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The adsorbent is a solid substance that can absorb certain components from the liquid phase. Most of the adsorbents are porous materials and the adsorption process takes place, especially in the porous wall or certain location inside that particle. The main objective of this research is to study the influence of the adsorbent's surface area based on shape variation from corn stalk with adsorption ability to reduce the water river's turbidity, the influence of time with adsorption capacity in reducing river water's turbidity, the influence of adsorbent with water river and adsorption capacity, and defining adsorption kinetics from corn stalks. The shape of corn stalks that have been used such as spherical, half of spherical shape, and quarter of spherical shape. The volume of the sample is 250 mL. The measurement time is 300 minutes. The mass variations that have been used are 10 g, 15 g, and 20 g. The variation of sample takeover in the morning, afternoon, and evening. The measurement of adsorbent adsorption capacity in term of decreasing the turbidity of Babura River's water is done by inputting the adsorbent into the sample, then the measurement of the water's turbidity proceed by using a turbidity meter. The analysis result for the influence of the adsorbent's surface area in decreasing Babura River's water in the shape's variation from spherical, half of spherical shape, and quarter of spherical shape is obtained in quarter of spherical shape. The highest amount of adsorbent in decreasing the turbidity of Babura River's water is 20 g. Adsorption kinetics that has been used in the measurement of decreasing Babura River's water turbidity is second order kinetics. [ABSTRACT FROM AUTHOR]

The issue of water sustainability is a major topic due to the lack of water sources and the scarcity of drinking water, so the search for alternatives began. In this paper, the effect of using three water sources will be studied (the tap water (as control reference mix.), the Tigris River, and the Pepsi Company factory). To study the physical and chemical properties, and the effect of this water on the concrete mixture, and for each source the concrete mixture was placed in cube molds and cylinders. Put the concrete mixture in a water basin for curing. Compression and splitting tests are performed at intervals of (7-28-90) days to evaluate these mixtures. From the results it was found that the compressive and splitting strength of concrete for tap water, Tigris River and Pepsi factory, which was recorded at the age of 7 days, the compressive strength of cubes was an average of 18.5 MPa, 19 MPa and 13 and the splitting strength was an average of 1.5 MPa and 1.4 MPa and 0.5 MPa, respectively, at the age of 28 days, which were recorded at 32.1 MPa, 28 MPa, and 16.4 MPa, respectively, and the splitting strength was 3 MPa, and 2.7 MPa, and 1.5 MPa, respectively, and at 90 days they were 36 MPa, 32 MPa, and 18 MPa, respectively, and the splitting strength was 3.2 MPa, 3 MPa, and 1.7 MPa respectively also was observed a decrease in compressive strength and splitting by more than 40% for Pepsi Baghdad company factory wastewater samples. Finally, the drinking water and the water of the Tigris River was suitable for making concrete mixtures [ABSTRACT FROM AUTHOR]

The present work consisted of the development of an electrode based on carbon paste modified with magnetic molecularly imprinted polymer (CPE-MagMIP) for 17-β-estradiol (E2) detection. The incorporation of magnetic material (MagMIP) improved sensor performance, an increase of over 317%. The proposed method resulted in a linear response range from 0.5 to 14.0 μM, and the detection limit (LOD) and quantification limit (LOQ) were equal to 0.13 and 0.44 μM, respectively. Under optimized conditions, the developed sensor obtained satisfactory parameters in E2 determination in water samples, demonstrating selectivity, accuracy, and precision, making it a promising method for monitoring E2 in environmental samples. [ABSTRACT FROM AUTHOR]

Abstract It is a critical to examine the migration behavior of radiocesium derived from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in river systems to predict the future contamination status and propose effective countermeasures to reduce exposure. We conducted a three-year-long observation (April 2015–March 2018) of the 137Cs concentration in two rivers which located surrounding the FDNPP. The result revealed a declining trend for the dissolved and particulate 137Cs concentration in river water from four to seven years after the FDNPP accident. The dissolved and particulate 137Cs concentrations for both rivers had similar temporal patterns and showed declining trends with time. However, the dissolved 137Cs concentration had longer half-life than the particulate 137Cs concentration and large seasonal variations related to water temperature. The environmental half-life for the dissolved 137Cs concentration was longer than previous reported values within three years after the accident, suggesting that the declining trend for the dissolved 137Cs concentration is gradually decreasing with time. The temperature dependency of the dissolved 137Cs concentration became weaker year by year. From the D 10 equation we proposed, the dissolved 137Cs concentration will likely remain at the same level for several decades. The results of the present study promote our understanding of both the medium- and long-term impacts of the FDNPP accident on river systems. Highlights • 137Cs concentration in river water was continuously monitored. • The environmental half-life was different between particulate and dissolved 137Cs. • Dissolved 137Cs concentration had seasonal variation related to water temperature. • Temperature dependency of dissolved 137Cs concentration became weaker with time. [ABSTRACT FROM AUTHOR]

In this study, residues of the neuropsychiatric and illicit drugs including stimulants, opioids, hallucinogens, antischizophrenics, sedatives, and antidepressants were determined in influent and effluent samples from a small wastewater treatment plant, a receiving creek, and river waters in the Four Rivers region of the Midwestern United States. Nineteen neuropsychiatric drugs, eight illicit drugs, and three metabolites of illicit drugs were detected and quantitated in the water samples using HPLC–MS/MS. Residual concentrations of the drugs varied from below the detection limit to sub-μg/L levels. The source of residual cocaine and benzoylecgonine in wastewater is primarily from human consumption of cocaine rather than direct disposal. Wastewater based epidemiology is utilized to estimate the community usage of drugs based on the concentration of drug residues in wastewater, wastewater inflow, and the population served by the centralized wastewater treatment plant. The per-capita consumption rate of methamphetamine (1740 mg/d/1000 people) and amphetamine (970 mg/d/1000 people) found in this study were the highest reported per-capita consumption rates in the USA. Antidepressant venlafaxine found to have the highest environmental emission from the WWTP (333 ± 160 mg/d/1000 people) followed by citalopram (132 ± 60.2 mg/d/1000 people), methamphetamine (111 ± 43.6 mg/d/1000 people), and hydrocodone (108 ± 90.1 mg/d/1000 people). Bee Creek, an immediate receiving water body, is found to be a source of several neuropsychiatric and illicit drugs including methamphetamine, methadone, alprazolam, oxazepam, temazepam, carbamazepine, venlafaxine, citalopram, sertraline, oxycodone, and hydrocodone ( p  < 0.036) in the Clarks River. [ABSTRACT FROM AUTHOR]

A method for simultaneous determination of 11 organophosphorus pesticides residues in river water by MWCNTs-solid phase extraction combined with ultra-high performance liquid chromatography/tandem mass spectrometry was developed. After centrifugation and filtration, the target pesticides were enriched with MWCNTs-SPE cartridge. Then the pesticides adsorbed on MWCNTs were eluted with ethyl acetate and dichloromethane, the eluent was dried-up under nitrogen flow and the residue was dissolved in methanol-water (1:1, v/v) as sample solution. The separation was accomplished on a C18 column with the mobile phase consisting of methanol and 0.1% formic acid at 0.20 mL/min in gradient elution. The pesticides were detected in multiple reaction monitoring mode by a triple quadruple mass spectrometer. Good linearities were obtained within 1-200 ng/L, with the correlation coefficients greater than 0.998. The detection and quantification limits were in the ranges of 0.02-1.00 ng/L and 0.07-3.33 ng/L, respectively. The recoveries and relative standard deviations were in the range of 88.3-124.9% and 0.12-20.5%, respectively. The method has been successfully applied to the detection of 34 urban river water samples from Chengdu, China and 7 organophosphorus pesticides were detected with the concentrations of 0.32-211 ng/L. [ABSTRACT FROM AUTHOR]

In this study, a pilot-scale adsorption-UF process equipped with an aerated system is established for arsenic removal from As-spiked Songhua river water. A newly synthesized amino-functionalized coffee cellulose adsorbent (PEI-coffee) which is derived from spent coffee powder is fully characterized and used for arsenic removal from water. The batch experiments revealed that the adsorption process could be well described by Langmuir model with a maximum adsorption capacity of 13.2 and 46.1 mg/g for As(III) and As(V), respectively. The negative value of △ H and △ G indicated the exothermic and spontaneous nature of As adsorption on PEI-coffee. The effects of operating parameters such as pH, initial concentration and adsorbent dosage, were optimized by response surface methodology (RSM) based on a central composite design (CCD). The combined adsorption - UF process was employed for arsenic removal from As-spiked Songhua river water. It was demonstrated that aeration not only increased the removal efficiency by oxidizing As(III) to As(V), but mitigated the membrane fouling process. Besides of the adsorption process, UF membrane could also reject arsenic through the electrostatic repulsion between arsenic species and membrane surface. After UF filtration, the dissolved As, suspended solids (SS), and TOC can be effectively eliminated. The saturated adsorbent was regenerated by using an eluting agent of 10 wt% NaCl and 10 wt% NaOH, the regenerated adsorbent still sustained a very high adsorption capacity after 6 cycles of adsorption-regeneration process. [ABSTRACT FROM AUTHOR]

A broad number of natural and synthetic progestins are widely used in human and veterinary therapies. Although progestins exhibit adverse effects in aquatic organisms, information about environmental occurrence and fate have been limited to several compounds, hampering the accuracy of risk assessments of the compounds. In this study, a selective and sensitive analytical method was established to simultaneously determine 19 natural and 42 synthetic progestins in environmental waters, and the synthetic progestins included 19-nortestosterone, 17α-hydroxyprogesterone and progesterone derivatives. All of the target compounds were effectively separated using an HSS T3 column, and the recoveries for effluent and river samples were 80–115% and 75–105%, respectively. The detection limits for the 61 analytes were in the range of 0.05–0.60 ng/L and 0.03–0.40 ng/L for the effluent and river samples, respectively. The developed method is applied to analyze the target progestogens in sewage effluent and river water samples from Beijing. The detected concentrations of natural progesterone metabolites (3α-hydroxy-5β-tetrahydroprogesterone) were up to 63 times higher than those of the parent compound. Of the three groups of synthetic progestins, the progesterone derivatives were detected for the first time and had the highest concentrations followed by the 19-nortestosterone and 17α-hydroxyprogesterone derivatives. In contrast to previous studies, the predominant derivative compounds of 19-nortestosterone were found to be 19-nortestosterone, gestodene and mifepristone, and those of 17α-hydroxyprogesterone were 6-epi-medroxy progesterone 17-acetate and melengestrol acetate. The toxicities and environmental risk of these emerging progestins deserves more attention in the future. [ABSTRACT FROM AUTHOR]

Temporal and spatial variations of selected toxic elements distributions were studied along the Kuantan River. Surface and bottom waters from 9 sampling stations were taken from the estuary towards the upstream of Kuantan River using Van-Dorn water sampler during the rainy and dry season. Water samples were filtered and the filter papers were dried under the laminar flow and weighed until constant weight obtained. Filter papers were analyzed using Teflon Bomb digestion processes. The concentration of particulate Pb, Cd and Cr were in the range of 0.646 to 174.859 mg L-1, 6.047 to 271.497 mg L-1 and ND to 14.480 mg L-1, respectively. Particulate Pb, Cd and Cr obtained mostly higher in May 2012 during the dry season. Particulate Cd and Cr were found above the limits authorize by International Commission for the Protection of the Rhine river against Pollution (ICPR). Apart from the anthropogenic activities, rainy and dry season also become the important factors affecting the particulate metals concentrations and distributions in the waters. [ABSTRACT FROM AUTHOR]

Abstract: The presence of introduced or non‐native bacteria in river water can create a selective pressure due to their ability to overcome fluctuations in physicochemical conditions and carbon source availability. The carbon source concentrations (monosaccharides and polysaccharides), physicochemical parameters (turbidity, total dissolved solids, biochemical oxygen demand, temperature and pH) and metabolic activity of Salmonella Oranienburg and Saintpaul were determined in water from the central Sinaloa state rivers. This study's results revealed that the carbohydrate availability and physicochemical conditions of river water make it a suitable niche for the establishment of Salmonella serotypes. Metabolic profiles showed that Salmonella Typhimurium could consume a wide variety of carbon sources but only at moderate levels; in contrast, Salmonella Oranienburg and Salmonella Saintpaul demonstrated intense carbon source utilization of a limited diversity of carbon sources. Carbohydrates, amino acids and carboxylic acids were the metabolites most utilized by the environmental Salmonella strains, demonstrating their superior ability to adapt to and survive in river water. [ABSTRACT FROM AUTHOR]

Celecoxib is an anti-inflammatory drug with antibacterial activity whose fate in surface water is unknown. Thus, some assays have been conducted under forced biological, photochemical and thermal conditions, and non-forced conditions, to establish its persistence and degradation products in river water. The results suggest that celecoxib dissolved in river water is not biologically degraded while it is minimally altered after its exposure to sunlight or high temperature (70 °C). Only the irradiation at 254 nm promotes its complete degradation. Celecoxib is degraded about 3%, in 36 weeks, when water was kept at room temperature and the exposure to sunlight was partially limited as it happens inside a body of water. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction; eleven degradation products were detected and the structures of nine of them were unequivocally proposed from the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. The long-term transformation products under non-forced conditions were 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonic acid, 4-[1-(4-sulfoaminephenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl]benzoic acid and a hydroxylated derivative. The degradation over time in presence of sediment was monitored, being slightly higher, about 4%. The adsorption equilibrium constants of celecoxib and degradation products on river sediment were estimated. [ABSTRACT FROM AUTHOR]

A total of 256 water samples were collected from the river, precipitation, and permafrost active layer in a typical small alpine catchment during the ablation periods in 2020 and 2021. The results indicated that every water body was alkaline, and the TDS and EC concentrations were in the following order: precipitation < river water < permafrost water. The cation concentrations in river and permafrost water exhibited the order of Na+ + K+ > Ca2+ ≈ Mg2+ and Na+ + K+ > Mg2+ > Ca2+, respectively; the anion concentration showed the order of SO 4 2− > Cl− > NO 3 −. The results revealed that permafrost and river water had similar geochemical compositions. Similar δ 2 H and δ18O values were also observed between river and permafrost water. Additionally, the water chemistry of rivers and permafrost revealed that the chemical weathering of carbonate and silicate rocks is an important source of riverine solutes; however, silicate weathering played a more crucial role. Both hydrochemistry and stable isotopes collectively indicated that there was a close hydraulic connectivity between the water content in river and permafrost active layer in the small alpine catchment. Based on the end-member mixing analysis model, the water in permafrost active layer and precipitation accounted for 62% and 38% of the runoff, respectively, indicating that it was dominated by permafrost during the ablation period. The warming and humidification of climate tend to facilitate permafrost degradation. Thus, studying the transformation of different water bodies in alpine regions is imperative to provide water resource security and sustainable development in alpine regions. • Hydrochemistry indicate the close hydraulic connectivity between river water and permafrost. Hydrochemistry indicate the close hydraulic connectivity between river water and permafrost. • The recharge proportions of permafrost water is 62% and precipitation contributing 38% in the sampling period. • The runoff of Shaliu river dominated by permafrost water in the ablation period. [ABSTRACT FROM AUTHOR]

In 2011, the accident at the Fukushima-Daiichi nuclear power plant dispersed radioactive cesium throughout the environment, contaminating the land, rivers, and sea. Suspended particles containing clay minerals are the transportation medium for radioactive cesium from rivers to the ocean because cesium is strongly adsorbed between the layers of clay minerals, forming inner sphere complexes. In this study, the adsorption and desorption behaviors of radioactive cesium from suspended clay particles in river water have been investigated. The radioactive cesium adsorption and desorption experiments were performed with two kinds of suspended particulate using a batch method with 137 Cs tracers. In the cesium adsorption treatment performed before the desorption experiments, simulated river water having a total cesium concentration ([ 133+137 Cs + ] total ) of 1.3 nM (10 −9 mol/L) was used. The desorption experiments were mainly conducted at a solid-to-liquid ratio of 0.17 g/L. The desorption agents were natural seawater collected at 10 km north of the Fukushima-Daiichi nuclear power plant, artificial seawater, solutions of NaCl, KCl, NH 4 Cl, and 133 CsCl, and ultrapure water. The desorption behavior, which depends on the preloaded cesium concentration in the suspended particles, was also investigated. Based on the cesium desorption experiments using suspended particles, which contained about 1000 ng/g loaded cesium, the order of cesium desorption ratios for each desorption agent was determined as 1 M NaCl (80%) > 470 mM NaCl (65%) > 1 M KCl (30%) ≈ seawater (natural seawater and Daigo artificial seawater) > 1 M NH 4 Cl (20%) > 1 M 133 CsCl (15%) ≫ ultrapure water (2%). Moreover, an interesting result was obtained: The desorption ratio in the 470 mM NaCl solution was much higher than that in seawater, even though the Na + concentrations were identical. These results indicate that the cesium desorption mechanism is not a simple ion exchange reaction but is strongly related to structural changes in the clay minerals in the suspended particles. Hydrated Na + ions expand the interlayer distance of the clay minerals, resulting in the facile desorption of cesium; in contrast, dehydrated K + ions reduce the interlayer distance and inhibit the desorption of cesium. In conclusion, the desorption of cesium from the suspended particles is controlled by the presence of sodium and potassium ions and the preloaded cesium concentration in the suspended particles. [ABSTRACT FROM AUTHOR]

An online ultra-high-performance-liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) method for detection and quantification of natural and synthetic estrogens and their conjugates in aqueous matrices was developed. Target compounds include the natural estrogen estradiol (E2) and its main metabolites estrone (E1) and estriol (E3), the synthetic estrogens ethinylestradiol (EE2) and diethylstilbestrol (DES) and their conjugates estrone 3-sulfate (E1-3S), estriol 3-sulfate (E3-3S), estradiol 17-glucuronide (E2-17G), estrone 3-glucuronide (E1-3G), and estriol 16-glucuronide (E3-16G). After pH adjustment, sample filtration and addition of internal standards (IS), water samples (5 mL) were preconcentrated on a Hypersil GOLD aQ column after which chromatographic separation was achieved on a Kinetex C18 column using methanol and water as a mobile phase. The experimental parameters, such as sample loading flow rate, elution time, the percentage of organic solvent in the aqueous-organic eluent mixture, pH, and volume of analyzed samples, were optimized in detail. The benefits of the method compared to previously published methods include minimum sample manipulation, lower detection limits, reduced total analysis time, and overall increased method accuracy and precision. Method detection limits (MDLs) are in subnanogram per liter, complying with the requirements of the EC Decision 2015/495 (Watch list) for hormones listed therein. Applicability of the developed method was confirmed by analysis of river and raw wastewater samples taken directly from urban sewerage systems before being discharged into the river. [ABSTRACT FROM AUTHOR]

The study describes the application of new methodologies for the simultaneous determination of As(III)/As(V), Sb(III)/Sb(V) and Tl(I)/Tl(III) ions in waters and bottom sediments of the Kłodnica River (Poland) with the hyphenated technique of high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) . Time and spatial correlations were determined in the changes of total and speciation concentrations of the above-mentioned analytes in Kłodnica river in 2012. The developed methodologies demonstrate high selectivity and limits of quantification at the level of 0.009–0.120 µg/L. Their repeatability, precision and recovery are appropriate for trace analyses of environmental samples. Time and spatial correlations, and concentrations of inorganic As, Sb and Tl ions demonstrated high variability both in water and bottom sediments. [ABSTRACT FROM AUTHOR]

Ceramic membrane ultrafiltration experiments were performed with 7-channel tubular membrane (molecular weight cutoff = 300 kD) at a constant transmembrane pressure and crossflow rate under recirculation mode. In the experiments, the fouling characteristics of river water (RW, dissolved organic carbon (DOC) = 3.4 mg/L) were compared with humic acid solution (HA1, DOC = 3.7 mg/L). Also, the fouling behaviors of secondary effluent (SE, DOC = 7.9 mg/L) were compared with HA2 (DOC = 8.5 mg/L). Fluorescence excitation-emission matrix, modified Hermia’s model, and resistance-in-series model were used to analyze the fouling characteristics. Results demonstrated that RW and SE could cause ceramic membrane fouling more rapidly due to their hydrophilic organic compositions in comparison with hydrophobic HA. [ABSTRACT FROM PUBLISHER]

High quality zeolite A was synthesized through a hydrothermal process using alkaline-assisted pre-activated halloysite mineral as the alumina and silica source. The synthesis conditions employed in this study were finely tuned by varying the activating temperature, sodium hydroxide content, water content and Si/Al ratio. The obtained zeolite A showed excellent adsorption properties for both single metal cation solutions and mixed cation solutions when the concentrations of the mixed cations were comparable with those in polluted natural river water and industrial wastewater. High adsorptive capacities for Ag + (123.05 mg/g) and Pb 2 + (227.70 mg/g) were achieved using the synthesized zeolite A. This observation indicates that the zeolite A synthesized from alkaline-assisted pre-activated halloysite can be used as a low-cost and relatively effective adsorbent to purify heavy metal cation polluted natural river water and industrial wastewater. [ABSTRACT FROM AUTHOR]

The genotoxicity of river water dissolved contaminants is usually estimated after grab sampling of river water. Water contamination can now be obtained with passive samplers that allow a time-integrated sampling of contaminants. Since it was verified that low density polyethylene membranes (LDPE) accumulate labile hydrophobic compounds, their use was proposed as a passive sampler . This study was designed to test the applicability of passive sampling for combined chemical and genotoxicity measurements. The LDPE extracts were tested with the umu test (TA1535/pSK1002 ± S9) and the Ames assay (TA98, TA100 and YG1041 ± S9). We describe here this new protocol and its application in two field studies on four sites of the Seine River. Field LDPE extracts were negative with the YG1041 and TA100 and weakly positive with the TA98 + S9 and Umu test. Concentrations of labile mutagenic PAHs were higher upstream of Paris than downstream of Paris. Improvement of the method is needed to determine the genotoxicity of low concentrations of labile dissolved organic contaminants. [ABSTRACT FROM AUTHOR]

Determination of residual pharmaceutical compounds in environmental water is gaining increasing interests. The task represents a substantial challenge to analysts because analytes present in quite complicated matrices and at very low concentrations. Despite the inherent low sensitivity associated with capillary electrophoresis (CE), it has been used successfully to determine different types of pharmaceutical compounds at very low levels that rival those reported by more commonly used methods for that purpose such as high performance liquid chromatography-mass spectrometry (HPLC-MS). Attempts to use CE for the determination of drugs in environmental water samples started nearly in the late 1990s; since then, different modes of CE including capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography together with different detection techniques (UV, fluorescence, MS) have been investigated and shown to be of adequate performance. A key to the success of CE for such low-level determination was the sample concentration steps that have been used including solid-phase extraction and more advanced approaches such as in-line sample concentration, large volume sample stacking, and others. The different reports that have been reported for this application in particular have been reviewed since late 1990s with emphasis on the attained limits of detections and sample treatment. The particularities of the separation conditions in each case have been discussed with some elaboration. [ABSTRACT FROM AUTHOR]

Interpretations of the geologic record of late Archean near-surface environments depend very strongly on an understanding of weathering and resultant riverine transport to the oceans. The late Archean atmosphere is widely recognized to be anoxic ( p O 2 , g = 10 − 5 to 10 − 13 bars ; p H 2 , g = 10 − 3 to 10 − 5 bars ). Detrital siderite (FeCO 3 ), pyrite (FeS 2 ), and uraninite (UO 2 ) in late Archean sedimentary rocks also suggest anoxic conditions. However, whether the observed detrital minerals could have been thermodynamically stable during weathering and riverine transport under such an atmosphere remains untested. Similarly, interpretations of fluctuations recorded by trace metals and isotopes are hampered by a lack of knowledge of the chemical linkages between the atmosphere, weathering, riverine transport, and the mineralogical record. In this study, we used theoretical reaction path models to simulate the chemistry involved in rainwater and weathering processes under present-day and hypothetical Archean atmospheric boundary conditions. We included new estimates of the thermodynamic properties of Fe(II)-smectites as well as smectite and calcite solid solutions. Simulation of present-day weathering of basalt + calcite by world-average rainwater produced hematite, kaolinite, Na–Mg-saponite, and chalcedony after 10 − 4 moles of reactant minerals kg −1 H 2 O were destroyed. Combination of the resultant water chemistry with results for granitic weathering produced a water composition comparable to present-day world average river water (WARW). In contrast, under late Archean atmospheric conditions ( p CO 2 , g = 10 − 1.5 and p H 2 , g = 10 − 5.0 bars ), weathering of olivine basalt + calcite to the same degree of reaction produced kaolinite, chalcedony, and Na–Fe(II)-rich-saponite. Late Archean weathering of tonalite–trondhjemite–granodiorite (TTG) formed Fe(II)-rich beidellite and chalcedony. Combining the waters from olivine basalt and TTG weathering resulted in a model for late Archean WARW with the composition Na + –Ca 2+ –Fe 2+ –Mg 2+ –Cl − – HCO 3 − –SiO 2,aq . The pH of the water was 6.3 and it is much richer in HCO 3 − , and in Mg + Fe relative to Ca + Na, compared to present-day WARW. At higher p H 2,g (e.g. 10 − 4.0 bars ) organic acid anions could be metastable. Our results are consistent with the thermodynamic stability of Fe(II)-clays, pyrite, uraninite, and, under some conditions, siderite during weathering and riverine transport. Overall, our results provide a basis for assessing the formation of organic hazes and the mobility of trace elements and nutrients due to fluctuations of the late Archean atmosphere. [ABSTRACT FROM AUTHOR]

The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants, whose effluents flow into aquatic environments; concentrations in the 0.1–100 ng/L range are commonly found in surface waters, and its fate is unknown. Here, biological, photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time. The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin (2 μg/L) in less than 6 hr, but indomethacin was detected over a period of 4 months when water was kept under the natural day–night cycle and the exposure to sunlight was partially limited, as occurs inside a body of water. The biological degradation in water was negligible, while the hydrolysis at pH 7.8 was slow. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction, and six degradation products were found; their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. 4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products, persisting for at least 30 weeks in water kept under non-stress conditions. Furthermore, the degradation in the presence of sediment was also monitored over time, with some differences being noted. The adsorption coefficients of indomethacin and degradation products on river sediment were calculated; long-term degradation products did not have significant adsorption to sediment. [ABSTRACT FROM AUTHOR]

The performance of a gross pollutant trap (GPT) was investigated at 51 catchments of the most polluted river in Malaysia, Klang River and its major attributes, Gisir River, Kemensah River, and Sering River for the entrapment of gross pollutants over the operation period of 10 months. The specific characteristics of gross pollutants generated from the different catchments were measured, and sorted into litter classification. The wet loads collected at the catchments ranged between 14 and 111 kg/ha, with majority of them was contributed by a significant amount of sediment and plastic. The water quality at the inflow and outflow channels was examined. GPT responded effectively for chemical oxygen demand, biological oxygen demand, ammonical nitrogen, and total suspended solids removal, reaching the maximum removal of 88, 94, 94, and 97%, respectively. The water quality index of the influent river water falls in Class V, derived as “very polluted,” while the downstream river water lies in the intermediate between Class IV and III, defined as “polluted” and “average,” respectively. These findings strongly supported the real practical applications of GPTs for the effective management and preservation of urban river systems. [ABSTRACT FROM PUBLISHER]

Toxic effects of the non-biodegradable drug chlorpromazine and its degradation products have been reported on microorganisms in aqueous media. Here, chlorpromazine degradation assays in forced and non-forced conditions have been done to know its persistence and degradation products in river water. Sunlight irradiation promotes the complete degradation of chlorpromazine (2 μg L −1 ) in less than 4 h, but if the exposure to sunlight is limited chlorpromazine is detected during 4 weeks in river water. Sixteen degradation products in surface water are described for first time after solid-phase extraction and analysis by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry; their structures are proposed from the molecular formulae of the fragment-ions observed in high-resolution tandem mass spectra. Hydroxylation and oxidation products such as chlorpromazine sulfoxide, 2-hydroxypromazine and 2-hydroxypromazine sulfoxide were predominant degradation products in the early stages; some benzo[1,4]thiazin-6-ol derivatives resulting from the breakdown of the phenothiazine core were the major and relatively stable products after 20 weeks under non-forced conditions. A degradation pathway of chlorpromazine in water is outlined. Moreover, it is shown that chlorpromazine is very strongly adsorbed on sediment while the degradation products that kept the promazine core have a notable capacity of sorption, too; sorption coefficients are calculated. Finally, a prediction about the toxicity of the degradation products in aquatic ecosystems suggests that some of them have toxicities similar, or even higher, than chlorpromazine. [ABSTRACT FROM AUTHOR]

The performance of a laboratory scale bioreactor was investigated for the biological pretreatment of contaminated river water over the operation period of 6 months. The biofilters were constructed as four identical 5.75 L tanks filled with different carrier supports. The physiochemical properties of the biomedia, including the specific surface area, void fraction, adsorption of methylene blue, and morphological characteristics were examined. The biofilters responded effectively for chemical oxygen demand, biological oxygen demand, ammonical nitrogen, and total suspended solids removal, reaching the maximum removal of 94, 88, 85, and 98%, respectively. The variation of morphological development and biofilm densities revealed the existence of different growth rates and microbial activities under different biomedia supports. The operation is significantly correlated to the unique features of the biomedia. These new engineered structural biomedia are expected to be a potential option to govern the successful water purification process under steady and transient state operations. [ABSTRACT FROM PUBLISHER]

A new, simple, and fast method is described for determining selenium based on a silver wire electrode flow-through voltammetric detector. A comparison was done between the sensitivity of disk silver, mercury-modified glassy carbon, and mercury-modified gold electrodes. The response of the flow-through voltammetric detector was evaluated with respect to each electrode's operating potential and pH in direct current mode. The limit of detection (3s) for Se(IV) was below 0.01 mg/L. The flow-through system does not need deposition times and the organic matter does not need to be removed before determining selenium in river water. [ABSTRACT FROM AUTHOR]

We report chromium (Cr) isotope compositions and concentrations (and additional geochemical and physicochemical data) of bedrock, soils and river waters from two geographically distinct basaltic river catchments, the Uruguay River catchment (Uruguay) and the Glenariff River catchment (Northern Ireland, United Kingdom), to investigate the processes that control Cr mobilisation and fractionation during weathering and riverine transport to the sea. Our results show that the Cr isotope compositions of soils are a function of the modal abundance and weathering rates of Cr-bearing minerals. The accumulation of weathering resistant Cr-spinels in the soils of Northern Ireland results in soils which are enriched in Cr and have δ 53 Cr values within the range of local bedrock ( δ 53 Cr value of −0.21 ± 0.12‰, 2 σ , n = 4). By contrast, the more easily weathered Cr-silicates in the bedrock of Uruguay results in greater Cr loss from the soil and a depletion in the heavy isotopes of Cr (with average δ 53 Cr value of −0.32 ± 0.04‰, 2 σ , n = 4) relative to the local bedrock ( δ 53 Cr value of −0.22 ± 0.08‰, 2 σ , n = 4). The river waters in both catchments are predominantly enriched in the heavy 53 Cr isotope relative to bedrock, although the range and average river water δ 53 Cr values differ significantly between each. The Uruguay rivers exhibit a restricted range in δ 53 Cr values, with a mean of +0.08 ± 0.06‰ (2 σ , n = 5) that represents a positive fractionation of +0.2‰ relative to bedrock, and is best explained by the unidirectional formation of Cr(VI) during weathering that has not been significantly modified by back-reduction to Cr(III). By contrast, the Glenariff stream and river waters (Northern Ireland) exhibit a wide range in δ 53 Cr values from −0.17 ± 0.3‰ (2 σ , n = 4) to +1.68 ± 0.3‰ ( n = 1) that appears to reflect the variable redox conditions of the catchment. In general, the values with the lowest 53 Cr enrichment have higher Cr concentrations, the lowest pH, highest dissolved organic carbon (DOC), and exhibit minimal Ce anomalies that is consistent with a greater proportion of Cr(III) released from more reducing (bog influenced) stream waters. The remaining waters have lower Cr concentrations, lower DOC, and more pronounced Ce anomalies, indicating that a greater proportion of Cr(VI) underwent partial back-reduction to Cr(III) either during weathering, or during riverine transport. Overall, the DOC appears to exert a control on the dissolved Cr speciation and magnitude of isotope fractionation in these river waters. The broader implications of these observations are that the prevailing redox conditions in a river catchment strongly influence the δ 53 Cr value of the river water flux emptying into seawater. Observations for this study need to be considered when developing a framework for interpreting palaeo-climates from the δ 53 Cr values of ancient authigenic marine sediments. [ABSTRACT FROM AUTHOR]

The stable isotopic composition of two rivers, the Vantaanjoki River and the Kokemäenjoki River, in southern and southwestern Finland was studied to resolve the transit times and travel routes of the river water in the two different catchments. The Kokemäenjoki River is dominated by great lake basins whereas the Vantaanjoki River has been reported having a significant groundwater component. The mean residence time of the young surface flow component could be resolved by sine function fitting onto the annual fluctuations of the isotopic signal, and the amount of base flow was estimated by using the isotopic composition of the river and groundwater. In this study, we found that the methods work for simple two component catchments. In more complex cases with three different components mixing, the solution becomes increasingly difficult and requires more study. [ABSTRACT FROM AUTHOR]

Alcohol ethoxylates (AEs) are a significant component of the non-ionic surfactant (NS) flux discharged into surface water. Due to the polydispersity of the majority of NS, they are easily recognizable by their ‘fingerprints’, i.e. a series of mass peaks which differ by m / z = 44, namely the m / z of a single oxyethylene subunit. Dodecanol ethoxylates (C 12 EO x ) represent AEs from both renewable and petrochemical sources. Therefore, C 12 E x are suitable fingerprints of NS in the aquatic environment. The aim of this work was to develop an LC–MS/MS method suitable for AE monitoring in river water. River water samples taken from the River Warta in Poznan (Poland) were extracted with ethyl acetate, evaporated, reconstituted in the mobile phase and processed by the LC – Multistage MS procedure (LC–MS/MS) using optimum multiple reaction monitoring (MRM). The method of multiple standard additions was used for the evaluation of each AE fingerprint concentration. The concentration of C 12 EO x having 2–9 oxyethylene subunits was determined. Standards for higher C 12 EO x are not yet available. The developed method offers an LOD of between 1 and 9 ng L −1 , and is suitable for the monitoring of NS fingerprints in river water. The range of C 12 EO 2–9 concentrations determined in the River Warta varied within two orders of magnitude in all cases. The lowest determined concentration was 17 ± 1 ng L −1 , while the highest was 2.6 ± 0.14 μg L −1 . The total concentration of C 12 EO 2 –C 12 EO 9 homologues varied between 1.4 and 11.2 μg L −1 . A relatively high concentration of short-chained homologues (2–5 oxyethylene subunits) was observed in the investigated river water. This provides evidence of a biodegradation pathway involving the gradual shortening of the AE oxyethylene chain. Distinct evidence was also obtained of unregulated NS discharges into the river. [ABSTRACT FROM AUTHOR]

Concentrations of Cs measured in water collected from seven rivers under base-flow conditions in eastern Fukushima Prefecture in 2014 were combined with previously reported data for the same sampling points from 2012 to 2013. Dissolved Cs concentrations at the sampling points were strongly correlated with the Cs inventories of the corresponding catchment areas. The ratios of the dissolved Cs concentrations to the Cs inventories have declined exponentially since the 2011 Fukushima nuclear power plant accident with an effective decreasing coefficient of 0.40 y (effective half-time of 1.7 y), within the range reported in European rivers following the Chernobyl accident. [ABSTRACT FROM AUTHOR]

We report the template-free fabrication of three-dimensional hierarchical nanostructures, i.e. , three-dimensional interconnected magnetic chemically modified graphene oxide (3D-Mag-CMGO), through a simple and low-cost self-assembly process using one-pot reaction based on solvothermal method. The excellent properties of the 3D-Mag-CMGO are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), FTIR, elementary analyzer (EA) and X-ray photoelectron spectroscopy (XPS). The easiness-to-handle of the magnetic dispersive solid phase extraction (Mag-dSPE) procedure is developed for preconcentration of 21 allergenic disperse dyes from river water. The obtained results show the higher extraction capacity of 3D-Mag-CMGO with recoveries between 80.0–112.0%. Furthermore, an ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC–MS/MS) method for determination of 21 allergenic disperse dyes in river at sub-ppt levels has been developed with pretreatment of the samples by Mag-dSPE. The limits of quantification (LOQs) for the allergenic disperse dyes are between 0.57–34.05 ng/L. Validation results on linearity, specificity, trueness and precision, as well as on application to the analysis of 21 allergenic disperse dyes in fifty real samples demonstrate the applicability to environment monitoring analysis. [ABSTRACT FROM AUTHOR]

Understanding the relationship between surface water and groundwater is important for the integrated management of water resources in arid regions. In the present study, the connectivity of river water and shallow groundwater along the Shidi River, China is estimated using a connectivity index, as well as analyses of hydrochemistry and isotopic signature. The three approaches for hydraulic connectivity assessment were compared and discussed. An end member mixing analysis was performed to estimate the contribution ratios of local precipitation, river leakage and groundwater lateral inflow to the total groundwater recharge along the river. The results show that medium connectivity is identified in all reaches of the river (upstream, midstream and downstream). Water table depth and river channel sediments are the major factors responsible for the spatial variation of the hydraulic connectivity. The CI approach can be adopted to generate preliminary assessment results of hydraulic connectivity, while the physiochemical and isotopic approaches should be used as a tool for results validation and verification. Groundwater lateral inflow is the most important recharge source of groundwater along the river, while river leakage only accounts for 18.4-27.0 % of the total recharge. This study is meaningful in integrated water resources management in arid regions and the methods used in this study can be adopted by other scholars in similar studies. [ABSTRACT FROM AUTHOR]

The present work aims at assessing the water quality index (WQI) in the surface water of Olt River by monitoring three sampling locations for a period of 12 months from December 2014 to November 2015.The surface water samples were subjected to comprehensive physico-chemical analysis involving major cations (Ca2+, Mg2+), anions (Cl-, SO42-, NO3 -, PO4 3-) and general parameters (pH, electrical conductivity, total dissolve solids, total hardness, turbidity). Results demonstrated that WQI values for the sectors of water analyzed, water is classified as excellent values between 12.97 to 21.23 in spring, winter, autumn seasons and good water class in summer season with WQI value of 29.42. The seasonal values of WQI indicates that surface water is affected more during the summer season than in spring, autumn and winter. This method appears to be more systematic and provide comparative evaluation of the water quality in different seasons of the year. Therefore, it may be helpful as marker for the public to better understand the quality of water as well as tool for the water quality management. [ABSTRACT FROM AUTHOR]

High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea . Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. [ABSTRACT FROM AUTHOR]

The Ra and Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of Ra and Ra were discussed according to their distribution characteristics. Ra and Ra activities (dpm/(100 L)) ranged from 14.13±0.22 to 19.22±0.42 and 17.72±0.66 to 30.96±1.47 in the surface water of the North Bay, respectively, and from 7.88±0.24 to 33.80±0.47 and 15.73±0.74 to 57.31±1.44, respectively, in the South Bay. The surface water near the estuary had a lower salinity and had a higher concentration of radium isotopes than the samples collected further away. The farther offshore the sample, the higher the salinity was, and the lower the radium isotope activity. The distribution of radium activities in the western part of Qinghai Lake is controlled by several factors, including Buha River runoff, desorption from suspended particles derived from the river, groundwater discharge, and a small amount of diffusion from the sediment. [ABSTRACT FROM AUTHOR]

In this study, antimony (Sb) isotopic composition was determined in natural water samples collected along two hydrosystems impacted by historical mining activities: the upper Orb River and the Gardon River watershed (SE, France). Antimony isotope ratio was measured by HG-MC-ICP-MS (Hydride Generation Multi-Collector Inductively Coupled Plasma Mass Spectrometer) after a preconcentration and purification step using a new thiol-cellulose powder (TCP) procedure. The external reproducibility obtained for δ 123 Sb measurements of our in-house Sb isotopic standard solution and a certified reference freshwater was 0.06‰ (2 σ ). Significant isotopic variations were evident in surface waters from the upper Orb River (−0.06‰≤ δ 123 Sb≤+0.11‰) and from the Gardon River watershed (+0.27‰≤ δ 123 Sb≤+0.83‰). In particular, streams that drained different former mining sites exploited for Sb or Pb–Zn exhibited contrasted Sb isotopic signature, that may be related to various biogeochemical processes occurring during Sb transfer from rocks, mine wastes and sediments to the water compartment. Nevertheless, Sb isotopic composition appeared to be stable along the Gardon River, which might be attributed to the conservative transport of Sb at distance from mine-impacted streams, due to the relative mobile behavior of Sb(V) in natural oxic waters. This study suggests that Sb isotopic composition could be a useful tool to track pollution sources and/or biogeochemical processes in hydrologic systems. [ABSTRACT FROM AUTHOR]

The geochemical behavior of rare earth elements (REEs) has been investigated mainly in geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. This behavior is assessed according to REE concentrations recorded along the REE series normalized with respect to upper continental crust. In this study based on a field approach, the geochemical behavior of REE was investigated in French stream waters. This study is based on FOREGS (Forum of European Geological Surveys) Geochemical dataset that consists on a sampling at regular mesh on all Europe. In France, 119 stream water samples were extracted in drainage basins < 100 km 2 . The aim of the study is that of describing the spatial variation of REEs and finding the hydro-topo-geochemical factors that affect their distribution by means of a Multivariate Factorial Kriging. On the basis of their atomic number and of the results of a preliminary Principal Component Analysis three REEs have been selected (La, Eu and Lu) and five physicochemical properties (pH, organic carbon, carbonates, Fe, Mn). A cokriging has been applied that shows a similar spatial organization of REEs: higher values are especially observed in the Aquitaine basin. In order to investigate more deeply on the different sources of variation acting in the study area, a factorial cokriging is applied. The first 2 regionalized factors have been estimated to give a synthetic description of the studied process at the different selected spatial scales. At higher spatial scales (250 km) environmental parameters like Fe, carbonates, and pH, supposed to be ascribed to the rock's nature or to other geological larger scale processes (i.e., hydrographic network and topography), have shown to affect REE distribution. At short range, only Eu and Mn weigh more, which are ascribed to the process of liberation of Mn oxides in rivers that also release the REEs sorbed onto these oxides. [ABSTRACT FROM AUTHOR]

Mo isotopic composition in large rivers is very important for understanding global Mo cycle. At present, temporal variation signatures in the δ 98/95 Mo in large rivers have not been investigated, which hinder a comprehensive understanding on the mechanism for the variations of Mo isotopic compositions in river water. In this study, we report a one-year-long time series (March 2010 to March 2011) of the δ 98/95 Mo of both the water and suspended particulates collected at Guiping, from the middle reaches of the Xijiang River (XJR), and of the water δ 98/95 Mo from the lower reaches of the Huanghe River (HHR, or Yellow River) collected at Lijin, China. The results indicate that the temporal variations in the concentration and δ 98/95 Mo of dissolved Mo in the XJR range from 4.32 to 10.5 nmol/L (mean 7.31 nmol/L) and 1.04‰ to 1.31‰ (relative to NIST 3134) (mean 1.20‰), respectively, but that the particulates have a lower δ 98/95 Mo (− 0.18‰ to 0.58‰). Analysis of the suspended particulates and other chemical parameters of the river water suggests that the weathering of silicates and sulfides is the main contributor to the dissolved Mo content in the XJR. Subsequently, the highly efficient preferential trapping of lighter δ 98/95 Mo by weathering products such as clay minerals, Fe–Mn oxides, and organic materials in soils and saprolites, which are abundant in the tropical catchment, is the key to the heavy Mo isotope signatures in the XJR. Furthermore, it seems that neither Mo-scavenging by suspended particulates during riverine transportation, nor the weathering of sulfates, significantly influences the δ 98/95 Mo of the XJR water. Cross comparison among the δ 98/95 Mo in the waters of the three largest rivers in China (the Changjiang (CJR), HHR, and XJR) indicates that the HHR has the highest Mo concentrations, but the lightest δ 98/95 Mo, the XJR has the lowest Mo concentrations but the heaviest δ 98/95 Mo, and the values for the CJR are intermediate between those for the other two rivers. This supports the conclusion that the efficiency of the selective trapping of Mo by soils and saprolites is the main factor controlling δ 98/95 Mo in these large rivers. The tropical/subtropical XJR catchment experiences intense chemical weathering, the semi-arid temperate HHR catchment experiences very little, and the CJR catchment falls somewhere between the two. Such a relationship between water Mo concentrations and δ 98/95 Mo agrees with previous observations from many large rivers worldwide. It is therefore suggested that chemical weathering on continents is the key to variations in the isotopic composition of Mo in the waters of large rivers. [ABSTRACT FROM AUTHOR]

This study provides an overview on Tl-speciation methods developed in the last years. Most of them require transformation of a species and do not allow direct detection of the species of interest. LC-MS and IC-ICP-MS methods are optimised for direct analysis of the Tl-species Tl+and (CH3)2Tl+(dimethylthallium (DMT)) in freshwater on a ng L−1level. The methods are applied in a study of water from Vicht River in Stolberg (Germany). Tl+is shown to be at least in part derived from anthropogenic sources among which the industrial sources may be significant. The natural occurrence of DMT is proven, although this Tl-species is temporally variable in abundance and Tl+predominates. [ABSTRACT FROM PUBLISHER]

During 2011–2014, we measured 3 H concentrations in river water samples collected during base flow conditions and during several flood events from two small rivers in a mountainous area in Fukushima Prefecture, which received deposition of 137 Cs from the Fukushima Dai-ichi Nuclear Power Plant accident. 3 H concentrations above background levels were found in water samples collected during both base flow conditions and flood events in 2011. The 3 H concentrations during flood events were generally higher than those during base flow conditions. The 3 H concentrations in both rivers during base flow conditions and flood events decreased with time after the accident and reached almost background levels in 2013. We also measured 3 H concentrations in freshwater samples from 16 other rivers and one dam in eastern Fukushima Prefecture from 2012 to 2014 during base flow conditions. The measured 3 H concentrations were higher than the background level in 2012 and decreased with time. The 137 Cs inventory in the catchment area at each sampling point was estimated from air-borne monitoring results in the literature and compared with the 3 H concentrations. We found surprisingly good correlations between 137 Cs inventories in the catchment areas and 3 H concentrations in the water samples. Further studies will be necessary to clarify the reason for the good correlation. [ABSTRACT FROM AUTHOR]

Nuclear accidents occurred in latest years highlighted the difficulty to achieve, in a short time, the quantification of alpha and beta emitters. Indeed, most of the existing methods, though displaying excellent performances, can be very long, taking up to several weeks for some radioisotopes, such as 90 Sr. This study focuses on alpha and beta radioisotopes which could be accidentally released from nuclear installations and which could be measured by inductively coupled plasma mass spectrometer (ICP-MS). Indeed, a new and rapid separation method was developed for 234,235,236,238 U, 230,232 Th, 239,240 Pu, 237 Np, 241 Am and 90 Sr. The main objective was to minimize the duration of the separation protocol by the development of a unique radiochemical procedure with elution media compatible with ICP-MS measurements. Excellent performances were obtained with spiked river water samples. These performances are characterized by total yields exceeding 80% for all monitored radionuclides, as well as good reproducibility (RSD ≤ 10%, n = 12). The proposed radiochemical separation (including counting time) required less than 7 h for a batch of 8 samples. [ABSTRACT FROM AUTHOR]

In this study, a novel material for the electrochemical determination of 17β-estradiol using an electrode based on reduced graphene oxide and a metal complex porphyrin has been applied to environmental monitoring. The electrochemical profile of the proposed electrode was analyzed by differential pulse voltammetry, which showed a shift of the oxidation peak potential of 17β-estradiol to 150 mV in a less positive direction compared to the bare reduced graphene oxide electrode. DPV experiments were performed in PBS at pH 7.0 to determine 17β-estradiol without any previous step of extraction, cleanup, or derivatization, in the range of 0.1–1.0 μmol L −1 with a detection limit archived at 5.3 nmol L −1 (1.4 μg L −1 ). The proposed sensor was successfully applied in the determination of 17β-estradiol in a river water sample without any purification step and was successfully analyzed under the standard addition method. All the obtained results were in agreement with those from the HPLC procedure. [ABSTRACT FROM AUTHOR]

In the present work, the analysis of seven fullerenes (C and C fullerenes and five functionalised fullerenes) has been performed in river samples collected in the vicinities of Barcelona (Catalonia, NE of Spain). The results of 48 samples (25 river waters, 12 river sediments and 11 wastewater effluents) are presented. Extracts of river water, river sediments and wastewater effluents were analysed by liquid chromatography (LC), using a pyrenylpropyl group bonded silica based column, coupled to a high-resolution mass spectrometer (HRMS), using a dual ion source, atmospheric pressure photoionisation/atmospheric pressure chemical ionisation source (APPI/APCI). The novel methodology presents good chromatographic separation, excellent selectivity and instrumental limits of quantification (ILOQ) in the femtogram order. Method limits of quantification (MLOQ) ranged from 2.9 to 17 pg/l and from 3.2 to 31 pg/l in surface waters and wastewaters, respectively. In wastewater effluents, the sums of C and C ranged from 0.5 to 9.3 ng/l. In surface waters, C fullerene was the most ubiquitous compound, being detected in 100 % of the samples in concentrations from 31 pg/l to 4.5 ng/l, while C concentrations ranged from less than the method limits of detection (MLOD) to 1.5 ng/l. The presence of fullerenes in both the large particulate (diameter Ø > 450 nm) and the colloidal ( Ø < 450 nm) fractions of surface waters should be noticed. In sediments, the concentrations of fullerenes were between the MLOD and 34.4 pg/g. In addition, nanoparticle tracking analysis (NTA) was used for the characterisation of water samples in terms of nanoparticle number concentration and size distribution. As far as our knowledge is concerned, this is the first time that NTA has been used for the characterisation of complex river waters with an environmental focus. [ABSTRACT FROM AUTHOR]

To investigate the behavior of nuclear accident-derived 137 Cs in river water under base-flow conditions, concentrations of dissolved and particulate 137 Cs were measured at 16 sampling points in seven rivers of Fukushima Prefecture, Japan, in 2012 and 2013. The concentration of dissolved 137 Cs was significantly correlated with the mean 137 Cs inventory in the catchment area above each sampling point in both sampling years. These results suggest that the concentration of dissolved 137 Cs under base-flow conditions is primarily determined by the 137 Cs inventory of the catchment area above the sampling point. However, the concentration of particulate 137 Cs did not show a clear relationship with either the mean 137 Cs inventory or the dissolved 137 Cs concentration, thus indicating that particulate and dissolved forms do not effectively interact in rivers. To evaluate the contribution of the 137 Cs inventory within catchment areas, we analyzed relations between the 137 Cs concentration and the mean 137 Cs inventory over the area within certain flow path lengths that were traced along the river and slope above the sampling point. Coefficients of determination for dissolved 137 Cs concentrations were highest for the longest flow path, i.e., the whole catchment area, and lower for shorter flow paths. Coefficients of determination for particulate 137 Cs concentrations were only moderately high for the shortest flow path in 2012, whereas the values were quite low for all flow paths in 2013. These results suggest that dissolved 137 Cs can originate from a larger area of the catchment even under base-flow conditions; however, particulate 137 Cs did not show such behavior. The results also show that under base-flow conditions, dissolved and particulate 137 Cs behave independently during their transport from river catchments to the ocean. [ABSTRACT FROM AUTHOR]

Monthly measurements (January–December 2013) of the photoformation rate, steady-state concentration and lifetime of nitric oxide radical (NO ) in the Kurose River in Higashi-Hiroshima City, Japan, were obtained. Each month, river water samples were collected at six different stations (upstream to downstream). NO was quantified using 4, 5-diaminofluorescein-2 (DAF-2) as a probe and triazolofluorescein (DAF-2T) as a standard. Results show that NO photoformation rate ranged from 0.01 to 35.4 (×10 −10 M s −1 ). The radical steady-state concentration in the river ranged from 0.02 to 68.5 (×10 −11 M). There was a strong correlation ( r 2 = 0.95) between NO photoformation rate and the nitrite concentration in the river suggesting that this anion is a major NO precursor. On average, 98% of the photoformed NO came from river nitrite, and this was calculated using the photoformation rate constant {5.7 × 10 −5 M(NO )s −1 M(NO 2 − ) −1 } of NO from the anion concentration found in the study. The NO lifetime ranged from 0.05 to 1.3 s in the river and remained fairly stable in the upstream and downstream samples. The OH radical, which was quantified during the study, had a photoformation rate of 0.01–13.4 (×10 −10 M s −1 ) and a steady-state concentration of 0.04–119 (×10 −16 M) with a lifetime that ranged from 0.3 to 22.5 (×10 −6 s). OH only accounted for ⩽0.0011% of the total NO scavenged, showing that it was not a major sink for river NO . [ABSTRACT FROM AUTHOR]

Results of stable isotope measurements (δ2H, δ18O) of daily grab samples, taken from the Danube River at Tulln (river km 1963) during 2012, show seasonal and short-term variations depending on the climatic/hydrological conditions and changes in the catchment area (temperature changes, heavy rains and snow melt processes). Isotope ratios in river water clearly reflect the isotopic composition of precipitation water in the catchment area since evaporation influences play a minor role. Average δ2H and δ18O values in 2012 are−78‰ and−11.0‰, respectively, deuterium excess averages 10‰. The entire variation amounts to 1.8‰ in δ18O and 15‰ in δ2H. Quick changes of the isotopic composition within a few days emphasise the necessity of daily sampling for the investigation of hydrological events, while monthly grab sampling seems sufficient for the investigation of long-term hydro-climatic trends.3H results show peaks (half-width 1–2 days, up to about 150 TU) exceeding the regional environmental level of about 9 TU, probably due to releases from nuclear power plants. [ABSTRACT FROM PUBLISHER]

A novel DNA microarray analysis targeting key functional genes involved in most nitrogen cycling reactions was developed to comprehensively analyze microbial populations associated with the nitrogen cycle. The developed microarray contained 876 oligonucleotide probes based on the nucleotide sequences of the nif, amo, hao/ hzo, nap, nar, nirK, nirS, nrf, cnor, qnor and nos genes. An analytical method combining detection by the designed microarray with whole community genome amplification was then applied to monitor the nitrogen cycling microorganisms in river water and wastewater treatment sludge samples. The developed method revealed that nitrogen cycling microorganisms in river water appeared to become less diverse in response to input of effluent from municipal wastewater treatment plants. Additionally, the nitrogen cycling community associated with anaerobic ammonium oxidation and partial nitrification reactors could be reasonably analyzed by the developed method. However, the results obtained for two activated sludge samples from municipal wastewater treatment plants with almost equivalent wastewater treatment performance differed greatly from each other. These results suggested that the developed method is useful for comprehensive analysis of nitrogen cycling microorganisms, although its applicability to complex samples with abundant untargeted populations should be further examined. [ABSTRACT FROM AUTHOR]

Per- and poly-fluoroalkyl substances (PFASs) have been widely detected in the hydrosphere. The knowledge on the distribution and composition patterns of PFAS analogues with different chain length significantly contribute to their source analysis. In the present study, a regional scale investigation of PFASs in surface river waters and adjacent ground waters was carried out in two cities of China with potential contamination, Tianjin and Weifang. A total of 31 water samples were collected, and 20 PFASs therein were measured by a high-performance liquid chromatograph–tandem mass spectrometer (HPLC–MS/MS). The possible sources of PFASs in the aquatic environment were assessed primarily by concentration patterns as well as hierarchical cluster analysis. In all 4 rivers investigated in the two cities, perfluoroalkyl carboxylic acids (PFCAs) were the dominant compounds contributing over 70% of the PFASs detected. Perfluorooctanoic acid (PFOA) was the dominant PFCA with a concentration range of 8.58–20.3 ng/L in Tianjin and 6.37–25.9 ng/L in Weifang, respectively. On the average, the highest concentration was observed in samples from Dagu Drainage Canal (Dagu) in Tianjin and those short-chain PFASs (C4–C6) was detected with a comparable level of the longer-chain PFASs (>C6). Specifically, perfluorobutanoic acid (PFBA) was dominant in the short-chain analogues. This indicates that a remarkably increasing input of short-chain PFASs might be related to wastewater treatment plant effluent or industrial discharges, which could be possibly due to the switch of manufacturing to short-chain products. In Weifang, precipitation and subsequent surface runoff as non-point sources could be significant inputs of PFASs into surface water while groundwater was possibly subjected to severe point sources with ∑PFASs concentration up to ~100 ng/L. The inconsistent distribution patterns in groundwater suggest complicated pathways of contamination. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mean annual HBCDs detected in river water in Japan ranged from 0.19 to 14ngL− 1. [•] HBCDs detected in sewage influent ranged from 16 to 400ngL− 1. [•] HBCDs detected in sewage effluent ranged from 0.39 to 12ngL− 1. [•] Over 90% of HBCDs were removed from wastewater in the sewage treatment plant. [•] Approximately 15kgyear− 1 of HBCDs flows into Osaka Bay from the study area. [Copyright &y& Elsevier]

Tetracyclines are antibiotics commonly used in swine farms to treat disease and promote growth. However, there are growing concerns regarding the discharge of animal feces into the environment owing to the potential for development and dissemination of tetracycline resistance genes (TRGs). In this study, farming wastewater from one Chinese swine farm as well as river water from seven locations downstream of the farm was sampled. Polymerase chain reaction (PCR) showed that 12 TRGs, including six efflux pump genes (tet(B),tet(C),tet(D),tet(E),tet(G) andtet(L)), five ribosomal protection proteins (RPPs) genes (tet(O),tet(M),tet(Q),tet(W) andtet(S)), and one enzymatic modification gene (tet(X)), were present in all wastewater and river water samples. Quantitative real-time PCR (qPCR) showed that the abundance oftet(C),tet(X),tet(O),tet(M),tet(Q) andtet(W) decreased with downstream flow. Among the detected TRGs,tet(C) had the highest abundance, ranging from 459.5 copies/16S rRNA gene copies in wastewater to 33.8 copies/16S rRNA gene copies in river water samples collected from the last location. Furthermore, pig-specificBacteroidales16S rRNA genetic marker was quantified by qPCR to determine the level of fecal pollution in the river water. Bivariate correlation analysis confirmed that the total relative abundance of the six TRGs was significantly correlated with the level of swine feces in the aquatic environment (R2= 0.63,P< 0.05), suggesting that swine feces mainly contributed to the spread of TRGs in the river water. Supplemental materials are available for this article. Go to the publisher's online edition ofJournal of Environmental Science and Health, Part Ato view the free supplemental file. [ABSTRACT FROM AUTHOR]

Interactions between river water and groundwater have been used to help understand the movement of water and to evaluate water quality in the semi-arid area of the North China Plain (NCP). Stable isotopes, chlorofluorocarbons (CFCs) and hydrochemistry were used to study the influence of surface water from the Xiao River on regional groundwater. Using a mass balance approach based on chloride concentrations, hydrogen and oxygen isotope ratios, the average fraction of surface water recharging to groundwater was 50-60 %. CFC results indicated that the groundwater recharge age varied from 22.5 to 39.5 years. The vertical flow velocity of groundwater was estimated at about 1.8-3.5 m year. Nitrate concentrations in groundwater varied from 9.42 to 156.62 mg L, and exceeded 50 mg L in most aquifers shallower than 80 m bordering the Xiao River. The δN-NO data indicate that the major sources of nitrogen in groundwater are human sewage and animal excreta. Because groundwater is the main source of drinking water, there should be concern about public health related to the elevated nitrate concentrations in the NCP. [ABSTRACT FROM AUTHOR]