determination for both scandium, and caesium. The results indicate that the suspended particle fraction can contribute up to 80% of the caesium contamination of periphyton samples. Active caesium uptake and accumulation by aquatic biota represents the remaining 20% of the total caesium contamination. ᮊ

- by Borut Smodiš and +1
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- Cell Adhesion, Multidisciplinary, River water, Plants

An ecological and hydrologic restoration of the Mississippi-Ohio-Missouri (MOM) Basin in the United States is proposed as the solution to the reccurring hypoxic conditions in the Gulf of Mexico. Nitrate-nitrogen is the cause of this eutrophication in the Gulf and its source is mainly due to increased fertilizer use in the American Midwest. In that same Midwest, the land has also been artificially drained and 80-90% of the original wetlands have been lost. Our proposed restoration involves the strategic creation and restoration of 2.2 million ha of wetlands in the MOM basin where in-field wetlands intercept agricultural runoff and diversion wetlands are overflowed by flooding river water. Case studies that total 50 wetland-years of data from Illinois, Ohio, and Louisiana are summarized as the basis for the restoration area estimate. Benefits of this restoration, in addition to solving the Gulf hypoxia, include water quality improvement, reduction of public health threats, habitat creation, and flood mitigation that will accrue to the locations in the MOM basin where the restoration occurs. Before the restoration commences, there is a need for formal and rigorous large-scale research in the basin to reduce uncertainties. (W.J. Mitsch).

- by William J Mitsch
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- Engineering, Ecological Engineering, Earth Sciences, Water quality
- by James Karr
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- Earth Sciences, Urban Development, Biological Sciences, Water Cycle

We measured rare earth element (REE) concentrations in river waters to characterize the suspended and dissolved river flux of the REE to the oceans. The REE pattern of river suspended materials is sensitive to drainage basin geology. A positive correlation is observed between La/Yb ratios and Nd model ages for the rivers studied. Major rivers have light REE enriched patterns relative to the North American Shale Composite (NASC), with (La/Yb)N = 1.6−2.7. River water dissolved material ( < 0.2 μm) is heavy REE enriched relative to suspended material, and the most pronounced negative Ce anomalies occur in rivers of high pH. Light REE concentrations vary by approximately 3 orders of magnitude and are inversely related to pH and major cation concentrations.From these data, we estimate that typical major river runoff has heavy REE depleted suspended material with (La/Yb)N ≈ 1.9. We conclude that the terrigenous input to the oceans from major rivers is heavy REE depleted relative to shales. From the available data, average river water dissolved material appears to be heavy REE enriched with (La/Yb)N ≈ 0.4. Estuarine removal processes lower the dissolved REE river flux by approximately 60% and result in a flux that is more heavy REE enriched with (La/Yb)N ≈ 0.2. Calculated oceanic residence times with respect to river input range from 2300 to 21,000 years, are shortest for Ce, and greatest for the heavy REE and La. Such long residence times may suggest the presence of additional sources of REE in seawater.

- by Stein B Jacobsen
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- Earth Sciences, Transport, River water, Physical sciences

Meso-scale characteristics of disturbances that bring about atmospheric disasters in pre-and mature monsoon seasons in Bangladesh are analyzed. Several types of meteorological instruments capable of observations with high temporal and spatial resolutions were introduced for the first time in this area to capture the meso-scale structure of rainfall systems. We installed an automatic weather station (AWS) and several automatic raingauges (ARGs) and utilized the weather radar of Bangladesh Meteorological Department (BMD). From the radar image in the summer of 2001 (16-18 July), a striking feature of the systematic diurnal variation in this area was elucidated. In these 3 days, the diurnal evolutions of convective activity were remarkably similar to each other, implying that this pattern can be understood as a typical response of local cloud systems to the diurnal variation of insolation under some summer monsoon situations. The ARG data show the difference in characteristics of rainfall between pre-and mature monsoon seasons. The short intense downpour tends to occur more frequently in the pre-monsoon season than in the mature monsoon season. The pre-monsoon rainfall also has clear diurnal variation with a peak that is more strongly concentrated in time. In the northern part the rainfall peak is found in between midnight and early morning, while it is observed in the daytime in central to western parts of the country. Two disaster cases caused

- by TAIICHI HAYASHI
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- Psychology, Remote Sensing, Natural Hazards, Instrumentation

The recent monitoring of drug residues in the aquatic environment has gained much interest as many pharmaceutical compounds can frequently be found in sewage treatment plant (STP) effluents and river water at concentrations up to several microgram/l. This article describes the analysis of various water samples for 18 antibiotic substances, from the classes of macrolid antibiotics, sulfonamides, penicillins and tetracyclines. Samples were preconcentrated via lyophilization and quantified using HPLC-electrospray-tandem-mass spectrometry. The investigated STP effluents and surface water samples showed frequent appearance of an erythromycin degradation product, roxithromycin and sulfamethoxazole with concentrations up to 6 micrograms/l. Neither tetracyclines nor penicillins could be detected at concentration levels above 50 and 20 ng/l, respectively. From the large number of ground water samples that were taken from agricultural areas in Germany, no contamination by antibiotics was dete...

- by Roman Hirsch
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- Agriculture, Multidisciplinary, Germany, River water
- by David Lean
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- Environmental Engineering, Water Treatment, Great Lakes, River water

In this study, we report for the first time, concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in sediments from a South African environment, particularly for the
largest catchment areas of the Western Cape, South Africa, an area associated with the largest agricultural sector with some of the produce and end-products intended for the international markets.
Sample preparation and analysis were based on the ISO 25101: 2009(E) method, using solid phase extraction (SPE) followed by liquid chromatography combined with electrospray tandem mass
spectrometry (LC-MS/MS). Sediment grain size analysis, core water characteristics and percent total organic carbon were also quantified. From the results, PFOS and PFOA were observed in all the river
sediment samples and were found in concentrations up to 19 ng/g and 187 ng/g for Salt River, 121 ng/g and 772 ng/g for Diep River, and 75 ng/g and 193 ng/g for Eerste River, for both PFOS and PFOA,
respectively. Some of these concentrations are higher than those previously reported in similar studies in various countries; this suggests there is cause for concern. Although sediment has a poor sorption capacity for both PFOS and PFOA in comparison with plants, the prevalence of PFOS and PFOA in sediment samples from rivers from which irrigation water is sourced for agricultural purposes, indicates a risk of agricultural produce contamination.

- by JBN Mudumbi
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- Sedimentology, Water quality, Rivers, Solid Phase Extraction

A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in indoor and outdoor air samples. The method includes pre-concentration of the compounds by percolating the air samples through the acidic solution, ion-pair extraction with bis-2-ethylhexylphosphate (BEHPA), derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC-MS analysis. Aliphatic and aromatic amines were isolated from aqueous samples using BEHPA as ion-pair reagent and derivatised with IBCF for their chromatographic analysis. Aliphatic and aromatic amines were then analysed with GC-MS in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl (isoBOC) derivatives. The obtained recoveries ranged from 75.6 to 96.8% and the precision of this method, as indicated by the relative standard deviations (R.S.D.) was within the range of 1.0-4.4%. The detection limits obtained from calculations by using GC-MS results based on S/N: 3 were within the range of 0.08-0.01 ng/m 3 .

- by mehmet akyuz
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- Engineering, Analytical Chemistry, Technology, Water
- by Atul D Bobdey
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- Water, Water quality, Environmental Monitoring, India

The upper part of the Moselle river basin, northeastern France, shows contrasting lithology and topography: granitic formations upstream in the Vosges mountains and carbonate platform downstream on the Lorraine plateau. We measured concentration and isotopic composition of dissolved SO 4 in the Moselle river and its main tributaries in order to identify the sources of sulfate. Rainwater, lichens, S-fertilizers and natural gypsum were also analyzed as potential sulfate sources. Along the Moselle river, dissolved SO 4 concentrations and S-O isotopes display relationships which suggest two major sources of sulfates: 1) a low concentration and low delta values (δ 34 S of 6-9‰ and δ 18 O of 6-9‰) component upstream and 2) a high concentration and high delta values (δ 34 S of up to 17‰ and δ 18 O of up to 13‰). These are likely 1) atmospheric S input with some retention time in forest soils as carbon-bonded sulfur and 2) sulfates from the dissolution of evaporites from the Muschelkalk and Keuper formations of the Lorraine plateau.

- by Marc Benoît
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- Geology, Geochemistry, Chemical Geology, Seasonality

A Chelex-100 resin separation technique followed by analysis with atomic absorption spectroscopy was evaluated for the study of thallium speciation in river waters. The detection limit for the method was 1.0 ng/l for both Tl(I) and Tl(III). Analysis of synthetic solutions consistently yielded >90% recovery of these two thallium forms with negligible cross contamination. Water samples from selected stations in polluted Huron River and Raisin River in Michigan were analyzed. Average dissolved thallium concentrations were found to be 21 ng/l for Huron River and 26 ng/l for Raisin River. The dominant thallium form found in these rivers was oxidized Tl(III) and the proportion of Tl(III) to the total dissolved thallium ranged from 43 to 73% and averaged of 66% in water samples analyzed. A signi®cant proportion of Tl(III) may also be in colloidal form. # 0003-2670/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 3 -2 6 7 0 ( 9 9 ) 0 0 3 5 8 -X

- by Jerome Nriagu
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- Analytical Chemistry, River water, Heavy Metal, Atomic Absorption Spectroscopy

Since most of the water source on the earth surface is saline in nature, hydrogen generation from saline water is of great importance. In this paper, we have developed a membrane protected anode, using anionic backbone of sulfonated polystyrene-block-(ethylene-ran-butylene)-block-polystyrene polymer (S-PSEBS) over the anode (IrO2/Ti) which is capable of electrostatically repelling the chloride ions (Cl−) from the electrode surface and thereby enhancing the oxygen evolution rather than the chlorine evolution. The electrochemical behavior of both polymer modified and bare IrO2/Ti electrodes were characterized by electrochemical polarization studies and the gas evolution efficiencies were calculated. The surface morphology of the electrodes was investigated using scanning electron microscope (SEM). The results suggest that nearly 95% oxygen evolution efficiency could be achieved when the surface of IrO2/Ti electrode was modified with a permselective membrane.► The S-PSEBS coated electrode was found to be more effective for oxygen evolution reaction in saline water electrolysis. ► The maximum oxygen evolution efficiency of 95% was achieved. ► The results proved that hydrogen can be generated from the earth abundant saline water.

- by Suresh Kannan Balasingam and +1
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- Renewable Energy, Hydrogen, Electrochemistry, Internal Combustion Engine

Pharmaceutical residues are increasingly found in wastewater treatment plant effluents and river water in very low concentrations at nanograms per liter levels in many countries. In this study, samples were collected from seven wastewater treatment plants (WWTPs) and downstream surface waters in Bangkok, Thailand during July and October 2009 and January 2010. Solid phase extraction (SPE) followed by high-pressure liquid chromatography-mass spectrometry-mass spectrometry (HPLC/MS/MS) technique were used to detect eight pharmaceuticals including caffeine, acetaminophen, roxithromycin, ciprofloxacin, trimethoprim, lincomycin, enrofloxacin, and erythromycin. Levels of pharmaceutical residues in the influents on average were the highest for caffeine (9;052 ng=L), followed by acetaminophen (8;630 ng=L), and roxithromycin (235 ng=L). The same three pharmaceuticals showed the top three levels in the effluents (caffeine: 797 ng=L, acetaminophen: 92 ng=L, and roxithromycin: 50 ng=L). The concentration of caffeine was also the highest in downstream surface water samples (2;393:4 ng=L). Acetaminophen (839:3 ng=L) and roxithromycin (54:7 ng=L) were at the second and third highest levels. Caffeine and acetaminophen in WWTP effluents were at very low levels compared with the influent concentrations.

- by Ranjna Jindal
- •
- Engineering, Modeling, Wastewater Treatment, Filtration

The biodegradability of water-extracted saponins of berries from the Endod plant, Phytolacca dodecandra L'Herit, was evaluated under OECD standardized conditions. Persistence of the saponins was evaluated by determination of saponin concentrations in water over a 30-day period, using a quantitative HPLC method and a semiquantitative hemolytic assay, which is considered a potential field method. The two methods were compared. Bioassays

- by Peter Furu
- •
- Water, Medicinal Plants, Saponins, River water

The chemical equilibrium model of HARVIE et al. (1984) has been extended to include borate species. The model is based upon the semi-empirical equations of and coworkers and is valid to high ionic strength (~14 m) and high borate concentration. Excellent agreement with the existing emf, isopiestic, and solubility data in the system (Na-K-Ca-Mg-H-CI-S0 4 -eO r B(OHkH20) is obtained. Calculated mineral solubilities are in general within 10% of their experimental values, even at high ionic strengths.

- by John Weare
- •
- Geology, Geochemistry, River water, Surface Water
- by George Zachariadis
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- Multivariate Statistics, Water, Water quality, Principal Component Analysis

A method is described for the determination of residues of the fungicides Folpet, Captan and Captatbl in river water using an isocratic high-performance liquid chromatographic system. Electrochemical detection with single and dual glassy-carbon electrodes was evaluated for possible amperometric detection of these fungicides; the reductive-oxidative detection mode with a dual electrode in the series configuration proved to be more appropriate than direct reductive detection with a single working electrode. To concentrate the fungicide residues, a cloud-point preconcentration step employing the non-ionic surfactant Triton X-114 was applied. Furthermore, the presence of the surfactant contributes to the stability of these analytes in aqueous solution, avoiding their hydrolysis. The method described shows good recoveries and good precision, with relative standard deviations of less than 10%. Detection limits of about 4/zg/I were achieved for all three liangicides studied for 15 ml of preconcentrated sample.

- by ENCARNACIÓN RODRÍGUEZ GONZALO
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- Engineering, Chemistry, Technology, Sample Preparation

Mimosa, Mimosa pigra L., was first reported in Sri Lanka in 1997. The species is mainly confined to the central and northwestern provinces of Sri Lanka. The plant has colonised along the river banks of the Mahaweli River, which is the main supplier of irrigation water to the agriculture-dominant dry zone of the country. Use of river sand for construction work was identified as a major method of seed dispersal, apart from seeds being transported with river water flow. GPS technology is currently being used for monitoring the extent of spread of this species. Mimosa seeds were 100% viable after four years of storage at room temperature (28±2°C) and also at 8°C. The onset of flowers was first observed at 12-14 weeks after planting. The initial growth of the weed was slow, but the height increased at a rate of 2.4-2.6 cm day-1 during the first 8-12 weeks. From 12 weeks, the stem dry weight of mimosa increased at a more rapid rate than the root dry weight. The relative growth rate (RGR) increased until onset of flowers and then decreased. The soil seed-bank density within the canopy diameter of the naturally grown mimosa plants varied from 2,336 to 46,410 seeds m-2. Glyphosate at the dosage of 1.44 kg active ingredient ha-1 effectively controlled mimosa seedlings less than six months old, when applied three times repeatedly at four-month intervals on the same set of seedlings. Mimosa seeds did not germinate in the presence of one-month old Panicum maximum Jacq. at a population density of 16 plants m-2. Awareness programs conducted for the communities in the infested areas have resulted in several community participatory activities to eradicate small patches of mimosa from the Central Province.

- by Buddhi Marambe
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- Seed Dispersal, Sri Lanka, Relative Growth Rate, River water

Concentrations of heavy metals in water of the Nhue River (a suburban/rural river) and one of its tributaries, the To Lich River (an urban river), in Hanoi, Vietnam had been monitored, and spatial and seasonal variations in their composition were evaluated by means of principal component analysis and cluster analysis. Heavy metal concentrations in water of the two rivers were generally lower than the surface water quality standard in Vietnam, except for manganese in several sites, although they were higher than the median values in freshwater of the world by 0.42-43 times in Nhue and 0.13-32 times in To Lich. The two multivariate analyses represented that the composition of heavy metals in river water of To Lich was distinctly different from that of Nhue. It was also suggested that metal concentrations and their composition in Nhue river water would be affected by inflowing water of To Lich and wastewater discharged from the up-and middlestream basin, and that they gradually recovered along the direction of water flow in the downstream area in rainy season.

- by Shuzo Tanaka
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- Principal Component Analysis, Environmental Monitoring, Rivers, Vietnam

Abstract:Aquatic macroinvertebrates play significant role in responding to a variety of environmental conditions of rivers and streams and therefore may be used as bio-indicators for water quality assessment. In the past, biological... more

- by Mahendra Pal Sharma
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- Water quality, Life Sciences, River water, Aquatic Macrophytes

The Equilibrium Phosphorus Concentration (EPC 0 ) of river bed sediments has been measured for a wide range of agricultural subcatchments and main river sites across two major eutrophic river basins: the Hampshire Avon and Herefordshire Wye catchments, to examine whether bed sediments are acting as sources or sinks of soluble reactive phosphorus (SRP) under low flows and times of greatest eutrophication risk. A conceptual reach-based model of interactions between bed sediment and river water has been used to estimate relative differences in bed-sediment SRP flux transfers. In this model, processes of SRP uptake and release are assumed to occur within an operationally defined 0.1 m river water 'boundary layer' and the uptake and release of SRP is assumed to be driven by a differential between the EPC 0 of the sediment and SRP concentration in the boundary layer. Most of the river monitoring sites in the Wye and Avon catchments had elevated SRP and boron (B) concentrations in the water column at low flows, linked to sewage effluent discharges. At these sites, bed sediments consistently acted as net sinks for SRP, demonstrating the role of bed sediments in riverine 'self-cleansing' mechanisms. In contrast, bed sediments were found to act as net sources of SRP under three circumstances: (i) where there was minimal sewage influence (in headwater streams of the Avon), (ii) where sewage inputs were subject to large hydrological dilution by water of low SRP concentration (in the main River Wye), (iii) where EPC 0 values were relatively high, as a result of deposition of particulates with high exchangeable P concentrations from diffuse sources or from effluents (immediately downstream of sewage treatment works (STWs)). Under baseflow conditions, high SRP concentrations from sewage effluent in the tributaries appear to 'swamp out' any potential release of SRP from the bed sediments. For rivers that are subject to effluent P-stripping, reductions in SRP in the overlying water could potentially result in changes to the in-stream P-cycling mechanisms, with bed sediments possibly switching from net sinks to net sources of SRP. This feature is of potential importance in relation to environmental management and phosphorus mitigation operations. q

- by Colin Neal
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- Hydrology, Environmental Management, Multidisciplinary, Phosphorus

Sampling and monitoring for cyanotoxins can be problematic as concentrations change with environmental and hydrological conditions. Current sampling practices (e.g. grab samples) provide data on cyanotoxins present only at one point in time and may miss areas or times of highest risk. Recent research has identified the widespread distribution of anatoxin-producing benthic cyanobacteria in rivers highlighting the need for development of effective sampling techniques. In this study we evaluated the potential of an in situ method known as solid phase adsorption toxin tracking (SPATT) for collecting and concentrating anatoxin-a (ATX) and homoanatoxin-a (HTX) in river water. Fifteen different adsorption substrates were screened for efficiency of ATX uptake, nine of which retained high proportions (>70%) of ATX. Four substrates were then selected for a 24-h trial in a SPATT bag format in the laboratory. The greatest decrease in ATX in the water was observed with powdered activated carbon (PAC) and Strata-X (a polymeric resin) SPATT bags. A 3-d field study in a river containing toxic benthic cyanobacterial mats was undertaken using PAC and Strata-X SPATT bags. ATX and HTX were detected in all SPATT bags. Surface grab samples were taken throughout the field study and ATX and HTX were only detected in one of the water samples, highlighting the limitations of this currently used method. Both Strata-X and PAC were found to be effective absorbent substrates. PAC has the advantage that it is cheap and readily available and appears to continue to sorb toxins over longer periods than Strata-X. SPATT has the potential to be integrated into current cyanobacterial monitoring programmes and would be a very useful and economical tool for early warning of ATX and HTX contamination in water.

- by Susanna Wood
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- Cyanobacteria, Environmental Monitoring, Rivers, Multidisciplinary
- by Homa Razmkhah
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- Water, Data Analysis, Water quality, Principal Component Analysis

Rates of pelagic primary production, respiration, and bacterioplankton dynamics were measured in relation to water quality parameters in three extensive shrimp ponds in the Mekong delta, Vietnam. There were few consistent differences in pelagic characteristics among different locations within these ponds, among the three ponds, or between the ponds and adjacent river Ž 14 .

- by Do Van Tien
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- Zoology, Water quality, Crustacea, Population Dynamics

The biodegradation of poly(ethylene glycol)s (PEGs) and poly(propylene glycol)s (PPGs), both being major by-products of non-ionic surfactants biodegradation, was studied under the conditions of the River Water Die-Away Test. PEGs were isolated from a water matrix using solid-phase extraction with graphitized carbon black sorbent, then derivatized with phenyl isocyanate and determined by HPLC with UV detection. PPGs were isolated from a water matrix by liquid-liquid extraction with chloroform, then derivatized with naphthyl isocyanate and determined by HPLC with fluorescence detection.

- by Joanna Zembrzuska
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- Rivers, Polymers, Water Pollution, Multidisciplinary

The sensitive multiresidual analytical method for simultaneous analysis of 14 most commonly used agricultural pesticides in Serbia was developed and optimized. The selected insecticides, fungicides and herbicides belong to seven chemical classes (organophosphates, neonicotinoids, carbamates, diacylhydrazines, benzimidazoles, triazines and phenylureas). The method was based on solid-phase extraction followed by liquid chromatography-tandem mass spectrometry. The following parameters that may affect the SPE procedure efficiency were optimized: the sorbent type in combination with different elution solvents, the sample pH and the sample volume. For each pesticide, MS n analysis was performed and distinctive ions and transitions were selected for identification and quantification, as well as for confirmation purposes. External matrix-matched calibration method was used to eliminate variable matrix effect and ensure precise quantification. Good recoveries (72-129%), and low limits of detection (0.4-5.5 ng L −1 ) and quantification (1.1-18.2 ng L −1 ) were achieved for all selected pesticides. The developed and optimized method was successfully applied in the analysis of several river waters, as well as ground waters in Serbia, influenced by agriculture. The most frequently detected pesticide was carbendazim. Dimethoate, carbofuran and propazine were also found in the investigated samples.

- by Tatjana Vasiljević and +1
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- Analytical Chemistry, Solid Phase Extraction, Pesticides, River water

Biochemical characterisation of Dickeya strains isolated from potato plants and river water samples in Finland showed that the majority of the strains were biovar 3. They thus resembled the strains recently isolated from potato in the Netherlands, Poland and Israel and form a new clade within the Dickeya genus. About half of the Finnish isolates resembling strains within this new clade were virulent and caused wilting, necrotic lesions and rotting of leaves and stems. Similar symptoms were caused by D. dianthicola strains isolated from one potato sample and from several river water samples. Frequently, the rotting caused by the Dickeya strains was visible in the upper parts of the stem, while the stem base was necrotic from the pith but hard and green on the outside, resulting in symptoms quite different from the blackleg caused by Pectobacterium atrosepticum. The presence of Dickeya in the symptomatic plants in the field assay was verified with a conventional PCR and with a real-time PCR test developed for the purpose. The virulent Dickeya strains reduced the yield of individual plants by up to 50% and caused rotting of the daughter tubers in the field and in storage. Management of Dickeya spp. in the potato production chain requires awareness of the symptoms and extensive knowledge about the epidemiology of the disease.

- by Johanna Nykyri
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- Microbiology, Plant Biology, Potato, real time PCR

This work assessed the impacts of land-use patterns in the Ruvu river basin on water quality in the river system. Seasonal changes in water quality parameters were also investigated. Ten river water-sampling stations were selected and samples were collected and analysed according to standard analytical procedures. The results showed that physico-chemical parameters of river water ranged as follows: pH, from 6.95 ± 0.09 to 8.07 ± 0.23; temperature, from 14.0 ± 0.06 to 31.1 ± 0.4°C; EC, from 39.8 ± 0.8 to 48,734 306 ls/ cm; TDS, from 19.9 ± 0.4 to 24,367 ± 152.9 mg/l; turbidity, from 3.0 ± 0.6 to 840 ± 69.3 NTU and DO, from 6.8 ± 0.02 to 16.78 mg/ l. The ranges for nutrient concentrations were NO 3 -N, from 0.006 ± 0.0003 to 0.62 ± 0.3 mg/l; NH 4 -N, from 0.34 ± 0.17 to 16.2 ± 0.5 mg/l; PO 4 -P, from 0.009 ± 0.001 to 1.75 ± 0.2 mg/l and TP, from 0.02 ± 0.003 to 3.56 ± 0.38 mg/l. Generally, water samples from stations with forested catchments had high levels of DO and low levels of NH 4 -N and NO 3 -N compared to those from farmland, industrial, residential and market places. There were clear seasonal variations showing an increase in the concentrations of nutrients during rainy season. The results show impairment of the water quality of the river by anthropogenic activities in the catchment. Water pollution prevention strategies to ensure prevention of pollution and protection of water resources in the Ruvu river watershed are recommended.

- by Elizabeth Ngoye
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- Geology, Geochemistry, Geophysics, Water quality

This paper describes the analysis of major failure of 28 MW horizontal hydro turbine shaft. The analysis of load carrying capacity of critical radius and fractography analysis are presented. Special emphasize is on metallurgical failure analysis of in-service crack initiation. The analysis of stresses is obtained by the finite element method and the developed model and load conditions are described. Finite element analysis is performed for case of normal service and start-up regime.

The rates of the oxidation of As(III) with H 2 O 2 were measured in NaCl solutions as a function of pH (7.5-10.3), temperature (10 -50C) and ionic strength (I ϭ 0.01-4). The rate of the oxidation of As(III) with H 2 O 2 can be described... more

- by Frank Millero
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- Geology, Geochemistry, River water, Surface Water

River Atna is situated in south-eastern Norway and stretches from approx. 1400 m a.s.l. in the Rondane Mountains, through Lake Atnsjøen, at 701 m a.s.l.; to the confluence with River Glomma at 338 m a.s.l. The catchment area is 1323 km 2 , oligotrophic and very susceptible to acid precipitation. The river water is very poor in nutrients and ions, and pH varies from 5.0 to 7.2. Samples were taken each year from 1987 to 2002 at three to five localities from 1280 to 380 m a.s.l. Insect larvae were collected by Surber sampling and by kick sampling. Malaise traps were used to collect adults of Plecoptera, Trichoptera, Chironomidae and Limoniidae. A total of 16 taxa of Ephemeroptera, 24 taxa of Plecoptera, 39 taxa of Trichoptera, 125 taxa of Chironomidae and 52 taxa of Limoniidae, were identified. Our results from Atna provide some support for a zonation of the river based on zoobenthos. The occurrence and abundance of functional groups among the Plecoptera, Trichoptera, and Chironomidae are discussed in relation to the River Continuum Concept (RCC). Our conclusion is that grazers dominate in the zoobenthos in streams in the treeless alpine region in Norway. Natural lakes, which occur in most watercourses in Norway, appear to cause a disturbance in relation to the original RCC concept, as the zoobenthos community in and below the lake outlet is dominated by collectors (filter feeders). The pattern found in the Atna watercourse is probably a general pattern for a northern watercourse in the Holarctic, where the glacial periods created lakes in most watercourses. The results of the long term sampling in Atna are discussed in relation to the practicalities and the cost-benefit of zoobenthos in efficient bio-monitoring in rivers.

- by Terje Bongard
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- Earth Sciences, Biological Sciences, Aquatic Insects, Environmental Sciences

1] ESWAT is a simulator that integrates catchment and river water quantity and quality processes. The integration leads to a high number of model parameters, which complicates model calibration. As the model is semidistributed, the water quality and quantity variables at different observation sites inside the catchment can, and should, be used during this process, in order to use all the available information. A simultaneous use of all the different observed series and a high number of free parameters, however, creates a complex mathematical problem. Existing methods such as Pareto-optimization are practically very difficult, if not impossible, to implement. We present therefore a new methodology that reduces the many objective functions to a single global criterion in an objective way, excluding the weighting problem. The global criterion then is minimized using a global search algorithm, i.e., the shuffled complex evolution method. The methodology is applied on the Dender River basin (Belgium), a heavily modified river basin with irregular flows.

- by Ann van Griensven
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- Environmental Engineering, Civil Engineering, Water quality, Water resources