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A total of 114 samples collected from hospital wastewaters and rivers in Addis Ababa, Ethiopia were tested for non-sorbitol fermenting bacteria and coliphages. Sorbitol MacConkey agar is mainly used in the detection of E. coli O157:H7. However, other emerging diarrhoeagenic enteropathogens such as Plesiomonas shigelloides, Edwardsiella tarda, Providencia alcalifaciens, Escherichia albertii, Escherichia vulneris and Escherichia fergusonii were detected in the samples using this medium. Information for most of the emerging enteropathogens is scarce in most countries including Ethiopia. A total of 20 different genera, 38 species of nonsorbitol fermenting bacteria were isolated. Escherichia coli O157 could not be detected from any of the samples. All these backgrounds may mask the detection of Escherichia coli O157. Even if sorbitol MacConkey agar has several background limitations, different emerging diarrhoeagenic non-sorbitol fermenting bacteria were detected in the majority of the rivers and hospitals' wastewaters samples. The correlation between coliphages and non-sorbitol fermenting bacteria were not significant. As several bacteria have been isolated on sorbitol MacConkey agar medium, it is essential that the most selective laboratory techniques will be desired for outbreak investigation of E. coli O157, but other non-sorbitol fermenting enteropathogens should also be detected using sorbitol MacConkey agar in low resources countries. [ABSTRACT FROM AUTHOR]

Copyright of Ecological Applications is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An ongoing hydrogen peroxide pilot project at a Connecticut water treatment facility showed promising benefits beyond disinfection precursor oxidation, such as reduced total organic carbon, lower chemical costs, and improved aesthetics. [ABSTRACT FROM AUTHOR]

This article is underpinned by the hypothesis that if Australia is to reassess and improve its relationship to and use of rivers and river systems, then more holistic ways of understanding rivers, and strategies for representing and communicating this understanding, must be developed and brought together. Held over two days in August 2019 at the Lismore campus of Southern Cross University, 'Speaking With the River' was an interdisciplinary symposium exploring the capacities of creative research practice to develop new understandings of rivers and river systems as simultaneously environmental, cultural, historical and economic phenomena. In this article, we bring together the voices and disciplinary insights from the symposium and the rivers of Northern New South Wales, and we reflect on the way that riverine language ran throughout our discussions and ideas, providing a connective model of confluences and conjunctions for the interdisciplinary enterprise we were engaged in. This article presents perspectives on rivers and river systems from law, history, art and science, exploring common ground and common purposes. Developing a legal framework for recognising the rights and 'voices' of rivers, that is informed by Indigenous knowledges, historical contexts, and scientific understanding, and that employs artistic innovation in representation and translation, is to us the ultimate goal of such an enquiry. While this paper does not undertake the formal steps of developing this framework, it provides the necessary background and instantiates its elements and working methods within the context of the Richmond River in Northern New South Wales. [ABSTRACT FROM AUTHOR]

Two recent works in Ottoman history, Faisal Husain's Rivers of the Sultan and Chris Gratien's The Unsettled Plain have brought environmental themes to the forefront of the field. These works demonstrate the importance of attending to seemingly peripheral areas like the highlands of southern Anatolia and the Tigris-Euphrates basin in Iraq, where in fact central issues of Ottoman imperialism are most visible. In these works, we find the management of diverse ecological zones as a critical feature of how the Ottoman state functioned. By centering the experiences of people, animals, plants, and disease across highlands, waterways, farms, pastures, and marshes, Husain and Gratien have prepared the way for a more inclusive form of historical writing in Ottoman studies. [ABSTRACT FROM AUTHOR]

Eighteenth century river hydraulics used both theory and measurement to address problems of flood safety, navigation and defense related to the rivers. In the late eighteenth century the Dutch overseer of the rivers, Christiaan Brunings, integrated hydraulic theory and meteorological practices, which enabled him to design a unique instrument for measuring river flow. The question is whether the unprecedented detail of measurements fits the putative empirical stance in the eighteenth century. The interactions between theory, instrument, measurement, and other knowledge practices are here assessed using experiences in similar measurement practices. I argue that Brunings had theoretical and embodied understanding of hydrodynamics, as he knew how to design an instrument for flow measurement of sufficient accuracy for his purpose in the sociopolitical context of river management. [ABSTRACT FROM AUTHOR]

For the first time data on parasite diversity of Syngnathidae fishes inhabiting the Black and the Sea of Azov, the rivers flowing into these seas and their estuaries accumulated in more than 30 articles and books during almost one century of investigations were summarized. A high level of parasitic organisms' richness is registered to date: 64 species from 45 genera, 35 families, 14 classes, 10 phyla have been recorded here from eighth species of Syngnathidae fish hosts: Syngnathus abaster Risso, 1827; S. acus L., 1758; S. schmidti Popov, 1927; S. tenuirostis Rathke, 1837; S. typhle L., 1758; S. variegatus Pallas, 1814; Nerophis ophidion (L., 1758); Hippocampus hippocampus (L., 1758). Host-parasite and parasite-host lists are provided, the results for Kinetoplastida, Sporozoa, Microsporidia, Myxozoa, Ciliophora, Platyhelminthes (Monogenea, Trematoda, Cestoda), Nematoda, Acanthocephala, Annelida, and parasitic Arthropoda are presented. Platyhelminthes and Ciliophora (19 and 18 species, respectively) turned out to be the most species-rich taxa of Syngnathidae parasites, while Trematoda was the richest (15 species) class among flatworms. The largest number of parasite species is known from three fish hosts: S. abaster parasite fauna comprises 54 species of 10 phyla (84% of total parasite fauna of this fish family in the region), S. typhle—27 parasite species belonging to six phyla (38%, respectively) and relatively pure parasites fauna in H. guttulatus, 14 species of six phyla (22%). [ABSTRACT FROM AUTHOR]

The quality of surface water has a significant impact on human health and the entire ecological system. Sewer spillages from the surrounding informal settlements discharging into the river, carrying high concentrations of fecal coliforms, are one of the major causes of extreme pollution in the rivers of South Africa. These informal settlements are common in many developing countries, and they are usually located near waterways to compensate for basic demands for water, sanitation, and recreational space, where municipal infrastructure lags behind urban growth. One major problem has been poor sanitation and poor waste disposal practices in the informal settlements, which has led to the contamination of water resources. This study aims to assess the extent to which poor sanitation in informal settlements impacts the water quality of South African rivers, given the rapid rise in population and unemployment rate. The study also highlights health and environmental issues in the local regions caused by poor sanitation. Contamination of water bodies is associated with serious health problems and fatalities. Therefore, there is a need for frequent monitoring and management of waste products discharged into the neighboring aquatic environments. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

End-point evaluation of stream health is essential for the quantification of water quality. To this end, many Multi-Metric Indices (MMIs) have been developed to quantify water quality. The most extensive work has occurred in North America and Europe, while other areas of the world are in development. In this study, we compared the use of relevant physical, chemical and biological parameters in MMIs to various other stream health indicators to assess water quality throughout a three-river corridor along the north central Pacific slope of Costa Rica. Analysis of the data suggested MMIs were the best indicators of water quality and, more specifically, insect MMIs were the most predicative. MMIs were also best at pinpointing anthropomorphic impact throughout the corridor. Further, less complex insect MMIs such as compilations of family diversity using Ephemeroptera, Plecoptera and Trichoptera (EPT) orders were equally as predictive as the more complex models. With a need to better understand and use citizen monitors to predict water quality in these tropical environments, less complex insect MMIs show promise as a solution. [ABSTRACT FROM AUTHOR]

We present a method for interactively authoring and simulating meandering river networks. Starting from a terrain with an initial low-resolution network encoded as a directed graph, we simulate the evolution of the path of the different river channels using a physically-based migration equation augmented with control terms. The curvature-based terms in the equation allow us to reproduce phenomena identified in geomorphology, such as downstream migration of bends. Control terms account for the influence of the landscape topography and user-defined river trajectory constraints. Our model implements abrupt events that shape meandering networks, such as cutoffs forming oxbow lakes and avulsions. We visually show the effectiveness of our method and compare the generated networks quantitatively to river data by analyzing sinuosity and wavelength metrics. Our vector-based model runs at interactive rates, allowing for efficient authoring of large-scale meandering networks. [ABSTRACT FROM AUTHOR]

Over time, the average global temperature has varied greatly, mainly due to natural phenomena. However, several anthropic activities have caused significant changes in the Earth's atmosphere, so that various greenhouse gases, especially CO2, have increased their atmospheric concentration and, consequently, produced an increase in the planet's temperature. These climatic changes, particularly global warming, can affect organisms in continental aquatic environments, including primary producers (e.g., macrophytes). Using photosynthetic parameters calculated from chlorophyll a fluorescence and measurements of chlorophyll a content, we assessed the potential effects of temperature increases predicted by two future scenarios from the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC), Representative Concentration Pathway 4.5 (RCP 4.5) and Representative Concentration Pathway 8.5 (RCP 8.5), on the photosynthetic responses of five aquatic macrophytes from tropical lotic ecosystems. Our results showed a trend of a reduction in the φPSII values associated, as a rule, with an increase in the heat dissipation values in the reaction centers of photosystem II, that is, parameter E. Such reductions in the φPSII associated with increases in parameter E suggest that most likely, even the less severe RCP scenario, RCP 4.5, is already sufficient to negatively and significantly affect the photosynthetic responses of most aquatic macrophytes tested in this experimental study. Considering that macrophytes, alongside macroalgae and periphyton, form the basis of autotrophic food webs in tropical lotic ecosystems, our results suggest that there is a real possibility that the negative effects produced by global warming on these primary producers are propagated, as a "cascade effect", indirectly affecting higher trophic levels as well. [ABSTRACT FROM AUTHOR]

The paper traces the particular moments of historical development of the Bratislava (now the capital of Slovakia) embankment along the Danube River during the 20th century until present. The observed territory is understood as a relatively newly formed terrain that resulted as a by-product of river regulation at the end of the 19th century. The emerged space offered attractive and spacious building plots for various new typologies and rather than a compact city block, these were mostly hosted in the container-like structures. Referencing the theoretical work of De Solà-Morales, the containers are understood as self-standing, large-volume envelopes creating a controlled platform for order and consumption. Research was focused on the study of visual archival materials and contributions in architectural journals of the period. The selected aspects were subsequently displayed in the form of author's schemes, which combine map data with an axonometric representation of the described objects. The paper distinguishes three different periods of embankment development that correspond to the political and economic historical framework and highlights the specific characteristics of each of them. While the interwar era brought the concept of free-standing palaces on the waterfront, the period of socialism was generally characterised by failed ambitious plans. Finally, the period of the neoliberal transformation of the city set the new condition for real estate market and resulted in the construction boom on the waterfront. The long-awaited construction on the waterfront is now in the hands of the private sector, while containers-like residence complexes and shopping malls are ultimately raising the questions about their generic nature. [ABSTRACT FROM AUTHOR]

We show how the dire state of the Earth's rivers entangles intimately with 'thingifying' processes at the heart of colonial modernity. Known in many precolonial and Indigenous contexts as person‐like kin, we describe how rivers the world over have been re‐done primarily as thing—amoral, controllable, a potential commodity like anything else.We develop and work with a provisory concept of kin as those constituents of environments that reciprocally nurture, and contribute to the substance of, one another's life and wellbeing.We show how kinship with rivers figures centrally in primarily Indigenous‐led struggles in various regions of the globe for the recognition and enforcement of river personhood and rights. This is partly because people are motivated to fight passionately for their kin.With some careful caveats, we argue that associating river kinship exclusively with Indigenous worlds undermines its potential for global impact. Thus, as an apposite case study, the latter part of the paper focuses on some of the social–ecological trends which we suggest are opening up the possibility for the re‐establishment of 'riverkinship' in the United Kingdom.We reflect on the potential for riverkinship to help cultivate political constellations fitting to the challenges of the Anthropocene. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Lateral carbon transport through the land-to-ocean-aquatic-continuum (LOAC) represents a key component of the global carbon cycle. This LOAC involves complex processes, many of which are prone to anthropogenic perturbation, yet the influence of natural and human-induced drivers remains poorly constrained. This study examines the radiocarbon (14C) signatures of particulate and dissolved organic carbon (POC, DOC) and dissolved inorganic carbon (DIC) transported by Swiss rivers to assess controls on sources and cycling of carbon within their watersheds. Twenty-one rivers were selected and sampled during high-flow conditions in summer 2021, a year of exceptionally high rainfall. Δ14C values of POC range from −446‰ to −158‰, while corresponding ranges of Δ14C values for DOC and DIC are −377‰ to −43‰ and −301‰ to −40‰, respectively, indicating the prevalence of pre-aged carbon. Region-specific agricultural practices seem to have an influential effect on all three carbon phases in rivers draining the Swiss Plateau. Based on Multivariate Regression Analysis, mean basin elevation correlated negatively with Δ14C values of all three carbon phases. These contrasts between alpine terrain and the lowlands reflect the importance of overriding ecoregional controls on riverine carbon dynamics within Switzerland, despite high spatial variability in catchment properties. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'. [ABSTRACT FROM AUTHOR]

Inland waters are significant, yet highly uncertain, natural sources of nitrous oxide (N2O). Many emission models assume that N2O is only emitted from freshwaters, and that N2O sink behavior is negligible. However, observational studies have reported N2O undersaturation, suggesting that inland waters can act as N2O sinks due to net N2O consumption. This study leverages data from the National Ecological Observatory Network (NEON) and an existing global emission model to examine the prevalence of and controls on N2O undersaturation in streams, rivers, and lakes across scales and biomes. We find that N2O undersaturation is prevalent in the NEON data set (14%–30% of samples) and process‐based model outputs (38%), occurring across biomes and spatial scales. Failing to account for undersaturation in the NEON data set could result in an 100% overestimation of N2O emissions. These results show that consideration of N2O sink behavior is needed for accurate emission estimates. Plain Language Summary: Nitrous oxide (N2O) is a climate‐relevant greenhouse gas that is increasing in the atmosphere due to human activities. It also contributes to stratospheric ozone depletion. Inland waters (e.g., streams, rivers, and lakes) are significant, yet uncertain, sources of N2O to the atmosphere. In general, emission models assume that N2O is produced in and emitted from inland waters. However, field observations have shown that inland waters can also act as sinks of atmospheric N2O, potentially offsetting emissions. Understanding when and where inland waters act as N2O sinks is needed for accurate emission estimates. This study uses a large observational data set and an existing global emission model to explore when, where, and to what extent inland waters act as N2O sinks. The results show that N2O sink behavior is common and may significantly offset emissions. Key Points: Nitrous oxide (N2O) undersaturation in inland waters is prevalent, indicating that inland waters periodically act as sinks of atmospheric N2OPeriodic N2O sink behavior occurs at most monitored sites and the frequency of N2O sink behavior is invariant to ecosystem size or biomeN2O sink behavior has the strong potential to partially offset N2O emissions from inland waters [ABSTRACT FROM AUTHOR]

Although the impact of hydrology on the ecological status of surface water bodies has been highly recognised, the hydrological regime alteration assessment has proven to be a challenging task. In this context, an extensive structured review analysis was used as a research method to investigate the strength and limitations of the hydrological regime alteration assessment methods as adopted by each member of the European Environment Agency and the cooperating countries, according to the Water Framework Directive 2000/60, as well as to propose future directions. The review was also widened to include the methods currently used worldwide in the hydrological alteration studies and the supporting software tools developed. The implementation of a common methodology on a European scale is not applicable, since a single approach would not be able to cope with the regional needs and conditions. The main limitation in almost all the methods developed by European countries and worldwide is the need for a flow time series of high temporal resolution, so as to also capture the systems' extreme high and low flows. Automatic monitoring systems for rivers can provide a solution. Additionally, hydrological modelling may provide the necessary data for the definition of the reference conditions. Nevertheless, the main limitations of the methodologies reviewed and the challenge for future development are the incorporation of the groundwater contribution to the hydrological regime and the development of quantitative relationships between flow alteration and ecological response. [ABSTRACT FROM AUTHOR]

I explore by way of a thought experiment the temporality of waterways in the context of restorative art interventions. As a substance that moves and gives form, and as a medium that retains and discharges, connects and divides, water that flows can make tangible the experiential flow of return and anticipation. Arguably, this bi‐directional structuring of time is pivotal to transformative and reparative action. If restoration means 'going back' to memories of ecologies and places, it does so with a generative thrust forward. This is the life‐enabling orientation of recuperation that I discern connects diverse phenomenological concepts: Deborah Bird Rose's 'multispecies knots of ethical time', the idea of 'afterness' as developed by Gerhard Richter, Gaston Bachelard's 'rhythmic time', and Gerald Vizenor's 'survivance'. I bring these concepts to: (a) artistic water restoration projects that make imaginable, palpable, and real sustainable human‐water relationships, with a focus on the public works in Sydney by Turpin + Crawford Studio; (b) perspectives on water and time that Australian Indigenous thinkers have shared during my ethnographic research; and (c) the re‐naturalization of a river in Germany's postindustrial Ruhr region. I propose that thinking with water ethically and recognizing its temporal diversity opens up perspectives on the deindustrialisation of rivers and other bodies of water. [ABSTRACT FROM AUTHOR]

Stable isotope analyses, specifically δ13C and δ15N, are useful tools increasingly used to understand ecosystem function, food web structures, and consumer diets. Although the iconic tigerfish Hydrocynus vittatus is regarded as an apex predator in southern African freshwater systems, little information is available regarding their feeding behavior and how this may change with growth or differ between ecosystems, with most information stemming from stomach content analyses (SCA). The aim of the present study was to address this lack of information through a baseline study of the diet of large and small tigerfish in various lentic and lotic ecosystems in South Africa using stable isotope methods. Fish and various food web components and food sources were collected from two river and two lake ecosystems in South Africa. The δ13C and δ15N values for all samples were determined and multivariate analyses and Bayesian analytical techniques applied to determine the feeding ecology of H. vittatus and how this may differ with size and habitat type. Analyses revealed a substantial difference in the type and abundance of food sources contributing to the diet of H. vittatus between ecosystems, most prominently between the lotic systems, where less dietary specialization was observed, and lentic systems where more specialization was observed. Furthermore, there was a distinct difference in diet between small and large tigerfish, especially in the lotic system, indicating an ontogenetic diet shift as tigerfish grow and further supporting previous SCA studies. This is the first study of its kind on the African continent for H. vittatus and the findings illustrate the value of stable isotope analysis in providing in‐depth information into the feeding ecology of consumers and how this may differ between size classes and habitat types. [ABSTRACT FROM AUTHOR]

Animals are a critical component of biogeochemical cycles. While animal mediated fluxes of nutrients and energy have received considerable attention, the impacts of these fluxes on microbial community structure and function are comparatively understudied. Here, we investigated if freshwater mussel influences on biogeochemical cycling in stream sediment are accompanied by changes in sediment microbial community composition and ecoenzymatic activity, and if these relationships change under different nutrient regimes.We predicted that mussel effects on ecosystem function are reflected by modified sediment microbial communities. We hypothesized that if changes in either sediment ecoenzymatic function or microbial community composition are driven by mussel‐derived nutrient amendments, we should see muted changes in microbial community assemblages or function when a given nutrient is abundant. However, if microbial communities and function are influenced by other mussel functions, then we should see uniform changes regardless of nutrient availability.We transplanted freshwater mussels and natural river sediment to flow‐through mesocosms and monitored changes in microbial community composition over 1 week. Our results indicate that mussels always changed sediment microbial community composition, but the way communities changed was dependent on ambient nutrient concentrations.On the final day we measured the activity of ecoenzymes known to correlate to microbial function and nutrient availability. Mussels homogenized the stoichiometric ratios of ecoenzyme activities, indicating a consistent function of sediment microbes associated with freshwater mussels. Our results suggest that mussels may promote functional redundancy in sediment microbial communities and highlight the importance of animals in controlling biogeochemical transformations under changing nutrient conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

In this study, six rivers exposed to important agricultural and industrial discharges were selected in Samsun, the region of Mid-Black Sea region. During the wet (February) and dry (July) seasons of 2022, river water samples were taken and analyzes were made using 36 water quality parameters, 19 of which were PTE. In the evaluation of the quality of these surface waters, water quality index, heavy metal indices, human health evaluation indices and multivariate statistical analyzes were used. In some results, Fe (260.9–804.9 µg/L) and Al (392.9–1411.5 µg/L) metals exceeded the limit standard values, while other PTEs remained within the limit standard values. In addition, seasonal significant differences were found in TOC, TP, NO3–N, NH4–N, TSS, phenol, hardness and temperature parameters (p < 0.05). On the other hand, three main components were identified explaining 91.21% of the water quality change with PCA, indicating that the sources of pollution were anthropogenic. As for the WQI values, they were determined to be higher in the wet seasons (29.12–67.26) than in the dry seasons (9.47–31.66). The Kızılırmak River has been exposed to the most intense pollution among the six rivers. In this river, the WQI, HPI and HEI values in the rainy season were 67.26, 21.21 and 18.84, respectively. It was determined that Cd and Pb values did not have any side effects except for the As value in the river where CR is low in adults. However, it was found that the As value (1.3E-04) in the Kızılırmak River is higher than the CR predicted standard limit (> 1.0E-04). [ABSTRACT FROM AUTHOR]

Eutrophication is one of the largest threats to aquatic ecosystems and chlorophyll a measurements are relevant indicators of trophic state and algal abundance. Many studies have modeled chlorophyll a in rivers but model development and testing has largely occurred at individual sites which hampers creating generalized models capable of making broad‐scale predictions. To address this gap, we compiled a large data set of chlorophyll a concentrations matched to other water quality, meteorological, and reach characteristic data for a diverse set of 82 streams and rivers across the United States. We used this data set and extreme gradient boosting, a tree‐based machine learning algorithm, to predict daily chlorophyll a concentrations. Furthermore, we tested several practical considerations of broad‐scale models, such as making predictions at sites not included in model training or the utility of in situ water quality data versus universally available remotely estimated model inputs. Predictions were very strongly correlated to observations when compared against a randomly withheld subset of days; however, the model had lower accuracy when applied to completely novel sites withheld from model training. Turbidity and total nitrogen were the two most important variables for predicting chlorophyll a. Although in situ variables improved modeled estimates and were identified as more important during model interpretation, using only remote inputs still resulted in highly correlated predictions with small bias. Testing a model across many sites allowed for identification of common variables relevant to chlorophyll a and highlighted several challenges for applying data‐driven models to new sites or at larger spatial scales. Plain Language Summary: One of the largest threats to freshwater and marine ecosystems is excess primary productivity stimulated by increased nutrient availability. An overabundance of algae can cause degradation of ecosystems and risks for public health. Chlorophyll a routinely collected as a proxy measure for algal abundance and provides a common currency to compare across aquatic ecosystems. We compiled a data set of chlorophyll a, additional in situ water quality variables, reach characteristics, and broadscale meteorology to model daily chlorophyll concentrations at 82 rivers across the United States. Machine learning was used to predict daily chlorophyll concentrations and several challenges of broad‐scale modeling were investigated, such as extrapolating predictions to new sites or tradeoffs between data quality and quantity. While the model performed well against a withheld set of days for testing, it performed noticeably worse when entire sites were withheld for model testing. Turbidity and total nitrogen were the two most important predictors, and although in situ data resulted in better predictions, estimates solely made from remote data sets have potential for use in widespread predictions. Testing a model across many sites allowed us to identify variables that are commonly relevant to chlorophyll a and highlighted needs for future improvement of broad‐scale models. Key Points: Predicted daily chlorophyll a concentrations across a diverse set of streams and rivers using a decision tree machine learning algorithmModel estimates performed well at sites that contributed some data to model training but not at sites totally withheld from model trainingUsing in situ data for model inputs increased accuracy but ubiquitous remote data sets can provide reasonable estimates at many more places [ABSTRACT FROM AUTHOR]

This paper uses long memory and fractional integration techniques to analyze the presence of time trends in the water temperatures of three large European rivers (the Rhine at Lobith, the Danube at Wienna, the Meuse at Eijsden) and two lakes (Saimaa in Finland, and Võrtsjäry in Estonia). Long memory is a feature frequently observed in hydrological data, and it is important to consider it to appropriately estimate the potential trends in the data. The results indicate the existence of significant positive trends in all the five series examined, possibly as a consequence of global warming. Interestingly, once the time trends are taken into consideration, the degree of persistence substantially decreases in all cases and the long memory property in the data disappears. [ABSTRACT FROM AUTHOR]

The accumulation of trace metals in the shells of bivalves allows quantitative assessments of environmental pollution and helps to reconstruct paleo aquatic environments. However, the understanding on how marine and freshwater mollusks control the level of trace elements in their shells remains very limited. Here, we compared the trace element composition of marine and freshwater bivalves from boreal and subarctic habitats, using examples of widely distributed species of marine (Mytilus edulis, M. trossulus) and freshwater (Anodonta anatina, Unio sp., Beringiana beringiana) mussels. Sizable differences in several trace element concentrations were detected between different species, depending on their environmental niches. A multiparametric statistical treatment of the shell's elemental composition allowed to distinguish the impact of external factors (water and sediment chemical composition) from active metabolic (biological) control. In particular, the obtained results demonstrated that Ba:Ca and Pb:Ca ratios in mussels' shells are closely related to the primary productivity of aquatic ecosystems. The Mn:Ca ratio allowed to constrain the environmental conditions of mussels' species depending on the trophic state of inhabited waterbody. Overall, the marine mussels exhibited stronger biological control of trace element accumulation, whereas trace element pattern in shells of freshwater mussels was chiefly controlled by environmental factors. The obtained results might help to use the trace element composition of bivalves in distinguishing marine and freshwater habitats of mollusks in paleo environments. [ABSTRACT FROM AUTHOR]

River water quality is of utmost importance because the river is not only one of the key water resources but also a natural habitat serving its surrounding environment. In a bid to address whether it has a qualified quality, various analytics are required to be considered, but it is challenging to measure all of them frequently along a river reach. Therefore, estimating water quality index (WQI) incorporating several weighted analytics is a useful approach to assess water quality in rivers. This study explored applications of ten machine learning (ML) models to estimate WQI for the Southern Bug River, which is the second-longest river in Ukraine. The ML methods considered in this study include artificial neural networks (ANNs), Support Vector Regressor (SVR), Extreme Learning Machine, Decision Tree Regressor, random forest, AdaBoost (AB), Gradient Boosting Regressor, XGBoost Regressor (XGBR), Gaussian process (GP), and K-nearest neighbors (KNN). Each data measurement consists of nine analytics (NH4, BOD5, suspended solids, DO, NO3, NO2, SO4, PO4, Cl), while the quantity of data is more than 2700 data points. The results indicated that all ML models demonstrate satisfactory performance in predicting WQI. However, GP outperformed the other models, followed by XGBR, SVR, and KNN. Furthermore, ANN and AB demonstrated relatively weaker performance. Moreover, a reliability assessment conducted on both training and testing datasets also confirmed the results of the comparative analysis. Overall, the results enhance the assertion that ML models can sufficiently predict WQI, thereby enhancing water quality management. [ABSTRACT FROM AUTHOR]

Estimating discharges Q(x, t) from altimetric measurements only, for ungauged rivers (in particular, those with unknown bathymetry b(x)), is an ill-posed inverse problem. We develop here an algorithm to estimate Q(x, t) without prior flow information other than global open datasets. Additionally, the ill-posedness feature of this inverse problem is re-investigated. Inversions based on a Variational Data Assimilation (VDA) approach enable accurate estimation of spatio-temporal variations of the discharge, but with a bias scaling the overall estimate. This key issue, which was already highlighted in our previous studies, is partly solved by considering additional hydrological information (the drainage area, A (k m 2) ) combined with a Machine Learning (ML) technique. Purely data-driven estimations obtained from an Artificial Neural Network (ANN) provide a reasonably good estimation at a large scale ( ≈ 10 3 m). This first estimation is then employed to define the first guess of an iterative VDA algorithm. The latter relies on the Saint-Venant flow model and aims to compute the complete unknowns (discharge Q(x, t), bathymetry b(x), friction coefficient K(x, t)) at a fine scale (approximately 10 2 m). The resulting complete inversion algorithm is called the H2iVDI algorithm for "Hybrid Hierarchical Variational Discharge Inference". Numerical experiments have been analyzed for 29 heterogeneous worldwide river portions. The obtained estimations present an overall bias (less than 30% for rivers with similar characteristics than those used for calibration) smaller than previous results, with accurate spatio-temporal variations of the flow. After a learning period of the observed rivers (e.g. one year), the algorithm provides two complementary estimators: a dynamic flow model enabling estimations at a fine scale and spatio-temporal extrapolations, and a low complexity estimator (based on a dedicated algebraic low Froude flow model). This last estimator provides reasonably accurate estimations (less than 30% for considered rivers) at a large scale from newly acquired WS measurements in real-time, therefore making it a potentially operational algorithm. [ABSTRACT FROM AUTHOR]

In recent decades, water availability, water use, water sharing and freshwater supply for basic human and economic needs have become central scientific and humanitarian issues. With increasing water scarcity in many regions and increasing frequency of extreme flooding in other regions, there is a need to improve predictive capacity, to collect a large amount of information on key hydrological variables such as flows or water stocks in lakes and floodplains and to best combine these data with hydrological and hydrodynamic models. Most of the world's water demand relies on continental surface waters (rivers, lakes, wetlands and artificial reservoirs) while less on underground aquifers and seawater desalination. However, ground-based hydrological survey networks have steadily and drastically decreased worldwide over the last decades. In this context, current remote sensing techniques have been widely used by several countries for water resource monitoring purposes. In this paper, we present such remote sensing techniques, in particular satellite altimetry and imagery, and discuss how they became essential for the study of the water cycle and hydrological phenomena on a broad range of spatial and temporal scales. Large lakes, rivers and wetlands play a major role in the global water cycle and are also markers, integrators and actors of climate change at work on Earth. We show several examples chosen from the literature that perfectly highlight both current scientific and societal issues, as well as the crucial role of space techniques to monitor terrestrial surface waters. [ABSTRACT FROM AUTHOR]

This paper outlines the nature of microplastic contamination in rivers and the risks to freshwater fishes. We discuss how input sources influence the concentration and composition of microplastics and examine factors that subsequently influence their spatiotemporal dynamics in a river system. We then discuss how the distributions and assemblages of microplastics can impact the risk of interactions with fishes, and the processes associated with the internalisation of microplastic into the body and across the organs and tissues. Finally, we examine the physical and toxicological effects of microplastic exposure in fish species, with special attention directed towards impacts at environmentally relevant concentrations. This review integrates expertise in fluvial geomorphological processes and how they influence the movement and storage of microplastics in river channel environments at a range of scales. We combine this knowledge with expertise in fish ecology and biology to set out a new and integrated analysis of microplastic dynamics in rivers and how these microplastics interact with fish. The integration of knowledge from these fields allows us also to comment upon the microplastic risk to fish and other biota in river environments. [ABSTRACT FROM AUTHOR]

Ancient Chinese civilization was deeply rooted in a profound understanding of the environment. This understanding formed the primitive worship and unique culture of mountains and rivers, which found expression in both official and folk contexts. This essay delves into the significant influence of mountains and rivers on the site selection, positioning, and composition of ancient Chinese settlements. Through an in-depth analysis of cases, this study demonstrates that iconic mountain and river elements served as the foundation for determining the spatial locations of ancient Chinese settlements and the core references for designed landscapes. The settlement and surrounding mountains and rivers form a well-conceived integrated spatial composition, which threads the whole planning and construction process. As the determining factors for the spatial axes and forms of settlements, mountains and rivers also became the central objects of the feng shui theory. Therefore, the human geography of ancient China is not only a reflection of functions but also the result of the builders' diligent pursuit of spatial and cultural layouts. The study of the cultural genes allows for a deeper understanding of the cultural landscape of ancient China, leading to a commitment to protecting traditional settlements and their intact environmental systems. [ABSTRACT FROM AUTHOR]

The lens of ontological politics explains the persistence of conflicts between upland ethnic minorities such as Karen peoples and state forest conservation agencies in Thailand. As can be seen with Karen communities in areas managed as national parks, such as the Ngao River basin, the environmental management practices employed by state agencies and ethnic minority communities enact different ontologies of conservation. We argue that shifting the focus of conservation discourse from forests to inland fish could present opportunities for both recognition of and government support for community-based conservation. We demonstrate how state forest conservation agencies foreclose other ontologies, thus precluding community-based conservation. Such ontological dominance, however, is more contested in the case of state agencies with jurisdiction over inland waters. By examining river management and conservation in the Ngao River basin, we consider how these communities make visible the agency of fish and other aquatic life through their knowledges and practices. We argue that Ngao Karen communities have demonstrated that they can account for and conserve aquatic life in inland waters in ways that the Thai state has been unable to do, thus legitimising otherwise marginalised ontologies for 'resource' management and conservation throughout Thailand. Abstract in Thai: rb.gy/j0ify [ABSTRACT FROM AUTHOR]

Late Quaternary fluvial channel deposits are notoriously difficult to date. In the midwestern United States, shells of aquatic mollusks can be found within many fluvial channel sediments and therefore can be radiocarbon (14C) dated to determine the age of the deposits. However, carbonate platform rocks are abundant in this region, potentially causing freshwater 14C reservoir effects (FRE) in mollusk shells. We 14C dated 11 aquatic gastropod and bivalve shell samples from specimens collected live from a stream in southwestern Ohio during three different years to assess the modern 14C reservoir effect. Modern samples yielded an average 14C FREmodern of 518 ± 65 14C yrs for 2020 (n=5), 640 ± 34 14C yrs for 2021 (n=2), and 707 ± 76 14C yrs for 2022 (n=4). We also 14C dated matched pairs of organic wood or charcoal and aquatic mollusk shells from late Pleistocene and Holocene deposits in the Four Mile Creek floodplain to determine the FREfossil. These samples, free of any potential influence from nuclear bomb testing, yielded an overall weighted mean FREfossil of 1029 ± 345 14C yrs. We then assess the advantages and limitations of both the FREmodern and FREfossil methods for determining freshwater reservoir effects. Finally, we apply the FREfossil correction to a series of shell ages from fluvial terrace deposits as a case study. The results indicate that although there is a 14C FRE in streams from the midwestern United States, aquatic shells can provide robust age control on fluvial channel deposits. More research is needed to understand the spatial and temporal variability of FREs, as well as any species effects, among various watersheds across the midwestern United States. [ABSTRACT FROM AUTHOR]

The carbon (C) cycle in inland waters, including carbon concentrations in and carbon dioxide (CO2) emissions from water surfaces, are at the forefront of biogeochemical studies, especially in regions strongly impacted by ongoing climate change. Towards a better understanding of C storage, transport and emission in Central Asian mountain regions, an area of knowledge that has been extremely poorly studied until now, here, we carried out systematic measurements of dissolved C and CO2 emissions in rivers and lakes located along a macrotransect of various natural landscapes in the Sayan–Altai mountain region, from the high mountains of the Western Sayan in the northwest of Tyva to the arid (dry) steppes and semideserts in the intermountain basins in the southeast of Tyva on the border with Mongolia. New data on major hydrochemical parameters and CO2 fluxes (fCO2) gathered by floating chambers and dissolved organic and inorganic carbon (DOC and DIC, respectively) concentrations collected over the four main hydrological seasons allowed us to assess the current C biogeochemical status of these water bodies in order to judge possible future changes under climate warming. We further tested the impact of permafrost, river watershed size, lake area and climate parameters as well as 'internal' biogeochemical drivers (pH, mineralization, organic matter quality and bacterial population) on CO2 concentration and emissions in lakes and rivers of this region and compared them with available data from other subarctic and mountain settings. We found strong environmental control of the CO2 pattern in the studied water bodies, with thermokarst lakes being drastically different from other lakes. In freshwater lakes, pCO2 negatively correlated with O2, whereas the water temperature exerted a positive impact on pCO2 in large rivers. Overall, the large complexity of counteracting external and internal drivers of CO2 exchange between the water surfaces and the atmosphere (CO2-rich underground DIC influx and lateral soil and subsurface water; CO2 production in the water column due to dissolved and particulate OC biodegradation; CO2 uptake by aquatic biota) precluded establishing simple causalities between a single environmental parameter and the fCO2 of rivers and lakes. The season-averaged CO2 emission flux from the rivers of Tyva measured in this study was comparable, with some uncertainty, to the C uptake fluxes from terrestrial ecosystems of the region, which were assessed in other works. [ABSTRACT FROM AUTHOR]

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As natural corridors, urban rivers are often under ecological pressures disturbing their environmental functions, and services over time and space. The landscape services (LS) has been accordingly introduced as an alternative method to evaluate such functions at the landscape scale. In this regard, public perceptions can seriously shape landscape changes, with potentially consistent or inconsistent implications for ecosystem sustainability over time and space. To shed light on this issue, the present study aimed to evaluate the LS of the Mehranrood River running through the city of Tabriz, Iran, from local users' perspective. For this purpose, approximately 365 questionnaires (with the Cronbach's alpha coefficient equal to 0.97) were developed based on the LS indicators and completed by the stakeholders. To analyze the results, structural equation modeling was applied. Afterward, the accuracy of the given model was checked by applying the root-mean-square error of approximation (RMSEA). The results showed that the service provision accounted for the largest number of factors. The cultural services were completely dependent on the presence of production/supply and regulation/maintenance services. The study results demonstrated that, the river had no efficient structures and functions from the stakeholders' perspective. They even believed that the ecological restoration of the Mehranrood River could deliver the potential ability to enhance its LS. Moreover, the respondents were willing to be in close contact with the river if it could be ecologically rehabilitated. Generally, ecological restoration could help boost urban resilience over time through the regeneration of ecological infrastructure, which required a transition from mechanical to ecological thought. [ABSTRACT FROM AUTHOR]

Complementarity is crucial when prioritizing sites for biodiversity conservation. Networks of conservation corridors (CCs) can contribute to regional representativeness by complementing biodiversity features included in existing protected areas (PAs). We ask whether criteria important for CC management and design are effective at prioritizing complementary sites, and how the consideration of species represented in PAs influence criteria performance. We focused on species turnover of generalist and specialist dragonflies across 88 riverine sites. Criteria assessed included site-level estimates of dragonfly species richness, estimates of local habitat quality and corridor width. Measures of local habitat quality were based on either dragonfly indicator species or proportion of alien vegetation. Results showed that CCs complement dragonfly diversity in PAs by contributing unrepresented generalist species. Of the criteria, corridor width was the most efficient at prioritizing complementary sites, while prioritization based on dragonfly indicator species or species richness underperformed. When aiming to prioritize CC sites that also complement sites situated in established PAs, wide corridors with low levels of alien vegetation should be favoured. [ABSTRACT FROM AUTHOR]

Abstract The elevations of water surfaces hold important information on the earth's oceans and land surface waters. Ocean sea surface height is related to the internal change of the ocean's density and mass associated with ocean circulation and its response to climate change. The flow rates of rivers and volume changes of lakes are crucial to freshwater supplies and the hazards of floods and drought resulting from extreme weather and climate events. The Surface Water and Ocean Topography (SWOT) Mission is a new satellite using advanced radar technology to make headway in observing the variability of the elevation of water surfaces globally, providing fundamentally new information previously not available to the study of earth's waters. Here, we provide the first results of SWOT over oceans, rivers, and lakes. We demonstrate the potential of the mission to address science questions in oceanography and hydrology.

Abstract The development of low‐oxygen zones threatening marine life (hypoxia) occurs annually in multiple coastal regions of the world. The largest estuary of the continental United States, the Chesapeake Bay, typically has ≈10 km3 of water with dioxygen concentrations

Microplastics, plastic particles less than 5 mm in length, are a ubiquitous pollutant in the environment, but research on freshwater microplastic contamination is lacking. A possible fate of microplastics in freshwater environments is to become entangled or aggregated in biofilms, which are matrices of algae, bacteria, and micro invertebrates that grow on underwater surfaces, following a progression of settling algae, periphyton, and finally invertebrate colonization. This in-situ study at the Oasis Marina at National Harbor in Oxon Hill, Maryland, examined how the taxonomic assemblages of freshwater biofilms in the Potomac River are associated with the number of microplastics aggregated within them. Aluminum discs, acting as artificial substrate for biofilm growth, were deployed at the water's surface and at 2 m depth to survey biofilm assemblage and were sampled monthly from October 2021–October 2022. Microplastic abundances in the water column were measured every 2 weeks over the same period. Spatial and temporal trends in trapped and suspended microplastics, water quality parameters (temperature, dissolved oxygen, pH, salinity, conductivity, turbidity, ammonia, nitrate, and phosphate), and biofilm assemblages were measured and compared to explore factors affecting the abundance of microplastics and their partitioning between the water column and biofilms. Water quality had no measurable impact on microplastic abundance in the water column at either depth, but temperature was negatively correlated to microplastic abundance in biofilms. As the weather warmed and biofilms progressed to invertebrate settling, they tended to contain fewer microplastics. This may have occurred because less biologically rich biofilms, primarily composed of unicellular algal colonies, provide a favorable surface for microplastic deposition. Understanding seasonal changes in biofilm assemblage and microplastic abundance may help track the fate of microplastics in freshwater systems, particularly in their interactions with lower trophic organisms.

The present research is a scientific documentation of a historical environmental event, which is the invasion of two species of non-native (exotic) aquatic plants for the Tigris River flowing in Mosul city center near Al-Dandan water purification plant. One of them is Azolla filiculoides Lam., a fern belonging to the family Salviniaceae, the other being Hydrilla verticellata (L. f.) Royle, a monocotyledons plant belonging to the family Hydrocharitaceae. The most important morphological characteristics of both species’ vegetative parts enable their identification. Morphological examination of H. verticellata leaf, revealed that it is monoecious biotype like that found in the states of America which are located in the northern latitudes, and not dioecious like the type found in southern latitudes states. It is recommend from the relevant specialists to monitor these two species and study the possibility of their conversion to invasive plants, It is also recommended from them to studying their impacts on the aquatic life of the river. Aim of the present study is to document the invasion of two alien hydrophytes to Tigris river that flow within Mosul city, North of Iraq.

Abstract The detection of river boundaries is a crucial branch of the intelligent perception of unmanned surface vehicles (USVs), it can be used to determine the driving areas of USVs, and also to ensure driving safety by limiting the effective drivable areas of USVs in the river areas. Aiming to detect the boundaries of incompletely structured river channels, this study proposes a real‐time detection method for river boundaries based on a Light Detection and Ranging (LiDAR) sensor. The point clouds that are disturbed by the water surface noise are filtered firstly, and then the spatial and geometric features are extracted separately from the point cloud detected above the water surface. To prevent the error detection and missing detection, the boundary point information is predicted and calibrated in real time by Extended Kalman Filter (EKF). A planning track generation algorithm for coastal autonomous cruise without relying on high‐precision maps, and a heading and distance adaptive control method by Proportional‐Integral‐Derivative (PID), and different driving line generation methods for driving along the narrow river and wide river are proposed respectively. The experimental data verification of river boundary detection shows that the algorithm is accurate, real‐time, and robust.

A total of 114 samples collected from hospital wastewaters and rivers in Addis Ababa, Ethiopia were tested for non-sorbitol fermenting bacteria and coliphages. Sorbitol MacConkey agar is mainly used in the detection of E. coli O157:H7. However, other emerging diarrhoeagenic enteropathogens such as Plesiomonas shigelloides, Edwardsiella tarda, Providencia alcalifaciens, Escherichia albertii, Escherichia vulneris and Escherichia fergusonii were detected in the samples using this medium. Information for most of the emerging enteropathogens is scarce in most countries including Ethiopia. A total of 20 different genera, 38 species of non-sorbitol fermenting bacteria were isolated. Escherichia coli O157 could not be detected from any of the samples. All these backgrounds may mask the detection of Escherichia coli O157. Even if sorbitol MacConkey agar has several background limitations, different emerging diarrhoeagenic non-sorbitol fermenting bacteria were detected in the majority of the rivers and hospitals` wastewaters samples. The correlation between coliphages and non-sorbitol fermenting bacteria were not significant. As several bacteria have been isolated on sorbitol MacConkey agar medium, it is essential that the most selective laboratory techniques will be desired for outbreak investigation of E. coli O157, but other non-sorbitol fermenting enteropathogens should also be detected using sorbitol MacConkey agar in low resources countries.

This article presents a critical review of the way inland navigation is constructed in the archaeological literature as an essential component of mobility in Mesolithic Ireland, with a particular focus on boats and rivers. Against a scarce background of direct archaeological and environmental evidence, a content analysis of the academic discourse highlights a dominant processual approach structured around three themes: seafaring and pioneering “events”; boat technology and performance; broad generalisations about the land- and waterscape. It is argued that such a narrative could be usefully revisited by adopting a small-scale, high-resolution approach that would explore human and material agency and integrate analogy as a method.

The article focuses on R.D. Moore's comment on a forestry and salmonid habitat study, particularly addressing spatial comparisons in stream ecology. Moore highlights limitations in spatial comparisons, challenges in disentangling catchment characteristics from harvesting impacts, and proposes geoclimatic gradients over harvest history as explaining temperature patterns.

Cutting-edge technology for fluvial monitoring has revolutionised the field, enabling more comprehensive data collection, analysis, and interpretation. Traditional monitoring methods were limited in their spatial and temporal resolutions, but advancements in remote sensing, unmanned aerial systems (UASs), and other innovative technologies have significantly enhanced the fluvial monitoring capabilities. UASs equipped with advanced sensors enable detailed and precise fluvial monitoring by capturing high-resolution topographic data, generate accurate digital elevation models, and provide imagery of river channels, banks, and riparian zones. These data enable the identification of erosion and deposition patterns, the quantification of sediment transport, the evaluation of habitat quality, and the monitoring of river flows. The latter allows us to understand the dynamics of rivers during various hydrological events, including floods, droughts, and seasonal variations. This manuscript aims to provide an update on the main research themes and topics in the literature on the use of UASs for river monitoring. The latter is achieved through a bibliometric analysis of the publication trends and identifies the field’s key themes and collaborative networks. The bibliometric analysis shows trends in the number of publications, number of citations, top contributing countries, top publishing journals, top contributing institutions, and top authors. A total of 1085 publications on UAS monitoring in rivers are identified, published between 1999 and 2023, showing a steady annual growth rate of 24.44%. Bibliographic records are exported from the Web of Science (WoS) database using a comprehensive set of keywords. The bibliometric analysis of the raw data obtained from the WoS database is performed using the R software. The results highlight important trends and valuable insights related to the use of UASs in river monitoring, particularly in the last decade. The most frequently used author keywords outline the core themes of UASs monitoring research and highlight the interdisciplinary nature and collaborative efforts within the field. “River”, “topography”, “photogrammetry”, and “Structure-from-Motion” are the core themes of UASs monitoring research. These findings can guide future research and promote new interdisciplinary collaborations.

Water supply is a crucial concern for planners across all countries, especially in rural communities. This paper proposes a multidimensional approach to examining the effective criteria for water supply projects in rural areas of Iran. The study compares alternative methods of project implementation and employs three multi-criteria decision-making (MCDM) methods: analytical hierarchy process (AHP), Fuzzy-AHP, and technique for order preference by similarity to ideal solution (TOPSIS) to prioritize criteria, sub-criteria, and alternatives. The results indicate that, among the five options analyzed, diverting water from the river and constructing temporary storage dams are the highest priorities, while pipeline branching to the nearby city or village is given the lowest priority. The study reveals that environmental and economic criteria are more critical than social-security and technical-management criteria, while negative environmental impacts and the possibility of risk-taking by subversive agents are the most important among the 14 sub-criteria studied. HIGHLIGHTS The most important criteria and sub-criteria in the implementation of rural water supply (RWS) projects are prioritized.; The fuzzy framework and TOPSIS techniques are integrated into the AHP approach to dissect different RWS choices.; The results indicate the great importance of environmental and economic criteria.; Technical-management and social-security criteria play a secondary role.;

Microplastics have become a major environmental concern around the world due to their potential impact on ecosystem functioning and biota. Microplastics enter freshwater systems through a variety of sources, with wastewater treatment work discharges being the most important source. The study aimed to determine the seasonal (i.e., hot–wet, cool–dry) variation in water and sediment microplastic abundances up- and down-stream of wastewater treatment works across two subtropical river systems (i.e., Crocodile and Luvuvhu) in South Africa. Overall, we found that microplastic type and distribution often did not show clear seasonal and site differences in water, hence microplastics were widespread across the studied systems and microplastic concentrations did not relate clearly to wastewater treatment works. This was further indicated by microplastic risk assessments which showed high pollution loads upstream. However, there were significant differences in sediment microplastic loads across seasons, indicating a source-sink effect towards the hot-wet season. The non-metric multidimensional scaling ordination based on microplastic densities for water and sediment discriminated slightly among systems, with major overlaps across the different locations and seasons. As a result, the current research indicates that seasonal context influences differences in microplastic concentrations, with the hot–wet season being associated with the high pollution loads, particularly within the sediments where this was more pronounced indicating the sink-source effect which is linked to sediments and not water. HIGHLIGHTS Fragments were the dominant microplastic group.; Microplastic type and distribution often did not show clear seasonal and site variations.; Microplastic risk assessments indicated high pollution loads upstream.; No clear impacts of wastewater treatment work.; Results useful in informing stakeholders on how to manage plastics and establish programmes.;

Kerala's Idukki district, which is situated on the Western Ghats of India, is susceptible to flooding and landslides. As a result of the 2018 Kerala floods, this disaster-prone region experienced drought conditions. In order to lessen the effects of future disasters, it is also necessary to identify and evaluate the district's groundwater potential (GWP). This work used three machine-learning (ML) algorithms – Random Forest (RF), Adaptive Boosting (AdaBoost), and Gradient Boosting (GB) – to model and produce GWP zonation maps for the Idukki district. Fourteen conditioning factors including elevation, slope, curvature, Topographic Roughness Index, lineament density, soil, geology, geomorphology, Topographic Wetness Index, Sediment Transport Index, drainage density, rainfall, land-use/land-cover (LULC), and Normalised Difference Vegetation Index were adopted as input parameters in the modelling. All showed prominence when they were examined for feature importance using the recursive feature elimination (RFE) method. The RF model outperformed the other two ML models in terms of fit, with an area under curve (AUC) value of 0.92, while the GB and AdaBoost models displayed less fit, with AUC values of 0.90 and 0.88, respectively. GWP maps produced by each model were reclassified into five zones – very high to very low – it was discovered that the zones were evenly spread throughout the Idukki region. HIGHLIGHTS Groundwater potential zones were identified using different machine-learning models such as Random Forest (RF), Adaptive Boosting (AdaBoost), and Gradient Boosting.; Fourteen groundwater conditioning factors were utilised to evaluate the groundwater potential zones.; Findings revealed that among all the machine-learning models Random Forest yields the most accurate results.; Validation was performed using well locations.;