Eutrophic Water Research Articles

A Nonlocal Reaction‐Diffusion‐Advection System Modeling the Phytoplankton and Zooplankton

ABSTRACTWe present a nonlocal reaction‐diffusion‐advection system that models the predator–prey relationship between zooplankton and phytoplankton species in a eutrophic vertical water column. The invasion dynamics of zooplankton are analyzed in terms of the spontaneous death rates and buoyant/sinking velocities of both phytoplankton and zooplankton. Our analysis reveals that the zooplankton species can successfully invade and coexist with the phytoplankton only under conditions of low spontaneous death rates and matching buoyant/sinking velocities with phytoplankton. Additionally, we derived asymptotic profiles for the unique positive steady state of this system when one of the sinking or buoyant velocities of either phytoplankton or zooplankton approaches infinity, while the other velocity remains fixed. These findings highlight the significant role of advection due to buoyancy in shaping the dynamics of plankton ecosystems.

Composition of the Low Molecular Weight Metabolome of Potamogeton perfoliatus (Potamogetonaceae) as an Indicator of the Transformation of the Ecological State of the Littoral Zone

The composition and nature of changes in the low-molecular-weight metabolome (NM) of Potamogeton perfoliatus L., growing in 6 biotopes of Lake Ladoga with different types of the anthropogenic load has been analyzed. According to the research results, it was found that the total number of low molecular weight organic compounds (LMWOCs) in the P. perfoliatus NM composition is directly dependent on anthropogenic load, which is well marked by the development of cyanobacteria. The greater the intensity of pollution or eutrophication of waters, or the higher the number of cyanobacteria, the lower the total number of LMWOCs and their concentration. A strongly pronounced dependence of the total concentrations of groups of NM compounds on the anthropogenic disturbance of the biotope and the concentration of cyanobacteria was revealed. A decrease in the number, relative amount, total concentration of carboxylic acids, number and content of unsaturated fatty acids, and, at the same time, an increase in the composition and content of phenols and the total content of aldehydes and ketones depends on an increase in anthropogenic pressure. The specific composition of NM of pierced pondweed depends on its response to biotic and abiotic factors of the aquatic environment, including anthropogenic ones. The revealed features of the change in the composition of P. perfoliatus NM make it possible to use it as an integral indicator of the anthropogenic impact on the littoral biotopes of water bodies and the deterioration of their ecological state.

Biological treatment of eutrophicated lagoon water with Tetradesmus dimorphus under ambient conditions: a sustainable alternative for lipid production

Biological treatment of eutrophicated lagoon water with Tetradesmus dimorphus under ambient conditions: a sustainable alternative for lipid production

Removal of Phosphate from Water by Iron/Calcium Oxide-Modified Biochar: Removal Mechanisms and Adsorption Modeling

Phosphorus (P) pollution is a leading cause of water eutrophication, and metal-modified biochar is an effective adsorbent with the ability to alter the migration capacity of phosphorus. This study uses bamboo as the raw material to prepare metal-modified biochar (ZFCO-BC) loaded with Fe and Ca under N2 conditions at 900 °C, and investigates its adsorption characteristics for phosphate. Batch experimental results show the adsorption capacity of the ZFCO-BC gradually increases (from 4.0 to 69.1 mg/g) as the initial phosphate concentration increases (from 2 to 900 mg/L), mainly through multilayer adsorption. Additionally, as the pH increases from 1 to 7, the adsorption capacity of the ZFCO-BC climbs to reach its maximum value of 48.4 mg/g with an initial phosphate concentration of 150 mg/L. At this pH, phosphate primarily exists as H2PO4− and HPO42−, which both readily react with Fe3+ and Ca2+ in the biochar. Furthermore, the addition of CO32−, HCO3−, NO3−, SO42−, F−, and Cl− each affect the removal rate of phosphate by less than 10%, indicating the ZFCO-BC has a highly efficient and selective phosphate adsorption capacity. A multi-column adsorption experiment designed to achieve long-term and efficient phosphorus removal treated 275.5 pore volumes (PVs) of water over 366 h. The cyclic adsorption–desorption experiment results show that 0.5 M NaOH can effectively leach phosphate from the ZFCO-BC. Observations at the molecular level from P K-edge XANES spectra confirm the removal of low-concentration phosphate is primarily dominated by electrostatic attraction, while the main removal mechanism for high-concentration phosphate is chemical precipitation. This study demonstrates that ZFCO-BC has broad application prospects for phosphate removal from wastewater and as a potential slow-release fertilizer in agriculture.

Assessment of the Trophic Status and Trend Using the Transitional Water Eutrophication Assessment Method: A Case Study from Venice Lagoon

The Transitional Water Eutrophication Assessment Method (TWEAM) is a multi-index set up for assessing the eutrophication risk and trend in transitional waters. It includes a selection of environmental variables, an ecological status indicator (i.e., Macrophyte Quality Index, MaQI) and the Transitional Water Quality Index (TWQI). Possible outcomes of the TWEAM include three trophic classes in terms of eutrophication risk: (i) eutrophic; (ii) non-eutrophic; (iii) mesotrophic. The method was applied on data collected at 28 stations in the Venice Lagoon over four triennial monitoring cycles (MC I-IV) in the period 2011–2022. The spatial variability and medium-term trend of eutrophication risk were investigated, highlighting a general improvement in trophic conditions over time, with a decrease in mesotrophic stations (representing 46% of total in MC-I and 25% in MC-IV) in favor of non-eutrophic stations (46% of total in MC-I and 73% in MC-IV). The main driver of observed positive changes is related to the colonization of sensitive macroalgae and aquatic angiosperms, resulting in an increase in the percentage of stations with MaQI in good/high ecological status from 25% in MC-I to 54% in MC-IV. Eutrophic sites showed a non-linear trend, particularly in choked areas of the central lagoon, with anthropogenic disturbances and low water renewal.

Application of GIS in Introducing Community-Based Biogas Plants from Dairy Farm Waste: Potential of Renewable Energy for Rural Areas in Bangladesh

Dairy production is one of the most important economic sectors in Bangladesh. However, the traditional management of dairy cow manure and other wastes results in air pollution, eutrophication of surface water, and soil contamination, highlighting the urgent need for more sustainable waste management solutions. To address the environmental problems of dairy waste management, this research explored the potential of community-based biogas production from dairy cow manure in Bangladesh. This study proposed introducing community-based biogas plants using a geographic information system (GIS). The study first applied a restriction analysis to identify sensitive areas, followed by a suitability analysis to determine feasible locations for biogas plants, considering geographical, social, economic, and environmental factors. The final suitable areas were identified by combining the restriction and suitability maps. The spatial distribution of dairy farms was analyzed through a cluster analysis, identifying significant clusters for potential biogas production. A baseline and proposed scenario were designed for five clusters based on the input and output capacities of the biogas plants, estimating the location and capacity for each cluster. The study also calculated electricity generation from the proposed scenario and the net greenhouse gas (GHG) emissions reduction potential of the biogas plants. The findings provide a land-use framework for implementing biogas plants that considers environmental and socio-economic criteria. Five biogas plants were found to be technically and spatially feasible for electricity generation. These plants can collectively produce 31 million m3 of biogas annually, generating approximately 200.60 GWh of energy with a total electricity capacity of 9.8 MW/year in Bangladesh. Implementing these biogas plants is expected to increase renewable energy production by at least 1.25%. Furthermore, the total GHG emission reduction potential is estimated at 104.26 Gg/year CO2eq through the annual treatment of 61.38 thousand tons of dairy manure.

The new fate of MCLR revealed by dialysis equilibrium and theoretical calculations: Influence from DOM and Fe(II)/Mn(II)

Microcystin-LR (MCLR) is a highly toxic pollutant widely distributed in eutrophic waters. The interplay between dissolved organic matter (DOM) and metal ions has been extensively reported; however, the impact of DOM-metal complexes on MCLR remains to be thoroughly studied. In this research, equilibrium dialysis was employed to study the kinetics and isotherms of MCLR adsorption by DOM, meanwhile the Density functional theory (DFT) calculations provided insights into the theoretical mechanisms of Fe(II)/Mn(II) involvement in the adsorption process. The adsorption kinetics revealed that the process is physicochemical, with chemisorption being the critical factor controlling the adsorption rate. The adsorption isotherms confirmed that Fe(II) alters the spatial arrangement of adsorption sites on the superficies of DOM, with the complexes of Fe(II) and DOM from the macrophyte-dominated regions of Lake Taihu (MDR-Fe(II)) showing the uppermost adsorption capacity of 6193.965 µg/g among all combinations. The influence of different cations (K+, Ca2+, Na+, Mg2+) on the adsorption of MCLR to DOM is divergent, with metals either reducing MCLR adsorption through competition for adsorption sites or increasing it by forming ternary complexes. The pH decrease reduced the affinity of DOM to metal ions while simultaneously enhancing MCLR adsorption through changes in its ionization state. DFT calculations demonstrated that Fe(II)/Mn(II) reduces the resistance to interaction between functional groups on DOM and MCLR, with carboxyl-Fe(II)-carboxyl interactions showing the highest binding energy (ΔG = −7.253 eV). Overall, Fe(II)/Mn(II) enhances the adsorption of MCLR via altering the structure and surface electrostatic potential distribution of DOM. This research indicates that the ultimate fate of MCLR in aquatic ecosystems is affected by DOM and metal ions.

Boosting the Phosphorus Uptake of La2(CO3)3·8H2O Based Adsorbents via Sodium Addition: Relationship between Crystal Structure and Adsorption Capacity

Excess phosphate contents in water bodies triggers eutrophication, which posts significant challenges to the aquatic ecosystem. Lanthanum-carbonate based adsorbents exhibit excellent phosphate binding properties for remediating eutrophication. However, they suffer from significant adsorption-capacity loss (>85%) at high pH. Little has been done on understanding this behavior for improving the phosphorus adsorption of lanthanum-carbonate adsorbents in alkaline environments (e.g. eutrophic water bodies). Here, we discover that La2(CO3)3·8H2O, when produced by a conversion reaction from NaLa(CO3)2·xH2O, exhibits high phosphate adsorption capacity in a wide pH window. Under alkaline conditions (e.g. pH = 10), its adsorption capacity decreases by only 8% compared to the value under neutral pH. By isolating three different lanthanum-carbonate based compounds and analyzing their molecular structures, we find that the trace amount of Na+ residual in our La2(CO3)3·8H2O alters the chemical environment surrounding the La3+ ions, which may significantly boost the phosphate uptake at high pH. Our results provide molecular insights for further tuning the material structure of phosphate adsorbents to achieve robust performances.

Eutrophication exacerbated organic pollution in lakes across China during the 1980s-2010s

Lakes are vital sources of drinking water and essential habitats for humans and various other living organisms. However, many lakes face organic pollution due to anthropogenic disturbance and climatic influence, and the spatiotemporal changes of organic pollution in lakes over a large area are still unclear. Based on three monitoring datasets of chemical oxygen demand (COD) in 390 lakes, this study demonstrated the apparent spatiotemporal differences of organic pollution in lakes during the 1980s-2010s and the effects of water eutrophication and salinization. Throughout China, lake organic pollution showed a general spatial trend of being more severe in the north compared to the south. This pattern is reflected in the positive linear correlations between in-situ COD concentrations and lake latitude, observed in both the 1980s (p < 0.05) and the 2010s (p < 0.01). In terms of spatial differences, the influence of total nitrogen concentrations increased from 0.27% in the 1980s to 35.24% in the 2010s. Moreover, with increasing human activity, 78.31% of the studied lakes (N = 83) showed increasing COD concentrations during the 1980s-2010s. In addition, the logarithmic dissolved organic carbon concentrations were linearly correlated with log water conductivities (Pearson's r = 0.49, p < 0.01), suggesting that lake expansion would attenuate organic pollution in saline lakes through dilution effects. These results are valuable for understanding the spatiotemporal dynamics of organic pollution and are crucial for effective management of organic pollution in different lakes.

Preparation and characterization of a novel active sediment capping material (geopolymer) for inhibiting phosphate releasing from sediment

In situ remediation of sediment can effectively control the release of phosphate in sediment and improve water eutrophication. The essential question of this remediation techniques lies in the development of stable, high-efficiency, low-cost and easily available active sediment capping materials. This study synthesised a novel sediment capping material using bulk solid waste, and phosphate inhibition mechanism of the materials was explored. Results indicated that GSCM was prepared under the conditions of NaOH concentration of 3M, hydrothermal temperature of 160℃, hydrothermal time of 36h and the mass ratio of 40wt.% SS to 60wt.% FA. The result of batch adsorption and compressive strength test suggested that phosphate adsorption capacity and compressive strength of GSCM were 2.15mg/g and 24.20MPa, respectively. The characterization result showed that GSCM was composed of sodium zeolite, riversideite, grossular and fayalite, exhibiting a uniformly distributed slit mesoporous structure. The in-situ inhibition efficiency of GSCM to P ranged from 76.65% to 86.72%, exceeding that of commercial zeolite. The in-situ inhibition mechanism was controlled by sodium zeolite and riversideite, and concluded by the following:1) Substitution between [SiO4] tetrahedra (within the sodium zeolite structure), -OH (on the surface of materials) and [PO4], 2) Coordination of [PO4] tetrahedra with Al active site within the sodium zeolite structure, 3) Precipitation reaction between phosphate and slow-release of Ca2+ from the riversideite.

Effect of Slow-Release Urea on Yield and Quality of Euryale ferox.

Slow-release urea, as an environmentally friendly fertiliser, can provide a continuous and uniform supply of nutrients needed by the crop, reduce the amount and frequency of fertiliser application, and promote the uptake and utilisation of nitrogen in crops. The production of E. ferox is often dominated by the application of quick-acting fertilisers, resulting in serious problems of over-fertilisation, inappropriate periods of fertilisation, eutrophication of soil and water due to fertilisation, and difficulties in applying fertilisers. Therefore, in this study, different amounts (CK, T1, T2, T3, T4, T5) of SRU (Slow-release Urea) were first applied, and T3 (18.8 kg·667 m-2) was found to significantly improve both yield and quality. Further, it was found that under different SRU (CK, S1, S2, S3, S4) application period treatments, application of 18.8 kg·667 m-2 at AFP20 (S2) period significantly increased the yield and quality of E. ferox. In the seed kernels of E. ferox, the total yield, soluble sugar content, total starch, and flavonoid content increased significantly by 10.35%, 36.40%, 5.91%, and 22.80%, respectively, compared with CK. In addition, the expression of key sugar transporter genes (EfSWEETs), flavonoid synthesis-related genes (EfPAL, EfDFR, etc.), and starch synthesis-related enzyme activities (SBE, SSS, GBSS) were significantly increased. By exploring the quantity of application and application period of SRU, this study was carried out to investigate the in-depth effect of SRU on the growth and development of E. ferox and to provide technical references for the increase in E. ferox yield, the improvement in E. ferox quality, and the simplification of fertiliser application.

The shifts in microbial interactions and gene expression caused by temperature and nutrient loading influence Raphidiopsis raciborskii blooms

Climate change and the trophic status of water bodies are important factors in global occurrence of cyanobacterial blooms. The aim of this study was to explore the cyanobacteria‒bacterial interactions that occur during Raphidiopsis raciborskii (R. raciborskii) blooms by conducting microcosm simulation experiments at different temperatures (20 °C and 30 °C) and with different phosphorus concentrations (0.01 mg/L and 1 mg/L) using an ecological model of microbial behavior and by analyzing microbial self-regulatory strategies using weighted gene coexpression network analysis (WGCNA). Three-way ANOVA revealed significant effects of temperature and phosphorus on the growth of R. raciborskii (P < 0.001). The results of a metagenomics-based analysis of bacterioplankton revealed that the synergistic effects of both climate and trophic changes increased the ability of R. raciborskii to compete with other cyanobacteria for dominance in the cyanobacterial community. The antagonistic effects of climate and nutrient changes favored the occurrence of R. raciborskii blooms, especially in eutrophic waters at approximately 20 °C. The species diversity and richness indices differed between the eutrophication treatment group at 20 °C and the other treatment groups. The symbiotic bacterioplankton network revealed the complexity and stability of the symbiotic bacterioplankton network during blooms and identified the roles of key species in the network. The study also revealed a complex pattern of interactions between cyanobacteria and non-cyanobacteria dominated by altruism, as well as the effects of different behavioral patterns on R. raciborskii bloom occurrence. Furthermore, this study revealed self-regulatory strategies that are used by microbes in response to the dual pressures of temperature and nutrient loading. These results provide important insights into the adaptation of microbial communities in freshwater ecosystems to environmental change and provide useful theoretical support for aquatic environmental management and ecological restoration efforts.

CoAl-LDH on ZIF-67 template inserted into the conductive matrix as a high-efficiency composite anode for facilitating phosphorus elimination

Phosphorus pollution can induce water eutrophication and critically threaten the stability of the aquatic ecosystem. Capacitive deionization (CDI) is a potential candidate for controlling phosphorus levels due to its lack of chemical requirements, eco-friendliness, and low energy demand. Herein, a novel ZIF-67-derived CoAl-LDH embedded in conductive carbon skeletons (CoAl-LDH/C) was successfully constructed by a self-sacrificial template strategy. A conductive carbon matrix is incorporated into LDH, which can alleviate the insufficient conductivity and aggregation issues for LDH. The results revealed that CoAl-LDH/C possesses superior phosphorus elimination properties (qm=32.7 mg P/g) at 1.2 V, benefiting from its abundant active sites, large mesoporous diameter, specific surface area, total pore volume, outstanding specific capacitance, and ion diffusion. Meanwhile, the energy consumption of CoAl-LDH/C is merely 3.398 kWh/kg and 0.024 kWh/m3. CoAl-LDH/C also proved flexible for practical applications regarding complex water quality (wide pH range, coexisting substances, natural water) and cyclic utilization. Finally, the potential mechanism illuminated that the phosphorus elimination process in an electric field engages with ligand exchange, anion exchange, electrostatic attraction, and hydrogen bonds. This work paves a promising concept for designing innovative LDH-based electrodes with excellent ion diffusion and superior conductivity to eliminate phosphorus efficiently.

Adaptable Plasmonic Membrane Sensors for Fast and Reliable Detection of Trace Low-Micrometer Microplastics in Lake Water.

In freshwater environments, low-micrometer microplastics (LMMPs) have captured significant attention due to their prevalence and toxicity. Yet, rapid detection of LMMPs (1-10 μm) at the single-particle level within complex freshwater matrices remains a hurdle. We developed an adaptable plasmonic membrane sensor for fast detection of individual LMMPs in eutrophic lake waters. The plasmonic membrane sensor functions both as a membrane filter and as a sensor for LMMP collection and analysis. Among the four types of membrane sensors, polycarbonate track-etch (PCTE) membrane sensors exhibit superior imaging quality for LMMPs due to their flat and homogeneous surfaces. Besides the significantly improved imaging contrast and reduced background interferences, the Raman intensity of LMMPs is enhanced by 48% ± 25% on PCTE membrane sensors compared to unmodified membranes. The increased Raman intensities of a chemical probe with an increasing gold layer thickness and a decreasing membrane pore size suggest a surface-enhanced Raman scattering effect from the membrane sensors. The membrane sensors achieve a detection limit of 1 μg/L and an ultrafast scanning time of 0.01 s for individual LMMPs across natural eutrophic lake water. The developed membrane sensors offer an adaptable tool for the swift and reliable detection of individual LMMPs in complex environmental matrices.

Sustainability Prediction by Evaluating the Emergy of a Co-Treatment System for Municipal Wastewater and Acidic Water Using Intermittent Electrocoagulation

The objective of this research was to evaluate the sustainability of a co-treatment system that combines Municipal Wastewater (MW) and Acid Mine Drainage (AMD) through the technique of intermittent electrocoagulation, applied as an advanced solution to improve contaminant removal efficiency and optimize energy balance. Four scenarios were analyzed: Treatment I (with a 1/7 ratio of urban wastewater to AMD), Treatment II (which includes an artificial wetland), Treatment IIIa (which introduces electrocoagulation to enhance sulfate removal and pH regulation), and Treatment IIIb (which employs a 1/15 ratio of AMD to eutrophic water). The methodology focused on calculating key sustainability indicators such as the Net Yield Ratio (EYR), Emergy Inversion Ratio (EIR), Environmental Loading Ratio (ELR), and Sustainability Index (SI), in order to assess the impact of each technology on the energy efficiency and environmental load of the system. The results showed that, although Treatment IIIa was effective in contaminant removal, the EIR increased to 0.18 and the ELR rose to 0.62, indicating a higher reliance on non-renewable inputs due to increased energy demand. However, Treatment IIIb, which combines electrocoagulation with eutrophic water, significantly improved the sustainability of the system, achieving an SI of 2.31 and an ELR of 1.22, reflecting a reduction in energy efficiency due to intensive use of external resources, but overall greater sustainability compared to the other scenarios. This research concludes that intermittent electrocoagulation, when integrated with synergistic resources like eutrophic water, can enhance contaminant removal efficiency and improve the use of renewable resources, minimizing environmental load and increasing the sustainability of wastewater treatment systems.

Water Quality Changes in the Xingkai (Khanka) Lake, Northeast China, Driven by Climate Change and Human Activities: Insights from Published Data (1990–2020)

Water quality degradation and eutrophication of lakes are global ecological and environmental concerns, especially shallow lakes. This study collected hydrochemical data from 2935 samples of the Chinese part of Xingkai (Khanka) Lake, based on 40 published papers spanning the period from 2001 to 2023. Using the water quality index (WQI), improved geo-accumulation index (Igeo), and redundancy analysis (RDA), we analyzed the overall contamination characteristics of the water environment in Xingkai Lake. Additionally, we explored the impact of climate change and human activities on the lake’s water quality. The results showed that the annual WQI for Xingkai Lake ranged from 47.3 to 72, with a general downward trend, indicating improving water quality. Notably, the average WQI in May and total nitrogen (TN) content decreased significantly, signaling further improvement in water quality. The average concentration of TN in sediments was 1401.3 mg/kg, reflecting mild contamination. The Igeo values for the heavy metals Hg and Cr were greater than 1, indicating moderate contamination, while the Igeo values for Cd and Pb were between 0 and 1, which is in the range of uncontaminated to moderately contaminated. Land use and climate change (average annual temperature and annual precipitation) were key factors influencing water quality, with cumulative explanatory ratios of 67.3% and 50.1%. This study utilized land-use change as a metric for human activities, highlighting the potential impacts of climate change and human activities on the water quality of Xingkai Lake. It offers vital insights for the sustainable management of Xingkai Lake and provides valuable references into the management of similar transboundary lakes.

A methodology to assess the phenology patterns of a eutrophic water body, using remote sensing data and principal component analysis

Chlorophyll-a concentrations in coastal and inland waters is acknowledged as an important factor to estimate Water Bodies Quality Status. Remote sensing analysis is a fast, cost-effective, and reliable methodology that can be used to assess the phenological patterns of aquatic ecosystems. The purpose of this study is to assess the phenology patterns of a eutrophic water body and present a novel methodology to fill in the missing values of the daily Surface Reflectance MODIS Aqua dataset. The proposed methodology is to apply Principal Component Analysis to generate the missing values from the chlorophyll-a concentrations and better assess Water Body's Trophic Status. The pilot study is Aitoliko Lagoon, a semi-closed Greek water body with eutrophication. The analysis reveals that sampling stations of swallow waters have higher variance in chlorophyll-a concentrations, favoring the deep waters sampling pixels for evaluating the water body's trophic status. The proposed PCA methodology showed a clear phenological pattern of chlorophyll-a with algae bloom from April and high chlorophyll-a concentrations until August, which is what is expected from a eutrophic lagoon and specifically for Aitoliko lagoon.

Integrating environmental sustainability into food-based dietary guidelines in the Nordic countries.

The overall aim of this paper was to provide background knowledge to the Nordic Nutrition Recommendations 2023 Committee for integrating environmental sustainability in a framework for national Food-Based Dietary Guidelines (FBDG) within the Nordics and Baltics. Additionally, this paper aims to give an overview of recent Nordic scientific literature on environmental impact of foods and dietary patterns and of the FBDG of the Nordics. Finally, we suggest methods for developing national sustainable FBDG. Nordic and Baltic studies on sustainability of diets were searched in August 2022 and complemented with additional relevant literature. The studies show that current diets are far from environmentally sustainable, exceeding planetary boundaries for most impact categories; meat and dairy products being the largest contributors to dietary greenhouse gas emissions (GHGEs) and land use. Scenario, modelling, optimisation and intervention studies confirm the potential of shifting towards more plant-based diets to improve overall diet quality in terms of both health and environmental sustainability. Such diets comprised of vegetables, fruits, legumes, potatoes, whole grain and refined cereal products, nuts, seeds and vegetable oils, with animal foods in moderate or limited amounts. The FBDG in the Nordics promotes more plant-based diets than the current average diet but could improve from further integration of environmental sustainability. To form basis for sustainable FBDG dietary modelling at the national level, prioritising health outcomes and nutritional adequacy is essential. Second, integrating environmental sustainability involves estimating the impact of food choices and amounts on GHGE, land and water use, eutrophication and biodiversity loss. Exploring positive and negative implications of fortified foods and supplementation in relation to nutrient intake, health and environmental sustainability may be needed. Implementing dietary transition requires solutions beyond FBDG to ensure affordability, acceptability and ease of adaption.

Research progress of nanoscale zero-valent iron in synergistic combinations of denitrifying bacteria for nitrate removal

Nitrate (NO3--N) is a common inorganic nitrogen pollutant in water. Excessive NO3--N can lead to water eutrophication and threaten human health. Nanoscale zero-valent iron (nZVI) has attracted much attention in NO3--N removal due to its high specific surface and excellent electron donor properties. The combination of nZVI and denitrifying bacteria (DNB) demonstrates high efficiency in converting NO3--N into N2. This approach not only substantially enhances the removal rate of NO3--N but also exhibits superior environmental sustainability compared with conventional chemical denitrification methods. Accordingly, it holds substantial promise for mitigating NO3--N pollution and warrants further exploration in the pollution control. Therefore, it is necessary to understand the interaction mechanism between nZVI and DNB for NO3--N removal. This paper details the factors affecting the removal of NO3--N by nZVI combined with DNB, reviews the latest research progress in this field, elaborates on the interaction mechanism between nZVI and DNB for NO3--N removal, and discusses the challenges and future research directions of NO3--N removal by nZVI combined with DNB. This review aims to provide a theoretical basis for the development of efficient approaches for the remediation of NO3--N pollution.

Fabrication of FeCu/CC Composite for Efficient Removal of Nitrate for Aqueous Solution Via Electrochemical Reduction Process

AbstractThe electrochemical nitrate reduction (ENR) for the conversion of nitrate to nitrogen gas is a significant strategy to remediate the eutrophication in surface water. However, the exploitations and practical applications of suitable electrocatalysts still face great challenges. In this study, FeCu bimetal microparticles were deposited onto surface of carbon cloth (CC) to fabricate the FeCu/CC electrocatalyst for the removal of nitrate. Among obtained catalysts, the sample with Fe/Cu molar ratio of 1 : 15 (Fe1Cu15/CC) exhibits the excellent electroreduction efficiency for nitrate removal (R(NO3−), &gt;90 %) but an ineffective selectivity of N2 formation (S(N2), ~23 %). After the anchor of reduced graphite oxide (rGO) to surface of Fe1Cu15/CC, at the optimized condition without the assistance of chlorine oxidation, R(NO3−) and S(N2) of rGO/Fe1Cu15/CC catalyst reach 94.2 % and 72.8 %. After 5 day endurance test, the values of R(NO3−) and S(N2) are still 82.9 % and 62.8 %, demonstrating the promising durability of this catalyst electrode. Meanwhile, the potential application of rGO/Fe1Cu15/CC was explored for the treatment of simulated wastewater discharged by urban wastewater treatment plant, the concentration of total nitrogen (TN) decreases from 15–1.17 mg/L, and this value is lower than TN threshold limit in Class IV of Chinese surface water quality standard.