Water Ecosystem Research Articles

Long-term variations in ecosystem water use efficiency in the Tibetan Plateau: Vegetation types, attribution methods and main drivers

Ecosystem water use efficiency (WUE) is a key indicator for understanding the response of carbon–water processes to environmental changes. However, as affected by uncertainty of WUE estimation and attribution, the individual contributions of environmental drivers to WUE changes and the underlying mechanisms remain unclear on the Tibetan Plateau (TP). Here, a theory-based analytical WUE model was modified by introducing an optimal stomatal behavior model, and used to estimate monthly WUE and their drivers during 1982–2018 for main vegetation types on the Tibetan Plateau (TP). Rationality of three mainstream analytical attribution methods—analytical-based partial derivative method (APDM), regression-based partial derivative method (NPDM), and climate elasticity method (CEM)—was examined. Furtherly, the contributions of various environmental drivers to WUE variation trend were estimated for various vegetation types. Results indicate that: (1) The modified model performed well in estimating WUE against with observed WUE at five eddy-covariance (EC) flux stations, which decreased the uncertainty of WUE estimation. WUE increased significantly in the TP with a slope of 0.49 × 10-2 g C kg−1 H2O yr−1 during 1982–2018 with forests increased most rapidly; (2) Only APDM captured both the variation and magnitude of WUE trends, and both NPDM and CEM failed to reproduce the magnitude of WUE trends, though CEM was better than NPDM benefited from its nonlinear structure. Through comparing these methods, we found that the nonlinear direct effects of these forcing variables on WUE change could be higher than their indirect effects caused by their interactions. (3) There are some differences in the main drivers of WUE trends for various vegetation types. Increase in WUE was mainly driven by the increase in leaf area index (LAI) for both steppes and meadows, while decreased air water vapor pressure deficit (VPD) and elevated CO2 showed higher positive effects for broad-leaf forests. The distinct response and extremely scarce EC observations of forests suggest that more attention should be paid to forests in the TP. This study could help in selection of attribution methods and understanding the mechanisms of carbon–water coupling of alpine ecosystems under a changing climate.

Unveiling Climate–Land Use and Land Cover Interactions on the Kerch Peninsula Using Structural Equation Modeling

This paper examines the effects of climatic factors, specifically temperature and precipitation, on land use and land cover (LULC) on the Kerch Peninsula using structural equation modeling (SEM). The Normalized Difference Vegetation Index (NDVI) was used as a mediator in the model to accurately assess the impact of climate change on vegetation and subsequent LULC dynamics. The results indicate that temperature exerts a significant negative influence on LULC in the early periods, inducing stress on vegetation and leading to land degradation. However, this influence diminishes over time, possibly due to ecosystem adaptation and the implementation of resilient land management practices. In contrast, the impact of precipitation on LULC, which is initially minimal, increases significantly, highlighting the need for improved water resource management and adaptation measures to mitigate the negative effects of excessive moisture. The NDVI plays a crucial mediating role, reflecting the health and density of vegetation in response to climatic variables. An analysis of lagged effects shows that both precipitation and temperature exert delayed effects on LULC, underscoring the complexity of water dynamics and ecosystem responses to climatic conditions. These results have important practical implications for land resource management and climate adaptation strategies. Understanding the nuanced interactions between climatic factors and LULC can inform the development of resilient agricultural systems, optimized water management practices, and effective land use planning. Future research should focus on refining models to incorporate nonlinear interactions, improving data accuracy, and expanding the geographic scope to generalize findings. This study highlights the importance of continuous monitoring and adaptive management to develop sustainable land management practices that can withstand the challenges of climate change.

Blind spots in global water quality monitoring

Abstract Poor water quality threatens human and environmental health, as well as the usability of water for sectoral purposes. Despite widespread recognition of its importance, our knowledge of water quality is severely impaired by a lack of information. However, global water quality data is required to assess the critical regions (hotspots) where pollution poses risks to safe water use, economic development and ecosystem services and health. Here, we identify blind spots in current water quality monitoring efforts, elucidating on the associated challenges for diagnosing water quality issues and the knock-on effect for both science and society. Furthermore, we provide recommendations for addressing these blind spots – on which strong emphasis is placed on improved accessibility and transparency of existing data in addition to increasing global water quality monitoring efforts.

Spatial-temporal distributions of phytoplankton shifting, chlorophyll-a, and their influencing factors in shallow lakes using remote sensing

Understanding phytoplankton dynamics is crucial for assessing water ecosystem health. However, traditional in-situ investigations often fall short of capturing the spatial-temporal variations of phytoplankton community structure and biomass on large scales. This study introduces a novel approach that harnesses the power of machine learning models coupled with Sentinel-2 satellite data to predict phytoplankton shifting and chlorophyll-a (Chla) in three large shallow lakes in central China from 2016 to 2021. We employed an array of machine learning algorithms, including the extreme gradient boosting method (XGBoost), random forest (RF), support vector machine (SVM), and K-nearest neighbor (KNN) to retrieve Chla and phytoplankton groups clustered by hierarchical cluster analysis based on the Bray-Curtis similarity index (HCA). The influences of environmental factors, including meteorology and nutrients, on phytoplankton dynamics were then explored. Our results identified four distinct phytoplankton groups, each exhibiting unique structural characteristics according to the HCA. The RF and XGBoost, utilizing top-of-atmosphere reflectance, provided the most accurate estimations of phytoplankton shifting and Chla, respectively. The red edge-red ratio emerged as a key variable in both models, underlining the significance of red edge bands in phytoplankton monitoring. We mapped spatial-temporal patterns of phytoplankton group occurrence and average Chla concentration across the three lakes. Our findings indicated that eutrophication extended periods of cyanobacteria domination and algal blooms, particularly in bays and nearshore areas. Redundancy analysis and classification and regression tree model highlighted temperature as a significant driver of phytoplankton shifting, while nutrient levels exhibited stronger influences on Chla. Our study underscores the potential of integrating machine learning models with Sentinel-2 data to enhance the monitoring and prediction of phytoplankton dynamics in shallow lakes. This approach offers valuable insights for the early detection of algal blooms and informed management strategies, contributing to the preservation and sustainable management of aquatic ecosystems.

Machine learning-based investigation of forest evapotranspiration, net ecosystem productivity, water use efficiency and their climate controls at meteorological station level

Evapotranspiration (ET), net ecosystem productivity (NEP), and ecosystem water use efficiency (EWUE) of forests are changing due to climate change. Traditional models using coarse-scale climate reanalysis data fail to capture local meteorological and hydrological conditions accurately. This study combines in situ meteorological observations, remote sensing, and advanced datasets (forest age, rooting depth, soil moisture) to estimate ET, NEP, and EWUE at forest meteorological stations via machine learning. About 60.6 % of stations showed a decrease in NEP from 2003 to 2010 to 2011–2019, while 63.9 % showed an increase in ET, and 58.9 % showed a decrease in EWUE. NEP and EWUE significantly declined in forests older than 60 years, with younger forests exhibiting higher NEP. EWUE in different forest types is driven by varying mechanisms, with DBF sites influenced by VPD and ENF sites by RSDN. EWUE of regions with inconsistent VPD data between site and reanalysis, such as northwestern North America, showed divergences from previous reanalysis-based studies but aligned more with atmospheric inversion findings. Slight summer VPD increases boosted NEP, especially in high-latitude areas, while early spring phenology and increased spring VPD reduced summer water availability. Incorporating more site-specific observations, such as plant traits, could enhance understanding of climate-plant-ecosystem relationships. This study underscores the potential of meteorological station-level data to improve forest carbon and water flux dynamics understanding, aiding forest management for carbon neutrality and climate adaptation.

Pywr-DRB: An open-source Python model for water availability and drought risk assessment in the Delaware River Basin

The Delaware River Basin (DRB) in the Mid-Atlantic region of the United States is an institutionally complex water resources system that provides drinking water for 13.5 million people, plus water for energy, industry, recreation, and ecosystems. This paper introduces Pywr-DRB, an open-source Python model exploring the impacts of reservoir operations, transbasin diversions, and minimum flow targets on water availability and drought risk in the DRB. Pywr-DRB draws on streamflow estimates from emerging data resources, bridging advances in large-scale hydrologic modeling with an improved representation of the basin's evolving water infrastructure and management institutions. Our detailed model diagnostic assessment demonstrates that Pywr-DRB provides substantial improvements over sole use of hydrologic models in capturing the DRB's dynamics. We also explore how water management alters model-derived risk estimates for low flows and water demand shortfalls. Our approach to diagnostic benchmarking and water systems modeling is broadly applicable to other major basins.

DIVERSITY OF FISH TYPES IN CIRAHAB SOURCE WATER AND WATER QUALITY FOR FISH ECOSYSTEMS IN CIRAHAB, CURUGGOONG VILLAGE PADARINCANG DISTRICT, SERANG-BANTEN

The research was conducted at water sources in Cirahab, Curuggoong village, Padarincang District, Serang-Banten Regency, research was conducted in January 2024, this research was conducted to determine the diversity of fish in the water source water ecosystem in Cirahab. The results obtained in the research There are 11 types of fish obtained during the research, including tilapia, goldfish, wader, betook, eel, nilem, chana, tawes, sili-sili, kampala (paitan) and catfish. The fish that dominate the waters of Cirahab are the wader fish which are often found there. Fishing is found in 3 places, namely places number 1, 2 and number 3. The category obtained in the fish diversity index is the "low" category because the value is -1.7255. The water parameters in Cirahab waters are ideal because they have a pH of 7, clarity of 90, water temperature of 23°C and an average depth of only 1 meter.

Framing water–energy–food–ecosystem (WEFE) nexus interactions in the Tana-Beles Sub-basin of Ethiopia

The water–energy–food–ecosystems (WEFE) provide vital resources that are essential to human existence. Exploring synergies and trade-offs in these systems has been of interest in recent years to increase economic gain while sustaining the environment. The Tana-Beles Sub-basin of Ethiopia is challenged by population density, climate change, and ecosystem degradation that requires a WEFE Nexus thinking. To understand the current WEFE nexus interactions in the basin, a systematic review of 102 scientific research articles published from 1991 to 2021 was undertaken. Additionally, the systematic review is complemented by spatial data analysis to identify synergies and trade-offs among the WEFE nexus indicators. The analysis revealed the dominance of food–water–ecosystem interdependencies in WEFE nexus research for the Tana-Beles Sub-basin. This dominance is driven by extensive food production activities, which lead to substantial water abstraction and hydrological alterations to meet the intensive water demands of crop cultivation. Simultaneously, the energy-ecosystem interactions are critical due to excessive biomass utilization that exceeds the biomass production potential of the area. Furthermore, the available vegetation cover of the area is very limited to supplement the growing fuel wood demands, which is exerting extreme land degradation and threatening the ecosystem in the sub-basin. This study identifies gaps in WEFE understanding, highlights specific challenges and opportunities within the basin, and calls for coordinated stakeholder action for sustainable resource management through a Nexus approach.

Water limitation regulates positive feedback of increased ecosystem respiration.

Terrestrial ecosystem respiration increases exponentially with temperature, constituting a positive feedback loop accelerating global warming. However, the response of ecosystem respiration to temperature strongly depends on water availability, yet where and when the water effects are important, is presently poorly constrained, introducing uncertainties in climate-carbon cycle feedback projections. Here, we disentangle the effects of temperature and precipitation (a proxy for water availability) on ecosystem respiration by analysing eddy covariance CO2 flux measurements across 212 globally distributed sites. We reveal a threshold precipitation function, determined by the balance between precipitation and ecosystem water demand, which separates temperature-limited and water-limited respiration. Respiration is temperature limited for precipitation above that threshold function, whereas in drier areas water limitation reduces the temperature sensitivity of respiration and its positive feedback to global warming. If the trend of expansion of water-limited areas with warming climate over the last decades continues, the positive feedback of ecosystem respiration is likely to be weakened and counteracted by the increasing water limitation.

Copper-supported MOF-derived carbon materials for highly efficient antibiotics removal

Facing the escalating issue of antibiotic pollution and the emergence of bacterial resistance in water ecosystems, photocatalytic technology has been widely studied as one of the efficient methods to remove antibiotics in aquatic ecosystem. Herein, the bimetallic organic framework materials Cu/Zn-BTC were synthesized with varying proportions of copper and zinc as metal joints and 1,3,5-phthalic acid as organic ligands. Subsequently, the zinc elements within the MOF were eliminated through high pyrolysis to obtain carbon materials derived from Cu/Zn-BTC (referred to as 1.3CZC, 1.4CZC, and 1.5CZC based on the copper-to-zinc ratio). Notably, the presence of different valence copper species facilitated to form type II heterojunction within MOF-derived carbon materials, where internal Cu0/Cu+ species combined with oxygen vacancies to create localized bands that prolonged the lifetime of photogenerated carriers and enhanced photocatalytic activity. X-ray photoelectron spectroscopy, Brunauer-Emmett-Taylor and other characterization methods were used to analyze the difference in structure and performance of different catalysts. 1.4CZC showed excellent performance, upon exposure to visible light for 30 min, the removal rate of tetracycline significantly increased to an impressive 92.4 %, while extending the exposure time to 60 min further improved the removal rate of ciprofloxacin to approximately 82.6 %. It provides a highly efficient antibiotics removal pathway by MOF-derived carbon materials.

Drought effects in Mediterranean forests are not alleviated by diversity‐driven water source partitioning

Abstract Tree species diversity in forest ecosystems could reduce their vulnerability to extreme droughts through improved microclimate and below‐ground water source partitioning driven by contrasting species‐specific water use patterns. However, little is known about the seasonal dynamics of belowground water uptake that determine whether diversity positively or negatively impacts tree carbon assimilation and water exchange. Using a network of 30 permanent plots in Mediterranean forests with increasing tree species diversity (from monospecific to four‐species mixtures), we examined the seasonal patterns of in‐situ aboveground carbon and water relations and belowground water sources on 265 trees from four pine and oak species over 2 years using hydraulic and stable isotope approaches. We found that increasing species diversity in broadleaf and conifer mixtures induced strong soil water source partitioning between oak and pine species. As conditions became drier during the summer in mixed stands, oak species took up water from deeper soil sources, while pines were systematically limited to shallow ones. Despite significant belowground moisture partitioning, stronger drought‐induced reductions in photosynthesis, stomatal conductance, and leaf water potential were still observed in diverse compared with monospecific stands for pines but with some benefits for oaks. Synthesis: Our findings reveal that tree species diversity promoted belowground water source partitioning in mixed oak and pine stands, potentially reducing competition for water in more diverse ecosystems. Yet, our results show that it is insufficient to buffer the adverse impacts of severe droughts on aboveground tree carbon and water use, leading to higher water stress, especially for pines.

Estimation and spatiotemporal analysis of actual evapotranspiration over Qinghai-Tibet Plateau using an Alpine Grassland-Adapted Priestley-Taylor model

Evapotranspiration (ET) is a crucial process in the land water cycle, energy balance, and carbon cycle, making it essential for understanding ecosystem health and climate change. The Qinghai-Tibet Plateau (QTP) is a vital contributor to the global water cycle and ecosystem, and its water resources and ecological environment are of great significance to the development and survival of Asia. To accurately estimate ET on the QTP, this paper proposes an improved Priestley-Taylor (PT) model based on shortwave infrared soil moisture index (SIMI). The model is applied to estimate ET on the QTP from 2011 to 2020, allowing for a comprehensive spatiotemporal analysis. The findings indicate that, (1) The PT-SIMI model has higher estimation accuracy than both the Modified Satellite-Based Priestley-Taylor (MS-PT) model and the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model at most sites, particularly in alpine grasslands sites, and demonstrates a greater sensitivity in capturing changes in soil moisture; (2) the spatial distribution of ET on the QTP demonstrates a declining pattern from southeast to northwest; (3) the average ET from 2011 to 2020 remains relatively stable at 478 mm/year; (4) notable spatial variations in ET are observed across the plateau, with noticeable upward trends observed in the central and western regions, while the south central region experiencing a decreasing trend. This study provides valuable insights into the water cycle and ecological environment of the QTP and its findings can support sustainable development in the region.

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.

Degradation and detoxification of 6PPD-quinone in water by ultraviolet-activated peroxymonosulfate: Mechanisms, byproducts, and impact on sediment microbial community

N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone (6PPD-Q) has been identified to induce acute toxicity to multifarious aquatic organisms at exceptionally low concentrations. The ubiquity and harmful effects of 6PPD-Q emphasize the critical need for its degradation from water ecosystems. Herein, we explored the transformation of 6PPD-Q by an ultraviolet-activated peroxymonosulfate (UV/PMS) system, focusing on mechanism, products and toxicity variation. Results showed that complete degradation of 6PPD-Q was achieved when the initial ratio of PMS and 6PPD-Q was 60:1. The quenching experiments and EPR tests indicated that SO4•− and •OH radicals were primarily responsible for 6PPD-Q removal. Twenty-one degradation products were determined through high-resolution orbitrap mass spectrometry, and it was postulated that hydroxylation, oxidative cleavage, quinone decomposition, ring oxidation, as well as rearrangement and deamination were the major transformation pathways of 6PPD-Q. Toxicity prediction revealed that all identified products exhibited lower acute and chronic toxicities to fish, daphnid and green algae compared to 6PPD-Q. Exposure experiments also uncovered that 6PPD-Q considerably reduced the community diversity and altered the community assembly and functional traits of the sediment microbiome. However, we discovered that the toxicity of 6PPD-Q degradation solutions was effectively decreased, suggesting the superior detoxifying capability of the UV/PMS system for 6PPD-Q. These findings highlight the underlying detrimental impacts of 6PPD-Q on aquatic ecosystems and enrich our understanding of the photochemical oxidation behavior of 6PPD-Q.

Relationship among micro-pollutants, economic growth, renewable energy, nanotechnology and ecological foot prints of China: evidence from panel data analysis.

An important concern is the availability of clean drinking water, which is an essential need for human survival. This issue arises due to the existence of hazardous micropollutants originating from various emission sources. Nanotechnology aids in the mitigation of micropollutants by assimilating and counteracting their effects, hence diminishing their influence on water and other ecosystems. The study investigates the relationship between nanotechnological progress, the adoption of renewable energy, environmental consequences, and economic growth in China, using the Environmental Kuznets Curve theory as a conceptual framework. The study employs panel cointegration tests to analyze structural breaks from 2000 to 2020. Nanotechnology is expected to reduce environmental degradation and the presence of micro-pollutants by increasing the use of renewable energy and promoting energy conservation. Nanotechnology is crucial for mitigating micro-pollutants and advancing sustainable development in this specific context. However, the literature also highlights the harmful consequences of nanoparticle emissions caused by nanotechnology on human and environmental health for a long duration, requiring more examination. This research is the first empirical inquiry into the relationship between improvements in nanotechnology, the use of renewable energy, economic growth, and ecological effect, all within the context of the Environmental Kuznets Curve theory. The results confirm the successful incorporation of all components with a focus on long-term outcomes. The findings suggest that the EKC hypothesis is relevant in China. In China, advancements in nanotechnology have a moderating effect on environmental degradation. The use of renewable energy sources in China enhances environmental circumstances. Given the offered empirical evidence, it is advisable for the government to have a leading role in the development of innovative nanotechnologies that have low emissions of nanoparticles. By using this approach, it will be possible to encourage the conservation of energy and the use of renewable sources in a more secure way, hence improving the effectiveness of sustainable development initiatives.

Hydrological drought assessment of the Sava River basin in South-Eastern Europe

ABSTRACT Hydrological drought poses significant challenges to water resources, ecosystems, and human activities, necessitating comprehensive investigation. Monthly streamflow data from 12 monitoring stations across the Sava River basin were utilized to compute the streamflow drought index (SDI). The Mann–Kendall test evaluated trends, and the SDI's hydrological states were classified based on cumulative streamflow volumes. The study identified an alarming 83.3% of stations exhibiting statistically significant decreases in summer streamflow, indicating a widespread and concerning trend of declining water availability in the Sava River basin. Drought severity was particularly pronounced in tributaries such as the Vrbas and Bosna rivers, emphasizing the heterogeneous nature of hydrological changes. These findings underscore the urgent need for adaptive water resource management strategies in the face of escalating hydrological drought risks, especially given the far-reaching consequences on agriculture, industry, ecosystems, and social well-being. The study provides crucial insights for developing targeted resilience measures tailored to the specific challenges presented by the diverse hydrological conditions in the Sava River basin.

Assessing benthic macroinvertebrate communities’ spatial heterogeneity in Mediterranean transitional waters through eDNA metabarcoding

Transitional waters are important habitats both for biodiversity and ecological functions, providing valuable natural resources and relevant ecosystem services. However, they are highly susceptible to climate changes and anthropogenic pressures responsible for biodiversity losses and require specific biomonitoring programs. Benthic macroinvertebrates are suitable as ecological indicators of transitional waters, being affected by biological, chemical, and physical conditions of the ecosystems about their life cycles and space-use behaviour. The advent of high-throughput sequencing technologies has allowed biodiversity investigations, at the molecular level, in multiple ecosystems and for different ecological guilds. Benthic macroinvertebrate communities’ composition has been investigated, at the molecular level, mainly through DNA extracted from sediments in marine and riverine ecosystems. In this work, benthic macroinvertebrate communities are explored through eDNA metabarcoding from water samples in a Mediterranean transitional water ecosystem. This research highlighted the validity of eDNA metabarcoding as an efficient tool for the assessment of benthic macroinvertebrate community structure in transitional waters, unveiling the spatial heterogeneity of benthic macroinvertebrate communities correlated to the measured environmental gradients. The results suggest that peculiar features of transitional water ecosystems, such as shallow waters and limited currents, facilitate the assessment of benthic macroinvertebrate communities through environmental DNA analysis from surface water samples, opening for more rapid and accurate monitoring programs for these valuable ecosystems.

A Comparative Study of Highland Riparian Landscape Structure in Ubud, Indonesia and Banaue, Philippines

Abstract In Southeast Asia, Indonesia and the Philippines boast unique riparian areas crucial for ecological balance. These zones, nestled in mountainous terrains, act as vital links between land and water ecosystems, rich in biodiversity and cultural significance. However, they face threats from human development, causing fragmentation and altering their functions. To comprehend these changes, a study compared the landscape structure of two mountain villages in Ubud, Indonesia, and Banaue, Philippines. Using the landscape profile method, the study examined the relationship between landscape elements, highlighting Batad and Tegalalang’s distinct characteristics and challenges. While both areas featured forests, agriculture, and built-up areas, Batad exhibited less fragmentation. Terraced rice fields played critical roles in supporting water flow and biodiversity but faced risks from agrochemical use. Tegalalang faced environmental challenges like inadequate waste management and water scarcity, emphasizing the need for sustainable practices. The study’s adaptation of the landscape profile method provided valuable insights into landscape fragmentation, aiding in understanding and addressing ecological complexities in riparian zones. This research highlights the importance of preserving and managing riparian areas in mountainous regions to sustain their ecological functions amidst growing human impacts.

Cytotoxicity evaluation of organophosphorus flame retardants using electrochemical biosensors and elucidation of associated toxic mechanisms

In recent years, organophosphorus flame retardants (OPFRs) have been widely used as substitutes for brominated flame retardants with excellent properties, and their initial toxicological effects on the water ecosystem and human health have gradually emerged. However, to date, research on the cytotoxicity and health risks of OPFRs is still limited. Therefore, this study aims to systematically explore the cytotoxic effects and toxic mechanisms of OPFRs on cells. Human liver cancer (HepG2) cells were adopted as an ideal model for toxicity evaluation due to their rapid growth and metabolism. This study proposes a sensitive electrochemical cell–based sensor constructed on a graphitized multi-walled carbon nanotube/ionic liquid/gold nanoparticle-modified electrode. The sensor was used to detect the cytotoxicity of tri(2-butylxyethyl) phosphate (TBEP), tributyl phosphate (TnBP), triphenyl phosphate (TPhP), tri(1,3-dichloro-2-propyl) phosphate (TDCIPP), tri(2-chloropropyl) phosphate (TCPP) and tri(2-chloroethyl) phosphate (TCEP) in the liquid medium, providing insight into their toxicity in water environments. The half-maximal inhibitory concentration (IC50) of TBEP, TnBP, TPhP, TDCIPP, TCPP and TCEP on HepG2 cells were 179.4, 194.9, 219.8, 339.4, 511.8 and 859.0 μM, respectively. Additionally, the cytotoxic mechanism of six OPFRs was discussed from the perspective of oxidative stress and apoptosis, and four indexes were correlated with toxicity. Furthermore, transcriptome sequencing was conducted, followed by a thorough analysis of the obtained sequencing results. This analysis demonstrated a significant enrichment of the p53 and PPAR pathways, both of which are closely associated with oxidative stress and apoptosis. This study presents a simplified and efficient technique for conducting in vitro toxicity studies on organophosphorus flame retardants in a water environment. Moreover, it establishes a scientific foundation for further investigation into the mechanisms of cytotoxicity associated with these compounds.

Radioactive elements in wastewater and potable water: Sources, effects, and methods of analysis and removal.

Radioactive effluents, originating from nuclear power plants, medical-nuclear applications, and various extraction industries worldwide, present a significant and dangerous contamination challenge. The concentrations of radioactive substances in wastewater, surface water, and potable water vary widely depending on the source and location. For example, cesium-137 levels in wastewater from nuclear facilities can range from 0.1 to 10 Bq/L, while tritium concentrations in surface water near nuclear plants can reach up to 100 Bq/L. Regulatory guidelines, like the maximum contaminant level of 0.185 Bq/L for combined radium-226 and radium-228 in drinking water, are critical for ensuring safety and environmental protection. Specifically, in Fukushima, Japan, cesium-137 levels in surface water range from 0.1 to 10 Bq/L due to the nuclear accident. In contrast, regions with natural uranium deposits, like parts of the United States, have reported radium-226 concentrations in potable water up to 1 Bq/L. These variations highlight the necessity for focused monitoring and evaluation to protect water quality and community health. Among various methods, Gamma spectrometry and inductively coupled plasma mass spectrometry are precise for radionuclide quantification, scintillation detectors, and ion exchange, and adsorption techniques efficiently remove radioactive substances from water. This critical review examines the sources, adverse effects, and analysis and remediation strategies for various radioactive elements in wastewater. By thoroughly evaluating the origins and potential dangers associated with radioactive effluents, this report emphasizes the urgent need for rigorous monitoring and effective treatment practices to maintain the integrity of water resources and ecosystems. PRACTITIONER POINTS: Comprehensive analysis of the radioactive elements frequently found in wastewater and drinking water. Assess the negative effects of radioactive elements in water systems. Examine the treatment methods used to eliminate radioactive pollutants from water sources. Outline effective methods and tactics for addressing and controlling radioactive contamination occurrences. Analyze the latest advancements in technology, regulatory enhancements, and optimal methods to guarantee the safety of drinking water and the sustainable handling of radioactive substances in wastewater.