Global water shortage and potable water safety; Today's concern and tomorrow's crisis

Screening and risk assessment of priority organic micropollutants for control in reclaimed water in China

Organic micropollutants (OMPs) in reclaimed water have been frequently detected over the past decades, posing significant risks to ecosystems and human health. Given the complexity of these pollutants and the differences in their risk and toxicity, current assessments remain incomplete. This study conducted a large-scale investigation of OMPs in reclaimed water across China and developed a comprehensive multi-criteria integrated scoring method based on OMP toxicity and exposure potential. This method aims to protect aquatic organisms and human health by screening and prioritizing OMPs in reclaimed water, classifying their priority levels, and creating a prioritized control list. The study quantified OMP exposure potential, environmental persistence, bioaccumulation, and impacts on ecology and human health. The survey detected 369 OMPs from 11 chemical classes, with 325 compounds passing pre-selection. According to the prioritization scheme, 29 OMPs were identified as high priority, 171 as medium priority, and 125 as low priority. The BPs and Other Industrial Chemicals categories had the highest average maximum concentrations, followed by HPCCs and PAEs. High-priority pollutants were dominated by PAHs and PCBs, each comprising 31.03 %. Medium- and low-priority groups were mainly composed of Pesticides. PAHs and PCBs showed higher risk quotients, indicating significant ecological risks, while PCB 126, BaP, and PFOA exhibited high toxicity and potential health risks. This study provides valuable information for controlling priority pollutants in Chinese reclaimed water and establishes a foundation for OMP risk management. Future research should intensify monitoring to ensure the safe and sustainable use of water resources.

Integration of ecosystem service composite index and driving thresholds for ecological zoning management: A case study of Qinling-Daba Mountain, China

Ecological zoning management is key to achieving synergistic ecological protection and coordinated regional development. Existing zoning methods are mostly based on functional attributes in a static state, which makes it difficult to capture the dynamic evolution of ecosystems and reveal their underlying mechanisms of change, thus limiting the possibility of precise regulation in practice. This study, using the Qinling-Daba (QB) Mountains as an example, thoroughly identifies thresholds between ecosystem service and driving factors, incorporates them into the ecological zoning system construction, and further formulates differentiated management measures. The results showed that the ecosystem services composite index (ESC) in the QB exhibited an overall increasing trend, characterized by a south-high, north-low distribution from 2000 to 2020. Geosocial factor predominantly exerted a negative impact on ESC but showed a tendency to weaken, while the climate-ecological factor demonstrated a positive influence with a tendency to strengthen. A nonlinear relationship was observed between ESC and key factors, with sensitive thresholds identified for the strength of impact and critical thresholds for maximum supply. In 2020, the enhancing areas were concentrated in the western QB characterized by complex terrain and a relatively fragile ecological environment; refining areas accounted for 84.12 %, distributed in the central region; protected areas were concentrated in the southeast region with better water and heat conditions. This study provides a new perspective and new pathways for zoned management, holding significant importance for enhancing refined management of mountain areas.

Engineering the dimensionality of porous Co3O4 for enhanced capacitive deionization performance

The intricate network of pores within the material matrix is frequently underutilized during ion diffusion. Here, the spatial dimension of the ZIF-9 derived porous material was precisely controlled by strategic modification of the carboxyl functional groups on the ligand chains for deriving 2D-Co3O4 architecture, which demonstrates substantially enhanced accessibility to its porous domains, and consequently leads to markedly improved desalination capacity.

Harnessing halophytes to mitigate the environmental impact of membrane desalination brine

This study presents an integrated and sustainable approach to valorise brine from brackish water desalination plants through the cultivation of halophytes in hydroponic systems. The objective of this study is to assess the effectiveness of halophytes in reducing brine salinity. The methodology includes halophyte acclimatisation, brine collection and analysis, experimental prototypes setup, and monitoring of plant physiological parameters as well as the physico-chemical properties of water. Halophytes were cultivated in three hydroponic systems using water media with varying salinity levels: brackish borehole water (3 g/L), and Reverse Osmosis (RO) desalination brines with salinities of 6 g/L and 9 g/L. The results showed a correlation between irrigation water salinity and halophyte growth, with the densest root development observed at higher salinity levels (9 g/L). The chemical analyses of halophytes revealed sodium and potassium accumulation in plant tissues, underscoring their capacity to reduce brine salinity. These findings highlight the potential of halophytes as a promising and sustainable solution for valorising brine from RO brackish water desalination.

Long-term storage of rainwater: Assessing the efficacy of disinfection methods on water quality and pathogenic species dynamics

Ultraviolet (UV) disinfection and solar pasteurization are commonly used methods for rainwater treatment, but the changes in water quality and pathogenic species during long-term storage require further investigation. This study conducts a 60-day static rainwater storage experiment to evaluate changes in microbial community structure and pathogen characteristics under different disinfection methods, providing guidance for the resource utilization of rainwater. The results show that both UV disinfection and solar pasteurization effectively reduce microbial diversity and the abundance of pathogenic species. During storage, UV disinfection is particularly effective in controlling pathogenic species, while solar pasteurization has a more pronounced effect on improving water quality. Pathogens species in UV-disinfected rainwater begin to increase around the 20th day of storage, whereas their growth in solar-pasteurized rainwater persists throughout the storage period. UV-disinfected rainwater is suitable for domestic non-potable uses and livestock in the early stages, but as storage time increases, it becomes more appropriate for agricultural use. The lowest health risk occurs on the 20th day, with secondary disinfection recommended on the 60th day. Similarly, during the first 20 days, solar pasteurized rainwater is comparable to UV-disinfected rainwater in terms of usability. However, by the 60th day, due to an increase in animal-associated pathogenic species, solar pasteurized rainwater becomes more suitable for agricultural use. Multiple disinfections on the 20th and 60th days are advised to reduce microbial risks. Additionally, UV disinfection reduces pathogenic diversity, forming stable microbial clusters, while solar pasteurization increases diversity and promotes complex interactions. These findings provide new insights into microbial community structure and pathogenic species changes during long-term rainwater storage and offer important guidance for rainwater reuse.

Visible Light Photo-Fenton with Hybrid Activated Carbon and Metal Ferrites for Efficient Treatment of Methyl Orange (Azo Dye)

Ensuring effective water purification is essential for addressing freshwater scarcity and achieving the United Nations Sustainable Development Goals (SDGs). An efficient hybrid mixture, composed of FeCr quantum dots doped into mesoporous silica SBA-15 support and activated carbon (AC) derived from olive mill solid wastes, has been developed for treating high optical density polluted aqueous environments. This hybrid, denoted as FeCr-SBA-15/AC, was examined for its efficacy in the adsorption and photo-Fenton degradation of met orange dye (MO), a model high-optical-density pollutant, under visible light exposure. Characterization of the prepared samples was conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Key parameters investigated included catalyst dosage, dye concentration, solution pH, and H2O2 concentration. Remarkably, the FeCr-SBA-15/AC hybrid exhibited superior photocatalytic activity, achieving a degradation efficiency of 97% for MO under optimized conditions (catalyst dosage = 0.75 g L-1, dye concentration = 20 mg L-1, pH = 5.47, and 0.5 mL H2O2) after 180 min of irradiation with visible light. This performance surpassed that of FeCr-SBA-15 alone by 20%, due to the synergistic effects of adsorption and photo-Fenton. The adsorption of MO onto AC followed the Freundlich model equilibrium isotherm, while the experimental data for the hybrid mixture aligned well with the pseudo-first-order Langmuir-Hinshelwood kinetic model with a rate constant of 0.0173 min-1. The leaching of Cr in the solution was very low-0.1 ppm-which is below the detection limit. These findings underscore the potential of the synthesized FeCr-SBA-15/AC hybrid as a cost-effective, environmentally friendly, and highly efficient photo-Fenton catalyst for treating wastewater contaminated by industrial effluents.

Typhoid and viral hepatitis in a child: revisiting the role of water, sanitation and hygiene (WASH) and vaccines in the epidemiology of faecal-orally transmitted diseases

This case report describes Hepatitis A and typhoid infections in a child hailing from an urban site in India within 4 weeks, thereby highlighting systemic issues with water quality and public health. The case sheds light on the broader public health challenges faced by low- and middle-income countries, including inadequate WASH (water, sanitation and hygiene) facilities, contributing to high incidences of faecal-orally transmitted diseases. In 2016, poor WASH was responsible for 60% of diarrhoeal deaths. The Sustainable Development Goals aim to improve global water and sanitation by 2030, emphasising the need for equitable access. Interim solutions like vaccination and point-of-use water treatment are vital. Vaccination against typhoid and hepatitis is especially crucial in areas with high disease prevalence and rising antimicrobial resistance. We must advocate for these vaccines to be included in the National Immunisation Schedules to ensure widespread, equitable coverage and support public health.

An Extremely Salt-Resistant Hydrogel-Based Solar Evaporator for Stable Saturated Brine Desalination

Hydrogel-based solar evaporators are widely concerned because of their excellent evaporation performance due to the "water activation" effect by reducing the evaporation enthalpy. However, the current challenge is the trade-off between a high evaporation rate and salt tolerance. Here, a 3D chitosan-based hydrogel evaporator with a directional vertical channel structure using a one-pot in situ strategy and directional freezing method, is innovatively designed. Owing to its vertical channel structure, salt ions can quickly return, while steam can overflow without obstruction, allowing the evaporator to achieve a high evaporation rate and exceptional salt resistance, simultaneously. Consequently, an extremely salt-resistant system is achieved, even in saturated brine (salinity of 26.47 wt.%), with no salt crystals accumulating after continuous over 8 h of evaporation and an excellent evaporation rate of 2.83 kg m-2 h-1 under one sun illumination. This is the best reported salt-resistant hydrogel-based evaporation system. With the record-high salt resistance, this work improves the practicality of hydrogel evaporators for high-salinity desalination.

Exploring the Synergistic Interplay of Optical, Morphological, and Catalytic Features in Ga-Doped ZnO Nanoparticles: Harnessing Their Potential for Photocatalytic Dye Degradation under UV-Green Light Irradiation

This work explores the synthesis and characterization of undoped ZnO, Ga-doped ZnO (Ga:ZnO), and γ-Ga2O3 quasi-spherical nanoparticles and their catalytic activity in Rhodamine B photodegradation under UV-visible light exposure. Gallium dopant incorporation into Ga:ZnO was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES), Fourier transform infrared (FT-IR), and powder X-ray diffraction (XRD), maintaining the hexagonal wurtzite structure with an additional zinc gallium carbonate Layered Double Hydroxide (LDH) phase at higher dopant concentrations. TEM images revealed no significant alteration in the morphology or size of the nanoparticles. 71Ga-NMR indicated the location of the gallium atoms within the ZnO lattice, showing coordination changes with an increasing dopant concentration. Ga-doped ZnO nanoparticles demonstrated reduced efficiency under UV light compared to commercial references. γ-Ga2O3 exhibited superior performance in UV-C for Rhodamine B degradation, diminishing under UV-A, attributed to nanoparticle agglomeration. ZnO and Ga:ZnO catalysts showed optimal performance under green light irradiation, highlighting their performances over the commercial zinc oxide material. Photoluminescence measurements suggested favorable gallium dopant incorporation, with no substantial variation of oxygen vacancies, consequently retaining the photocatalytic properties of ZnO, which are crucial for Rhodamine B degradation under green light irradiation. This study elucidates the intricate relationship among gallium doping, material properties, and photocatalytic performance, providing valuable insights for developing advanced photocatalysts.

Silicon enhanced phosphorus uptake in rice under dry cultivation through root organic acid secretion and energy distribution in low phosphorus conditions

Dry cultivation of rice (DCR) is one of the important rice cultivation practices aimed at addressing freshwater resource shortages. However, the non-renewable nature of phosphate resources constrains agricultural development. In the context of the contradiction between rice, water, and phosphorus, there is little research on using the silicon phosphorus relationship to improve the phosphorus availability and uptake of DCR. This experiment used field soil and established five fertilization treatments: no phosphorus application, low phosphorus and normal phosphorus (0, 25, 75 kg·ha-1 P2O5) (0P, 25P, 75P), along with two silicon levels (0, 45kg·ha-1 SiO2), resulting in the treatments 0P, 0PSi, 25P, 25PSi, and 75P. The soil phosphorus components and plant phosphorus uptake were analyzed. The results showed that adding silicon to 25P increased the Olsen-P content (14.37%) by increasing Ca8-P (9.04%) and Al-P (19.31%). Additionally, root and leaf phosphorus content increased by 7.6% and 5.8%, respectively, comparable to the levels observed in the 75P treatment. On one hand, adding silicon increases malate (40.48%) and succinate (49.73%) content, enhances acid phosphatase activity, and increases the abundance of Bradyrhizobium, Paenibacillus, and Bacillus, as well as the proportion of Fusarium, forming an "organic acid microbial" activated phosphorus system. On the other hand, the addition of silicon alleviated phosphorus limitations by reducing ATP consumption in roots through a decrease in ATPase and P-ATPase content. This also minimized excessive NSC transport to roots, thereby promoting shoot growth by downregulating SUT1, SWEET11, SUS2, and CIN2. In addition to optimizing root-to-shoot ratio and providing sufficient energy, silicon addition also increases root volume and upregulates OsPT2, OsPT4, and OsPT8, thereby promoting phosphorus uptake. In summary, 25PSi optimizes the root-to-shoot ratio and promotes phosphorus conversion and uptake through organic acid, microbial, and energy pathways. Applying silicon is beneficial for the sustainable and efficient management of phosphorus in DCR.

Application of aquatic macroinvertebrates in water quality assessment of the Nyabarongo and Akagera Rivers in Rwanda

Riverine pollution is an increasing threat to ecosystem integrity and economic development, thus a need for effective monitoring to guide the management of ecosystem health. Opportunely, aquatic macroinvertebrates have been proven to indicate the health status of the rivers. However, there is scanty information about their use in Rwanda. This study used macroinvertebrates to assess the water quality of the Nyabarongo and Akagera Rivers following the Tanzania River Scoring System (TARISS). The study was carried out between May 2023 and March 2024 and covered 13 sampling sites. Macroinvertebrates were collected using a kick sampling method while water samples were collected following standard methods for measuring water properties. Sites were clustered, and multivariate methods were used to assess dissimilarities in taxa distribution. Further, the Focal Principal Component Analysis (FPCA) was performed to assess the association of macroinvertebrates with water physico-chemical parameters. Collected macroinvertebrates belonged to 34 families dominated by Chironomidae, Baetidae, and Culicidae. The TARISS metrics (mean ± standard deviation) indicated a score of 44.53 (± 2.69), a taxa number of 11 (± 0.6), and an average scope per taxa (ASPT) of 4.07 (± 0.8). Dissolved oxygen had a significant positive influence on the distribution and abundance of the Libellulidae family. Conversely, dissolved oxygen and electric conductivity had a significant negative relationship with the Caenidae and Aeshnidae families, respectively. The low values of the TARISS metrics portend the poor water quality of the Nyabarongo and Akagera Rivers. Thus, management practices and regular biomonitoring are recommended to ensure that the ecosystem health of these rivers is maintained.

A game-theoretic framework for sustainable water allocation in agriculture: Enhancing economic and water efficiency in Akrotiri district (Cyprus)

Water scarcity is an escalating issue in Mediterranean countries, including Cyprus, where climate change, population growth, rapid urbanization, and economic development place significant pressure on water resources. This study focuses on optimizing the allocation of recycled water for agricultural use in the Akrotiri district, using a game theory approach to maximize net benefits (NB) associated with crop production by considering conventional and nonconventional water resources. A linear optimization framework is developed in which eighteen crop types act as players in a cooperative game, contributing to an overall benefit- and cost-sharing model. Optimal water allocation schemes prioritize crops with high economic productivity and low water demand, enhancing both sustainability and profitability. Based on the available water for irrigation in 2022 (baseline case), the NB is 23 million euros whereas the required subsidies, sourced from external entities, amount to 2 million euros. Groundwater recharge via managed aquifer recharge (MAR) is included as a scenario leading to a similar NB but increases subsidies to 3.5 million euros. Additional scenarios explore losses from aging infrastructure (increase of subsidies up to 70 %), water quality constraints due to the presence of pollutants (NB and subsidies are 15 and 4 million euros, respectively), various storage strategies (reduction of subsidies about 20 % of the baseline value) and future scenarios based on projected climatic conditions, resulting in the highest subsidies of nearly 9 million euros. This methodology offers a robust decision-making tool for policymakers and planners, helping to navigate the complexities of water allocation under uncertain future climatic conditions.

Urban groundwater supplies facing dual pressures of depletion and contamination in China

Groundwater is essential to urban water supplies throughout the world, but we do not understand how quantity and quality issues may jeopardize the ability of cities to meet their water needs. Here, we present a national analysis of both quantity and quality challenges facing China's urban groundwater supply security, using high-resolution groundwater depletion modeling and a recently compiled dataset detailing quality violations in drinking groundwater sources. We estimate that 180 cities (about half of the prefecture-level-and-above cities), accounting for 311 million urban residents, face at least one groundwater pressure between 2016 and 2021. Cities that face dual quantity and quality pressures pinpoints hotspots of intense groundwater threats- Specifically, 40 cities, mainly situated in Northeast China and the middle to lower reaches of the Yellow River, are exposed to dual groundwater pressures. The results highlight the interconnected and possibly mutually reinforcing nature of groundwater depletion and quality issues. The logistic regression models indicate that groundwater depletion and quality violations are associated with natural water endowment and anthropogenic factors. Particularly, drinking groundwater quality issues are clustered in relation to socioeconomic gaps, with larger, wealthier cities being less prone to such problems. We argue that securing drinking water sources in small and poor cities through integrated groundwater management and economic assistance should be an important national priority for achieving groundwater supply sustainability.

Efficient radiative cooling based on spectral regulation and atmospheric water harvesting with sunflower design

Inspired by the fog-collecting abilities of the Namib Desert beetle, researchers have developed wettability-engineered surfaces for fog collection. However, these approaches fall short in arid regions where fog is absent. To address these challenges, we developed a dual-sided structure based on radiative cooling. The radiation cooling material on the upper surface can achieve energy free cooling. The lower surface is a pattern with heterogeneous wettability, composed of wedge-shaped and conical structures, which can achieve rapid droplet accumulation and directional transport. The radiation cooling material adjusted by spectrum can achieve a temperature difference of up to 14.2°C, enabling the composite material to achieve a maximum water collection efficiency of 602.5 g·m-2·h-1 under RH of 80% conditions. This study provides an effective solution to alleviate water scarcity in arid regions.

Reversible Sol-Gel Transitions Mediated Organics Selective Uptake and Release for Simultaneous Water Purification and Chemicals Recovery

The separation and recovery of useful organics from wastewater have been a promising alternative to tackling water pollution and resource shortages, while strategies that truly work have rarely been explored. Herein, a reversible CO2 triggered sol-gel state transformation mediated selective organics uptake-release system using a surface modified carbonitride (S-CN) is proposed and exhibits remarkable organics recovery performance from wastewater. Results show that CO2 can serve as a cross-linker for linking S-CN particles to form a hydrogel by electrostatic interaction and hydrogen bonding, which can be recycled to the pristine sol state simply by removing the cross-linked CO2 with Ar purging. The reversible sol-gel transformation achieves nearly complete uptake of valuable organics from wastewater with high selectivity at the first sol-to-gel stage through electrostatic interaction, hydrogen bonding, and π-π interactions together, and it recovers 90% of the organics uptaked by releasing them into a concentrated solution at the second gel-back-to-sol stage.

Blood Trihalomethanes and Human Cancer: A Systematic Review and Meta-Analysis

The control of waterborne diseases through water disinfection is a significant advancement in public health. However, the disinfection process generates disinfection by-products (DBPs), including trihalomethanes (THMs), which are considered to influence the occurrence of cancer. This analysis aims to quantitatively evaluate the relationship between blood concentrations of THMs and cancer. Additionally, the relationship between blood chloroform concentration and cancer is analyzed separately. Following PRISMA guidelines, we conducted a thorough search in the PubMed, Web of Science, and CNKI databases. Statistical analysis was performed using Review Manager 5.4 software. After screening, seven studies meeting the evaluation criteria were included. A total of 1027 blood samples from patients with cancer and 7351 blood samples from the control group were collected. The average concentration of THMs in the blood of the experimental group was 46.71 pg/mL, while it was 36.406 pg/mL in the control group. The difference between the two groups was statistically significant (SMD = -0.36, 95% CI: -0.45 to -0.27, p < 0.00001). However, due to the limited research data on the relationship between blood THMs and cancer, the conclusions drawn exhibit high heterogeneity. Additionally, we discussed the carcinogenic mechanisms of THMs, which involve multiple biological pathways such as oxidative stress, DNA adduct formation, and endocrine disruption, with variations in accumulation and target sites potentially leading to different cancer types, for which evidence is currently lacking. In the future, further epidemiological and animal model studies on THMs should be conducted to obtain more accurate conclusions.

Optimizing soil remediation with multi-functional L-PH hydrogel: Enhancing water retention and heavy metal stabilization in farmland soil

Agricultural soils face severe challenges, including water scarcity and heavy metal contamination. Optimizing soil remediation efficiency while minimizing inputs is essential. This study assessed the water retention and heavy metal adsorption properties of L-PH hydrogel through aqueous experiments. Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectroscopy (XPS) elucidated the adsorption mechanisms. The results showed that L-PH hydrogel exhibited high water absorption efficiency, with Zn2+ removed via electrostatic interactions and cation exchange, and Cd2+ and Cu2+ adsorbed through coordination complexation. Soil experiments tested water retention and heavy metal leaching under various application methods (M1 = 0-10 cm mixed, M2 = 10-20 cm mixed, T1 = 5-10 cm layered, T2 = 10-15 cm layered) and rates (NL = 0 %, L1 = 0.1 %, L2 = 0.2 %, L3 = 0.5 %). L-PH reduced water infiltration, enhanced soil water retention, and decreased heavy metal mobility across all treatments. The highest water retention was observed in the M1 method. Under M1L1, cumulative leaching of Cd2+, Cu2+, and Zn2+ decreased by 68.84 %, 33.44 %, and 83.60 %, respectively. Two-way ANOVA revealed that application rate had a greater effect on leaching than the method. FTIR and XRD analyses showed that at low concentrations (L1, L2), L-PH formed coordination bonds with Cd2+ and Cu2+, creating Cd(HCOO)2·2(NH2)2CO and Cu(HCOO)(OH) in the soil. Zn2+ was stabilized through adsorption and precipitation, forming Zn(OH)2, thereby reducing leaching. Higher concentrations of L-PH may have further interacted with Zn, leading to dissolution and adsorption/precipitation processes. Redundancy analysis (RDA) analysis suggests that an increase in organic carbon and moisture content in soil aggregates larger than 2 mm, along with a decrease in bioavailable heavy metals, may enhance heavy metal stabilization, reducing their movement and leaching. This study offers valuable insights into addressing the twin challenges of water scarcity and heavy metal pollution.

Incorporating functionalized graphene oxide into diethylene triamine-based nanofiltration membranes can improve the removal of emerging organic micropollutants

The presence of emerging organic micropollutants (OMPs) in drinking and potable waters is a matter of great concern due to the health hazards associated with these. In this work, we present the preparation and application of a thin-film nanocomposite (TFN) membrane containing functionalized graphene oxide to effectively remove low-molecular-weight OMPs from water. Graphene oxide was functionalized with amino silane to enhance its cross-linking capability during the formation of the polyamide active layer via interfacial polymerization of diethylene triamine and trimesoyl chloride. The TEM analysis showed that amino silane functionalized GO had 2-3 layered sheets, while non-functionalized graphene oxide appeared multilayered or stacked. XPS analysis confirmed the successful functionalization of GO. Characterization of the membranes with advanced techniques confirmed the successful incorporation of the GO and its functionalization: spectra from Fourier Transform Infra Red spectroscopy had the characteristic peaks of GO and NH groups; scanning Electron Microscopy (SEM) images showed a continuous presence of GO nanosheets. Contact angle measurements showed the TFN membranes to be more hydrophilic than their thin film composite (TFC) counterparts. Incorporating functionalized oxide nanosheets in the active polyamide layer produced additional water permeation channels, resulting in an improvement of ∼25 % in permeate flux compared to the pristine TFC and the TFN membrane with non-functionalized GO. The removal efficiencies of four OMPs commonly found in natural waters: Amitriptylene HCl (ATT HCl) and Bisphenol-A (BPA), Acetaminophen (ACT), and Caffeine (CFN) were determined for the synthesized membranes. The TFN membrane with functionalized GO outperformed its TFC counterpart with ∼100 % removal for BPA, ∼ 90 % for CFN and ATT HCl, and ∼80 % removal for the low molecular weight ACT. The high-efficiency rejection of OMPs was attributed to the synergistic effects of size exclusion as well as the reduced specific interactions between the functional groups.

Improvement of water quality through coordinated multi-trophic level biomanipulations: Application to a subtropical emergency water supply lake

Artificial emergency water source lakes have been built in most cities in the middle and lower reaches of the Yangtze River, China, to ensure water safety for residents. However, these new ecosystems are prone to algal blooms or other degraded water quality conditions. A newly built water supply lake in the lower reaches of the Yangtze River was selected as a model system to test whether the coordinated manipulation of fish and submerged macrophyte communities could enhance ecosystem function and quality. The coordinated manipulations spanned a five-year period, aiming to enhance both top-down and bottom-up control of phytoplankton. As a result of these manipulations, the catch per unit effort of small-bodied zooplanktivorous fishes decreased by >95 % from year two and remained low. The coverage and biomass of submerged macrophytes increased year by year. Water transparency increased from 1.07 to 3.33 m. Total phosphorus and total nitrogen showed a decreasing trend (not significant though). The annual mean biomass of Cyanophyta, Chlorophyta and Bacillariophyta decreased from 2.99 to 0.03 mg/L, 3.90 to 0.16 mg/L, and 3.50 to 0.3 mg/L, respectively. The biomass of phytoplankton in different groups decreased in all four seasons. The annual mean biomass of Cladocera and Copepoda remained low. The biomass of Cladocera and Copepoda decreased in summer, fall, and winter. The Ecosystem Health Index - increased from 15.9 to 32.0. The pros and cons of the various top-down and bottom-up control measures employed are discussed. This research presents a valuable case study on the enhancement of ecosystem structure and function in newly constructed emergency water supply lakes and offers insights into the restoration of other subtropical shallow lakes.

Whole genome sequencing approaches for taxonomic profiling and evaluation of wastewater quality

Tracking metagenomic abundance in wastewater is undoubtedly a powerful tool to detect emerging variants and improve community health. However, there are a few factors that limit environmental water-based genomic monitoring: sampling variability, incomplete coverage, genetic fragmentation, degradation, data analysis and interpretation. The decreasing costs of high-throughput sequencing and high-end supercomputers have increased the use and accuracy of genomic data for microbial detection and monitoring in wastewater samples within any given region. To better understand the microbial dynamics and to determine the target sequencing throughput required to establish taxa that may pose as bio-indicators of an epidemiological outbreak, wastewater samples were collected from distinct locations within the Emirate of Abu Dhabi, United Arab Emirates using appropriate sampling methods. A reference database of ∼27,000 known species was developed and used for further analysis. The results showed that 15 % of data in each sample matched any of ∼27,000 known bacterial, viral, fungal, or protozoan species. Despite the high fraction of unclassified data (85 %), more than 2000 species from >800 genera across >30 phyla were detected in each sample. Both 5 Gb and 10 Gb of sequenced data detected the top ∼2000 species with highest abundance. Doubling the target sequencing throughput (i.e., 10 Gb vs 5 Gb) detected ∼500 additional low-abundance species per sample however it did not affect the overall sample composition or translate into higher per-sample species diversity captured. There was a marginal increase in the number of species detected in each sample beyond 0.20 Gb of classified data. Overall, the results indicate that sequencing to a 3 Gb throughput detects nearly 95 % of all species in the samples.

Efficient solar-driven freshwater generation through an inner hierarchical porous metal-carbon layer bridging synergistic photothermal evaporation and adsorption photodegradation

Solar-driven interfacial evaporation has emerged as a promising avenue for clean water production, leveraging solar energy to extract water vapor from salty and polluted water sources. However, a critical challenge remains, during the photothermal evaporation process, organic pollutants and small water-soluble molecules can transfer into distilled steam, degrading the purity of the collected water. Herein, we develop a multifunctional clean water generation system that integrates photothermal conversion, adsorptive filtration and subsequent photocatalytic purification within a unified platform. This system features an inner hierarchical porous metal-carbon layer derived from ZIF-67 carbonization, seamlessly bridging a wood carbon scaffold and BiOBr nanosheets (BiOBr@ZCW) to smoothly facilitate synergistic actions between photothermal evaporation and adsorption-photodegradation processes. This BiOBr@ZCW configuration not only minimizes thermal dissipation, facilitating a high evaporation rate of 1.67 kg m-2 h-1 and an efficiency of 85% under standard solar irradiation but also enhances the photocatalytic degradation of the rhodamine B organic pollutant with a remarkable 98.43% degradation rate within just 20 minutes. This integrated system offers a robust solution to the challenges of water purification by ensuring both high efficiency in solar steam generation and effective pollutant degradation.

Enhancement of Tomato Fruit Quality Through Moderate Water Deficit

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar-acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation.

Effectiveness of the upscaled use of a silver-ceramic (silver ionization) technology to disinfect drinking water in tanks at schools in rural India

In many low- and middle-income countries, school children consume untreated water that has been pumped into storage tanks. The water is often of poor quality and consumption can cause gastrointestinal illnesses resulting in missed school days, growth stunting, and cognitive impairment. This study deployed a silver-ceramic technology (MadiDrop) to disinfect drinking water in school storage tanks. While silver ionization is effective at the household scale, relatively little research has been conducted on its effectiveness at the community scale. To address this gap, we assessed disinfection via MadiDrop at three schools that serve vulnerable populations in rural India. Tank inflow and treated outflow samples were tested for total coliforms (TCs) and Escherichia coli (EC). TC was significantly reduced overall and in two of three intervention tanks. Compared to the baseline, reductions in TC were significant in all three tanks and overall, while EC reductions were significant overall and in two of three tanks. TC reduction was negatively correlated with silver concentration and tank residence time, and silver concentrations were maintained below the drinking water quality guideline. While the intervention could be considered successful, several barriers and caveats are provided as are study limitations and areas for future research.

Removal of Fe2+ in coastal aquaculture source water by manganese ores: Batch experiments and breakthrough curve modeling

Excessive Fe2+ in coastal aquaculture source water will seriously affect the aquaculture development. This study used manganese sand to investigate the removal potential and mechanism of Fe2+ in coastal aquaculture source water by column experiments. The pseudo-first-order kinetic model could better describe Fe2+ removal process with R2 in the range of 0.9451-0.9911. More than 99.7% of Fe2+ could be removed within 120 min while the removal rate (k) was positively affected by low initial concentration of Fe2+, high temperature, and low pH. Logistic growth (S-shaped growth) model could better fit the concentration variation of Fe2+ in the effluent of the column (R2>0.99). The Fe2 breakthrough curve could be fitted by Bohart-Adams, Yoon-Nelson, and Thomas models (R2>0.95). Smooth slices with irregular shapes existed on the surface of manganese sand after the reaction while Fe content increased significantly on the surface of manganese sand after the column experiment. Moreover, FeO (OH) was mainly formed on the surface of manganese sand after the reaction. PRACTITIONER POINTS: Fe2+ in coastal aquaculture source water could be removed by manganese ores. The pseudo-first-order kinetic model better described the Fe2+ removal process. FeO (OH) was mainly formed on the surface of manganese sand after the reaction.

Synergistically Utilizing a Liquid Bridge and Interconnected Porous Superhydrophilic Structures to Achieve a One-Step Fog Collection Mode

Conventional fog collection efficiency is subject to the inherent inefficiencies of its three constituent steps: fog capture, coalescence, and transportation. This study presents a liquid bridge synergistic fog collection system (LSFCS) by synergistically utilizing a liquid bridge and interconnected porous superhydrophilic structures (IPHS). The results indicate that the introduction of liquid bridge not only greatly accelerates water droplet transportation, but also facilitates the IPHS in maintaining rough structures that realize stable and efficient fog capture. During fog collection, the lower section of the IPHS is covered by a water layer, however due to the effect of the liquid bridge, the upper section protrudes out, while covered by a connective thin water film that does not obscure the microstructures of the upper section. Under these conditions, a one-step fog collection mode is realized. Once captured by the IPHS, fog droplets immediately coalesce with the water film, and are simultaneously transported into a container under the effect of the liquid bridge. The LSFCS achieves a collection efficiency of 6.5 kg m-2 h-1, 2.3 times that of a system without a liquid bridge. This study offers insight on improving fog collection efficiency, and holds promise for condensation water collection or droplet manipulation.

Groundwater quality prediction and risk assessment in Kerala, India: A machine-learning approach

Despite its critical importance for health, agriculture, and the economy, and its key role in supporting climate change adaptation, groundwater quality remains vulnerable to contamination and is often neglected until significant deterioration. The groundwater resources of Kerala, one of the southernmost states of India, are under escalating stress and scarcity, despite a high well density with 62% of the population relying on groundwater from approximately 6.5 million open wells. This study investigates the detailed hydrogeochemistry and predicts groundwater quality zones of the state using machine-learning techniques viz, extreme gradient boosting (XGBoost), support vector regression (SVR), artificial neural network (ANN) and random forest (RF) regression. The hydrogeochemical analysis reveals varying groundwater quality across the state. Among the different machine learning models, RF shows higher goodness of fit (R2: 0.922) with minimal prediction error (root mean square error: 6.29 and mean absolute error: 3.12). The predicted groundwater quality was validated using the spatially distributed stiff diagrams, visually representing water composition trends of each well. The very good, good, moderate and poor groundwater quality zones occupy 31.7%, 40.4%, 20.4%, and 7.4% of the state aligning accurately with the groundwater quality scenario of the state. Additionally, groundwater drinking risk assessment was conducted, considering that 7.4% of the state experiences poor-quality groundwater. Integrating groundwater quality maps with population data, the study assessed potential health risks due to consuming untreated water. Nearly 0.59 million people across 252 local self-government bodies (LSGs) are susceptible to consuming poor quality groundwater, which may pose potential health risks. This observation provides valuable insights for sustainable groundwater management and public health safeguarding and the findings of the present study are useful for achieving sustainable development goal (SGD) 6 (clean water and sanitation) and long-term groundwater management in Kerala.

A multi-index comprehensive evaluation method for assessing the water use balance between economic society and ecology considering efficiency-development-health-harmony

Quantitative assessment of the water use balance between economic society and ecology (EEWB) is the basis for coordinating the competitive relationship of water use between human activity and ecological requirements and. It is of great significance for optimizing the water resources carrying capacity and achieving a healthy regional water balance. Based on the concept of harmonious balance, this paper puts forward the definition and connotation of EEWB regarding the competition in water use between economic society and ecology. And, a novel framework for assessing the EEWB is proposed. It has four aspects relating to water resources, economic society, ecology, and human-water relationship. Linked to these aspects the Data Envelopment Analysis (DEA) technique, Water Ecological Footprint (WEF) model, InVEST model and indicators system of human-water relationship are used to establish a water resources efficiency index (IEEWB-W), economic society high-quality development index (IEEWB-ES), ecology health index (IEEWB-E), harmony index of human-water relationship (IEEWB-H). The four indices were then integrated into the water use balance between economic society and ecology index (IEEWB) with Euclidean distance, thus forming the EEWB quantification method system. Finally, the temporal and spatial characteristics of EEWB during 2010-2022 was diagnosed in Henan Province and cities of China. Results reveal that: (1) The water resources utilization efficiency exhibit a changing trend of initial decrease followed by subsequent increase; (2) Southern cities in Henan Province have a higher economic society development level compared to northern cities; (3) IEEWB-E in Henan Province is below 0.60, indicating that the regional ecology health remains consistently vulnerable; (4) IEEWB-H in Henan Province shows an increasing trend, indicating that a gradual improvement and overall upward development in the human-water relationship; (5) IEEWB multi-year average was within [0.53, 0.65] in Henan Province, indicating a state of Proximity imbalance. The low level of ecological health is the primary influencing factor. These findings will contribute to a better understanding of the water use balance between economic society and ecology and provide scientific reference for achieving a healthy regional water balance.

Efficient Degradation of Ofloxacin by Magnetic CuFe2O4 Coupled PMS System: Optimization, Degradation Pathways and Toxicity Evaluation

Magnetic CuFe2O4 was prepared with the modified sol-gel method and used for enhanced peroxymonosulfate (PMS) activation and ofloxacin (OFL) degradation. The OFL could almost degrade within 30 min at a catalyst dosage of 0.66 g/L, PMS concentration of 0.38 mM, and initial pH of 6.53 without adjustment, using response surface methodology (RSM) with Box-Behnken design (BBD). In the CuFe2O4/PMS system, the coexisting substances, including CO32-, NO3-, SO42-, Cl- and humic acid, have little effect on the OFL degradation. The system also performs well in actual water, such as tap water and surface water (Mei Lake), indicating the excellent anti-interference ability of the system. The cyclic transformation between Cu(II)/Cu(I) and Fe(III)/Fe(II) triggers the generation of active radicals including SO4•-, •OH, •O2- and 1O2. The OFL degradation pathway, mainly involving the dehydrogenation, deamination, hydroxylation, decarboxylation and carboxylation processes, was proposed using mass spectroscopy. Moreover, the toxicity assessment indicated that the end intermediates are environmentally friendly. This study is about how the CuFe2O4/PMS system performs well in PMS activation for refractory organic matter removal in wastewater.

Occurrence, toxicity, and control of halogenated aliphatic and phenolic disinfection byproducts in the chlorinated and chloraminated desalinated water

Seawater desalination is widely used to overcome the freshwater shortage worldwide. However, even after three-stage reverse osmosis treatment, the desalinated water still contained 14.6 μg/L of aliphatic disinfection byproducts (DBPs), 384.2 ng/L of bromophenolic DBPs, 3.5 ng/L of iodophenolic DBPs, 1024.7 μg/L of Br-, 2.8 μg/L of I-, and 2.4 mg C/L of dissolved organic carbon (DOC). After the desalinated water was disinfected with chlor(am)ine, the concentrations of halogenated aliphatic and phenolic DBPs further increased, and bromophenolic DBPs were the toxicity forcing agents. When surface water was mixed with desalinated water and then chlorinated, the yield of aliphatic and phenolic DBPs significantly elevated. Separately chlorinating desalinated water and surface water before mixing could mitigate this adverse situation. Chloramine disinfection was more conducive to reducing the total calculated toxicity of disinfected desalinated waters and mixed waters compared to chlorine disinfection. The treatment of desalinated water with granular activated carbon could effectively remove DOC and UV254, leading to a reduction in the content of total organic halogen after chlor(am)ination. Although anion exchange resin could adsorb Br-, it also released the organic precursors of DBPs, ultimately increasing the yield of DBPs. The results of this study can provide a reference for the seawater desalination industry to improve seawater pre-treatment and desalination processes and thus minimize the DBPs.

Synthesis and Mechanism of a Green Scale and Corrosion Inhibitor

A new green water treatment agent, a poly(aspartic acid)-modified polymer (PASP/5-AVA), was synthesized using polysuccinimide and 5-aminovaleric acid (5-AVA) in a hybrid system. The structure was characterized, and the scale and corrosion inhibition performance were carried out with standard static scale inhibition and electrochemical methods, respectively. The mechanism was explored using XRD, XPS, SEM, and quantum chemistry calculations. The results indicated that PASP/5-AVA exhibited better scale and corrosion inhibition performance than PASP and maintained efficacy and thermal stability of the scale inhibition effect for a long time. Mechanistic studies indicated that PASP/5-AVA interferes with the normal generation of CaCO3 and CaSO4 scales through lattice distortion and dispersion, respectively; the combined effect of an alkaline environment and terminal electron-withdrawing -COOH groups can induce the stable C- ionic state formation in -CH2- of the extended side chain, thus enhancing its chelating ability for Ca2+ ions. At the same time, the extension of the side chain length also enhances the adsorption ability of the agent on the metal surface, forming a thick film and delaying the corrosion of the metal surface. This study provides the necessary theoretical reference for the design of green scale and corrosion agents.

Integrated simulation-surrogate-optimization modeling framework for multiple tradeoffs among socioeconomic and ecological targets in reservoir operations

Integrated reservoir water quantity and quality management is significant for water supply security and river ecosystem health. However, the spatiotemporal heterogeneity of water quality and the nonuniform response of multiple indicators to operation changes make it difficult to determine optimal operation schedules. This study proposes a coupled simulation-surrogate-optimization modeling approach for compromising multiple water quantity and quality targets in reservoir operations. The Environmental Fluid Dynamics Code (EFDC) was used to simulate spatiotemporal reservoir water quality dynamics. Subsequently, an ecological damage assessment method was established, accounting for the spatiotemporal heterogeneity of multiple water quality indicators and the nonlinear relationship between the water quality deterioration and ecological damage. To quickly simulate the ecological damage, a surrogate model was developed using the nonlinear autoregressive network with exogenous inputs (NARX). Finally, the surrogate model was integrated into a reservoir operation optimization model for compromising socioeconomic and ecological targets. By applying the methods to China's Danjiangkou Reservoir as a case, it was shown that more even nutrient distribution in the reservoir increased water eutrophication area while reducing concentration peak values, which helped decrease the ecological damage. Operation changes could lead to opposite effects on in-reservoir and downstream ecological targets, increasing operation optimization complexity. Both ecological and socioeconomic benefits significantly increased (by 9.4%-16.4%) during dry years under the optimized operation scheme, implying that synergies were obtained. This study offers implications and a management tool for reservoir operations to address the multiple tradeoffs among socioeconomic and ecological benefits.

Carbon and boron nitride quantum dots as optical sensor probes for selective detection of toxic metals in drinking water: a quantum chemical prediction through structure- and morphology-dependent electronic and optical properties

Toxic metals present in drinking water pose a serious threat to the environment and human beings when present in abundance. In this work, we investigated the sensing ability of quantum dots (pristine CQDs, boron/nitrogen/sulphur (B/N/S)-doped CQDs, and BNQDs) of various sizes and morphologies (rectangular, circular, and triangular) towards toxic metals such as arsenic (As), cobalt (Co), nickel (Ni), copper (Cu), and lead (Pb) using quantum chemical density functional theory calculations in both gas and water phases. We probed the structural, electronic, and optical properties of the QDs. All the modelled QDs are energetically stable. Frontier molecular orbital analysis predicted that BNQDs are more chemically stable than all other CQDs. UV-vis absorption and Raman spectra analyses helped to understand the optical properties of all the QDs. Further, adsorption studies revealed that triangular pristine CQDs and sulphur-doped CQDs show higher adsorption affinity towards the toxic metals. The magnitude of adsorption energies follows the trend Ni > Pb > As > Cu > Co in most of the QDs. Several pristine and doped CQDs exhibited chemisorption towards the toxic metals, and hence, they can be used as adsorbents. However, a majority of BNQDs showed physisorption towards the metals, and therefore, they can be used as efficient optical sensors compared to CQDs. Further, the sensing ability of the QDs was explored through optical phenomena such as changes in UV-vis absorption spectra and fluorescence after metal adsorption. When compared to pristine CQDs and B/N/S-doped CQDs, metal complexation caused significant changes in the UV-vis absorbance peak intensities in BNQDs along with peak shifts. Moreover, metal interaction with the QDs increased their fluorescence lifetime with the highest values observed in Co-adsorbed triangular H18C46 (152.30 ns), Pb-adsorbed rectangular H15C30S (21.29 ns), and As-adsorbed circular B27N27H18 (2.99 μs) among pristine CQDs, B/N/S-doped CQDs, and BNQDs, respectively. Overall, we believe that our first-of-its-kind computational prediction of the optical sensing ability of tailor-made zero-dimensional systems such as QDs will be a great aid for experimentalists in designing novel and rapid optical probes to detect toxic metals in drinking water.

Water quality and dissolved load in the Chirchik and Akhangaran river basins (Uzbekistan, Central Asia)

Uzbekistan (Central Asia) is experiencing serious water stress as a consequence of altered climate regime, past over-exploitation, and dependence from neighboring countries for water supply. The Chirchik-Akhangaran drainage basin, in the Tashkent province of Uzbekistan, includes watersheds from the Middle Tien Shan Mountains escarpments and the downstream floodplain of the Chirchik and Akhangaran rivers, major tributaries of the Syrdarya river. Water in the Chirchik-Akhangaran basin is facing potential anthropogenic pressure from different sources at the scale of river reaches, from both industrial and agricultural activities. In this study, the major and trace element chemistry of surface water and groundwater from the Chirchik-Akhangaran basin were investigated, with the aim of addressing the geogenic and anthropogenic contributions to the dissolved load. The results indicate that the geochemistry of water from the upstream catchments reflects the weathering of exposed lithologies. A significant increase in Na+, K+, SO42-, Cl-, and NO3- was observed downstream, indicating loadings from fertilizers used in croplands. However, quality parameters suggest that waters are generally suitable for irrigation purposes, even if the total dissolved solid indicates a possible salinity hazard. The concentration of trace elements (including potentially toxic elements) was lower than the thresholds set for water quality by different regulations. However, an exceedingly high concentration of Zn, Mo, Sb, Pb, Ni, U, As, and B compared with the average river water worldwide was observed. Water in a coal fly-ash large pond related to the Angren coal-fired power plants stands out for the high As, Al, B, Mo, and Sb concentration, having a groundwater contamination potential during infiltration. Spring waters used for drinking purposes meet the World Health Organization and the Republic of Uzbekistan quality standards. However, a surveillance of such drinking-water supplies is suggested. The obtained results are indicators for an improved water resource management.

High performance B2O3/MWCNTs and TiB/MWCNTs nano-adsorbents for the co-sorption of cyanide and phenol from refinery wastewater

The refinery industry has witnessed tremendous activity aimed at producing petrochemicals for the benefit of the teeming populace. These activities are accompanied by the discharge of wastewater containing chemical substances and elements that have negative impacts on the ecosystem. The presence of phenol and cyanide contaminants in refinery wastewater poses serious health hazards to humans, necessitating their removal. In this study, boron oxide-doped multi-walled carbon nanotubes (B2O3/MWCNTs) and titanium boride-doped MWCNT (TiB/MWCNTs) nanoadsorbents were prepared via a wet impregnation method and characterized using High-Resolution Transmission Electron Microscopy (HR-TEM), X-Ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). HR-TEM images depict the nanostructure of the nanoadsorbent, the presence of doped materials, and the internal, external, and wall thickness of B2O3/MWCNTs and TiB/MWCNTs nanoadsorbents. XRD results indicate that the nanomaterials were monocrystalline with average crystallite sizes of 22.75 nm and 16.79 nm for B2O3/MWCNTs and TiB/MWCNTs, respectively. The formation of B2O3 and TiB was observable in the results obtained from the XPS at the binding energy of 192 and 193.1 eV, respectively. The application of the produced B2O3/MWCNTs and TiB/MWCNTs nanoadsorbents for the removal of phenol and cyanide from refinery wastewater was explored in a batch adsorption system. The effects of contact time, adsorbent dosage, and adsorption temperature were investigated. To the best of our knowledge, the incorporation of B2O3 and TiB in MWCNTs resulted in the highest adsorption capacities for phenol and cyanide from aqueous solutions. The highest percentage removal of 100% for phenol and 99.06% for cyanide was observed for the TiB/MWCNTs nanoadsorbent at a residence time of 70 minutes, a temperature of 60 °C, and 0.3 g of adsorbent. The isotherm models show that cyanide and phenol removal obeyed the Langmuir isotherm, indicating monolayer adsorption over B2O3/MWCNTs nanoadsorbent. Furthermore, cyanide and phenol removal depict multilayer adsorption on the TiB/MWCNT nanoadsorbent. The research shows that B2O3/MWCNTs are proficient in cyanide sorption, while TiB/MWCNT favors phenol sorption due to their respective adsorption capacities.

Spatiotemporal evolution and decoupling effects of sustainable water resources utilization in the Yellow River Basin: Based on three-dimensional water ecological footprint

Clarifying the spatiotemporal evolution of sustainable water resources utilization (SWU) and its decoupling effects from economic growth (EG) is essential for the effective management of water ecosystems and sustainable development of basins. However, the traditional Ecological Footprint model limits the ability to compare SWU within a basin, and existing studies need to pay more attention to the importance of water renewability in quantifying SWU. Based on the capital flow and capital stock perspectives, this study constructed an evaluation method for SWU and its decoupling effect from EG by combining the three-dimensional Water Ecological Footprint (WEF), sustainable reclassification, and the Tapio model, and explored different types of SWU enhancement strategies. The results indicate that: (1) From 2010 to 2022, the SWU of the Yellow River Basin (YRB) shows a decreasing and then increasing trend and is generally in water ecological deficit, with a lower SWU in the middle and lower reaches. Overall, the per capita WEFsize decreased by 0.73% per year, while the WEFdepth increased by 0.26% per year, the pressure and stress on the SWU of the YRB are still significant. (2) Agricultural freshwater use and domestic greywater discharge dominate the WEF of the basin, and the problem of inversion of the water use structure with the industrial structure is evident. (3) Spatial differentiation within the basin is apparent, and SWU shows a spatial distribution of western strength and eastern weakness, with significant consumption of water capital stock due to insufficient water capital flow as the main reason. (4) Topio decoupling analysis shows that WEF and EG are mainly strongly decoupled, with WEF lagging behind EG; the decoupling relationship between SWU and EG evolves from END-SD-WD, reduces the consumption of water capital stock and increasing water capital flow is a reasonable way to realise its stable strong decoupling. This study is essential for SWU studies of large river basins in arid and semi-arid regions. It provides insights into the sustainable management and rational allocation of water resources in the YRB and other similar basins worldwide.

Recent developments of (bio)-sensors for detection of main microbiological and non-biological pollutants in plastic bottled water samples: A critical review

The importance of water in all biological processes is undeniable. Ensuring access to clean and safe drinking water is crucial for maintaining sustainable water resources. To elaborate, the consumption of water of inadequate quality can have a repercussion on human health. Furthermore, according to the instability of tap water quality, the consumption rate of bottled water is increasing every day at the global level. Although most people believe bottled water is safe, it can also be contaminated by microbiological or chemical pollution, which can increase the risk of disease. Over the last decades, several conventional analytical tools applied to analyze the contamination of bottled water. On the other hand, some limitations restrict their application in this field. Therefore, biosensors, as emerging analytical method, attract tremendous attention for detection both microbial and chemical contamination of bottled water. Biosensors enjoy several facilities including selectivity, affordability, and sensitivity. In this review, the developed biosensors for analyzing contamination of bottled water were highlighted, as along with working strategies, pros and cons of studies. Challenges and prospects were also examined.

A novel mathematical model for simultaneous optimization of desalination plant location and water distribution network; A case study

In recent decades, water scarcity has turned into a serious problem spanning many countries, now even capable of causing or inflaming ethnic and national conflicts. While our planet has very limited freshwater resources, it has huge amounts of saltwater in seas and oceans. There is a very limited number of ways that can make saltwater drinkable, the most important of them is desalination. This study aimed to provide a method for the simultaneous optimization of desalination plant location and its water distribution network based on mathematical modeling. For this purpose, the authors formulated a non-linear mathematical model with the objective of minimizing the costs of water production and transmission. A genetic algorithm was also developed for solving the proposed nonlinear model. The method was used in a case study of Sistan and Baluchestan, which is one of Iran's most water stressed provinces. The proposed genetic algorithm managed to provide an acceptable solution for this problem in 3.74 s. The best solution was found to be constructing a desalination facility with a capacity of 394,052 cubic meters per day in a single location, that is, the city of Chabahar. The water transmission lines needed for transporting water to other parts of the province and their capacities were also determined.

A regulatory framework for bottled water quality monitoring: A case of Emfuleni local municipality

Background

The quality of drinking water has recently become of utmost concern to consumers worldwide, especially in areas where Water Service Authorities (WSAs) failed to provide safe water. To combat this challenge, government entities regulate water to ensure that safe water is provided. The Emfuleni Local Municipality (ELM) has experienced cases of water contamination by human excretion, whereby communities were affected. As a result, there was a sharp increase in bottled water (BW) use, which however gave rise to unregulated and counterfeit versions of popular brands. This situation poses threats to public health.

Aim

This study sought to determine the regulation of drinking water and to assess whether environmental health practitioners (EHPs) monitor the quality of water sources (BW and tap water) in ELM as outlined by the National Environmental Health Norms and Standards (NEHNS).

Settings

The study was conducted in the Emfuleni Local Municipality in South Africa.

Methods

A quantitative cross-sectional study design was employed in this research. Fifteen online questionnaires using a Google Forms survey were distributed amongst all EHPs servicing ELM. Secondary data that included the Integrated Development Plan (IDP) and Service Delivery Budget Implentation Plan (SDBIP) for the 2017-2020 financial years were also evaluated, specifically for water quality monitoring (tap and bottled water). The dataset was analysed using the Statistical Package for the Social Sciences (SPSS) version 29.

Results

Due to complexity in the legislation and NEHNS in relation to Municipal Health Services (MHS), bottled water was not sampled at all. A number of EHPs were also not conversant with the regulations governing BW. Moreover, NEHNS consider bottled water as food, which does not fall under the MHS.

Conclusion

There should be clarity in the legislation to ensure that bottled water monitoring is intensified to protect public health within the WSAs.

Contribution

The findings of this study could assist policy-makers to make informed decisions on water quality monitoring, as well as clarify legislative issues on bottled water.

Release potential, neglected leakage and reduction countermeasures of COD and Ammonia in MSWLs

In order to eliminate the impact of the industrial revolution on the environment and improve the water ecological environment, pollutant discharge reduction is imperative. With the acceleration of global discharge reduction process, the huge pollutant release potential and potential environmental effects of municipal solid waste landfills gradually appear, but its release amount and intensity have not been quantitatively revealed. We propose a coupling method of parameter stochastic simulation and physical process model simulation to estimate the hidden leakage of large-scale regional municipal solid waste landfills, and provide a methodology for estimating the hidden leakage of landfills in other countries and even in the whole world by taking China, which has the largest amount of waste generation among developing countries, as an example. Prior to the implementation of stringent construction quality control and assurance management requirements, the average annual leachate generation potential over the entire life cycle of 2600 landfills in China was estimated to be 4.66 × 108 m3, in which the concentrations of COD and NH3-N are 5.38 × 102-6.48 × 104 mg/L and 6.10-3.50 × 103 mg/L, respectively, and the total amounts are 5.21 × 103-7.81 × 108 t and 8.09 × 102-6.65 × 107 t, respectively. About 14 % of these pollutants may leak into the environmental media through the landfill liner with the average number of holes of 21.5/ha. For different regions, the overall release, discharge and leakage of COD and NH3-N in East China account for 35.70 %, 36.68 % and 29.60 % respectively, making it the region with the highest potential for discharge and risk of leakage. Meanwhile, the implementation of mandatory regulations related to leachate generation and control has led to a significant reduction in the leakage of pollutants. For instance, comprehensively detecting and repair of holes in the impermeable liner has reduced the number of holes to 2/ha, resulting in a reduction of >90 % in the leakage of pollutants.

Towards sustainable management of polyacrylamide in soil-water environment: Occurrence, degradation, and risk

Polyacrylamide (PAM) possesses unique characteristics, including high water solubility, elevated viscosity and effective flocculation capabilities. These properties make it valuable in various sectors like agriculture, wastewater treatment, enhanced oil recovery, and mineral processing industries, contributing to a continually expanding market. Despite its widespread use globally, understanding its environmental fate at the soil-water interface remains limited. This article aims to provide an overview of the occurrence, degradation pathways, toxicity, and risks associated with PAM in the bioenvironment. The findings indicate that various degradation pathways of PAM may occur in the bioenvironment through mechanical, thermal, chemical, photocatalytic degradation, and/or biodegradation. Through a series of degradation processes, PAM initially transforms into oligomers and acrylamide (AM). Subsequently, AM may undergo biodegradation, converting into acrylic acid (AA) and other compounds such as ammonia. Notably, among these degradation intermediates, AM demonstrates high biodegradability, and the bioaccumulations of both AM and AA are not considered significant. Ensuring the sustainable use of PAM necessitates a comprehensive understanding among policymakers, scholars, and industry professionals regarding PAM, encompassing its properties, applications, degradation pathways, toxic effect on humans and the environment, and relevant regulations. Additionally, this study offers insights into future priority research directions, such as establishing of a reliable source-to-destination supply chain system, determining the maximum allowable amount for PAM in farmlands, and conducting long-term trials for the PAM-containing demolition residues.

Assessing the Influence of Hand-Dug Well Features and Management on Water Quality

Underground water quality can be affected by natural or human-made influences. This study investigates how the management and characteristics of hand-dug wells impact water quality in 3 suburbs of Kumasi, Ghana, using a combination of qualitative and quantitative research methods. Descriptive analysis, including frequency and percentages, depicted the demographic profiles of respondents. Box plot diagrams illustrated the distribution of physicochemical parameters (Total Dissolved Solid [TDS], Electrical Conductivity [EC], Turbidity, Dissolved Oxygen [DO], and Temperature). Factor analysis evaluated dominant factors among these parameters. Cluster analysis (hierarchical clustering) utilized sampling points as variables to establish spatial variations in water physicochemical parameters. Cramer's V correlation test explored relationships between demographic variables and individual perceptions of water management. One-way ANOVA verified significant mean differences among the physicochemical parameters. Logistic regression models assessed the influence of selected well features (e.g., cover and apron) on TDS, pH, Temperature, Turbidity, and DO. The findings revealed that proximity to human settlements affects water quality, and increasing turbidity is associated with unmaintained covers, significantly impacting water quality (P < .05). Over 80% of wells were located within 10 to 30 m of pollution sources, with 65.63% situated in lower ground and 87.5% being unmaintained. Other significant contamination sources included plastic bucket/rope usage (87.50%), defective linings (75%), and apron fissures (59.37%). Presence of E. coli, Total coliform, and Faecal coliform rendered the wells unpotable. Factor analysis attributed 90.85% of time-based and spatial differences to organic particle decomposition factors. However, Cramer's V correlation analysis found establishing association between demographic factor associations with individual perceptions of hand-dug well management difficult. It is encouraged to promote hand-dug well construction and maintenance standards to ensure that wells are properly built and protected from contamination sources.

Biofortification of Plant- and Animal-Based Foods in Limiting the Problem of Microelement Deficiencies-A Narrative Review

With a burgeoning global population, meeting the demand for increased food production presents challenges, particularly concerning mineral deficiencies in diets. Micronutrient shortages like iron, iodine, zinc, selenium, and magnesium carry severe health implications, especially in developing nations. Biofortification of plants and plant products emerges as a promising remedy to enhance micronutrient levels in food. Utilizing agronomic biofortification, conventional plant breeding, and genetic engineering yields raw materials with heightened micronutrient contents and improved bioavailability. A similar strategy extends to animal-derived foods by fortifying eggs, meat, and dairy products with micronutrients. Employing "dual" biofortification, utilizing previously enriched plant materials as a micronutrient source for livestock, proves an innovative solution. Amid biofortification research, conducting in vitro and in vivo experiments is essential to assess the bioactivity of micronutrients from enriched materials, emphasizing digestibility, bioavailability, and safety. Mineral deficiencies in human diets present a significant health challenge. Biofortification of plants and animal products emerges as a promising approach to alleviate micronutrient deficiencies, necessitating further research into the utilization of biofortified raw materials in the human diet, with a focus on bioavailability, digestibility, and safety.

Treating reverse osmosis brine of petrochemical wastewater using preparative vertical-flow electrophoresis (PVFE) with multi-objective optimization by response surface method

Electrochemical desalination is an effective method for recovering salts from reverse osmosis (RO) brine. However, traditional technologies like bipolar membrane technology often face challenges related to membrane blockage. To overcome this issue, a preparative vertical-flow electrophoresis (PVFE) system was used for the first time to treat RO brine of petrochemical wastewater. In order to optimize the PVFE operation and maximize acids and bases production while minimizing energy consumption, the response surface method was employed. The independent variables selected were the electric field intensity (E) and flow rate (v), while the dependent variables were the acid-base concentration and energy consumption (EC) for acid-base production. Using the central composite design methodology, the operation parameters were optimized to be E = 154.311 V/m and v = 0.83 mL/min. Under these conditions, the base concentrations of the produced bases and acids reached 3183.06 and 2231.63 mg/L, respectively. The corresponding base EC and acid EC were calculated to be 12.57 and 11.62 kW·h/kg. In terms of the acid-base concentration and energy consumption during the PVFE process, the electric field intensity was found to have a greater influence than the flow rate. These findings provide a practical and targeted solution for recycling waste salt resources from RO brine.

Enhancing the anti-biofouling property of solar evaporator through the synergistic antibacterial effect of lignin and nano silver

Solar desalination is an effective solution to address the global water scarcity issue. However, biofouling poses a significant challenge for solar evaporators due to the presence of bacteria in seawater. In this study, an anti-biofouling evaporator was constructed using the synergistic antibacterial effect of lignin and silver nanoparticles (AgNPs). The AgNPs were easily synthesized using lignin as reductant under mild reaction conditions. Subsequently, the Lignin-AgNPs solution was integrated into polyacrylamide hydrogel (PAAm) without any purification steps, resulting in the formation of Lignin/AgNPs-PAAm (LAg-PAAm). Under the combined action of AgNPs and the hydroquinone groups present in oxidized lignin, LAg-PAAm achieved over 99 % disinfection efficiency within 1 h, effectively preventing biofilm formation in pore channels of solar evaporators. The anti-biofouling solar evaporator demonstrated an evaporation rate of 1.85 kg m-2 h-1 under 1 sun irradiation, and maintained stable performance for >30 days due to its high efficient bactericidal effect. Furthermore, it also exhibited exceptional salt-rejection capability attributed to its superior hydrophilicity.

Efficient dye adsorption of mesoporous activated carbon from bamboo parenchyma cells by phosphoric acid activation

In order to solve the environmental damage caused by the discharge of dyes as industrial wastewater, the development of efficient and sustainable adsorbents is the key, while most of the previous studies on bamboo parenchyma cells have focused on their microstructural, functional and mechanical properties, and few of the properties in adsorption have been investigated. To evaluate the role of the unique microstructure of bamboo parenchyma cells on adsorption after carbonization and activation, PC-based activated carbon (PPAC) was fabricated by the phosphoric acid activation method and tested for adsorption using methylene blue (MB). The effect of mesoporous structure on MB adsorption was investigated in detail using PPAC-30C impregnated with phosphoric acid at a concentration of 30%. The results showed that the adsorption performance was influenced by single-factor experiments (e.g., pH, activated carbon dosing). The adsorption isotherms and kinetics could conform to the Langmuir model (R2 = 0.983-0.994) and pseudo-second-order kinetic model (R2 = 0.822-0.991) respectively, and the maximum MB adsorption capacity of adsorbent was 576 mg g-1. The adsorption mechanism of MB on PPAC-30C includes physical adsorption, electrostatic attraction, hydrogen bonding, and the π-π conjugation effect, which was dominated by physical adsorption. The results of this study show that PPAC has good application prospects for cationic dye removal.

Characterizing the water resource-environment-ecology system harmony in Chinese cities using integrated datasets: A Beautiful China perspective assessment

Integrated management and synergistic improvement of the water system is a topic of widespread concern. This study innovatively integrates three functions of quality assessment, synergy evaluation, and driving influence determination to establish a systematic framework assessing water system harmony. A case study of 336 Chinese cities is further performed by combining multi-scale and multi-source datasets. The results show China's water system quality has improved from 2015 to 2022. Development in the water resource, environment, and ecology subsystems have been differentiated, with 0.05 %, 4.33 %, and -1.64 % changes, respectively. The degradation of water ecology and the weak synergy with the other two subsystems have limited China's water system harmony. Water environment improvement played a contributive role in improving the water system quality. The contribution structure of water resources, environment, and ecology has shifted towards equilibrium in recent years. We found and highlighted the north-south differentiation of water system harmony in Chinese cities. The Beijing-Tianjin-Hebei and its surroundings, the Yangtze River Delta, and the middle reaches of the Yangtze River are identified as priority regions for water system harmony improvement. The primary contribution of this study is to propose an assessing concept of water resource-environment-ecology system harmony, establish well-structured assessment methods, and integrate the multiple data sources. The novel methods and findings, including the indicator system, application of data mining and decomposing methods, and the city-level water system harmony map, deconstruct and quantify the complex and diverse water system, supporting clearer and more efficient water management policymaking.

Coupling coordination and driving mechanisms of water resources carrying capacity under the dynamic interaction of the water-social-economic-ecological environment system

The water resources carrying capacity (WRCC) is a complex and comprehensive system that is jointly influenced by water resources, society, the economy and the ecological environment. Previous WRCC studies have primarily focused on estimating the overall level of regional WRCC. Few studies have explored the interactions among the various elements in the WRCC system and their influence on the WRCC evolution. Therefore, the purpose of this paper is, on the one hand, to explore the dynamic interactive relationships within the WRCC system from the perspectives of water resources, society, the economy and the ecological environment using a coupling coordination degree model and a panel vector autoregressive (PVAR) model, and on the other hand, to determine the evolutionary driving mechanism of the WRCC using the geographically and temporally weighted regression (GTWR) model to improve the regional WRCC. Taking 21 cities in Guangdong Province as an example, the results show that (1) the coupling coordination degree among the four WRCC subsystems in Guangdong Province shows an overall upward trend from 2009 to 2020, and the coordination between water resources utilization and other subsystems needs to be further strengthened. (2) The economic subsystem is the core of the WRCC system with reinforcing effects on both water resources and social subsystems but significant inhibitory effects on the ecological environment subsystem. Notably, the development of the ecological environment plays a crucial role in promoting social and economic development. (3) From 2009 to 2020, the development of the WRCC in Guangdong Province is initially driven by social and economic development, followed by economic development and ecological environmental protection, and then mainly by ecological environmental protection, which gradually becomes the primary driving force. This study provides a new entry point for studying the regional WRCC and formulating targeted measures for enhancing the regional WRCC.

Preparation of N-MG-modified PVDF-CTFE substrate composite nanofiltration membrane and its selective separation of salt and dye

Poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) is considered an ideal membrane material for the treatment of complex environmental water due to its exceptional thermal stability and chemical resistance. Thus, to expand its application in the field of nanofiltration (NF) membranes, in this study, N-methylglucamine (N-MG) was used to hydrophilically modify PVDF-CTFE, overcoming the inherent hydrophobicity of PVDF-CTFE as a porous substrate membrane, which leads to difficulties in controlling the interfacial polymerization (IP) reaction and instability of the separation layer structure. The -OH present in N-MG could replace the C-Cl bond in the CTFE chain segment, thus enabling the hydrophilic graft modification of PVDF-CTFE. The influence of the addition of N-MG on the surface and pore structure, wettability, permeability, ultrafiltration separation, and mechanical properties of the PVDF-CTFE substrate membrane was studied. According to the comparison of the comprehensive capabilities of the prepared porous membranes, the M4 membrane with the addition of 1.5 wt% N-MG exhibited the best hydrophilicity and permeability, indicating that it is a desirable modified membrane for use as an NF substrate membrane. The experiments showed that the rejection of Na2SO4 by the NF membrane was 96.5% and greater than 94.0% for various dyes. In the test using dye/salt mixed solution, this membrane exhibited a good separation selectivity (CR/NaCl = 177.8) and long-term operational stability.