Adjacent River Research Articles

Identification of potential microbial risk factors associated with fecal indicator exceedances at recreational beaches

BackgroundFecal bacterial densities are proxy indicators of beach water quality, and beach posting decisions are made based on Beach Action Value (BAV) exceedances for a beach. However, these traditional beach monitoring methods do not reflect the full extent of microbial water quality changes associated with BAV exceedances at recreational beaches (including harmful cyanobacteria). This proof of concept study evaluates the potential of metagenomics for comprehensively assessing bacterial community changes associated with BAV exceedances compared to non-exceedances for two urban beaches and their adjacent river water sources.ResultsCompared to non-exceedance samples, BAV exceedance samples exhibited higher alpha diversity (diversity within the sample) that could be further differentiated into separate clusters (Beta-diversity). For Beach A, Cyanobacterial sequences (resolved as Microcystis and Pseudanabaena at genus level) were significantly more abundant in BAV non-exceedance samples. qPCR validation supported the Cyanobacterial abundance results from metagenomic analysis and also identified saxitoxin genes in 50% of the non-exceedance samples. Microcystis sp and saxitoxin gene sequences were more abundant on non-exceedance beach days (when fecal indicator data indicated the beach should be open for water recreational purposes). For BAV exceedance days, Fibrobacteres, Pseudomonas, Acinetobacter, and Clostridium sequences were significantly more abundant (and positively correlated with fecal indicator densities) for Beach A. For Beach B, Spirochaetes (resolved as Leptospira on genus level) Burkholderia and Vibrio sequences were significantly more abundant in BAV exceedance samples. Similar bacterial diversity and abundance trends were observed for river water sources compared to their associated beaches. Antibiotic Resistance Genes (ARGs) were also consistently detected at both beaches. However, we did not observe a significant difference or correlation in ARGs abundance between BAV exceedance and non-exceedance samples.ConclusionThis study provides a more comprehensive analysis of bacterial community changes associated with BAV exceedances for recreational freshwater beaches. While there were increases in bacterial diversity and some taxa of potential human health concern associated with increased fecal indicator densities and BAV exceedances (e.g. Pseudomonas), metagenomics analyses also identified other taxa of potential human health concern (e.g. Microcystis) associated with lower fecal indicator densities and BAV non-exceedances days. This study can help develop more targeted beach monitoring strategies and beach-specific risk management approaches.

The occurrence of Antibiotic-Resistant Escherichia coli in the Upper Citarum River and surrounding wastewater effluents

Wastewater has the potential to introduce antibiotic-resistant bacterial contamination into the adjacent river, posing environmental health risks to surrounding community. However, there is limited data on the bacterial resistance pattern in aquatic environments of developing countries. This study aimed to explore the hazard level of Antibiotic-Resistant Escherichia coli from effluents and river water based on the enumeration and resistance pattern towards thirteen antibiotics of varying potency. Escherichia coli enumeration was performed on samples collected from nine segments of the Upper Citarum River, and the effluents of two hospitals, six farms, five pharmaceutical companies, and two municipal treatment plants. Agar dilution on Chromocult® Coliform Agar ES was utilized to profile antibiotic susceptibility. The results show that Escherichia coli from farm wastewater has the highest average number (43.347 CFU/100mL) and the widest range of antibiotic resistance (up to eight type), followed by Escherichia coli from domestic, hospital and pharmaceutical effluent. Meropenem-resistant Escherichia coli is already detected in all effluent sources. Escherichia coli in the river water was resistant to thirteen types of antibiotics, and the load was increasing downstream. It is important to take immediate and effective measures to address bacterial resistance occurrence in the aquatic environments.

ИСТОРИЯ АРХЕОЛОГИЧЕСКОГО ИЗУЧЕНИЯ ГОРОДИЩА ГУНДЕЛЕН-2

The article is about the history of the archaeological examination of the Gundelen-2 site. The monument is situated on a high rocky ledge on the right bank of the Gundelen river, a tributary of the Baksan river, between the settlements of Zayukovo and Kendelen. The fortified hamlet is situ-ated in an important and strategically beneficial location, from which the entire adjacent river val-ley and the entrance to the Baksan canyon are easily seen. The town is located on a rocky ledge that runs north-south and is made of sandstone rocks, with steep cliffs on three sides: the southern, eastern, and western. On the northern side, where there is no natural protection, the settlement is protected by a number of fortifications - two ditches and a pair of ramparts. The size of the set-tlement in the widest place reaches 70 meters, and in length 220 m. The Gundelen-2 settlement is part of an archaeological monument complex that includes the Zayukovo-3 burial site and the Gundelen-2 rock catacomb burial ground (Fig. 1). The complex has been known since the 30s. XX century and has been visited numerous times by researchers over the subsequent decades, but serious study of the monuments did not begin until the 10s. XXI cen-tury.

Influence of inter-river water diversion on estuary pollution control: A case study of Liaodong Bay

Long-term mass transport processes in offshore seas are controlled by seasonal residual currents. The Euler residual mass transport velocity field was calculated form seasonal residual current patterns in shallow sea area, comparing with polluted water changes in typical years. The following conclusions were made: closed local large loops of the Euler residual mass transport led to polluted waters in the northeast Liaodong Bay, and the bay's optimal physical self-purification occurred in winter (Euler residual mass transport diffuses polluted water masses) and spring (overall self-purification capacity of the bay plays a role after winter). The central waters were clean while pollutants were discharged into near-shore waters, leading to perennial pollution in some near-shore waters. Pollution in Liaodong Bay could be alleviated or eliminated via diversion of water from the Daliaohe River (flowing into the northeast corner of Liaodong Bay and carrying > 65% of the total amount of pollutants discharged into the top of the bay) into the Liaohe River and Daling River. The percentage of inorganic nitrogen carried by 10% of the flux of the Daliaohe River was 5.70% of that discharged into Liaodong Bay. If 10% of the flux of the Daliaohe River was discharged into the Daling River, the annual total environmental carrying capacity of inorganic nitrogen increased 4.48%. Many bays in the world have adjacent river flows, such as Gulf of Mexico, Gulf of Guinea, and Bay of Bengal. Based on the Euler residual mass transport field, the water transfer between adjacent rivers could make better use of the Euler residual mass transport capacity to mitigate the water pollution of the estuaries.

Laboratory investigation of the plume-to-plume interaction in a rotating tank

This paper aims to understand the characteristics and dynamical processes of two rotating buoyant fluids (two adjacent river plumes) under ideal geostrophic conditions and further reveal their interaction mechanism. Experimental studies were conducted on a rotating tank, where the discharge (Qup) and density anomaly (g′up) in the upstream inflow were modified to investigate the resultant dynamics over two plumes. Instantaneous velocity fields were measured using the particle image velocimetry to re-construct the 3D plume structure. Based on high-resolution velocity measurements, the upstream coastal current wraps around the downstream bulge and transports further downstream, in association with the downstream coastal current. An alongshore transport equilibrium theory applicable to the plume-to-plume system was proposed to classify the plume alignment types at the laboratory scale. We discover that the increasing Qup or g′up promotes the alongshore transport and inhibits the offshore extension of the downstream bulge. The g′up adjustment decides the alignment types of two interacting plumes, while the Qup adjustment determines the degree of the interaction effect. Coastal currents transform from parallel to vertical alignment as g′up decreases until they become weak coastal currents where the alignment cannot be recognized. The alignment types directly modify the mass and momentum dynamic balance and can further affect the mass exchange between plume water and ambient water. The mechanisms of two interacting plumes provide a comprehensive perspective on the multi-source river plume system in nature, such as adjacent mountainous rivers, delta estuaries, and buoyancy-driven coastal current systems.

Assessment of crAssphage as a human fecal source tracking marker in the lower Great Lakes

CrAssphage or crAss-like phage ranks as the most abundant phage in the human gut and is present in human feces-contaminated environments. Due to its high human specificity and sensitivity, crAssphage is a potentially robust source tracking indicator that can distinguish human fecal contamination from agricultural or wildlife sources. Its suitability in the Great Lakes area, one of the world's most important water systems, has not been well tested. In this study, we tested a qPCR-based quantification method using two crAssphage marker genes (ORF18-mod and CPQ_064) at Toronto recreational beaches along with their adjacent river mouths. Our results showed a 71.4 % (CPQ_064) and 100 % (ORF18-mod) human sensitivity for CPQ_064 and ORF18-mod, and a 100 % human specificity for both marker genes. CrAssphage was present in 57.7 % or 71.2 % of environmental water samples, with concentrations ranging from 1.45 to 5.14 log10 gene copies per 100 mL water. Though concentrations of the two marker genes were strongly correlated, ORF18-mod features a higher human sensitivity and higher positive detection rates in environmental samples. Quantifiable crAssphage was mostly present in samples collected in June and July 2021 associated with higher rainfall. In addition, rivers had more frequent crAssphage presence and higher concentrations than their associated beaches, indicating more frequent and greater human fecal contamination in the rivers. However, crAssphage was more correlated with E. coli and Enterococcus at the beaches than in the rivers, suggesting human fecal sources may be more predominant in driving the increases in E. coli and Enterococcus at the beaches when impacted by river plumes.

Effects of wetland connectivity on overwintering and movement behaviours of Australian freshwater turtles

AbstractFreshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety‐Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re‐entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter.

Fatala River Basin (Republic of Guinea, Africa): Analysis of Current State, Air Pollution, and Anthropogenic Impact Using Geoinformatics Methods and Remote Sensing Data

This study conducts an in-depth analysis of anthropogenic transformation and air pollution within the confines of the Fatala River Basin situated in the Republic of Guinea, Africa. The foundation of this investigation relies upon interdisciplinary geoinformatics methodologies and data acquired through remote sensing, specifically drawing from Sentinel-5P and Sentinel-2 satellite datasets. The primary objectives encompass scrutinizing the extant ecological conditions characterizing the Fatala River Basin and assessing the anthropogenic influences within its geographic expanse. The utilization of remote sensing data, as facilitated by the Sentinel-5P satellite, emerges as a potent instrument for meticulously monitoring environmental transformations. A comprehensive analysis of the designated area, conducted through remote sensing methodologies, is employed to ascertain the concentrations of various atmospheric constituents, including nitrogen dioxide, sulfur dioxide, formaldehyde, methane, ozone, and carbon monoxide. The findings gleaned from this inquiry reveal that, notwithstanding the dynamic growth of the extractive industry centered around the world’s preeminent bauxite province, the Fouta Djallon–Mandingo, the anthropogenic transformation of the Fatala River Basin exerts a comparatively minor influence on air quality. Statistical assessments, including correlation analysis, conducted between computed parameters delineating anthropogenic alterations within the Fatala River Basin, and a comprehensive atmospheric pollution index elucidate a lack of a significant nexus. It has been determined that air pollution within the Fatala River Basin is notably influenced by topographical features and the transport of contaminants from adjacent river basins. Consequently, this article makes a substantial contribution to our comprehension of the contemporary ecological state of the Fatala River Basin in the Republic of Guinea. It also holds significant importance in elucidating the ecological challenges specific to the researched region.

Causes of Morphological and Genetic Heterogeneity of White Fish <i>Coregonus lavaretus</i> sensu lato in the Arctic Part of the Lena River Basin

The results of the morphological and genetic analysis of populations/forms/species of tanned whitefish from the middle and lower reaches of the river are presented. Lena, and adjacent rivers. There are reasons to believe that, despite the significant heterogeneity of whitefish in Siberia, a small number of stable forms/species inhabit the water bodies of the Siberian Arctic. These are East Siberian (C. lavaretus pidschian n. brachymystax), glacial plain (C. lavaretus pidschian n. glacialis), and Yukagir whitefish (C. lavaretus pidschian n. jucagiricus), as well as their hybrid populations. The glacier-plain whitefish and its derivatives differ from the East Siberian whitefish in plastic features, but they are identical in meristic ones. Molecular genetic studies have shown that in most glacier-plain whitefish form extensive loosely connected networks of haplotypes, which corresponds to the long-term existence of populations in favorable conditions. The East Siberian whitefish haplotypes are closely related to the whitefish haplotypes from the water bodies of Southern Siberia and have a radial structure. Such a structure of median networks indicates a recent decline in the number of East Siberian whitefish followed by expansion, which is directly related to the events of the Quaternary glaciations.

Структура рыбного населения бассейна реки Море-Ю (бассейн Хайпудырской губы Баренцева моря)

By the obtained results, the local ichthyofauna includes 17 species of fish from 12 families. Fish population of the More-Yu River basin has 14 fish species and differs significantly in different parts of its middle and lower courses. Nine species have been found in different-type lakes in the More-Yu River basin. Among them, peled is a dominating fish species in the majority of lakes. Also popular are broad whitefish, grayling and pike (recorded in five of six lakes studied). The surveyed lakes and river parts differ by the relative fish density and diversity level. Strange is the absence of ide, roach, and perch in the More-Yu River basin. This situation seems to be related not to the climatic conditions but to the glacial history and the presence of watersheds with adjacent river basins.

Holocene landscape evolution of the Brahmaputra River valley in the upper Assam Basin (India): Deduced from the soil-geomorphic studies

The Brahmaputra River basin exhibits a variety of landforms, including alluvial fans, old and active floodplains, and piedmont belts. The surface expression of the subsurface basement ridge, known as the Brahmaputra Arc, is characterized by paleosol exposures aligned along its crestal region. Using Optically Stimulated Luminescence (OSL) chronology and paleopedological studies, four stages of landform development have been identified in this region, influenced by neotectonics and climate change. The soils in the study area have been categorized into four members of the Quaternary Brahmaputra Morphostratigraphic Sequence (QBMS). QBMS-I (<1.77 ka) represents the youngest soil found in the active floodplains, QBMS-II (2–3.65 ka) includes the Mikri hills piedmont and adjacent river plains, QBMS-III (4–6.5 ka) covers most parts of the study area and is formed on alluvium. The oldest unit QBMS-IV (>7 ka) is exposed on the crest of the Brahmaputra Arc. These soils provide insights into the geomorphologic history of the region, with QBMS-II and III recording multiple avulsions during the Holocene. Micromorphological studies indicate that these soils have undergone multi-phase development under varying redox conditions. The Mid-Miocene compression in the foreland basin led to the formation of the Brahmaputra Arch, and subsequent sedimentation covered the crestal part. Presently, erosion and removal of sediment from the crestal region have exposed older soils as paleosols. Two alluvial fans occur in the study area, the older one located in the central part and the younger one in the northeast corner. The Naga hill piedmonts also exhibit a similar distribution, with the older segment in the central part and younger segments in the northern and southern parts. These patterns of piedmonts and alluvial fans suggest distinct tectonic episodes responsible for sediment redistribution in the study area. The proximity of the Brahmaputra Arc and the Naga thrust in the central part further supports this observation. The findings of this study are consistent with the episodes of neotectonic activity in the nearby Ganga plain, highlighting their regional relevance. Overall, the study provides valuable insights into the evolution of landforms in the Brahmaputra River basin, highlighting the role of neotectonics and climate change in shaping the landscape.

ADDRESSING THE IMPACTS OF TEXTILE INDUSTRIES ON ENVIRONMENT AND SOCIO- ECONOMIC CONDITION OF BANK TOWN AND BARAIGRAM AREA: A MANAGEMENT PERSPECTIVE

Textile industry is a well-established industrial sector in Bangladesh and ranked top in terms of export earnings. Because of its high value addition and huge growth and employment opportunities, textiles a thrust sector of the country. Textile industry of Bangladesh includes yarn and fabric manufacturing, dyeing and printing, making ready-made garment products and exporting them. A huge quantity of solid and liquid wastes is dumped out of the textile industries in Bank Town and Baraigram Area. The toxic effluents and solid waste of the textile industries contaminate soil, air and the water of the adjacent Karnatali river and leads to severe ailments such as eye diseases, skin irritations, kidney failure and gastrointestinal problems. Besides the ETP of these industries are not used properly. The industries in this area are adjacent to the locality. So, the government needs to be conscious about the externalities of the project. Because these unplanned industries could cause severe damages to agricultural land and species of Karnatali River. Not only the adverse environmental impact but also the socio-economic issues such as availability of inputs, skilled workers and markets, provision of adequate accommodation for the workers and standard of living condition. To make it fruitful, environment friendly, long according the detailed feasibility and EIA study of the project. There also needs address the probable risks of the project on the surrounding agricultural lands, river human health, surrounding environment and socio-economic condition of the people After addressing those problems necessary and fruitful initiatives the planning perspectives should have to be taken to make this contemporary policy fruitful for the environment, surrounding areas, people and finally for the economic structure of the country.

Simulation of Water Quality in a River Network with Time-Varying Lateral Inflows and Pollutants

Non-point source pollution inflow is one of the main causes of water quality decline in urban river networks. In this paper, aiming at the problem of non-point source pollutant transport in river network, the lateral outflow term in the Saint-Venant equation is improved from the previous constant to the time-varying flow process, and a mathematical model considering the time-varying source and sink term is established. Based on the initial rainfall intensity, surface confluence and non-point source pollutant concentration, a method for calculating the time-varying lateral pollutant input of nodes and tributaries with linear increase and exponential decay in the initial rainfall period is proposed. Based on the principle of proximity, the watershed is divided into districts. According to the principle of elevation, the non-point source pollutants are allocated to the calculation nodes of adjacent rivers in a certain proportion and incorporated into the model calculation so as to improve the mathematical model of river network water quality and apply it to the simulation of river network water quality in Maozhou River Basin. Verified by the measured data, the NSE values of the improved model are 0.805 and 0.851, respectively, indicating that the model has reliable hydrodynamic and water quality simulation accuracy, indicating that the model can be applied to the calculation of non-point source pollutants in the basin. Based on the improved model, the variation of COD concentration in the Maozhou River of Shenzhen before and after optimized water replenishment was calculated, and the time variation and spatial distribution law of the sudden drop of water quality in the river network caused by the inflow of non-point source pollution in the initial rainfall runoff and the rapid recovery after optimized water replenishment were revealed.

Site suitability analysis of hydrokinetic river energy resources at community microgrids on the Kuskokwim River, Alaska

A simple multiparameter tool for quantifying site suitability for riverine hydrokinetic (HK) energy project development is presented and applied to sites in Alaska. Given the high energy costs and diesel fuel dependence of small islanded microgrid communities and adjacent river energy resources, many communities in Alaska are excellent candidates for early adaptation of HK technologies. Seven isolated communities located along the Kuskokwim River in southwest Alaska are evaluated using this method to determine whether riverine HK projects are likely to succeed. While similar models have been developed for wave and tidal energy, to our knowledge, no such tool exists for riverine HK energy. Factors considered in the analysis include the economic viability, energy demand, distance to power distribution lines, HK resource, presence of environmentally sensitive areas, population, and climate change risk or usteq at each community. Modeling of the technical resource adjacent to each community indicates that HK technology could meet or even exceed the energy requirements of the communities during the ice-free open water season (June to October). Although the communities have similar characteristics, the site suitability varies due to variations in the economic, environmental, and technical constraints among the communities. Based on these factors, the most promising community for a riverine HK installation is Aniak, although the highest resource was observed at Chuathbaluk. The approach is easily adaptable to other regions of Alaska or elsewhere with similar hydrologic and geographic constraints.

Impacts of seasonal variations and wastewater discharge on river quality and associated human health risks: A case of northwest Dhaka, Bangladesh

Surface water pollution caused by the discharge of effluents from industrial estates has become a major concern for Dhaka (Bangladesh). This study aims to have a concise look at the severe river water pollution, mainly from effluents discharged from the tannery village. Effluent samples were collected from five ejected points, including the central effluent treatment plant (CETP), twenty adjacent river water, and two pond water nearby Hemayetpur, Savar. Thirty-one parameters have been observed at these sampling points for three seasons, from April 2021 to January 2022. The results obtained from water quality indices, i.e., water quality index (WQI), entropy water quality index (EWQI), and irrigation water quality index (IWQI), show that most studied surface water samples ranked “unsuitable” for consumption, irrigation, and anthropogenic purposes. The highest health risk was observed downstream of Hemayetpur city at the Savar CETP discharge site, indicating higher levels of heavy metal in the river water following the tannery village. Carcinogenic and non-carcinogenic human health risks could be triggered mainly by water consumption as concentrations of arsenic (As), chromium (Cr), nickel (Ni), and lead (Pb) exceeded the upper benchmark of 1 × 10−4 for adults and children. The results of the carcinogenic risk assessment revealed that children were more vulnerable to health hazards, and quick corrective action is required to control the increased levels of heavy metals at all sample locations. Therefore, through bioaccumulation, human health and the environment are affected in these areas. Using river water for consumption, household work, or even irrigation purposes is not advisable. This study's result highlighted that properly implementing compatible policies and programs is required to improve effluent treatment methods and provide biodegradability to the Dhaleshwari River.

Using fish hard‐part microchemistry and genetics to quantify population impacts of low‐use lock‐and‐dam structures on the Alabama River

AbstractObjectiveWe used two approaches, fish hard‐part microchemistry and genetics, to quantify effects of low‐use lock‐and‐dam structures on riverine fish movement. Each approach varied in temporal scope, with microchemistry addressing effects within a lifetime and genetics addressing effects across generations.MethodsWater samples and individuals of two species (Paddlefish Polyodon spathula and Smallmouth Buffalo Ictiobus bubalus) were collected from four river sections that were separated by three low‐use lock‐and‐dam structures on the Alabama River. Quarterly water samples were collected from 15 sites during 2017–2018, and concentrations of Sr, Ba, Mn, Mg, and Ca were quantified using mass spectrometry.ResultWater elemental signatures were spatially variable but temporally consistent. The Sr:Ca ratios in fish hard parts differed significantly among river sections for both species. Additionally, discriminant function analyses classified fish to their river capture section with accuracy between 55% and 74% for Paddlefish (errors nearly always assigned individuals to adjacent river sections) and 37–47% for Smallmouth Buffalo. Population genetic analyses included fish from each river section, as well as from Alabama River tributaries and a neighboring watershed. Genotyping‐by‐sequence techniques identified 1,889 and 3,737 single nucleotide polymorphisms postfiltering in Paddlefish and Smallmouth Buffalo, respectively, which we used to estimate population diversity indices and conduct differentiation analyses. Analysis of molecular variance, discriminant analysis of principal components, Bayesian clustering, and pairwise comparisons of FST values indicated no strong evidence for genetic divergence in either species among river sections.ConclusionWithin‐lifespan results based on hard‐part microchemistry suggested a potential for population isolation. However, longer‐term genetic effects were not apparent, possibly because the life span of these large and relatively long‐lived species means that few generations have passed since dam construction, and there could be sufficient mixing or population connectivity to prevent genetic divergence across river sections, particularly at the most downstream structure.

Persistent transmission of carbapenem-resistant, hypervirulent Klebsiella pneumoniae between a hospital and urban aquatic environments

The increasing prevalence of infections caused by carbapenem-resistant hypervirulent Klebsiella pneumoniae strains (CR-hvKP) prompts the question of whether these strains also circulate outside of clinical settings. However, the environmental occurrence and dissemination of CR-hvKP are poorly studied. In the current study, we investigated the epidemiological characteristics, and dissemination dynamics of carbapenem-resistant K. pneumoniae (CRKP) isolated from a hospital, an urban wastewater treatment plant (WWTP), and adjacent rivers in Eastern China during one year of monitoring. A total of 101 CRKP were isolated, 54 were determined to be CR-hvKP harboring pLVPK-like virulence plasmids, which were isolated from the hospital (29 out of 51), WWTP (23 out of 46), and rivers (2 out of 4), respectively. The period with lowest detection rate of CR-hvKP in the WWTP, August, corresponded with the lowest detection rate at the hospital. Comparing the inlet and outlet of the WWTP, no significant reduction of the detection of CR-hvKP and relative abundance of carbapenem resistance genes was observed. The detection rate of CR-hvKP and the relative abundance of carbapenemase genes were significantly higher in the WWTP in colder months compared to warmer months. Clonal dissemination of CR-hvKP clones of ST11-KL64 between the hospital and the aquatic environment, as well as the horizontal spread of IncFII-IncR and IncC plasmids carrying carbapenemase genes, was observed. Furthermore, phylogenetic analysis showed that the ST11-KL64 CR-hvKP strain has spread nationally by interregional transmission. These results indicated transmission of CR-hvKP clones between hospital and urban aquatic environments, prompting the need for improved wastewater disinfection and epidemiological models to predict the public health hazard from prevalence data of CR-hvKP.

Hospital and community wastewater as a source of multidrug-resistant ESBL-producing Escherichia coli.

Hospitals and wastewater are recognized hot spots for the selection and dissemination of antibiotic-resistant bacteria to the environment, but the total participation of hospitals in the spread of nosocomial pathogens to municipal wastewater treatment plants (WWTPs) and adjacent rivers had not previously been revealed. We used a combination of culturing and whole-genome sequencing to explore the transmission routes of Escherichia coli from hospitalized patients suffering from urinary tract infections (UTI) via wastewater to the environment. Samples were collected in two periods in three locations (A, B, and C) and cultured on selective antibiotic-enhanced plates. In total, 408 E. coli isolates were obtained from patients with UTI (n=81), raw hospital sewage (n=73), WWTPs inflow (n=96)/outflow (n=106), and river upstream (n=21)/downstream (n=31) of WWTPs. The majority of the isolates produced extended-spectrum beta-lactamase (ESBL), mainly CTX-M-15, and showed multidrug resistance (MDR) profiles. Seven carbapenemase-producing isolates with GES-5 or OXA-244 were obtained in two locations from wastewater and river samples. Isolates were assigned to 74 different sequence types (ST), with the predominance of ST131 (n=80) found in all sources including rivers. Extraintestinal pathogenic lineages frequently found in hospital sewage (ST10, ST38, and ST69) were also found in river water. Despite generally high genetic diversity, phylogenetic analysis of ST10, ST295, and ST744 showed highly related isolates (SNP 0-18) from different sources, providing the evidence for the transmission of resistant strains through WWTPs to surface waters. Results of this study suggest that 1) UTI share a minor participation in hospitals wastewaters; 2) a high diversity of STs and phylogenetic groups in municipal wastewaters derive from the urban influence rather than hospitals; and 3) pathogenic lineages and bacteria with emerging resistance genotypes associated with hospitals spread into surface waters. Our study highlights the contribution of hospital and municipal wastewater to the transmission of ESBL- and carbapenemase-producing E. coli with MDR profiles to the environment.

Natural attenuation and remobilization of arsenic in a small river contaminated by the volcanic eruption of Mount Iou in southern Kyushu Island, Japan

The active volcano Mount Iou, in the southern part of Japan, erupted in 2018 for the first time in approximately 250 years. Geothermal water discharged from Mount Iou had high concentrations of toxic elements, such as arsenic (As), which could seriously contaminate the adjacent river. In this study, we aimed to clarify the natural attenuation of As in the river through daily water sampling for approximately eight months. The risk of As in the sediment was also evaluated using the sequential extraction procedures. The highest As concentration (2000 μg/L) was observed upstream but typically remained below 10 μg/L downstream. Dissolved As was the main form in the river water on non-rainy days. Arsenic concentration in the river naturally decreased through dilution and sorption/coprecipitation with Fe, Mn, and Al (hydr)oxides during flow. However, peaks in As concentration were frequently observed during rainfall events, possibly due to sediment resuspension. Furthermore, the range of pseudo-total As in the sediment was 4.62–14.3 mg/kg. Total As content was highest upstream before decreasing further along the flow. When using the modified Keon method, 44–70% of the total As existed as more reactive fractions associated with (hydr)oxides.

Fluvial‐Aeolian Interaction and Compositional Variability in the River‐Fed Yarlung Tsangpo Dune System (Southern Tibet)

AbstractRiver‐fed dune fields characterized by relatively low quartz content are much more common on Earth than generally assumed, and the aeolian dune field system in the Yarlung Tsangpo (Upper Brahmaputra) river catchment is considered a typical example. As one of the highest‐altitude fluvial‐aeolian systems on Earth, the dune fields in different wide tracts of the Yarlung Tsangpo valley, made of sand entirely blown from the adjacent river bed, provides an excellent natural laboratory in which to investigate the diverse factors controlling textural and compositional changes induced by aeolian processes. To this aim, the textural (grain‐size, roundness) and compositional (petrography, heavy minerals) properties of multiple size classes of fluvial and aeolian sands were quantified. The results show that sediment composition is markedly controlled by grain size, with greater intrasample than intersample variability. Grain‐size controlled compositional differences cannot be exclusively ascribed to hydraulic‐sorting effects. Independent of their density or shape, quartz, sedimentary rock fragments, zircon, apatite, and epidote grains are observed to be on average smaller than feldspars, volcanic rock fragments, and pyroxenes. This indicates that the original size of minerals in source rocks also played a significant role, limiting their availability in finer (e.g., garnet) or coarser (e.g., apatite) classes. In the river‐fed dune system, the lower content of phyllosilicates and higher grain roundness could represent useful criteria to distinguish aeolian from fluvial sand. The efficient aeolian abrasion of river‐fed sediments on the Tibetan Plateau may be an effective mechanism for the production of dust deposited as vast loess covers during the Quaternary.