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Microplastic pollution in the marine environment is of concern, with evidence of harmful effects on marine biota and ecosystems. There is still a knowledge gap of the mass of plastics supplied to the ocean and plastics observed in the ocean, indicating a missing sink. Therefore, baseline and monitoring data are needed to inform policy and regulatory measures. The goal of this study was to collect harmonised data of microplastics from the surface of the ocean using the Neuston Microplastic Catamaran. This study shows that the surface water of the coastal ocean in the North Sea holds/sustains high concentrations of microplastic, which exceed previously recorded measurements from the North-East Atlantic and Scottish Waters, indicating that the total stock of plastics might be much higher than previously determined. Microplastics were detected in all samples with concentrations ranging from 857 to 25,462 items km-2. The majority of microplastics analysed were fragments of polyethylene, polypropylene, and polystyrene in the size range of 1,000-5,000 µm. Mesoplastics (>5,000 µm) mainly in the form of filaments were found with concentrations ranging from 0 to 2,139 items km-2, and macroplastics (>5,000 µm) in the form of fragments and filaments were also found with concentrations ranging from 0 to 1,078 items km-2. These fragments and filaments likely originate from the break-up of common macrolitter items in the environment, such as plastic bags, bottles, and fishing gears, which are commonly comprised of similar polymers to those found in the present study. Our findings demonstrate that litters of all size classes are abundant in surface water, highlighting that it is a key compartment for the transport of marine litter and should be monitored to better our understanding of the fate and danger of plastic contamination in our ocean. [ABSTRACT FROM AUTHOR]

Purpose. Provide an assessment of the quality of the massif of surface waters of the Siverskyi Donets River within the Kharkiv region in 2023 based on the determination of water quality indices. Methods. The methods of the modified water pollution index (WPI) and the combinatorial water pollution index (CWPI). Results. State of the river water at the observation point of the v. Pechenigy according to the method of the modified water pollution index WPIF is estimated as II class characterized as "clean", WPIH - I class, "very clean"; according to the method of the combinatorial index of water pollution CWPIF - class III a, "dirty", CWPIH - class I, "slightly polluted". State of the river water at the observation point of the v. Eschar according to the method of the modified water pollution index of WPIF is estimated as III class characterized as "moderately polluted", WPIH - II class, "clean"; according to the method of the combinatorial index of water pollution CWPIF - class III b, "dirty", CWPIH - class II, "polluted". State of the river water at the observation point of the v/ Zadonetskyi according to the method of the modified index of water pollution, WPIF is estimated as III class characterized as "moderately polluted", WPIH is II class, "clean"; according to the method of the combinatorial index of water pollution CWPIF - class III b, "dirty", CWPIH - class I, "slightly polluted". Conclusions. It was determined that there are changes in water quality along the watercourse of the Siverskyi Donets River within the Kharkiv Region in 2023. There is a deterioration of water quality after the confluence of the Uda River, by 1.69 times the magnitude of the index change, then the state of water quality improves by 1.25 times the magnitude index changes, probably due to self-cleaning processes and lower anthropogenic load. The quality of water according to WPI indicators varies from 0.25 to 1.47 (from "very clean" to "moderately polluted"). The quality of water according to the CWPI indicators varies from 1.0 to 3.83 (from "slightly polluted" to "dirty"). It was established that according to both assessment methods and both standards, the quality of water in the Pechenigy reservoir, p. Pechenegs the best, and the worst water quality in the Siverskyi Donets River below the mouth of the Uda River, village Eschar.

Evaporative water concentration takes place in arid or semi-arid environments when stationary water bodies, such as lakes or ponds, prevalently lose water by evaporation, which prevails over outflow or seepage into aquifers. Absence or near-absence of precipitation and elevated temperatures are important prerequisites for the process, which has the potential to deeply affect the photochemical attenuation of pollutants, including contaminants of emerging concern (CECs). Here we show that water evaporation would enhance the phototransformation of many CECs, especially those undergoing degradation mainly through direct photolysis and triplet-sensitized reactions. In contrast, processes induced by hydroxyl and carbonate radicals would be inhibited. Our model results suggest that the photochemical impact of water evaporation might increase in the future in several regions of the world, with no continent likely being unaffected, due to the effects of local precipitation decrease combined with an increase in temperature that facilitates evaporation. [ABSTRACT FROM AUTHOR]

Relevance. The assessment of the state of natural waters includes the determination of a number of physico-chemical indicators, on the basis of which various indices and classifications are developed. However, they do not take into account a number of pollutants that have a significant impact on the state of the reservoir, for example, polyaromatic hydrocarbons. The article considers some aspects of determining priority pollutants, which include polyaromatic hydrocarbons, according to environmental hazard criteria: toxicity, carcinogenicity, prevalence, frequency of occurrence, source of origin (anthropogenic or natural). Hydrochemical parameters such as pH, dissolved oxygen content, biological oxygen consumption (BPK5), and ion content are taken into account to determine water quality. An attempt was made to assess the impact of polyaromatic hydrocarbons on the ecological state of water bodies and to take into account their contribution to changes in the values of the water pollution index. All these data prove the relevance of the study. Aim. To establish the composition of polyaromatic hydrocarbons in the surface waters of small reservoirs of the Tomsk region to assess anthropogenic load and to show the relationship with the indices of natural water quality. Methods. Extraction, liquid adsorption chromatography, high-performance liquid chromatography, capillary electrophoresis, amperometry, titrimetry. Results. Small lakes of the Tomsk region were studied for the content of 13 polyaromatic hydrocarbons. The authors have carried out the identification by high-performance liquid chromatography with fluorimetric detection. The total content of polyaromatic compounds in the studied surface water samples varies from 0.37 to 0.54 mcg/l. In the polyaromatic hydrocarbons mixture in aqueous samples, there is an increased content of light 2–3 nuclear polyarenes with better solubility (naphthalene, fluorene and phenanthrene), as well as benz[a]anthracene. The content of inorganic components represented by cations and anions does not exceed the maximum permissible concentrations. The water pollution index was calculated; all lakes are moderately polluted, closer to polluted. The paper demonstrates the dependence of the water pollution index coefficient on the content of high-molecular polyaromatic hydrocarbons and the ratio of high-molecular to low-molecular polyaromatic hydrocarbons. It is shown that the higher the value of the water pollution index coefficient, the higher the proportion of difficult-to-oxidize components in surface waters.

Antimicrobial resistance (AMR) is a world-wide public health threat that is projected to lead to 10 million annual deaths globally by 2050. The AMR public health issue has led to the development of action plans to combat AMR, including improved antimicrobial stewardship, development of new antimicrobials, and advanced monitoring. The National Antimicrobial Resistance Monitoring System (NARMS) led by the United States (U.S) Food and Drug Administration along with the U.S. Centers for Disease Control and U.S. Department of Agriculture has monitored antimicrobial resistant bacteria in retail meats, humans, and food animals since the mid 1990's. NARMS is currently exploring an integrated One Health monitoring model recognizing that human, animal, plant, and environmental systems are linked to public health. Since 2020, the U.S. Environmental Protection Agency has led an interagency NARMS environmental working group (EWG) to implement a surface water AMR monitoring program (SWAM) at watershed and national scales. The NARMS EWG divided the development of the environmental monitoring effort into five areas: (i) defining objectives and questions, (ii) designing study/sampling design, (iii) selecting AMR indicators, (iv) establishing analytical methods, and (v) developing data management/analytics/metadata plans. For each of these areas, the consensus among the scientific community and literature was reviewed and carefully considered prior to the development of this environmental monitoring program. The data produced from the SWAM effort will help develop robust surface water monitoring programs with the goal of assessing public health risks associated with AMR pathogens in surface water (e.g., recreational water exposures), provide a comprehensive picture of how resistant strains are related spatially and temporally within a watershed, and help assess how anthropogenic drivers and intervention strategies impact the transmission of AMR within human, animal, and environmental systems. [ABSTRACT FROM AUTHOR]

Great importance is given to maintaining lentic ecosystems, threatened by human-induced consequences worldwide. The present study hypothesized to assess differences in species-environment relationships and ecological status of 15 lakes (saline water systems, high-altitude freshwater lakes, and other freshwater lakes) in the Konya Closed River Basin using phytoplankton indices throughout wet and dry periods. Results of canonical correspondence analysis separated saline and freshwater (high-altitude) habitats, which were characterized by different phytoplankton species. Total phosphorus (TP), electrical conductivity (EC), nickel-Ni, and altitude were the most influential environmental factors affecting phytoplankton dispersal in these ecosystems. Saline lakes were under pressure of high EC, TP, and Ni, while high-altitude freshwater ecosystems were associated with the elevation. Lake Uyuz, associated with TP and Ni, is characterized by Anabaenopsis elenkinii, Cocconeis pediculus, Euglena viridis, Lepocinclis acus, Lepocinclis ovum, and Lepocinclis oxyuris. Several phytoplankton species such as Dunaliella salina, Nitzschia communis, Nitzschia inconspicua, Nitzschia vermicularis, and Navicula cincta were found in saline and saline soda lakes with high EC gradients. Freshwater lakes are characterized by Tabellaria flocculosa, Pinnularia anglica, Fragilaria pararumpens, Eunotia bilunaris, and Pinnularia microstauron. Results of the phytoassessment displayed a high ecological status for Lake Sülüklü but a bad ecological status for Lake Uyuz. The modified phytoplankton trophic index can be an appropriate phytoplankton metric for determining the environmental conditions of lakes in the Konya Closed system. The Søndergaard metric based on total phytoplankton and cyanobacteria biovolume also supported the ecological statuses of lakes. This work underlined the importance of phytoplankton ecological integration in saline water systems and high-altitude freshwater lakes, as well as the determination of the ecological statuses of various lakes in the semiarid eco-region. [ABSTRACT FROM AUTHOR]

This study investigates the prevalence of resistance and virulence genes in Klebsiella isolates from surface waters in Northern Portugal, within the broader context of freshwater quality challenges in Southern Europe. The aim of this research is to explain how Klebsiella dynamics, antibiotic resistance, and biofilm formation interact in surface waters. Antimicrobial susceptibility was examined using the Kirby–Bauer disk diffusion method against 11 antibiotics and screening for Extended-Spectrum Beta-Lactamase (ESBL) production using the double-disk synergy. PCR was employed to detect resistance and virulence genes, while biofilm production was assessed using the microplate method. Out of 77 water isolates, 33 Klebsiella (14 Klebsiella spp. and 19 K. pneumoniae strains) were isolated. ESBL production was observed in 36.8% of K. pneumoniae and 28.6% of Klebsiella spp. High resistance rates to blaCTX-U were observed in both. The papC gene was prevalent, signifying potential environmental risks. Biofilm production averaged 81.3% for K. pneumoniae and 86.9% for Klebsiella spp. These findings underscore the intricate interplay between Klebsiella's dynamics and freshwater quality, with ESBL's prevalence raising concerns about waterborne dissemination and public health implications. This work supports the need for vigilance of Klebsiella in surface waters in Southern Europe. [ABSTRACT FROM AUTHOR]

The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them. [ABSTRACT FROM AUTHOR]

This study was the first attempt to identify the sources of total oxidized nitrogen (TON) and inorganic phosphorus (IP) in the water of the Selenga River—the main tributary of Lake Baikal. To identify TON and IP sources, the data on nutrient concentrations in water of Selenga River and its tributaries as well as the data on river runoff were collected and mapped. On the basis of the obtained data, the values of TON and IP exported from different parts of Selenga watershed were evaluated and mapped using geospatial techniques. In addition, critical source areas (CSAs) which accumulate soil pollutants from nonpoint pollution sources and release them into the surface water during storm events were identified in most polluted watershed areas. It was found that the values of TON exports in most parts of the Selenga watershed varied in the range 0–50 kg/km2/yr, whereas the values of IP exports varied in the range 0–5 kg/km2/yr. Obtained data on TON export were in agreement with those obtained earlier by foreign researchers using global models of nutrient export, whereas data on IP exports were two times higher than those previously modelled. [ABSTRACT FROM AUTHOR]

Microplastic pollution in the marine environment is of concern, with evidence of harmful effects on marine biota and ecosystems. There is still a knowledge gap of the mass of plastics supplied to the ocean and plastics observed in the ocean, indicating a missing sink. Therefore, baseline and monitoring data are needed to inform policy and regulatory measures. The goal of this study was to collect harmonised data of microplastics from the surface of the ocean using the Neuston Microplastic Catamaran. This study shows that the surface water of the coastal ocean in the North Sea holds/sustains high concentrations of microplastic, which exceed previously recorded measurements from the North-East Atlantic and Scottish Waters, indicating that the total stock of plastics might be much higher than previously determined. Microplastics were detected in all samples with concentrations ranging from 857 to 25,462 items km−2. The majority of microplastics analysed were fragments of polyethylene, polypropylene, and polystyrene in the size range of 1,000–5,000 µm. Mesoplastics (>5,000 µm) mainly in the form of filaments were found with concentrations ranging from 0 to 2,139 items km−2, and macroplastics (>5,000 µm) in the form of fragments and filaments were also found with concentrations ranging from 0 to 1,078 items km−2. These fragments and filaments likely originate from the break-up of common macrolitter items in the environment, such as plastic bags, bottles, and fishing gears, which are commonly comprised of similar polymers to those found in the present study. Our findings demonstrate that litters of all size classes are abundant in surface water, highlighting that it is a key compartment for the transport of marine litter and should be monitored to better our understanding of the fate and danger of plastic contamination in our ocean.

Abstract Cholera infection results from the ingestion of water or food contaminated with toxigenic Vibrio cholerae. This study evaluated the occurrence of toxigenic V. cholerae in Asata River, Enugu Metropolis, Nigeria, and estimated V. cholerae infection risks from use of the River water for drinking, domestic and recreational purposes. Vibrio was detected and quantified using membrane filtration technique and thiosulfate–citrate–bile salts–sucrose agar. Isolates were screened by PCR, using specific primers targeting the internal transcribed spacer (its) region between 16 and 23S rRNA and the cholera toxin (ctx) gene. Sequenced 16SrRNA gene amplicons of two selected isolates were used for phylogenetic analysis. Quantitative microbial risk assessment (QMRA) was conducted using the β-Poisson dose–response model. About 81% (58/72) of Asata River samples recorded Vibrio counts above 1.0 $$\times$$ × 103 cfu/100 mL. Of the fifty Vibrio isolates screened, its was detected in 54% (27/50), out of which 74% (20/27) had the ctx gene of toxigenic V. cholerae. Evolutionary relatedness of the sequenced isolates to V. cholerae was revealed. The estimated risks of cholera infection in persons exposed to untreated Asata River water were above 0.5 for all the exposure scenarios, for both the rainy and dry seasons. The risks were highest (~ 0.9) for exposure via drinking water and annual risk of infection was deduced to have a probability of 1.0. Therefore, dependence on the untreated Asata River water for drinking, recreational, domestic and irrigation purposes may present a potential public health risk of cholera outbreak. We recommend increased monitoring and surveillance of River water for Vibrio abundance and that Asata River be protected from further degradation.

Arsenic is ranked as a significant global health hazard associated with potable water. The present study assesses the arsenic pollution of the surface waters in the mountainous regions of the central part of the North Caucasus due to the presence of geochemical anomalies and the potential health risk by its consumption for the residents. The studies were carried out from 2016 to 2022. The surface waters of 5 main rivers of the region (Kuban, Malka, Baksan, Chegem and Cherek) with their main tributaries have been studied. Samples were taken during the period of intensive melting of glaciers (summer). The determination of the soluble form of arsenic was carried out using the method of atomic absorption spectrometry. In general, arsenic concentrations in this region are lower than Clark values for river waters. Along with this, watercourses with high and very high concentrations of arsenic have been identified. Elevated concentrations of arsenic in surface waters spatially coincide with the location of geochemical anomalies. The most polluted is the Baksan River. The levels of surface waters pollution from natural and anthropogenic sources are almost the same (up to 100 µg/dm3). In this regard, an assessment of the health hazard was carried out. For residents receiving drinking water from wells located at the southern foot of Elbrus, the carcinogenic risk for adults was 4.51×10-4, which is unacceptable for the general population. The non–carcinogenic risk was 1.00 - the maximum permissible risk causing concern.

In this study, four tributaries (Başpınar, Gölcük, Sukesen and Yavrucak Creeks) of Mogan lake under anthropogenic pressure and declared as a Special Environmental Protection Area were investigated with the following goals: a) Determination of the variations in potentially toxic element concentrations (Cr, Ni, Cu, Zn, As, Cd, Hg, Pb) in the creek waters between different months (December 2002, February 2023, April 2023), b) Calculation of potentially toxic elements indexes (Heavy Metal Pollution Index-HPI and Heavy Metal Evaluation Index-HEI) in terms of irrigation water quality, based on international and national values, c) Determination of the potential ecological risk (PER) status of the creeks in terms of irrigation water quality, d) Comparison of potentially toxic element concentrations with the environmental quality standard values specified in the current “Turkish Surface Water Quality Regulation”. According to the findings; a) In terms of overall potentially toxic element levels, the creeks are ranked as follows: Başpınar Creek> Sukesen Creek>Gölcük Creek>Yavrucak Creek. The heavy metal As was identified as having the highest contribution to metal pollution and the potentially toxic element concentrations in all creeks in February and April were found to be higher compared to that in December, b) The HPI value was found to be less than 15 for all months and creeks, with the highest HPI value of 13.21 calculated in Başpınar Creek in February, c) The HEI values were found to be less than 10 (ranging from 0.02 to 0.84), indicating a low level of potentially toxic element pollution according to this index, d) In terms of irrigation water quality, all creeks exhibited a low level of PER, with the highest PER value of 13.54 belonging to Başpınar Creek, e) The detected potentially toxic element concentrations in all four creeks did not exceed the maximum EQS values provided. In this context, it has been determined that the potentially toxic element levels in creek waters, due to anthropogenic activities, are not currently causing significant pollution. However, it is noted that Başpınar Creek is at a higher risk compared to other creeks. Furthermore, because of the ongoing anthropogenic activities in the basin, long-term metal monitoring studies are important in terms of the sustainability of Lake Mogan.

ABSTRACTThe Yertis (Irtysh) river is the largest left tributary of the Ob. The river is 4.248 km long and flows through the territories of three countries: China (618 km), Kazakhstan (1.589 km), and Russia (2.041 km). The purpose of this study is to analyze the concentrations of Hg, Cd, Pb, Cu, Zn in the surface waters of the transboundary river Yertis in comparison with the clarkes of elements in the hydrosphere, their spatial distribution, and change over time. The survey was conducted at six observation points within the Republic of Kazakhstan: Boran village, Ust-Kamenogorsk city, Predgornoe village, Semey city, Aksu city, Pavlodar city. The analysis of available information has allowed obtaining heavy metals distribution in space and change in time. The increased content of Hg, Cd, Zn was determined in the surface waters of the Yertis river in relation to clarkes of the hydrosphere. At the same time, a decreased content of Pb and Cu was found. The highest values of clarke concentration of elements were Cd (7), Hg (2.6), and Zn (1.7). Consequently, heavy metals have the greatest interest because their high levels in water have toxic effects on hydrobiont and benthic communities and on human health, who use these waters for household purposes.

Cholera infection results from the ingestion of water or food contaminated with toxigenic Vibrio cholerae. This study evaluated the occurrence of toxigenic V. cholerae in Asata River, Enugu Metropolis, Nigeria, and estimated V. cholerae infection risks from use of the River water for drinking, domestic and recreational purposes. Vibrio was detected and quantified using membrane filtration technique and thiosulfate–citrate–bile salts–sucrose agar. Isolates were screened by PCR, using specific primers targeting the internal transcribed spacer (its) region between 16 and 23S rRNA and the cholera toxin (ctx) gene. Sequenced 16SrRNA gene amplicons of two selected isolates were used for phylogenetic analysis. Quantitative microbial risk assessment (QMRA) was conducted using the β-Poisson dose–response model. About 81% (58/72) of Asata River samples recorded Vibrio counts above 1.0 × 103 cfu/100 mL. Of the fifty Vibrio isolates screened, its was detected in 54% (27/50), out of which 74% (20/27) had the ctx gene of toxigenic V. cholerae. Evolutionary relatedness of the sequenced isolates to V. cholerae was revealed. The estimated risks of cholera infection in persons exposed to untreated Asata River water were above 0.5 for all the exposure scenarios, for both the rainy and dry seasons. The risks were highest (~ 0.9) for exposure via drinking water and annual risk of infection was deduced to have a probability of 1.0. Therefore, dependence on the untreated Asata River water for drinking, recreational, domestic and irrigation purposes may present a potential public health risk of cholera outbreak. We recommend increased monitoring and surveillance of River water for Vibrio abundance and that Asata River be protected from further degradation. [ABSTRACT FROM AUTHOR]

A new ionic liquid modified polymer gel containing methylimidazolium groups (poly(MIA)) is proposed as a sorbent for the separation and enrichment of trace inorganic and organic arsenic species in surface waters. The poly(MIA) was synthesized by chemical modification of polymeric precursor using post-polymerization modification of poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate). The composition, structure, morphology, and surface properties of the prepared particles were characterized using elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption–desorption measurements. Optimization experiments showed that at pH 8, monomethylarsonic acid (MMAs), dimethylarsinic acid (DMAs), and As(V) were completely retained on the poly(MIA), while the sorption of As(III) was insignificant. The desorption experiments revealed that due to the weaker binding of organic arsenic species, selective elution with 1 mol/L acetic acid for MMAs + DMAs, followed by elution with 2 mol/L hydrochloric acid for As(V), ensured their quantitative separation. The adsorption kinetic and mechanism were defined. The analytical procedure for As(III), As(V), MMAs, and DMAs determination in surface waters was developed and validated through the analysis of certified reference material. [ABSTRACT FROM AUTHOR]

Based on the generalization of the results of regime observations by environmental monitoring services, an analysis of the dynamics of the ecological state of watercourses in the sub-basin of the Syan River (at six observation points) has been carried out. The dynamics of water use in the Syan River sub-basin for 2021–2022 were analyzed, according to which the total discharge in the Syan sub-basin in 2022 decreased by a quarter. The discharge of polluted wastewater in 2022 was a third higher, accordingly, the discharged volume of treated sewage was also lower than in 2021. An analysis of potentially possible sources of pollution of water bodies in the Syan River sub-basin has been carried out. The most significant impact on the water quality change here is caused by the wastewater discharges of municipal enterprises: the municipal enterprises “Novoyavorivskvodokanal” and “Yavorivvodokanal”. A significant cause of surface water pollution is the discharge of wastewater by the private sector. The Yavoriv quarry “Sіrka” causes the ingress of sulfates into the Shklo River, a significant trend towards their reduction has been observed from 2020 to 2022 by 71.9 %. In Lviv region, agriculture accounts for about 11%, which also negatively affects the state of water bodies. According to the results of monitoring of surface waters within the Ukrainian part of the Vistula River basin, presented by the Basin Water Resources Management of the Western Bug and Syan Rivers for 2021–2022, a high total content of pesticides was observed in 2022, in particular, at the observation point of the Vishnya River in Mostyska – about 5.5 µg/dm3 . Also, a high content of manganese, zinc and iron was recorded here. The analysis of monitoring observations of the state of water bodies in the Syan River sub-basin and the calculated water pollution coefficients based on them show that the cleanest water in this area is the water of the Vyar River (the highest Pollution Index in 2021 – 1.463) and the water of the Zavadivka River (the highest Pollution Index in 2021 – 1.218). The most polluted water was the water of the Vishnya River at the observation point in Mostyska, especially due to the high content of iron (7.6 MPC) and manganese (30 MPC), where the pollution coefficient in 2020 was 4.761, and in 2022, it decreased by half. Also, the water of the Shklo River in urbantype settlement Krakivets was quite polluted, where the pollution coefficient in 2022 was 2.057. The BOD5 value was highest in 2021 in the Shklo River – 3.5 MPC and in the Vishnya River in Chernove village – 2.9 MPC, however, in 2022, it decreased to 1.8 MPC across the study area. The COD value in 2021 in all investigated observation points was above the norm, the highest in the Vishnya River, in Chernove village – 2.3 MPC, in 2022, it significantly decreased across the study area, the highest was in the Shklo River in urban-type settlement Krakivets – 1.6 MPC. A high content of ammonium salts and nitrites was recorded in 2022, respectively: in the Shklo River – 3.8 MPC and 2.7 MPC; in the Vishnya River in Chernove village – 2.5 MPC and 3.2 MPC. The phosphate content was highest in 2022 in the Vishnya River in Chernove village (2.6 MPC), however, in 2021 and 2022, it was below the permissible level across the study water area. In all observation points of the Syan River sub-basin, a significant zinc content was observed in the water, the highest was in 2020 in the Vyаr River in Pidmostychi village (5.2 MPC) and in 2022 in the Shklo River in urban-type settlement Krakivets – 4.7 MPC. A high content of sulfates was observed in the Shklo river, especially in 2020 (4.4 MPC), which may be the cause of the influence of the Yavorivsky “Sirka” quarry. Regarding the assessment of water quality in the Syan River sub-basin by pollution levels, in all observation points during the analyzed period, the water is mainly characterized as “slightly polluted”, only at the observation point of the Vishnya River in Mostyska in 2020 and 2021 – “moderately polluted”, in the Zavadivka River, Grushiv village in 2020 the water was “slightly polluted; bordering on clean”. [ABSTRACT FROM AUTHOR]

The current level and origin of hydrocarbons (HCs): aliphatic (AHCs) and polycyclic aromatic (PAHs) were determined (September 2021 and May and September 2022) in suspended particulate matters (SPM) of surface waters (for AHCs, 20 µg/l; for PAHs, 130 ng/l, fluorescent method) and in bottom sediments of the coastal areas of the Caucasian sector of the Black Sea of the Russian Federation. Despite a decrease in the HC concentrations in the surface waters in recent years, the most polluted areas include, as before, Kerch Strait. HC accumulate in the bottom sediments, which leads to an increase in their content in the composition of Corg (for AHCs, up to 14.2% in the Tuapse region and 13.1% in the Novorossiisk region). It has been established that, along with pollution, the HC levels are greatly influenced by natural processes (the productivity of the area and fluid flows from the sedimentary formation). [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a world-wide public health threat that is projected to lead to 10 million annual deaths globally by 2050. The AMR public health issue has led to the development of action plans to combat AMR, including improved antimicrobial stewardship, development of new antimicrobials, and advanced monitoring. The National Antimicrobial Resistance Monitoring System (NARMS) led by the United States (U.S) Food and Drug Administration along with the U.S. Centers for Disease Control and U.S. Department of Agriculture has monitored antimicrobial resistant bacteria in retail meats, humans, and food animals since the mid 1990’s. NARMS is currently exploring an integrated One Health monitoring model recognizing that human, animal, plant, and environmental systems are linked to public health. Since 2020, the U.S. Environmental Protection Agency has led an interagency NARMS environmental working group (EWG) to implement a surface water AMR monitoring program (SWAM) at watershed and national scales. The NARMS EWG divided the development of the environmental monitoring effort into five areas: (i) defining objectives and questions, (ii) designing study/sampling design, (iii) selecting AMR indicators, (iv) establishing analytical methods, and (v) developing data management/analytics/metadata plans. For each of these areas, the consensus among the scientific community and literature was reviewed and carefully considered prior to the development of this environmental monitoring program. The data produced from the SWAM effort will help develop robust surface water monitoring programs with the goal of assessing public health risks associated with AMR pathogens in surface water (e.g., recreational water exposures), provide a comprehensive picture of how resistant strains are related spatially and temporally within a watershed, and help assess how anthropogenic drivers and intervention strategies impact the transmission of AMR within human, animal, and environmental systems.

Evaporative water concentration takes place in arid or semi-arid environments when stationary water bodies, such as lakes or ponds, prevalently lose water by evaporation, which prevails over outflow or seepage into aquifers. Absence or near-absence of precipitation and elevated temperatures are important prerequisites for the process, which has the potential to deeply affect the photochemical attenuation of pollutants, including contaminants of emerging concern (CECs). Here we show that water evaporation would enhance the phototransformation of many CECs, especially those undergoing degradation mainly through direct photolysis and triplet-sensitized reactions. In contrast, processes induced by hydroxyl and carbonate radicals would be inhibited. Our model results suggest that the photochemical impact of water evaporation might increase in the future in several regions of the world, with no continent likely being unaffected, due to the effects of local precipitation decrease combined with an increase in temperature that facilitates evaporation.

This study aims to present an overview of incorporating the Water Framework Directive into Italian law through Law 152/06. Subsequently, it will focus on a case study involving 34 rivers in the Salerno Province, utilizing data obtained from ARPA Campania. This work analyses the macro pollution indicators of the observed rivers using two aggregated indexes, namely PLM and PLMeco. These indexes were introduced by Italian legislation in 1999 and 2006, respectively. The results show the quality of the river and the variations observed over the years in the Province of Salerno, utilizing non-parametric tests.

This work aims to understand the distribution and migration mechanisms of U and Mo between surface sediment and water in acid mine drainage (AMD) regions near a molybdenum mining region. A series of river sediment and water samples near the Jinduicheng mining area, one of the largest deposits of molybdenite ore in Asia, were collected and analyzed. Our results indicate that: (1) The pH value of river water samples increases with distance from upstream to downstream, while the pH has poor correlation with Mo and U; (2) The content of Mo and U in the sediment are significantly higher than the background value, which suggests potential pollution; (3) The content of Mo and U in the water and sediments in the lower reaches of the Wenyu river is significantly linearly related with the distance from the mining area, suggesting that AMD is a potential source; (4) BCR analysis shows that Mo in river sediments mainly existed as the residual, while U mainly existed as the non-residual; (5) The distribution coefficient Kd(Mo) exceeds Kd(U), indicating that Mo is enriched in sediments while U is more prone to porewater. [ABSTRACT FROM AUTHOR]

Lake Baikal was studied as a model for elucidating the general pattern of o-phthalic acid diester (PAE) distributions in surface waters with background pollution levels. The influence of factors including congeners, concentrations, sampling points, seasons, years, and potential sources was considered and the environmental risk for various hydrobionts was established. Priority PAEs in Baikal waters are represented by dimethyl phthalate (DMP), diethyl phthalates (DEP), di-n-butyl phthalate (DnBP) and di-(2-ethylhexyl)phthalate (DEHP). Statistically valuable average concentrations and ranges for DMP, DEP, DnBP, and DEHP were 0.02 (0.01–0.02), 0.07 (0.06–0.09), 0.55 (0.47–0.66), and 0.30 (0.26–0.34) µg/L, respectively. The main factors determining PAE concentrations were the year and season of sampling, whereas sampling points were not among the factors influencing PAE levels. The distribution of PAEs in the water body was characterized by (i) an even distribution of minor hydrophilic DMP and DEP congeners in the whole water body, (ii) a maximum concentration of hydrophobic DnBP and DEHP congeners in the upper and near-bottom layers of the water column, and (iii) a low concentration of hydrophobic congeners in the near-shore area. The main PAE source was found to be the atmospheric transfer of polluted air masses, while the supply of PAEs from coastal sources to the pelagic zone was low. The contribution of biogenic sources to the background level of PAEs in the surface waters of Lake Baikal was established. The ecological risk of the background concentration level of PAEs for Lake Baikal biota was estimated. It was found that (i) DMP and DEP congeners do not represent a risk, or represent a very low risk, (ii) the concentration levels of dominant DnBP and DEHP congeners represent a low risk for crustaceans and fishes but (iii) a rather high risk for algae at a DEHP concentration of 0.30 µg/L. [ABSTRACT FROM AUTHOR]

The study of pollution and risk assessment of surface water in watersheds is important for the use and management of surface water, as well as for the stability of ecosystems and human health. This study focused on a typical watershed in an arid zone, the Urumqi River basin; divided the basin into upper, middle, and lower reaches according to the main uses of the surface water in the region; and collected surface water samples from the basin. We collected 41 surface water samples from the upper, middle, and lower reaches of the Urumqi River Basin, a typical arid zone watershed. The characteristics and spatial distribution of metal elements in the surface waters of the basin were analysed, the pollution status was evaluated, and risk assessments of the effects of these metal elements on natural ecosystems and human health were carried out. The results showed that (1) the average concentration of the metal element Al in the surface water of the Urumqi River Basin was 663.73 µg·L−1, which was 3.3 times that of the standard limit value (200 µg·L−1), with an exceedance rate of 100%, and the standard deviation value was 136.05 µg·L−1, with a large difference in spatial distribution. Spatial distributions for Al, Cu, Cr, Fe, Mn, and Zn were higher upriver and midstream than downriver, and for Pb and As, they were higher upriver, midstream, and downriver than downriver. (2) The values of the single-factor pollution index of the metal elements Zn, As, Pb, Mn, Cr, and Cu in the upper, middle, and lower reaches of the watershed were all less than 1, which is within the safe range. The integrated pollution indexes of 0.03~0.27 were all less than 0.7, which is within the safe range, and the integrated pollution of the upper reaches was significantly greater than that of the middle and lower reaches. (3) The total ecological risk of the basin ranged from 0.09 to 13.72, which is much lower than the low-risk indicator value of 150, and the ecological risk of the upper reaches was higher than that of the middle and lower reaches. (4) The health risk assessment showed that the total health risks of the eight metal elements to adults and children showed an upstream > downstream > midstream pattern, all of which exceeded the ICRP recommended value (10−5). The average annual total health risks of the carcinogenic metal elements chromium and arsenic to adults and children were 10−6 and 10−5 a−1, respectively, with arsenic concentrations exceeding the ICRP recommended value (10−5). Arsenic and lead in the surface waters of the Urumqi River Basin are important indicators of health risk and need to be prioritised as indicators for environmental risk management. [ABSTRACT FROM AUTHOR]

The work contains generalized approaches and features of anthropogenic load on the basins of small rivers within Lutsk town. The reasons for the deterioration of quality of the surface water in Lutsk are considered. The assessment of the level of anthropogenic load on river basins in the city of Lutsk was carried out. A number of practical actions are presented that could stop anthropogenic processes and improve the use of small rivers.

This paper is devoted to the study of the chemical and biological properties of river waters and the relationship between them. We examined the hydrochemical and bacterial properties of surface water in 3 waterbodies: the Mezha River, a pond in Zapovedny village (Central Forest Nature Reserve, Tver Oblast) and the lower reaches of the Don River (Rostov Oblast). The biodiversity of bacteria was determined based on their growth on dissolved organic matter (DOM). Among bacterioplankton capable of growing on DOM as the only source of carbon, the predominant species in the Don River were Pseudomonas and Deinococcus, in the Mezha River – Pseudomonas and Janthinobacterium, in the pond – Arcicella. In terms of sanitary and microbiological indicators, none of the waterbodies complied with the Sanitary Rules and Regulations 1.2.3685- 21 for surface waters. The content of most of the studied elements and heterotrophic bacteria in stagnant waterbodies was lower than in flowing streams. The concentration and activity of heterotrophic bacteria in the studied waters correlated positively with the content of biophilic elements in them and negatively with the absence of a current. We showed that there is a strong correlation between bacterial and chemical indicators due to common factors: eutrophication, features of the physical and geographical conditions of the territory, and the presence of a current or animal waste products.

The article "Corrigendum: Microplastics in sea surface waters in the Southern Bight of the North Sea" published in Frontiers in Marine Science addresses errors in the original publication related to the unit of measurement used for microplastics. Corrections were made to ensure accuracy in the description of sampling methods and sizes of microplastics analyzed. The authors acknowledge the errors and emphasize that the scientific conclusions of the study remain unchanged. [Extracted from the article]

Chemical pollution caused by synthetic organic chemicals at low concentrations in the environment poses a growing threat to the ecological status of aquatic ecosystems. These chemicals are regularly released into surface waters through both treated and untreated effluents from wastewater treatment plants (WWTPs), agricultural runoff, and industrial discharges. Consequently, they accumulate in surface waters, distribute amongst environmental compartments according to their physicochemical properties, and cause adverse effects on aquatic organisms. Unfortunately, there is a lack of data regarding the occurrence of synthetic organic chemicals, henceforth micropollutants, in South American freshwater ecosystems, especially in Chile.To address this research gap, we present a comprehensive dataset comprising concentrations of 153 emerging chemicals, including pesticides, pharmaceutical and personal care products (PPCPs), surfactants, and industrial chemicals. These chemicals were found to co-occur in surface waters within Central Chile, specifically in the River Aconcagua Basin. Our sampling strategy involved collecting surface water samples from streams and rivers with diverse land uses, such as agriculture, urban areas, and natural reserves. For sample extraction, we employed an on-site large-volume solid phase extraction (LVSPE) device. The resulting environmental extracts were then subjected to wide-scope chemical target screening using gas chromatography and liquid chromatography high-resolution mass spectrometry (GC- and LCHRMS).The dataset we present holds significant value in assessing the chemical status of water bodies. It enables comparative analysis of pollution fingerprints associated with emerging chemicals across different freshwater systems. Moreover, the data can be reused for environmental risk assessment studies. Its utilisation will contribute to a better understanding of the impact and extent of chemical pollution in aquatic ecosystems, facilitating the development of effective mitigation strategies.

Rivers, creeks, streams are integrators of biological, chemical and physical processes occurring in a catchment linking land cover from the headwaters to the outlet. The dynamics of human and animal pathogens in catchments have been widely studied in a large variety of contexts allowing the optimization of disease risk reduction. In parallel, there is an emerging awareness that crop pathogens might also be disseminated via surface waters especially when they are used for irrigation. However, there are no studies on the extent to which potential plant pathogens are present – nor about their dynamics - along the full course of a catchment. Here we have compared the seasonal dynamics of populations of the Pseudomonas syringae (Psy) and the Soft Rot Pectobacteriaceae (SRP) species complexes along a 270 km stretch of the Durance River from the upstream alpine reaches to the downstream agricultural production areas at the confluence with the Rhone River at Avignon. Among 168 samples collected at 21 sites in fall, winter, spring and summer of 2016 and 2017, Psy strains were detected at all sampling sites and in 156 of the samples at population densities up to 105 bacteria L-1. In contrast, SRP strains were detected in 98 of the samples, mostly from the southern part of the river, at population densities that did not exceed 3 ´ 104 bacteria L-1. Among the biological and chemical parameters that were characterized at each sampling site, temperature was the only factor that explained a significant amount of the variability in population size for both species complexes. Psy densities decreased with increasing temperature whereas SRP densities increased with increasing temperature. River-borne populations of SRP were composed mainly of Pectobacterium versatile and P. aquaticum that have little known epidemiological importance. Only a few strains of Pectobacterium and Dickeya species reputed for their epidemiological impact were observed. In contrast, Psy populations at all sites were dominated by a genetic lineage of phylogroup 2 known from other studies for its broad host range and its geographic and habitat ubiquity. Our observations suggest that surveillance of river water for SRP could be leveraged to signal diagnostic and management reactions to avoid disease outbreaks. In contrast, the constant presence of Psy throughout the catchment in absence of regular and widespread disease outbreaks due to this group of bacteria suggests that surveillance should focus on future changes in land use, river water conditions and agronomic practices that could destabilize the mechanisms currently holding Psy outbreaks in check.

From the novel results of comprehensive geological–hydrobiogeochemical studies conducted on Olkhon Island (Lake Baikal), it follows that the phenomenon of geophagy among wild and domestic ungulates on the island is caused by the deficiency of light subgroup rare earth elements (LREE) in plant food and natural waters, while not denying the possible role of other factors. This deficiency reflects the low LREE specificity of the most abundant metamorphic terrigenous carbonate rocks on the island, as well as their overlying eluvium–deluvium and soils. The resulting specificity of the landscapes may be the cause of the LREE imbalance in the nervous and hormonal systems of the body, which makes the animals regularly and periodically consume clay (kaolinite) products from weathering, enriched with the necessary nutritional elements. The identified cause of geophagy on Olkhon Island is likely to extend to a significant part of geophagy cases among animals, including humans, especially in the equatorial zone of the Earth. [ABSTRACT FROM AUTHOR]

The aquatic environment faces increasing threats from a variety of unregulated organic chemicals originating from human activities, collectively known as chemicals of emerging concern (CECs). These include pharmaceuticals, personal-care products, pesticides, surfactants, industrial chemicals, and their transformation products. CECs enter aquatic environments through various sources, including effluents from wastewater treatment plants, industrial facilities, runoff from agricultural and residential areas, as well as accidental spills. Data on the occurrence of CECs in the marine environment are scarce, and more information is needed to assess the chemical and ecological status of water bodies, and to prioritize toxic chemicals for further studies or risk assessment. In this study, we describe a monitoring campaign targeting CECs in surface waters at the Swedish west coast using, for the first time, an on-site large volume solid phase extraction (LVSPE) device. We detected up to 80 and 227 CECs in marine sites and the wastewater treatment plant (WWTP) effluent, respectively. The dataset will contribute to defining pollution fingerprints and assessing the chemical status of marine and freshwater systems affected by industrial hubs, agricultural areas, and the discharge of urban wastewater. Dataset: 10.5281/zenodo.7845557 Dataset License: CC-BY-NC-SA 4.0 [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) in the environment is a globally concerning issue. This study sought to improve the understanding of human health risks from an environmental AMR proliferation perspective. Surface water concentrations of 11 most used antibiotics in the United States were simulated for the Columbia and Sacramento River watersheds using the Pharmaceutical Assessment and Transport Evaluation (PhATE) model. The predicted environmental concentrations (PECs) and literature-reported measured environmental concentrations (MECs) of antibiotics were compared to the predicted no effect concentrations (PNECs) of three frameworks proposed as protective of AMR selection. For all of the studied antibiotics, PECs (except for moxifloxacin, a 4th generation fluoroquinolone), and at least one published MEC, were above the safe limit proposed by at least one of the three frameworks. The results indicate that a variety of different antibiotics with different mechanisms of action and physico-chemical properties are likely in environmental compartments at or above the concentrations currently proposed as safe from an AMR proliferation perspective. Understanding environmental occurrence of antibiotics is important for assessing environmental exposures and, when compared to PNECs for resistance selection, can-either alone or in combination with other methods- more specifically indicate where there are potential risks of AMR proliferation.

Background. The study area is one of the main regions of the Russian Federation, where intensive development and production of hydrocarbons are carried out. They are directly accompanied by a very significant anthropogenic impact on the environment in general, and on water bodies in particular. The article, based on the analysis of chemicals concentration in surface waters, bottom sediments and coastland soil, gives an assessment of water bodies quality on the territory of the oil and gas industry. Purpose. The purpose of the study is to assess the quality of surface waters, benthic ecosystem and coastland soil of water bodies on the territory of oil and gas fields of the Middle Ob region. Materials and methods. On the basis of chemical analysis, concentrations of chemical elements were determined in samples of surface waters, bottom sediments and coastland soil of water bodies. Based on the concentration of chemical elements in a particular environment, the index of surface water pollution was determined by the calculation method, the state of the coastland soil and the benthic ecosystem was assessed. Results. The calculation of the integral assessment of water quality shows that the studied water bodies range from moderately polluted to extremely polluted. Quality deterioration of the benthic ecosystem is observed in most of the studied water bodies. Conclusion. The study of the environmental condition of water bodies by the quality of surface waters, bottom sediments and the coastland soil shows the negative anthropogenic impact of the oil and gas industry on the studied water bodies.

In order to understand the distribution of fluorine in surface environments, also linked to fluoride deposits, this paper discusses the role of rift systems in fluorine enrichment of surface waters, with two examples: the Sardinia Island and the East African Rift. The main goal of this study is aimed to highlighting the areas that could potentially host fluorine in the surface waters in order to make it easier the lecture also for people to search and read not experts in the field, such as the biomedical field. Furthermore, potentialities and limitations of the currently available defluoridation techniques were examined, in order to identify the best intervention technology. From a careful review of the literature, to the addition of the extensive field observations in Sardinia and Ethiopia carried by the authors in the previous decades, we highlight the origin, processes and evolution of F-migration in Rift systems. The given examples of Sardinia and Ethiopia show that the origin and consequent behaviour of fluorine is strictly controlled by the rift systems. In this framework, the availability of fluorine for surface waters depends on two possible types of sources: a direct supply and an indirect supply. Directly from spring waters and ground waters fed by hydrothermal systems related to rifting, and indirectly from the leaching of products of rift-related activities, such as fluorite-bearing deposits, sedimentary or meta-sedimentary rift-related sequences, and volcanic or metavolcanic complexes emplaced along rift structures. The whole geological history of a given area must be taken into account in interpreting its present fluorine geochemistry. In conclusion, we underline the aspects of a possible control of these areas where fluoride exposure might lead to a long-term harm to local communities and we point out the nowadays best remediation-technologies, discussing their pro and cons in their applicability to different scales and social-contexts.

During Antarctic summers in the 2018—2021 period, physical, chemical, and biological parameters of the upper layer of seawater were continuously recorded using the FerryBox (FB) software and measuring system installed on-board the Ukrainian krill fishing trawler F/V More Sodruzhestva. The main hydrological fronts of the South Atlantic and the Southern Ocean were crossed from Cape Town to the Antarctic Peninsula. About 800,000 one-minute FB measurements were used in this research to determine and identify marine structures. The paper aims to estimate the spatial-temporal variability of oceanographic parameters of the surface layer of water in the Southern Ocean based on the FB data analysis. We use classical methods of analysis of hydrological structures, graphical, comparative, and statistical types of analysis of the field data, as well as data from the Copernicus Marine Environment Monitoring Service (CMEMS). Trawling areas were considered as hydrological landfills. We found a decrease in the total number of front crosses: from 8.6% in the 2018—2019 season to 3.9% in the 2020—2021 season. Analysis of the quality of information obtained from the FB showed that after adjustment the measurements allow solving various oceanographic problems, such as identifying frontal zones and detailing their hydrological structure, determining surface water masses and variability of their distribution limits, highlighting significant cycles in time of the measured parameters, studying the gas component of the upper sea layer water. A comparative analysis of the results of the FB observations with the CMEMS data showed their qualitative consistency.

The Sado basin (~8000 km2) is an area where intensive agriculture occurs. However, this region still has few data about the water levels of priority pesticides such as fungicides, herbicides, and insecticides. Therefore, water samples were collected every two months at nine sites along the Sado River Estuary and analyzed by GC-MS/MS to determine the influx of pesticides in that ecosystem. More than 87% of the pesticides were quantified, and 42% and 72% were above the maximum totals established by the European Directives 98/83/EC and 2013/39/EU, respectively. Fungicides (91%), herbicides (87%), and insecticides (85%) attained average annual amounts of ≈3.2 µg/L, ≈1.0 µg/L, and ≈12.8 µg/L, respectively. A mathematical approach was used to evaluate the hazard of the pesticide mixture at the maximum concentrations found in this area. The assessment identified invertebrates as the most at-risk trophic level and identified two chemicals (chlorpyriphos and cyfluthrin) as the primary culprits. This assumption was supported by acute in vivo assays using Daphnia magna. These observations, and the high concentrations of phosphates, indicate that the status of the Sado waters poses environmental and potential human health risks. [ABSTRACT FROM AUTHOR]

Data from monitoring programs with high spatial resolution but low temporal resolution are often overlooked when assessing temporal trends, as the data structure does not permit the use of established trend analysis methods. However, the data include uniquely detailed information about geographically differentiated temporal trends driven by large-scale influences, such as climate or airborne deposition. In this study, we used geographically weighted regression models, extended with a temporal component, to evaluate linear and nonlinear trends in environmental monitoring data. To improve the results, we tested approaches for station-wise pre-processing of data and for validation of the resulting models. To illustrate the method, we used data on changes in total organic carbon (TOC) obtained in a monitoring program of around 4800 Swedish lakes observed once every 6 years between 2008 and 2021. On applying the methods developed here, we identified nonlinear changes in TOC from consistent negative trends over most of Sweden around 2010 to positive trends during later years in parts of the country. [ABSTRACT FROM AUTHOR]

This work was conducted at the Pardo River hydrographic basin, which is a federal watershed belonging to the Paranapanema River hydrographic basin (PRHB) in Brazil (São Paulo State and Paraná State). The aim was to realize an integrated hydrochemical and radiometric (U-isotopes and 210Po) approach, highlighting the water/soil-rock and surface water/groundwater interactions, with implications to the weathering processes occurring there. The study area has been often considered one of the best preserved/unpolluted river in São Paulo State, contributing to the water supply of several cities distributed along its banks. However, the results reported here suggest possible lead diffuse pollution caused by the use of phosphate fertilizers in agricultural activities taking place in the basin. The analyzed groundwaters and surface waters tend to be neutral to slightly alkaline (pH of 6.8–7.7), possessing low mineral concentration (total dissolved solids up to 500 mg/L). SiO2 is the major dissolved constituent in the waters, while bicarbonate is the dominant anion, and calcium is the preponderant cation. The effects of the weathering of silicates to control the dissolution of constituents in the liquid phase have been identified from some diagrams often utilized in hydrogeochemical studies. Chemical weathering rates have been estimated from hydrochemical data associated to analytical results of the natural uranium isotopes 238U and 234U concerning to samples of rainwater and Pardo River waters. The fluxes in this watershed are permitted to obtain the following rates: 11.43 t/km2 year (sodium), 2.76 t/km2 year (calcium), 3.17 t/km2 year (magnesium), 0.77 t/km2 year (iron), and 8.64 t/km2 year (uranium). This new dataset constitutes valuable information for people engaged on the management of the Pardo River watershed, as well as to researchers interested on comparative studies considering the available data from other basins worldwide. [ABSTRACT FROM AUTHOR]

Anthropogenic sources of nutrients cause eutrophication in coastal waters. Narraganset Bay (USA), the largest estuary in New England, has large seasonal zones of hypoxia. In response, management strategies have been implemented to reduce nutrient loadings. In this study, a mechanistic, mass balance fate and transport modeling framework was developed and applied to Narragansett Bay to improve our understanding of the processes governing hypoxia. Discrete and continuous observations were used for model comparison and evaluation. Simulations captured the general trends and patterns in dissolved oxygen (DO) with depth and space. Simulations were unable to capture the wide diurnal range of observed continuous DO and phytoplankton concentrations, potentially suggesting the need for improved understanding of processes at this time scale. Mechanistic modelling scenarios were performed to investigate how different sources of nutrients affect DO. Results suggest tributary sources of nitrogen affected upper layers of DO, while sediment oxygen demand and nutrient fluxes affected deeper waters. This work highlights the importance of understanding and simulating the legacy effects of historic nutrient loading to estuary systems to understand the magnitude and timing of long-term recovery due to reductions in nutrient loadings. [ABSTRACT FROM AUTHOR]

Modern research proves the need to include waterbodies in regional and global models of carbon exchange. The concentration of carbon dioxide in surface waters is generally higher than that upon the equilibrium state with a partial atmospheric pressure of 400 µatm. The study of the functioning and regional role of aquatic systems, especially in regard to inorganic carbon dynamics, is insufficient, especially in circumboreal regions. The review highlights the theoretical foundations and relevance of studies of dissolved carbon dioxide; methodological approaches to assessing this indicator, as well as the role of dissolved CO2 in natural waters of boreal and arctic regions. Soil organic matter and dissolved carbon dioxide are the main sources of CO2 in surface waters, but this contribution has not yet been quantified. This is due to the underestimation of the abiotic aspects of soil gas exchange, the absolute predominance of studies of gas exchange at the soil/atmosphere interface without taking into account the interaction with groundwater, and methodological difficulties in measuring gas concentrations in ground and surface waters. Instrumental measurement methods are not standardized, and the calculated values have very high systematic and analytical errors. The conclusion points to the need to study the hydrological continuum: from a source (terrestrial ecosystems) to large rivers and lakes, with particular attention to the incorporation of CO2 from groundwater into the carbon budget of the entire watershed. [ABSTRACT FROM AUTHOR]

Link for citation: Lepokurova O.E., Ivanova I.S., Pyrayev A.N. Stable isotopes of hydrogen, oxygen and carbon when interpreting formation conditions of surface water bodies of Yamalo-Nenets autonomous region. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 6, рр.7-19. In Rus. The relevance. Stable isotopes are widely used in geochemistry for solving various genetic problems, which is associated with the assumption of the constancy of the original isotopic composition of any element, subsequently changed under the influence of various processes. In the practice of surface water studies, isotope methods are used for solving not only direct genetic problems, but also for various related problems. In arctic regions affected by permafrost, water isotopes are increasingly being used to assess the contribution of melt water to the balance of total river flow, especially in conditions of accelerated melting, which leads to changes in the hydrological regime and the overall structure of the landscape. The analysis of the isotope composition of dissolved inorganic carbon is of particular research interest, since it gives an idea of the participation of organic matter released during the thawing of permafrost peat in isotope exchange with water. The joint use of the chemical and isotopic characteristics of water bodies will make it possible to study in detail the genesis, features of the formation and interaction of these waters with the environment. The main aim: clarification of the genesis and conditions of formation of surface water bodies in the Arctic regions of Western Siberia, subject to the influence of permafrost, using the composition of stable isotopes H, O, C. Objects: surface water bodies of the tundra and forest-tundra natural zones of the Yamalo-Nenets Autonomous Region. Field work took place in August 2020. Water samples for the isotopic composition were taken from three large rivers – Ob, Taz, Pur, and in the right tributary of Pur River – Ngarka-Khadytayakha, 7 large lakes (from 2500 to 300000 m2), 1 small thermokarst lake (12 m2) and from 3 depressions (the initial stage of formation of thermokarst lakes); and 2 soil cross sections. A total of 17 water samples. In addition, 5 peat samples were taken from one soil cross section from five depth intervals up to 55 cm. Methods. Chemical composition of water was analyzed by standard methods (titration, inductively coupled plasma mass spectrometry, photometry, ion chromatography and high-temperature catalytic oxidation method) at the Problematic Research Laboratory of Hydrogeochemistry of Tomsk Polytechnic University. The study of the isotopic composition of oxygen, hydrogen and carbon of water-dissolved carbon dioxide was carried out in the Analytical Center for multi-elemental and isotope research SB RAS using Isotope Ratio Mass Spectrometer FinniganTM MAT 253 equipped by H/Device and GasBench II for sample preparation. Results. Isotope composition of oxygen, hydrogen and carbon in waters and dissolved inorganic carbon for surface waters of the tundra and forest-tundra zones of the YaNAO are presented. It is shown that each object (soils, depressions, lakes and rivers) is characterized by individual intervals of δD, δ18О, δ13С (dissolved inorganic carbon) values, which indicates different specifics of their formation and allows them to be differentiated. Comparison with the already available data on δD, δ18O of atmospheric precipitation, surface water and snow in the region revealed that river and soil waters, in comparison with other water bodies, were formed in colder conditions. The δ13CDIC values indicated the presence of two sources of carbon in the surface waters of the region: biogenic (light) and soil diffusion, which inherits the isotopic composition of the atmosphere (heavy). The first one is dominates in soil waters, depressions, shallow lakes and, apparently, in stagnant river waters. In large lakes and in the active course of the river, soil diffusion CO2 is more pronounced. The effect of permafrost thawing in the region is demonstrated by lighter δD and δ18O values (thawed waters), as well as by lighter δ13СDIC values (additional biogenic carbon is released from soils and peat). A scheme of possible distribution and exchange of stable isotopes H, O and C in natural waters and dissolved inorganic carbon for investigated region was developed. The obtained results can be used for determining genesis of the region natural waters; for clarifying conditions of waters and dissolved inorganic carbon formation; for identifying permafrost degradation processes and evaluating its rate; for paleoclimate reconstructions etc.

A new ionic liquid modified polymer gel containing methylimidazolium groups (poly(MIA)) is proposed as a sorbent for the separation and enrichment of trace inorganic and organic arsenic species in surface waters. The poly(MIA) was synthesized by chemical modification of polymeric precursor using post-polymerization modification of poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate). The composition, structure, morphology, and surface properties of the prepared particles were characterized using elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption–desorption measurements. Optimization experiments showed that at pH 8, monomethylarsonic acid (MMAs), dimethylarsinic acid (DMAs), and As(V) were completely retained on the poly(MIA), while the sorption of As(III) was insignificant. The desorption experiments revealed that due to the weaker binding of organic arsenic species, selective elution with 1 mol/L acetic acid for MMAs + DMAs, followed by elution with 2 mol/L hydrochloric acid for As(V), ensured their quantitative separation. The adsorption kinetic and mechanism were defined. The analytical procedure for As(III), As(V), MMAs, and DMAs determination in surface waters was developed and validated through the analysis of certified reference material.

The relevance. Monitoring the levels of chemicals in the surface waters of mining areas and environmental assessment of their condition are the most important measures to ensure the quality of drinking water and reduce risks to public health. At the same time, to date, there is no information on the concentrations of heavy metals and metalloids in the surface waters of the Avzyan gold region. The main aim is to determine the content of trace elements, including heavy metals and metalloids, to identify the reasons for their increase in the surface waters of Avzyan gold region, and to assess the environmental risk to public health. Objects: surface waters in the middle reaches of the Bolshoy Avzyan and Bolshoy Inzer rivers and their tributaries, draining both known deposits of indigenous and placer gold in the Avzyan gold region, and the proposed gold mining sites. Methods: inductively coupled plasma-atomic emission spectrometry. Results. The surface waters of the Avzyan gold region are characterized by an unfavorable ecological condition. The main contaminant element is antimony, exceeding the maximum allowable concentration by 1,2...7,6 times in all selected samples. The level of water contamination with this element in most samples is high and extremely high. Based on the results of the research, a map of the degree of contamination of surface waters with antimony was built. In many cases, there is an average of 1,6...5,0-fold excess of the maximum allowable concentration for iron, manganese, tungsten, copper, aluminum, vanadium, in single samples – for arsenic and molybdenum. Areas of extremely high contamination for aluminum, molybdenum, and a high level of contamination for tungsten were locally established. According to the values of the coefficients of complexity of pollution (8,7…30,4 %) and the values of the coefficients of complexity of high and extremely high levels of pollution (up to 4,3 %), the surface waters of Avzyan gold region are moderately toxic and belong to the I–II category of pollution. Based on the values of the total hazard coefficients, a non-carcinogenic risk to public health was determined, which consists in possible adverse consequences and is mainly associated with high concentrations of antimony in water. The increase in the concentrations of polluting elements in surface waters is due to natural (geogenic) factors – geochemical and mineralogical features of rocks involved in the geological structure of deposits and ore occurrences of the Avzyan gold region. Arsenic concentrations naturally increase in the tributaries of the Bolshoy Avzyan river, forming local scattering streams near gold deposits. The migration ability of antimony in comparison with arsenic is manifested to a greater extent. The predominant dissolved forms of arsenic are the oxyanions HAsO42– and H2AsO4–, antimony – Sb(OH)6–. An increase in the concentrations of these metalloids in the Bolshoy Avzyan river and its tributaries is associated with the dissolution of silicate minerals and iron hydroxides, as well as with the dissolution of pyrite-containing carbonate rocks of the Suran formation. The ongoing development of deposits of indigenous and placer gold currently does not have a great impact on the increase in the content of these elements in surface waters.

Yaremche tourist destination aggregates a significant number of tourist accommodation establishments, hotels, green estates, etc., wastes from which cause both direct and diffuse pollution of surface waters. The seasonal changes and fluctuations of physical and chemical indicators of surface water quality of the Prut River basin within the framework of regular monitoring within Yaremche tourist destination on the basis of the field researches carried out by the authors have been investigated. The observation program included two hydrological seasons: the spring high water period and the autumn low of 2021. The surface waters from the Prut River and its tributaries in the area from the village of Dora (suburbs of Yaremche) upstream to the village of Vorokhta were studied. Samples were taken at ten observation points. Regulatory approved methods and certified equipment were used to perform laboratory tests. During the spring floods of 2021, the pH value was relatively stable in all samples with an average of -7.8. The content of ammonium ions (NH₄⁺) in the samples taken during the flood period is slightly increased compared to the low tide period. The highest recorded value of ammonium (0.5 mg/dm3 ) is in the line of the Kamianytsia River, Mahura tract, in other samples it ranges from 0.15 to 0.25. The content of phosphates (PO₄³⁻) has reached the highest recorded value (0.15 mg/dm3 ), and the total mineralization of the water of the Prut River in Yaremche is mostly weak and moderate (150-250 mg/m3 ). The lowest rates of mineralization occur during the spring floods, the highest are characteristic of the winter low, which generally corresponds to the natural conditions of seasonal changes. The values of the qualitative composition of waters in the low tide period in terms of nitrates in all samples are higher than in the period of spring floods. The highest concentration of nitrates (56.7 mg/dm3 ) was recorded in the autumn in the area of the Zhonka River, in the town of Yaremche downstream of the concentrated accumulation of green estates and hotels. The obtained laboratory results show that except for nitrate pollution, all other analyzed indicators of physicochemical composition of surface waters in the study area are within acceptable limits. Both periods of the study belong to the tourist off-season with the fewest visitors during the year. The obtained results prove that under these conditions the self-cleaning property of surface waters can cope with direct and diffuse pollution both in the period of high water and in the period of low water

Antifreeze proteins (AFPs) protect organisms from freezing by binding to ice crystals to prevent their growth. Here, we have investigated how the area of an AFP's ice‐binding site (IBS) changes its antifreeze activity. The polyproline type II helical bundle fold of the 9.6‐kDa springtail (Collembola) AFP from Granisotoma rainieri (a primitive arthropod) facilitates changes to both IBS length and width. A one quarter decrease in area reduced activity to less than 10%. A one quarter increase in IBS width, through the addition of a single helix, tripled antifreeze activity. However, increasing IBS length by a similar amount actually reduced activity. Expanding the IBS area can greatly increase antifreeze activity but needs to be evaluated by experimentation on a case‐by‐case basis. [ABSTRACT FROM AUTHOR]

Small river basins are complex self-regulatory systems, as well as indicators of the state of the environment due to the level of anthropogenic pressure. Since any changes in the regime of small rivers are reflected in the entire hydrographic chain, the problem of estimating the anthropogenic load on small rivers of Ukraine is relevant for modern hydrochemistry and hydroecology. The main sources of water pollution are industrial and domestic effluents, which increase the inflow of pesticides, heavy metal ions, etc. Aquatic ecosystems of small rivers are subject to intense mechanical and biochemical effects, and about 80% of pollutants are washed into water bodies. Water bodies located on the territory or near large cities and urban areas are particularly exposed to man-made pollution. In the territory of the Dniester river basin, natural landscapes are maximally preserved in comparison with other regions of Western Ukraine, but in modern conditions we observe an increase in the negative anthropogenic impact on the quality of natural waters. Hydrodynamic barriers or hydrodynamically active areas (HAA) of mountain rivers, which are significantly saturated with oxygen in the water flow, which activates the processes of biochemical and biological selfcleaning of natural waters, are important to increase the efficiency of self-purification processes. Natural biological cleaning of pollutants in small rivers is highly effective due to the overgrowth of aquatic vegetation. The aim of the work was to establish the ability of the aquatic ecosystem of a small river to self-purify on the basis of hydrochemical indicators of water quality. The compliance with sanitary and hygienic requirements of hydrochemical indicators of Kolodnytsia river water of the right tributary of the Dniester was analyzed and possible regularities of their changes were established, as well as the main factors of anthropogenic impact on a small river and the possibility of laboratory modeling of such rivers. It was found that in the Kolodnytsia River the processes of self-cleaning are quite active, which are caused by the hydrological characteristics of the river and the presence of hydrodynamically active areas in the foothills of the basin. Therefore, at present there is no steady excess of pollutants relative to the MPC. [ABSTRACT FROM AUTHOR]

As the plan for the building's sector energy transition proceeds, solutions of technology that exploit the primary resources available in each geographic location need to be advanced. In coastal regions, configurations such as heat pumps, which use nearby water as a heat sink to produce the necessary heating and cooling energy for the built environment, are widely used. Increasing research attention is given to these systems' integration, design, installation, and optimization. The main reason for this attention is the nearly stable water temperatures throughout the year, which occurs in certain depths in lakes and seas. The present study aims at designing such a system using a case study in Alexandroupoli, Greece. Key remarks for the design process are provided, especially in the proposed closed-loop seawater heat pump (CL-SWHP) configuration, while a novel approach toward dimensioning optimization for the system is introduced. The simulation is conducted during winter and summer scenarios to investigate the systems' load coverage capabilities. The results indicate that the system reached the setpoint temperatures for the heating and cooling scenarios and produced the necessary thermal energy for the load of the case study. The techno-economic approach concluded that the proposed system is more viable than the conventional system, as its Levelized Cost of Energy (LCoE) and operational costs were significantly cheaper. Its LCoE was 0.18 €/kWh, while the conventional system's 0.37 €/kWh. Further investigation is required for hybrid scenarios of the proposed system, where photovoltaic panels (PVs) will provide the necessary electrical energy to reduce the energy cost further. [ABSTRACT FROM AUTHOR]

Surface water samples were collected using a low-tech aquatic debris instrument (LADI) at six nearshore locations on the north and northwestern coasts of Iceland to investigate the prevalence of mesoplastic (5–10 mm) and microplastic (0.3–5 mm) in the region. This sampling strategy involved sampling each transect three times for a total of 18 samples collected in order to assess uncertainties related to heterogeneous distribution of plastic in surface waters. Samples in all six nearshore locations contained meso- and/or microplastic, though concentrations were highly variable. Visual, physical, and FTIR analyses were performed on 71 suspected plastic particles collected, confirming and identifying 40 of those particles as one of six types of plastic: polypropylene (PP), polyethylene (PE), high-density polyethylene (HDPE), polyester, low-density polyethylene (LDPE), and polyvinyl chloride (PVC). Lines originating from fishing gear were the most prevalent types of plastic detected across the samples. This study is among the first to quantify and identify microplastic particles collected in Icelandic nearshore surface waters. [ABSTRACT FROM AUTHOR]

Purpose. Analysis of domestic and foreign experience in solving the problem of chemical pollution of surface waters and improving the existing "Methodology for calculating the amount of compensation for damages caused to the state as a result of violations of legislation on protection and rational use of water resources." Methods. Information analysis, theoretical and calculation, systems analysis. Results. In European countries, the assessment of the economic consequences of chemical pollution of surface waters is based on the provisions of Directive 2004/35 / EC "On environmental liability with regard to the prevention and remedying of environmental damage". The implementation of this Directive is carried out by creating a system of environmental liability based on the "polluter pays" principle not only for non-compliance with the limit of discharge of pollutants into water bodies, but also for violation of the properties and nature of aquatic ecosystems and their restoration. It is established that the consequences of not all forms of environmental damage can be eliminated by using the mechanism of environmental responsibility. For this mechanism to be effective, one or more sources of pollution must be identified, the damage must be specific and calculable, and a causal link must be found between the damage and one or more identified sources of pollution. In addition, liability is not an appropriate tool for large-scale, diffuse pollution, when it is impossible to establish a link between negative environmental impacts and the actions or inaction of certain individuals. Based on the analysis of national regulations and methodological approaches to assessing the economic consequences of chemical pollution of surface waters in European and other foreign countries, an algorithm is proposed to take into account the levels of acute lethal toxicity of return waters. Conclusions.. The algorithm for assessing the environmental impact of chemical pollution of surface waters must take into account the provisions of Article 16 of WFD 2000/60 / EC "Strategies against water pollution", in particular in paragraph 1.2.6 of Annex V "Surface water status" emphasizes " obtain data on the acute and chronic effects of chemical pollution of surface waters on the representatives of the "basic set of taxa" - algae, crustaceans and fish.