Surface Water Ecosystems Research Articles

Characteristics of organic matter driven by Eichhornia crassipes during co-contamination with per(poly)fluoroalkyl substances (PFASs) and microplastics (MPs)

Co-contamination with MPs and PFASs has been recorded, particularly in surface-water environments. Floating macrophyte microcosms are an important part of the surface water ecosystem, and dissolved organic matter (DOM) driven by floating macrophytes (FMDDOM) is critical for maintaining material circulation. However, knowledge gaps remain regarding the impact of MPs and PFASs co-pollution on FMDDOM. An greenhouse simulation experiment was conducted in this study to investigate the effects of four PFASs, perfluorooctanoic acid (PFOA), perfluoro-octane-sulfonic acid (PFOS), perfluoro-2-methyl-3-oxahexanoic acid (Gen X), and potassium 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B), on FMDDOM sourced from Eichhornia crassipes (E. crassipes), a typical floating macrophyte, in the presence and absence of polystyrene (PS) MPs. Four PFASs increased FMDDOM release from E. crassipes, leading to a 32.52–77.49 % increase in dissolved organic carbon (DOC) levels. PS MPs further increased this, with results ranging from −21.28 % to 26.49 %. Based on the parallel factor analysis (PARAFAC), FMDDOM was classified into three types of fluorescent components: tryptophan-like, humic-like, and tyrosine-like compounds. Contaminants of MPs and PFASs modified the relative abundance of these three components. Protein secondary structure analysis showed that fluorocarbon bonds tended to accumulate on the α-helix of proteins in FMDDOM. The relative abundance of fluorescent and chromophorous FMDDOMs varied from 0.648 ± 0.044 to 0.964 ± 0.173, indicating that the photochemical structures of the FMDDOM were modified. FMDDOM exhibits decreased humification and increased aromaticity when contaminated with MPs and PFASs, which may be detrimental to the geochemical cycling of carbon. This study offers a theoretical basis for assessing the combined ecological risks of MPs and PFASs in floating macrophyte ecosystems.

Critical review on toxic contaminants in surface water ecosystem: sources, monitoring, and its impact on human health.

Surface water pollution is a critical and urgent global issue that demands immediate attention. Surface water plays a crucial role in supporting and sustaining life on the earth, but unfortunately, till now, we have less understanding of its spatial and temporal dynamics of discharge and storage variations at a global level. The contamination of surface water arises from various sources, classified into point and non-point sources. Point sources are specific, identifiable origins of pollution that release pollutants directly into water bodies through pipes or channels, allowing for easier identification and management, e.g., industrial discharges, sewage treatment plants, and landfills. However, non-point sources originate from widespread activities across expansive areas and present challenges due to its diffuse nature and multiple pathways of contamination, e.g., agricultural runoff, urban storm water runoff, and atmospheric deposition. Excessive accumulation of heavy metals, persistent organic pollutants, pesticides, chlorination by-products, pharmaceutical products in surface water through different pathways threatens food quality and safety. As a result, there is an urgent need for developing and designing new tools for identifying and quantifying various environmental contaminants. In this context, chemical and biological sensors emerge as fascinating devices well-suited for various environmental applications. Numerous chemical and biological sensors, encompassing electrochemical, magnetic, microfluidic, and biosensors, have recently been invented by hydrological scientists for the detection of water pollutants. Furthermore, surface water contaminants are monitored through different sensors, proving their harmful effects on human health.

Integrative genome-centric metagenomics for surface water surveillance: Elucidating microbiomes, antimicrobial resistance, and their associations

Surface water ecosystems are intimately intertwined with anthropogenic activities and have significant public health implications as primary sources of irrigation water in agricultural production. Our extensive metagenomic analysis examined 404 surface water samples from four different geological regions in Chile and Brazil, spanning irrigation canals (n = 135), rivers (n = 121), creeks (n = 74), reservoirs (n = 66), and ponds (n = 8). Overall, 50.25 % of the surface water samples contained at least one of the pathogenic or contaminant bacterial genera (Salmonella: 29.21 %; Listeria: 6.19 %; Escherichia: 35.64 %). Furthermore, a total of 1,582 antimicrobial resistance (AMR) gene clusters encoding resistance to 25 antimicrobial classes were identified, with samples from Brazil exhibiting an elevated AMR burden. Samples from stagnant water sources were characterized by dominant Cyanobacteriota populations, resulting in significantly reduced biodiversity and more uniform community compositions. A significant association between taxonomic composition and the resistome was supported by a Procrustes analysis (p < 0.001). Notably, regional signatures were observed regarding the taxonomic and resistome profiles, as samples from the same region clustered together on both ordinates. Additionally, network analysis illuminated the intricate links between taxonomy and AMR at the contig level. Our deep sequencing efforts not only mapped the microbial landscape but also expanded the genomic catalog with newly characterized metagenome-assembled genomes (MAGs), boosting the classification of reads by 12.85 %. In conclusion, this study underscores the value of metagenomic approaches in surveillance of surface waters, enhancing our understanding of microbial and AMR dynamics with far-reaching public health and ecological ramifications.

Planktonic foraminifera response to the azores high and industrial-era global warming in the central-western Mediterranean Sea

The Mediterranean Sea is warming about 20 % more rapidly than global ocean and this phenomenon is impacting ecosystems and biodiversity. Planktonic foraminifera are an important component of surface and subsurface water ecosystems and food chains. Their species communities have been altering across the oceans since the Industrial Era, in response to the ongoing climate change, especially in the western Mediterranean Sea, where a significant productivity decrease has been recently reported.Here we show planktonic foraminifera and multispecies stable isotopes from three short sediment cores, recovered on the eastern flank of the Sicily Channel, central Mediterranean Sea. Results fully confirm the planktonic foraminifera productivity decrease in the Industrial Era, which is especially relevant for the second half of the 20th century. The planktonic foraminifera productivity decrease matches with a higher number of Large Azores High events, i.e., the establishment of an exceptional and persistent winter atmospheric high-pressure ridge over the western-central Mediterranean Sea. This is an unprecedented atmospheric phenomenon for the last millennia Mediterranean Sea history, as a direct response of the global warming. Surface productivity and DCM species are especially declining since ∼1960 CE, at expenses of winter mixed layer taxa, suggesting that the Azores High activity prevents a sustained water column vertical mixing and surface water nutrient fuelling. Our results document and confirm that the climate change has already been affecting Mediterranean marine ecosystems and the basic level of the trophic chain, by extending the surface water stratification period.

Determining rainwater dissolved organic carbon to reveal atmospheric carbon deposition in China's karst city: Variations, origins, and deposition flux

A large amount of organic carbon (OC) in the atmosphere are transferred to the Earth's surface through dry (40%) and wet (60%) deposition. Therefore, wet deposition is an important physical pathway for the removal of atmospheric OC. Identifying the variations of DOC in wet deposition (rainwater) is essential for clarifying the earth-surface C balance. The present study detected the DOC content in 96 daily rainwater samples collected over an entire year in a karst city, with abundant rainfall in Southwest China. The DOC concentrations varied between 1.03–37.7 mg C L−1, while the VWM value stood at 2.76 mg C L−1, which is similar to the worldwide and Asian averages. The yearly DOC wet deposition flux was calculated as 2.88 g C m−2 yr−1. Both the VWM concentration and flux of rainwater DOC exhibit pronounced seasonal variations and regional differences, primarily controlled by precipitation and the external input of OC. The sources of rainwater DOC were multifaceted, including urban waste emission, agricultural activities, and fossil fuel combustion (especially coal combustion), while the contribution from natural sources was limited. Additionally, the C: N (2.08) ratio of rainwater is significantly lower than the Redfield ratio (6.625), indicating the importance of considering the impact of nutrient components in rainfall on the material cycling of surface water ecosystems. This work will benefit the knowledge of the present status of rainwater DOC and its deposition flux on the karst regional scale and further on a global scale, and contribute to a better understanding of the C geochemical cycle on the territorial system.

An integrated approach to assess human health risk of neonicotinoid insecticides in surface water of the Yangtze River Basin, China

Neonicotinoids are widely used insecticides that have raised considerable concerns for both environmental and human health. However, there lack of comprehensive evaluation of their accumulation in surface water ecosystems and exposure to various human groups. Additionally, there's a distinct lack of scientific evidence describing the carcinogenic and non-carcinogenic impacts of neonicotinoids from surface water. Using an integrated approach employing the Relative Potency Factor (RPF), Hazard Index (HI), and Monte Carlo Simulation (MCS), the study assessed neonicotinoid exposure and risk to four demographic groups via dermal contact and mistaken oral intake pathways in the Yangtze River Basin (YRB), China. Neonicotinoid concentrations range from 0.1 to 408.12 ng/L, indicating potential risk (10−3 to 10−1) across the studied demographic groups. The Incremental Lifetime Cancer Risk (ILCR) for dermal contact was within a moderate range of 2.00 × 10−3 to 1.67 × 10−2, while the mistaken oral intake was also within a moderate range of 3.07 × 10−3 to 7.05 × 10−3. The Hazard Index (HI) for dermal exposure ranged from 1.49 × 10−2 to 0.125, while for mistaken oral intake, it varied between 2.69 × 10−2 and 0.14. The findings highlight the importance of implementing specific interventions to address neonicotinoid exposure, especially among demographic groups that are more susceptible. This research underscores the urgent need for targeted strategies to address neonicotinoid risks to vulnerable populations within the YRB while contributing to insights for effective policies to mitigate neonicotinoid exposure in surface water ecosystems globally.

Overview of the Eutrophication in Romanian Lakes and Reservoirs

In this paper, attention is drawn to the deterioration of Romanian surface water ecosystems due to eutrophication, an important environmental issue both at national and international levels. An inventory of existing studies dealing with the issue of the eutrophication of lakes and reservoirs in Romania is made, aiming to identify the main problems Romania is facing in monitoring, classifying, and managing eutrophic ecosystems. On Web of Science, the keyword “Eutrophication”, with “Romania” as country/region, leads to 50 publications, which are analyzed in this review. The number of articles found does not reflect the real environmental issue represented by eutrophic lakes and reservoirs in Romania. At a national level, only 126 lakes and reservoirs have been monitored and assessed between 2018 and 2020, in terms of ecological status/ecological potential. Thus, at a global evaluation, 77% of natural lakes and 33% of artificial ones do not reach the quality objectives. The results of this study showed that the frequency of measurements taken by water quality indicators is not the strongest point of measurement campaigns, as it is not sufficient for the diagnosis of eutrophic lakes, and supplementary measures must be undertaken to better understand and mitigate this phenomenon.

Microbial phylogenetic divergence between surface-water and sedimentary ecosystems drove the resistome profiles

Antibiotic pollution and the evolution of antibiotic resistance genes (ARGs) are increasingly viewed as major threats to both ecosystem security and human health, and have drawn attention. This study investigated the fate of antibiotics in aqueous and sedimentary substrates and the impact of ecosystem shifts between water and sedimentary phases on resistome profiles. The findings indicated notable variations in the concentration and distribution patterns of antibiotics across various environmental phases. Based on the partition coefficient (Kd), the total antibiotic concentration was significantly greater in the surface water (1405.45 ng/L; 49.5 %) compared to the suspended particulate matter (Kd = 0.64; 892.59 ng/g; 31.4 %) and sediment (Kd = 0.4; 542.64 ng/g; 19.1 %). However, the relative abundance of ARGs in surface water and sediment was disproportionate to the abundance of antibiotics concentration, and sediments were the predominant ARGs reservoirs. Phylogenetic divergence of the microbial communities between the surface water and the sedimentary ecosystems potentially played important roles in driving the ARGs profiles between the two distinctive ecosystems. ARGs of Clinical importance; including blaGES, MCR-7.1, ermB, tet(34), tet36, tetG-01, and sul2 were significantly increased in the surface water, while blaCTX-M-01, blaTEM, blaOXA10-01, blaVIM, tet(W/N/W), tetM02, and ermX were amplified in the sediments. cfxA was an endemic ARG in surface-water ecosystems while the endemic ARGs of the sedimentary ecosystems included aacC4, aadA9-02, blaCTX-M-04, blaIMP-01, blaIMP-02, bla-L1, penA, erm(36), ermC, ermT-01, msrA-01, pikR2, vgb-01, mexA, oprD, ttgB, and aac. These findings offer a valuable information for the identification of ARGs-specific high-risk reservoirs.

Effect of Environmental Conditions on the Composition of Zooplankton in the Middle Stream of the Likhoborka River

The relevance is due to the paucity of official data on the state of surface water ecosystems In Rusia in terms of hydrobiological indicators and the prospects for the development of hydrobiological research as part of engineering and environmental surveys. The aim of the work is to continue the research of the ecological conditions of the Likhoborka basin with the identification of spatial and temporal patterns in the state of zooplankton. The objectives of the work were: to assess the study of the Likhoborka aquatic ecosystem; to perform a comprehensive environmental survey with plankton sampling and hydrobiological analyses; to link the values of water quality indicators along the length of the river to sources of pollution. The article presents the results of an ecological survey of the Likhoborka river watershed: a list of pollution sources, methods of reconnaissance, detailed examination and hydrobiological analysis of samples taken in the middle stream in June 2022. The work is the next stage of the educational environmental monitoring of the water protection zones of the rivers of Moscow. Throughout the surveyed area from the Golovinsky Ponds to Dmitrovskoe Highway, the degree of water pollution according to the Pantle and Buck index is moderate. Daphnia are abundant in Golovinsky ponds. Along the length of the area, rotifers predominate. The total salinity increases from 185 to 821 mg/l. The greatest contribution to pollution is made by polluted waters of the Likhoborka and the Norishka, which are concentrated through the reservoirs. There are practically no living hydrobionts in the Likhoborka reservoir.

Linking Groundwater to Surface Discharge Ecosystems: Archaeal, Bacterial, and Eukaryotic Community Diversity and Structure in Quebec (Canada).

Aquifer systems are composed of water flowing from surface recharge areas, to the subsurface and back to the surface in discharge regions. Groundwater habitats harbor a large microbial biomass and diversity, potentially contributing to surface aquatic ecosystems. Although this contribution has been widely studied in marine environments, very little is known about the connection between underground and surface microbial communities in freshwater settings. Therefore, in this study, we used amplicon sequencing to analyze the archaeal, bacterial, and eukaryotic community diversity and structure in groundwater and surface water samples, spanning the vast regions of the Laurentides and Lanaudières in the Quebec province (Canada). Our results show significant differences between subsurface and surface taxa; with more fungi, Amoebozoa, and chemolithoautotrophic prokaryotes involved in nitrogen-, sulfur-, and iron-cycling dominating the underground samples; while algae, ciliates, methanogens, and Actinobacteria dominate the surface discharge waters. Microbial source tracking suggested that only a small portion of the microbial communities in the groundwater contributed to the surface discharge communities. However, many taxa were shared between both habitats, with a large range of functional diversity, likely explaining their survival in both subsurface and surface water ecosystems.

Insight into the enhancing mechanism of exogenous electron mediators on biological denitrification in microbial electrolytic cell

Sustained nitrate accumulation in surface water ecosystem was continuously grabbing public attention. Autotrophic denitrification by electron supplement has been applied to overcome the requirement of carbon source, thus the new problem that how to improve the efficiency of extracellular electrons transfer to denitrifiers comes to us. The addition of exogenous electron mediators has been considered as an important strategy to promote extracellular electrons transfer in reductive metabolism. To date, knowledge is lacking about the promoting effects and pathways in nitrate removal by electron mediators. Here, we fully investigated the performance of nitrogen removal as well as quantified the characteristics of biofilms with six electron mediators (riboflavin, flavin mononucleotide, AQS, AQDS, biochar and Nano-Fe3O4) treating in microbial electrolytic cell system. The six electron mediators promoted nitrate removal rate by 76.03–90.43 % with electron supplement. The growth and activity of cathodic biofilm, conductive nanowires generation and electrochemically active substance synthesis of extracellular polymeric substances were facilitated by electron mediator addition. Electrochemical analysis revealed that conductivity and redox capacity of cathodic biofilm was increased for accelerating electron transfer. Moreover, they upregulated the abundance of denitrifying communities and denitrifying genes accordingly. Their denitrification efficiency varied due to their promotion ability in the above different strategies and conductive characteristics, and the efficiency could be concluded as: Nano-Fe3O4 > riboflavin > flavin mononucleotide > AQS ≈ AQDS > biochar. This study revealed how addition of electron mediators promoted denitrification with electron supplement, and compared their promoting efficiency in several main aspects.

Ubah gulma menjadi emas: studi kasus pengolahan eceng gondok menjadi humus aktif &amp; enzimatik di Waduk Jatiluhur Purwakarta

Water hyacinth increase flourishingly and spread rapidly and it potentially harms aquatic ecosystems as it covers water surface and endanger water ecosystems. In Jatiluhur reservoir, the water hyacinth has spread up to 10% of the entire reservoir. Therefore, society's participation in developing active humus/compost and liquid fertilizer from water hyacinth is advantageous for Tirta Emas farmers group in Desa Jatimekar, Kecamatan Jatiluhur, Purwakarta. Furthermore, this study aimed to observe the involvement of PT Pegadaian in the goldifying water hyacinth collaboration program by KUBMN. This study was a literature research as the research was conducted by collecting numerous literature sources such as research articles, books and reports regarding goldifying weeds or water hyacinths and the role of PT. Pegadaian in the program. In the library research, the researchers collected more than 50 research articles, books and study reports regarding water hyacinth's benefits and it's economic potentials. Thus, this study identified that the goldifying program of PT Pegadaian was advantageous in some aspects such as: 1) Ecological aspects: Water environment in Jatiluhur reservoir was better. Because the negative impacts of water hyacinth could be decreased and it was more controllable. 2) Economic aspect: people's income increased as a result of liquid fertilizer from water hyacinth program and sustainable fish cultivation. 3). Social aspect: the beauty of nature in Jatiluhur reservoir without water hyacinth, the emergence of tourist attractions and a harmony relationship between PTJ II as reservoir's manager and people in society.

Evaluation of ecosystem services of surface waters of Ukraine in the ecological and economic dimension

The key issues of the development of a modern system of ecological and economic evaluation indicators of biodiversity are studied. In particular, the emphasis is on the ecosystem services of surface waters. It was found that surface water ecosystems provide a number of ecosystem functions and services important for the sustainable functioning of the natural environment. Although the need for these services is constantly increasing, the capacity of aquatic ecosystems to provide such services is decreasing. To achieve the goal, the article used a system of general scientific and special methods of the modern theory of the ecosystem approach and general ecological assessment, analysis and synthesis, generalization and systematization, abstract-logical method, etc. Based on the results of the analytical assessment of the Water Strategy of Ukraine until 2050, it was found that the document presents a limited ecosystem approach and lacks indicators that indicate the need to preserve water ecosystem services and identify their ecological and economic value. In this context, scientific approaches to the evaluation of ecosystem services of surface waters are substantiated and developed, which are represented by an algorithm consisting of four consecutive steps, namely: analysis of the formation of ecological and economic evaluation of ecosystem services; study of the ecological and economic state of surface waters in Ukraine and the peculiarities of their ecosystem services; development of the methodology of ecological and economic assessment of the value dimension of ecosystem services of surface waters; development of proposals for the implementation of ecological and economic assessment of ecosystem services of surface waters in the Water Strategy of Ukraine. Further research has prospects in the direction of theoretical and methodological substantiation and development of a domestic mechanism for evaluating the ecosystem services of surface water as a component of biodiversity from the standpoint of the ecosystem approach and general ecological assessment.

Baseline study on identification, characterization, distribution and abundance of microplastics in surface water from Ennore to Kovalam along the east coast of India

Microplastics, as growing contaminants in current scenario, are an ecological threat to the surface water ecosystem. Our primary goal is to investigate the identification, characterization, distribution and abundance of microplastics throughout India's east coast, from Ennore to Kovalam. In accordance with the NOAA protocol, microplastics were examined in surface water samples. At all sampling sites, polymers like polyethylene (43%), polypropylene (42%) and polystyrene (15%) were often found. Surface water (total sample location = 34) were found to be contaminated with various types of microplastics ranging from 6 to 30 items/Location with a mean value of 12 items/Location. Microplastics examined from surface water in a variety of colours, including white (26%), black (16%), grey (12%), red (14%), blue (12%), yellow (10%) and green (10%). Microplastics identified by stereo microscope as well as analytical methods such as SEM and FTIR were utilized to explore the characterization of microplastics. The following are the most typical types of microplastic found in surface water: Fibres (59%), films (24%), fragments (10%) and pellets (7%). This research work is a baseline for study about microplastics contamination site from Ennore to Kovalam on East Coast of India.

Using cyanobacteria and other phytoplankton to assess trophic conditions: A qPCR-based, multi-year study in twelve large rivers across the United States

Phytoplankton is the essential primary producer in fresh surface water ecosystems. However, excessive phytoplankton growth due to eutrophication significantly threatens ecologic, economic, and public health. Therefore, phytoplankton identification and quantification are essential to understanding the productivity and health of freshwater ecosystems as well as the impacts of phytoplankton overgrowth (such as Cyanobacterial blooms) on public health. Microscopy is the gold standard for phytoplankton assessment but is time-consuming, has low throughput, and requires rich experience in phytoplankton morphology. Quantitative polymerase chain reaction (qPCR) is accurate and straightforward with high throughput. In addition, qPCR does not require expertise in phytoplankton morphology. Therefore, qPCR can be a useful alternative for molecular identification and enumeration of phytoplankton. Nonetheless, a comprehensive study is missing which evaluates and compares the feasibility of using qPCR and microscopy to assess phytoplankton in fresh water. This study 1) compared the performance of qPCR and microscopy in identifying and quantifying phytoplankton and 2) evaluated qPCR as a molecular tool to assess phytoplankton and indicate eutrophication. We assessed phytoplankton using both qPCR and microscopy in twelve large freshwater rivers across the United States from early summer to late fall in 2017, 2018, and 2019. qPCR- and microscope-based phytoplankton abundance had a significant positive linear correlation (adjusted R2 = 0.836, p-value < 0.001). Phytoplankton abundance had limited temporal variation within each sampling season and over the three years studied. The sampling sites in the midcontinent rivers had higher phytoplankton abundance than those in the eastern and western rivers. For instance, the concentration (geometric mean) of Bacillariophyta, Cyanobacteria, Chlorophyta, and Dinoflagellates at the sampling sites in the midcontinent rivers was approximately three times that at the sampling sites in the western rivers and approximately 18 times that at the sampling sites in the eastern rivers. Welch's analysis of variance indicates that phytoplankton abundance at the sampling sites in the midcontinent rivers was significantly higher than that at the sampling sites in the eastern rivers (p-value = 0.013) but was comparable to that at the sampling sites in the western rivers (p-value = 0.095). The higher phytoplankton abundance at the sampling sites in the midcontinent rivers was presumably because these rivers were more eutrophic. Indeed, low phytoplankton abundance occurred in oligotrophic or low trophic sites, whereas eutrophic sites had greater phytoplankton abundance. This study demonstrates that qPCR-based phytoplankton abundance can be a useful numerical indicator of the trophic conditions and water quality in freshwater rivers.

Relationships between biomass of phytoplankton and submerged macrophytes and physicochemical variables of water in Lake Caohai, China: Implication for mitigation of cyanobacteria blooms by CO2 fertilization

Reducing nutrient input in aquatic ecosystems has been widely recognized as a way to mitigate eutrophication. The paradigm of nutrient limitation by N and P is pervasively accepted, without considering the possibility of C limitation. However, our assumption that C might affect the aquatic biological composition, lacks fieldwork support. We tested the co-limitation of C/N/P on the growth of submerged macrophytes and phytoplankton in the Caohai Lake, a typical shallow karst lake in southwestern China. This study documented the seasonal variations in the concentration and comparative availability of nutrients C/N/P, in addition to physicochemical parameters, submerged macrophytes biomass, and phytoplankton composition in the lake. Our results show that dissolved inorganic carbon plays a substantial role in enhancing the primary production of phytoplankton and macrophytes, which suggests that primary production can be suppressed not only by P and/or N (as generally believed) but also by C, owing to the unique physicochemical characteristics that prevail in typical karst regions. Additionally, submerged macrophytes have been found to inhibit phytoplankton growth. Further analysis showed that the proportion of Cyanobacteria over Chlorophyta and Bacillariophyta throughout the year was reduced at dissolved carbon dioxide/total nitrogen (CO2/TN) ratios (>0.2) and dissolved carbon dioxide/total phosphorus (CO2/TP) ratios (>10) in this study. Isotopic evidence further indicated that the abundance of Cyanobacteria was reduced when CO2 >30 µmol/L. In summary, the combined results suggest that when controlling N and P, CO2 fertilization may significantly affect both the growth and composition of phytoplankton communities/submerged macrophytes and carbon sequestration in karst surface water ecosystems. This implies a new “paradigm” in the mitigation of cyanobacteria blooms by adding more CO2 to aquatic ecosystems with low pCO2, during which carbon sequestration may also be enhanced.

Радиоэкологические проблемы в районе размещения Лермонтовского предприятия «Алмаз» по добыче и переработке урановой руды. Обзор

This paper presents the comprehensive analysis of long-term study of radioecological situation at the site of the former Lermontov Production Association “Almaz” (LPA “Almaz”). The history of LPA and "uranium heritage" objects creation has been considered: the association consisted of two mines with adits and rock dumps, the hydrometallurgical plant and a dump. Emissions and discharges of natural radionuclides during the LPA “Almaz” operation (1950-1991) and the impact of radiation on human health and the environment after its shutdown were assessed. Though a lot of remediation work was made, in the near future radiation safety in the territory of the former LPA “Almaz” location is not guaranteed. The important radioecological problems in the territory of the enterprise location have been specified. Areas of terrestrial ecosystems, industrial and residential buildings in which the content of radon isotopes in the atmosphere exceeded the standards have been identified. Heavy natural radionuclides with high specific activity have been found in dumps, and the increased content of the radionuclides have been found in the soil of adjacent agricultural fields. Risks of exceeding the established national radiation safety standards NRB-99/2009 for natural radionuclides in underground waters of mines and in some foodstuffs produced near the tunnels have been assessed. Gaps in radioecological data for a number of radionuclides, ecosystems and food groups have been identified. The necessity of further monitoring of the radiation situation at the objects of LPA ”Almaz” and in the territory of the enterprise location is substantiated. The program for radioecological monitoring of the lowest atmospheric layer, terrestrial (natural, agricultural, anthropogenic) and aquatic (groundwater and surface water) ecosystems. Monitoring objects, parameters to be measured, list of radionuclides, as well as periodicity of taking samples and making measurements in objects of the LPA ”Almaz” and adjacent territory have ben specified. Monitoring will provide data for a correct assessment of human and biota radiation doses, with account for all dose-generating radionuclides and exposure pathways.

Predicting ammonia nitrogen in surface water by a new attention-based deep learning hybrid model

Ammonia nitrogen (NH3–N) is closely related to the occurrence of cyanobacterial blooms and destruction of surface water ecosystems, and thus it is of great significance to develop predictive models for NH3–N. However, traditional models cannot fully consider the complex nonlinear relationship between NH3–N and various relative environmental parameters. The long short-term memory (LSTM) neural network can overcome this limitation. A new hybrid model BC-MODWT-DA-LSTM was proposed based on LSTM combining with the dual-stage attention (DA) mechanism and boundary corrected maximal overlap discrete wavelet transform (BC-MODWT) data decomposition method. By introducing attention mechanism, LSTM could selectively focus on the input data. BC-MODWT could decompose the input data into sublayers to determine the main swings and trends of the input feature series. The BC-MODWT-DA-LSTM hybrid model was superior to other studied models with lower average prediction errors. It could maintain NASH Sutcliffe efficiency coefficient (NSE) values above 0.900 under the lead time up to 7 days, and the area under the receiver operating characteristic (ROC) curve could reach 0.992. The hybrid model also had higher prediction accuracies at the peak spots, indicating that it was capable of early warning when sudden high NH3–N pollution occurred. The high forecasting accuracy of the suggested hybrid method proved that further improving LSTM model without introducing more complex topologies was a promising water quality prediction method.

ASSESSMENT OF THE IMPACT OF INDUSTRIAL DISCHARGES ON SURFACE WATER QUALITY IN THE KOLA PENINSULA

The Murmansk Region is part of the Russian Arctic enormously rich in diverse natural resources. The intensive development of the mining industry on the Kola Peninsula, the exploration and exploitation of new mineral reserves have augmented the pollution of surface waters in rivers and lakes with metals. The aim was to assess the quality of surface water ecosystems exposed to heavy anthropogenic pressure in the Murmansk Region. The analysis of the main physical and chemical parameters of surface waters revealed water bodies with both extremely high and low pH values, with low redox potential, and high salinity. The study of the spatial distribution of concentrations of a wide range of metals showed that Cu, Ni, Co, Pb, Cd, Mn, Sr, Al, and Fe were the main pollutants of water bodies in the Kola Peninsula. Using statistical analysis techniques were identified the pollutants characteristic for different areas, which require closer attention and further control. The assessment of the quality of surface waters and potential risks to human health led to the conclusions that Monchegorsk, Olenegorsk and Apatity areas were heavily polluted with metals, water toxicity in the areas is high, and the use of this water is fraught with a high risk of carcinogenic and non-carcinogenic effects. The results of this study will serve as a background for future environmental and health risk assessments, as well as for the development of an integrated set of actions for surface water quality management on the Kola Peninsula.

Commons, communities and commodification: a review of reforms in land, water and local democracy in Kerala, India

ABSTRACT As India is releasing its third National Water Policy in the last 20 years, this paper seeks to review the earlier policies relevant to a critical yet under-studied surface water ecosystem of rural community ponds. The paper examines how the notion of commodification informed the policies on water, land and local democracy, impacting the governance of rural community ponds in the state of Kerala, India. The review shows that while earlier country-level policies largely showed a tendency to treat water as a commodity, decommodification tendencies are perceptible in the water policy of Kerala. Nonetheless, the land reforms in Kerala resulted in Dalit Bahujans being systematically excluded from accessing land, even though it ended the operation of commoditised human bodies, and enforced land ceilings. Huge tracts of plantations were kept out of the purview of land reforms, signifying the operation of commodification. A positive aspect of the land ceilings was that many private enclosures like rural ponds were transferred to the state. The reforms in local democracy, to a great extent, led to accessible policy-making. The framework of ‘double movement’ is useful in analysing the trends in environmental sociology and evaluating policies related to socio-ecological systems.