River Water Research Articles

Pollution Monitoring via Potentiometric Membrane Sensors for the Determination of Chlorpromazine Hydrochloride in the Presence of Its Main Photo-Degradation Products in River Water

The utilization of membrane sensors for the monitoring and determination of pharmaceutical environmental pollutants has emerged as a crucial objective in recent years. Given the extensive use of chlorpromazine hydrochloride (CPZ) in medicine, its presence in the environment, particularly in surface water such as rivers, is highly probable. Prolonged exposure of river water to sunlight and the photo-degradability of CPZ may enhance its photo-degradation. For the purpose of measuring CPZ in the presence of its primary photo-degradants, two sensitive and selective membrane electrodes were developed. These were synthesized utilizing two ion-pairing agents: sodium tetraphenylborate (TPB) and phosphotungstic acid (PTA). The electrodes exhibited a linear range that extended from 1 × 10−6 M to 1 × 10−2 M. The membrane electrodes of CPZ-TPB and CPZ-PTA exhibited slopes of 59.90 ± 0.60 mV/decade and 58.90 ± 0.80 mV/decade, respectively. The sensors mentioned above showed acceptable performance in a pH range of 2.0 to 6.0. All test parameters were optimized to provide superior electrochemical performance. The fabricated membranes were effectively employed to sensitively quantify CPZ in the presence of its principal photodegradants. The developed sensors were successfully employed to quantify CPZ in river water samples without necessitating pre-treatment procedures.

Plant and soil responses to sediment deposition and nutrient‐enrichment in healthy, deteriorating, and newly created coastal marshes of the Mississippi River Delta

Coastal marshes vulnerable to sea‐level rise may benefit from sediment amendments to increase elevation. However, nutrient‐loading to estuaries may counter elevation gain through reduced root production and/or increased decomposition. Here, we test if belowground plant productivity, root decomposition, and marsh accretion response to nutrient‐loading differs with sediment addition in three marsh types: a healthy intermediate salinity marsh, a deteriorating brackish marsh, and a created marsh in Barataria Basin, Louisiana, United States. In this region, wetland loss is rapid, and a major restoration project is underway to introduce Mississippi River water, sediment, and nutrients to offset marsh loss. Porewater nutrient concentrations, vegetation structure, belowground productivity and decomposition, and accretion rates were measured over 450 days. Experimental nitrate additions yielded high porewater ammonium‐N concentrations in the Deteriorating marsh but had a smaller effect in Healthy and Created marshes. Belowground productivity in the Deteriorating marsh was neutral to negatively affected by nutrient and sediment treatments, whereas positive effects occurred in Healthy and Created marshes. Despite elevation increase from sediment treatments, and substantial effects of nutrient treatments on porewater nutrient concentrations, belowground decomposition and surface accretion rates were not affected by treatments. Sediment deposition increased species richness in the Healthy marsh and added sediment and added nutrients with sediment increased plant height in the Created and Deteriorating marshes, respectively. Over the timescale measured, experimental sedimentation and pulsed nutrient input had few consistent effects on belowground ingrowth, decomposition, or surface accretion. Our findings highlight that response to nutrient pulses are complex and depend on baseline marsh conditions.

Origin of Intercrystalline Brine Formation in the Balun Mahai Basin, Qaidam: Constraints from Geochemistry and H-O-Sr Isotopes

The Balun Mahai Basin (BLMH), located in the northern Qaidam Basin (QB), is endowed with substantial brine resources; however, the genetic mechanisms and potential of these brine resources remain inadequately understood. This study investigated the intercrystalline brine (inter-brine) in BLMH, performing a comprehensive geochemical analysis of elemental compositions and H-O-Sr isotopes. It evaluated the water source, solute origin, evolutionary process, and genetic model associated with this brine. Moreover, a mass balance equation based on the 87Sr/86Sr isotopic ratio was developed to quantitatively evaluate the contributions of Ca-Cl water and river water to the inter-brine in the study area. The results suggest that the hydrochemical type of inter-brine in the north part of BLMH is Cl-SO4-type and in the south part is Ca-Cl-type. The solutes in brine are mainly derived from the dissolution of minerals such as halite, sylvite, and gypsum. The hydrochemical process of brine is controlled by evaporation concentration, water–rock interaction, and ion exchange interaction. Hydrogen and oxygen isotopes suggest that the inter-brine originates from atmospheric precipitation or ice melt water and has experienced intense evaporation concentration and water–rock interaction. The strontium isotopes suggest that the inter-brine was affected by the recharge and mixing of Ca-Cl water and river water, which controlled the spatial distribution and formation of brine hydrochemical types. The analysis of ionic ratios suggest that the inter-brine is derived from salt dissolution and filtration, characterized by poor sealing and short sealing time in the salt-bearing formation. The differences in hydrochemical types and spatial distribution between the north and the south are fundamentally related to the replenishment and mixing of these two sources, which can be summarized as mixed origin model of “dissolution and filtration replenishment + deep replenishment” in BLMH.

Multi-Criteria Analysis for Geospatialization of Potential Areas for Water Reuse in Irrigated Agriculture in Hydrographic Regions

As the climate crisis progresses, droughts and the seasonal availability of fresh water are becoming increasingly common in different regions of the world. One solution to tackle this problem is the reuse of treated wastewater in agriculture. This study was carried out in two significant hydrographic regions located in the southeast of Brazil (Mogi Guaçu River Water Management Unit—UGRHI-09 and Piracicaba River Basin—PRB) that have notable differences in terms of land use and land cover. The aim of this study was to carry out a multi-criteria analysis of a set of environmental attributes in order to classify the areas under study according to their levels of soil suitability and runoff potential. The integrated analysis made it possible to geospatialize prospective regions for reuse, under two specified conditions. In the UGRHI-09, condition 1 corresponds to 3373.24 km2, while condition 2 comprises 286.07 km2, located mainly in the north-western and central-eastern portions of the unit. In the PRB, condition 1 was also more expressive in occupational terms, corresponding to 1447.83 km2; and condition 2 was perceptible in 53.11 km2, predominantly in the central region of the basin. The physical characteristics of the areas studied were decisive in delimiting the areas suitable for the reuse of treated wastewater.

Trace Element Composition of Surface Water in Almaty City and Human Health Risk Assessment

This investigation meticulously examined the elemental composition of 64 water samples collected during the seasons of spring, summer, autumn, and winter of the year 2023. The average seasonal concentrations of arsenic (As), beryllium (Be), cobalt (Co), cadmium (Cd), copper (Cu), lithium (Li), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), uranium (U), mercury (Hg), aluminum (Al), barium (Ba), chromium (Cr), iron (Fe), manganese (Mn), strontium (Sr), vanadium (V), zinc (Zn), calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and chlorine (Cl) as well as SO4 and dry residue were computed at 16 strategically selected sites along the Bolshaya and Malaya Almatinka, Esentai, and Kargalinka rivers situated in Almaty. The sampling locations were categorized into three distinct sectors: upper (adjacent to mountainous regions), middle (urban zone), and lower (exceeding city limits), thereby facilitating the examination of discrepancies in water quality and elemental concentrations. The results reveal that surface water resources in Almaty, particularly concerning As, Ni, Cr, U, and Pb, may present a considerable carcinogenic risk if utilized for consumption purposes. This is especially alarming given that these rivers constitute a vital source of drinking water for the inhabitants of the city. Specifically, at two sampling locations along the Bolshaya and Malaya Almatinka rivers in proximity to significant urban thoroughfares, untreated river water displayed an elevated carcinogenic risk (CR ~ 10−2). These results highlight the urgent necessity for enhanced water treatment and ongoing monitoring to safeguard public health.

Fluorescent “On‐Off‐On” Probe for Cascade Detection of Ag(I) and Ascorbic Acid Using Folic Acid Protected Copper Nanoclusters

AbstractFolic acid (FA) protected copper nanoclusters (FA‐CuNCs, λex=350 nm, λem=445 nm) were synthesized and used as a fluorescent “on‐off‐on” probe for the cascade detection of Ag+ and ascorbic acid (AA). The fluorescence emission of FA‐CuNCs at 445 nm was quenched significantly by Ag+ due to the analyte‐induced aggregation followed by the formation of larger nanoparticles. However, when AA was added to the in‐situ generated Ag@FA‐CuNCs, the fluorescence emission of FA‐CuNCs was recovered at 445 nm because of the AA‐directed reduction of Ag+ to Ag0. The experimental conditions, such as pH, incubation time, and quencher Ag+ concentrations, were optimized to achieve improved sensitivity. The detection limit for Ag+ and AA was estimated as 37.1 nM and 0.27 μM with a linearity range of 2.49–22 μM and 4.71–81.53 μM, respectively. In real sample analysis, the recoveries of Ag+ ions in river water and AA in orange juice samples were found between 99–93 % and 97–94 % using the probes FA‐CuNCs and Ag@FA‐CuNCs, respectively. Overall, this work offers a viable method for the sequential detection of Ag+ and AA using FA‐CuNCs via a fluorescence “on‐off‐on” switch mechanism.

Pyrene Based Schiff Base for Cascade Fluorescent "On-Off" Detection of Aluminium(III) and Fluoride Ions and its Applications in Live Cells Imaging.

An easy-to-prepare pyrene-based Schiff base PNZ was synthesized by condensing equimolar amount of 1-pyrenebutyric hydrazide with 2-hydroxy-naphthaldehyde, and employed as a fluorescent chemosensor for in-situ cascade detection of aluminium (Al3+) and fluoride (F-) ions. In DMSO:H2O (1 : 1, v/v), the weakly emissive PNZ showed a significant fluorescence enhancement at 455 nm selectively upon the addition of Al3+ due to the complexation-induced formation of a pyrene excimer. Schiff base PNZ and Al3+ formed a complex in 2 : 1 binding ratio with the estimated binding constants of K1:1=9826.01 M-1 and K2:1=3188.49 M-1. The sensing mechanism was explored by performing quantum mechanical calculations and 1H-NMR titration of PNZ with Al3+. The in-situ formed PNZ-Al3+ complex species enabled the fluorescent turn-off detection of F-. Using PNZ and PNZ-Al3+, the concentrations of Al3+ and F- ions can be detected down to 2.89×10-7 M and 1.88×10-7 M, respectively. The cytotoxicity of the PNZ and its ability to bioimage Al3+ and F- ions was examined in the human cervical cancer cell line. Finally, the receptor PNZ was applied for the quantification of Al3+ and F- ions in various real samples, such as tap water, river water, rainwater, mouthwash, and toothpaste.

Construction of Mo-Doped CuO Incorporated on Carbon Black Modified Disposable Sensor for the Voltammetric Detection of Metol in Environmental Samples

Abstract In this study, a molybdenum-doped copper oxide (Mo–CuO) composite was synthesized via a hydrothermal method and combined with carbon black (CB) to form Mo–CuO@CB. This composite was used to modify a screen-printed carbon electrode (SPCE) for the detection of Metol (MT), an industrial pollutant harmful to both human health and the environment. Structural and surface characterization was performed using high-resolution transmission electron microscopy, field-effect scanning electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, X-rssy photoelectron spectroscopy, and X-ray diffraction. Electrochemical techniques, including differential pulse voltammetry and cyclic voltammetry, were used to assess the sensor's performance. The Mo–CuO@CB@SPCE sensor exhibited a low detection limit of 2.7 nM, and limit of quantification is 82 nM, a broad linear range (5.0 × 10−9 – 170 mol L-1), and high sensitivity (4.148 μA μM⁻¹ cm⁻²), benefiting from the catalytic activity of Mo–CuO and the large surface area of CB. With recovery rates ranging from 96 % to 100.6% in pond, river, and tap water, the sensor effectively detects MT in environmental samples, ensuring reliable monitoring of this persistent pollutant.

Evaluation the ecological service value of the Yangtze River water systems

Evaluation the ecological service value of the Yangtze River water systems

The pangenome analysis of the environmental source Salmonella enterica highlights a diverse accessory genome and a distinct serotype clustering.

Salmonella remains the leading cause of foodborne infections globally. Environmental reservoirs, particularly aquatic bodies, serve as conduits for the fecal-oral transmission of this pathogen. While the gastrointestinal tract is traditionally considered the primary habitat of Salmonella, mounting evidence suggests the bacterium's capacity for survival in external environments. The application of advanced technological platforms, such as next-generation sequencing (NGS), facilitates a comprehensive analysis of Salmonella's genomic features. This study aims to characterize the genomic composition of Salmonella isolates from river water, contributing to a potential paradigm shift and advancing public health protection. A total of 25 river water samples were collected and processed, followed by microbiological isolation of Salmonella strains, which were then sequenced. Genomic characterization revealed adaptive mechanisms, including gene duplication. Furthermore, an open pangenome, predisposed to incorporating foreign genetic material, was identified. Notably, antibiotic resistance genes were found to be part of the core genome, challenging previous reports that placed them in the accessory genome.

Land-Use Impacts on Soil Erosion: Geochemical Insights from an Urban Drinking Catchment, South-Central Chile

We investigate the influence of land use and land cover (LU/LC) changes on soil erosion and chemical weathering processes within the Nonguén watershed in the Coastal Cordillera of south-central Chile. The watershed is divided into three sub-basins, each characterized by distinct LU/LC patterns: native forest and exotic plantations. A comprehensive geochemical analysis, including trace elements and lithium (Li) isotopes, was conducted on river water and suspended sediment samples collected from streams within these sub-basins to assess how land management practices, particularly plantation activities, influence the geochemical composition of river systems. Our results show that sub-basins dominated by exotic plantations exhibit significantly higher concentrations of major and trace elements in suspended sediments compared to sub-basins dominated by native forests. The elevated trace element concentrations are primarily attributed to increased physical erosion due to forestry activities such as clear-cutting and soil disturbance, which enhance sediment mobilization. Notably, concentrations of elements such as Fe, Al, and As in plantation-dominated sub-basins are raised to ten times higher than in native-dominated sub-basins. In contrast, sub-basins with native forest cover exhibit lower levels of sediment transport and trace element mobilization, suggesting that native vegetation exerts a stabilizing effect that mitigates soil erosion. Despite the substantial differences in sediment transport and element concentrations, Li isotopic data (δ7Li) show minimal fractionation across the different LU/LC types. This indicates that land use changes impact the chemical weathering processes less compared to physical erosion. The isotopic signatures suggest that physical erosion, rather than chemical weathering, is the dominant process influencing trace element distribution in plantation-dominated areas. The study provides critical insights into how forestry practices, specifically the expansion of exotic plantations, accelerate soil degradation and affect the geochemical composition of river systems. The increased sediment loads, and trace element concentrations observed in plantation-dominated sub-basins, raise concerns about the long-term sustainability of forest management practices, particularly regarding their impacts on water quality in urban catchment areas. These results are of significant relevance for environmental management and policy, as they underscore the need for more investigation and sustainable land use strategies to minimize soil erosion and preserve water resources in regions undergoing rapid LU/LC changes.

Impact of Improper Waste Disposal on Surface and Ground Water

Pollution in water occurs when harmful substance (often chemicals or biological) contaminate streams, river, lakes, oceans or other bodies of water, degrading water quality and rendering it unhealthy to humans, animal and the environment. The widespread problem of water pollution is jeopardizing our health. Water pathogens, in form of disease-causing bacteria and viruses from human and animal waste, are a major reason of illness from contaminated drinking water. Owing to the improper treatment facilities, waste is often discharged into the surface and ground water sources. Water bacteria can be limited by recycling used plastic, standard disposal of chemicals, oils or non-biodegradable items and proper collection and transportation of solid waste to a processed disposal site. In addition, waste water should be treated properly to prevent adverse health risk of the user of both surface water and ground water in the aquatic ecosystems.

Bibliometric perspectives in mapping the progress of river water quality index studies

ABSTRACT This paper employs a bibliometric analysis to guide researchers in forecasting the trajectory of research related to the development of the river water quality index. It scrutinizes issues such as variable selection, weight allocation, and the formulation of the function, which are key concerns in the river WQI development. This study also addresses gaps in the existing literature by examining how information about river water quality indices is disseminated, focusing on aspects such as contributing research and prevalent keywords. While bibliometric analysis has been widely applied in various research domains, its use in developing river water quality indices has been comparatively limited. To address this, the current study conducts a bibliometric analysis to identify trends in index creation and to assess the current state of the literature in the field of water quality indices. This examination includes a comprehensive review of papers published in the Scopus database from 1973 to 2024, relevant to the river WQI. Utilizing tools such as R, VOSviewer, and BiblioMagika, the research uncovers patterns in publication among authors and organizations. A finding is that China and India have emerged as leading contributors to publications in this field, indicating their pivotal role in the advancing river water quality index research.

Impact of water physicochemical properties on the survival of Oncomelania hupensis snails, the intermediate host of Schistosoma japonicum.

Schistosoma japonicum, the causative agent of schistosomiasis, heavily relies on its single intermediate host, the Oncomelania hupensis snail, for its life cycle. Controlling these snails effectively plays a pivotal role in curbing the transmission and prevalence of this disease. While prior research has extensively investigated the impact of environmental factors such as temperature and vegetation on snail survival, growth, and reproduction, the contribution of water physicochemical properties has been notably underexplored. This study presents laboratory experiments designed to comprehensively explore the influence of water physicochemical properties on snail survival, offering valuable insights into environmental factors for more precise predictions of snail distribution. We meticulously conducted laboratory snail survival experiments using water from different sources (river water/tap water), and employed a statistical approach amalgamating principal component analysis with Cox regression to preliminarily investigate the effects of different water physicochemical properties on the survival of snails. Our analysis indicates that after a 6-month laboratory snail survival experiment, the survival rate in the tap water group was significantly higher than that in the river water group for infected snails (χ2 = 7.74, p = 0.005), while the difference in survival rates for non-infected snails was not statistically significant (χ2 = 0.61, p = 0.434). The Principal Component-Cox regression analysis revealed that in the infected snail group, total phosphorus, pH value, five-day biochemical oxygen demand, conductivity, and nitrite were protective factors for snail survival, while phosphate and total nitrogen were risk factors. In the non-infected snail group, total phosphorus, pH value, five-day biochemical oxygen demand, conductivity, and nitrite were protective factors for snail survival, and total nitrogen, ammonia nitrogen, phosphate, and nitrate were risk factors. This study underscores the substantial impact of water quality's physicochemical properties on snail survival. The effects of water quality on snails are complex, and maintaining an appropriate level of organic matter content and controlling the pH value at a weak alkalescency level prove beneficial for snail survival. These findings hold significant promise for advancing our understanding of snail-borne diseases and optimizing control strategies.

Environmental Health Risk Assessment in Tabing Banda Gadang Subdistrict, Padang City

Sanitation problems in Indonesia still involve deviant social behavior, namely defecation habits anywhere. According to World Health Organization, around 2.5 billion people worldwide do not have access to proper sanitation facilities. Indonesia itself is ranked second after India, with a high number of people still defecating in the open; this is due to people's habits, which are very difficult to change because they have been inherited. The use of surface water sources, namely river water, with physical water quality that does not meet requirements, the absence of facilities for wastewater disposal, and the absence of household waste management can cause health hazards to the environment. The research aims to know the risky health environment in the sub-district Tabing Banda Gadang, Padang City. Study method This Quantitative nature descriptive analytic with approach Studies Evaluation Risk Health Environment is a participatory study to understand the condition of sanitation and hygiene facilities and community behaviors at the household scale, the results of data processing and analysis that can describe the determination of risk areas from each region to the village/sub-district level. The results of the study found that the risk areas were Water Sources with results of Not enough risk (value 28), Domestic Wastewater with Medium risk (value 68), Medium Risk Waste (value 51), high risk of waterlogging (value 58) and Clean and Healthy Living Behavior is not enough risky (value 32) it can be concluded that the sanitation risk index of Tabing Banda Gadang Village is included in the Current Risk with a value of 237. Tabing Banda Gadang Village is at high risk of waterlogging, so it is recommended that the Village facilitate the construction of drainage by coordinating with the Department of Housing and Public Works to resolve the waterlogging problem.

THE IN-CONTROL PERFORMANCE OF THE ROBUST MULTIVARIATE SYNTHETIC CONTROL CHARTS FOR MONITORING MEAN SHIFT

Multivariate synthetic control chart enables monitoring of multiple process variable simultaneously and hence, negate the inflation of false alarm rates as can be seen in an individual statistical chart. A robust version of the synthetic chart is necessary to mitigate the issue faces by the traditional multivariate synthetic chart, which is unable to produce reliable parameter estimates when Phase I data are contaminated. Therefore, this study proposed three new robust multivariate synthetic control charts (CMRCD, CWS and CWP) which were constructed via minimum regularized covariance determinant (MRCD) and winsorized modified one-step M-estimator (WMOM) for efficient process monitoring. The effectiveness of the proposed robust charts was evaluated in terms of false alarm rates by comparing their in-control performances to the traditional multivariate synthetic chart, Cmean, which is based on the sample mean. Via extensive simulation studies, the findings indicate that the proposed robust control charts outperform the traditional chart regardless of the dimensions or the level of contaminations in the dataset. The real data study further validates that the CMRCD, CWS and CWP perform better than the Cmean. Specifically, the three robust control charts show significant observations, illustrating better capability in monitoring river water quality when compared to the Cmean, i.e., the traditional multivariate synthetic chart.

Assessment of physiochemical parameters of the Tawi River of Jammu and Kashmir, India for drinking and agricultural purposes

ABSTRACT Water is one of the essential components and nature's significant segment that provides substantial support to sustain life. The main aim of this study is to assess the ecological strategy of the Tawi River, Jammu & Kashmir, India for drinking and irrigation purposes. The Tawi River is one of the central lifelines of Jammu city. In this study, physicochemical parameters such as pH, TDS, Ca2+, Mg2+, complete alkalinity, EC, sodium, hardness, potassium, and chlorides are considered to analyze the quality of the Tawi River water. These critical parameters affecting water quality were examined in conformity to IS 10500:2012 that had aligned with the international standards such as EU directives (80/778/EEC), Council directives (98/83/EC), USEPA standard (EPA 816-F-02-013), and WHO guidelines (3rd Edition Vol. 1, 2008). Besides WQI quantification and examination, the quality of water is also segregated through different quality classes for accurate information. It is observed that many significant parameters are beyond the prescribed permissible limits indicating the unsuitability of water for household consumption without proper treatment. On the other hand, examination of parameters such as SAR, MH, KR, PI, and %Na indicates that the quality of the Tawi River water is, however, reasonable for irrigation purposes.

The Central American Seaway: Do Magdalena Flocs Mimic Deep Water Neodymium?

A common assumption for the interpretation of seawater Neodymium isotopes is that the signal is a mixture of distally advected waters. A review of the local paleogeography and bedrock Nd isotopic composition (n = 712) of the largest drainage basins of the Caribbean Sea shows: (a) unradiogenic sedimentary and crystalline sequences in the cratonic-derived eastern Andes; (b) very radiogenic sequences in the western Andes and Panama Isthmus; and (c) intermediate values in between them (Cauca River drainage basin). These local signatures can be matched to the Miocene-Pliocene record of Ocean Drilling Project sites ODP-998, 999, and 1000, dating the arrival of major inter-Andean drainages to the Caribbean Sea. The birth of the Atrato River at 15 Ma, following closure of the Central American Seaway, delivered very radiogenic Nd isotopes to the Caribbean Sea (εNd: +5.5), while arrival of Magdalena River waters at 11 Ma brought very unradiogenic values (εNd << −8). Later excavation of the Cauca River canyon at ∼7 Ma added a moderately radiogenic source (εNd: +1.9), modulating Magdalena River signatures to the Caribbean Sea. Flocculates forming in tropical deltas and estuarine environments carried these signals in hyperpicnal flows to slowly mixing Caribbean bottom waters, mimicking distally advected water.

An Efficient LC–HRMS-Based Approach to Evaluate Pesticide Contamination in Water Bodies with Measurement Uncertainty Considerations

Over recent decades, the global occurrence of pesticide residues in aquatic environments has been a pivotal issue; however, their trace-level concentrations necessitate the establishment of ultra-sensitive and reliable analytical approaches. To this end, the present study describes the optimization and validation of an LC-HRMS-based method for the accurate determination of 18 pesticides in river and sea water, accompanied by a measurement uncertainty estimation. This method was applied to analyze 17 real samples from agriculture and aquaculture-impacted areas in Greece and Albania. Different solid-phase extraction (SPE) protocols were tested. For the analysis, cutting-edge Orbitrap MS technology and MS/MS fragmentation, along with the use of matrix-matched calibration curves, provided unprecedented accuracy (<5 ppm) and sensitivity for the confirmation of positive detections. Regarding method performance, exceptional linearity was obtained; the limits of quantification ranged from 1.7 ng L−1 to 90 ng L−1, recoveries varied from 61% to 96% in river water, while slightly higher recoveries (60–111%) were observed in seawater. In all cases, repeatability and intra-laboratory reproducibility were below 15%. The measurement expanded uncertainty (U′, k = 2) was estimated considering precision and bias. MU% values were lower than 50% in all cases, as recommended in SANTE guidelines and applied to the quantified results. The matrix effect study exhibited negative values (<20%) for all compounds. Application to real samples showed a low pesticide contamination load that should not be underestimated.

Greenhouse gas emissions from urban river waters of China's major cities

Urban rivers are emerging as potent emitters of greenhouse gases (GHGs). However, the magnitude and drivers of GHG emissions from urban rivers are not well understood at a national level. Using a quantitative synthesis of 4633 data records collected from urban river waters of 23 major Chinese cities, this study delved into a systematic analysis of GHG emissions from urban rivers across China. The study showed that GHG emissions in these urban rivers varied spatially and temporally, with the highest carbon emission (CO2 + CH4) from the rivers draining large metropolitan areas and during the summertime. CO2, CH4, and N2O concentrations in the urban river waters ranged from 22.53 to 1052.20 (188.41 ± 223.10) μmolL−1, 0.02 to 21.32 (1.35 ± 1.59) μmolL−1, and 0.01 to 16.81 (0.21 ± 0.72) μmolL−1, respectively, with an average flux of 148.98 ± 245.30 mmolm−2d−1 for CO2, 9.41 ± 25.08 mmolm−2d−1 for CH4, and 0.19 ± 0.65 mmolm−2d−1 for N2O. Urban rivers also received large domestic sewage with high nutrient and carbon loadings due to huge populations, indicating the effect of wastewater treatment plant effluent and urban runoff on GHG production. These findings imply that direct GHG contributions from rivers in urban areas should be accurately quantified and consequently be included in GHG inventories of riverine GHG emissions.