Search Results (2,642)

This study conducts a detailed and systematic Life Cycle Assessment (LCA) of demineralized (DEMI) water production at the Al-Hilla Second Gas Power Plant in Iraq, employing the Open LCA-ReCiPe 8 Midpoint (H) method to evaluate potential environmental impacts across 18 midpoint categories. The analysis focuses on the production of 1 cubic meter of high-purity water, offering a comprehensive evaluation of the environmental burdens associated with chemical usage, energy consumption, and resource depletion. The results indicate that terrestrial ecotoxicity is the most dominant impact category (20.383 kg 1,4-DCB-eq), largely driven by the extensive use of treatment chemicals such as coagulants, disinfectants, and antiscalants. Climate change follows as the second highest impact category (3.496 kg CO₂-eq), primarily due to significant electricity consumption during energy-intensive stages, particularly reverse osmosis (RO) and electro-deionization (EDI). These stages also contribute notably to fossil resource depletion (1.097 kg oil-eq) and particulate matter formation, reflecting the heavy reliance on fossil fuel-based energy in the region. Additional environmental concerns identified include human toxicity (both carcinogenic and non-carcinogenic), freshwater and marine ecotoxicity, and metal/mineral resource depletion, all of which underscore the need for improved chemical and material management throughout the treatment process. While impacts from categories such as ozone layer depletion, ionizing radiation, and eutrophication are relatively low, their cumulative effect over time remains a concern for long-term sustainability. The energy assessment reveals that the RO and EDI units alone account for over 70% of the total energy consumption, estimated at 3.143 kWh/m³. This research provides insights into minimizing environmental burdens in water treatment systems, especially in regions facing energy and water stress. Full article

Eutrophication, a growing environmental concern, exacerbates algal blooms and alters the physical and chemical properties of water, thereby diminishing biodiversity, water quality, and ecosystem services. While various control strategies have been developed, most are designed for temperate regions and may not be applicable to tropical systems, which differ ecologically and climatically. This study reviewed 84 articles published between 2000 and 2024, focusing on eutrophication management in tropical and subtropical lakes. The studies were categorized into physical (8), chemical (17), and biological (59) approaches. Over time, research activity has increased, with Asia leading in publication output. Among biological strategies, biomanipulation—especially the use of macrophytes—emerged as the most common and effective strategy. Macrophytes are preferred due to their strong antagonistic interaction with algae, ease of implementation, cost-effectiveness, and minimal ecological risks. While the review also addresses the limitations of each method, it concludes that macrophyte-based biomanipulation remains a promising tool for mitigating eutrophication in tropical and subtropical freshwater ecosystems. In this context, effective lake restoration requires balancing ecological goals with human needs, supported by stakeholder engagement, community education, and multi-sectoral governance. Full article

Nitrate pollution in water bodies has become a global environmental problem, and its excessive presence not only leads to eutrophication of water bodies but also threatens human health through the drinking water pathway. Therefore, it is urgent to develop new adsorbents with high adsorption capacity, good selectivity and excellent regeneration performance to solve the problem of nitrate pollution. In this study, reed straw (RS), trimethylamine-modified reed straw (MRS) and triethylamine-modified reed straw (ERS) were prepared by quaternary amination modification for nitrate removal. The adsorption performance, desorption performance, adsorption characteristics under disturbed environment and dynamic adsorption performance were investigated experimentally, and the adsorption mechanism was analyzed by various characterization means. The adsorption performance followed the order ERS (12.25 mg·g⁻¹) > MRS > RS, demonstrating that quaternary amination modification, particularly with triethylamine, significantly enhanced the NO₃⁻-N adsorption capacity. ERS exhibited excellent regeneration stability (over 80% after nine cycles) and high selectivity towards NO₃⁻-N in the presence of competing anions (Cl⁻, SO₄²⁻, humic acid). In the dynamic adsorption experiment, ERS had a breakthrough time of 290 min at a packing height of 3.3 cm, with an adsorption capacity of 10.74 mg·g⁻¹ and good adaptability to flow rate. In the actual wastewater application, the initial NO₃⁻-N removal rate was over 95%, the dynamic desorption rate reached 99.2% and the peak nitrate concentration of the desorbed solution reached 27 times of the initial value, confirming its high efficiency regeneration and enrichment ability. The study shows that the amine-modified reed straw adsorbent has a good potential for application and provides a new way for wastewater treatment plants to solve the problem of nitrate removal 12.25 mg·g⁻¹. Full article

Most lacustrine dissolved organic matter (DOM) still lacks comprehensive environmental sources and molecular characterization, especially in plateau lakes. Herein, macrophytes and algae from contrasting lakes of the Yunnan-Guizhou Plateau, together with Suwannee River fulvic acid (SRFA), were used to characterize the total identified DOM (Bulk-DOM) and low-molecular-weight DOM (LMW-DOM, <200 Da). To address this, we combined spectroscopy with Fourier transform ion cyclotron resonance (FT-ICR) and Orbitrap mass spectrometry (MS). Algae-derived DOM (ADOM) exhibited endogenous DOM characteristics, while macrophyte-derived DOM (MDOM) showed the characteristics of endogenous and terrigenous DOM. ADOM contained numerous heteroatoms, with high proportions of proteins, carbohydrates, and lipids. The chemical structures of ADOM were more aliphatic and degradable than that of MDOM. Conversely, MDOM and SRFA had higher degree of humification and aromaticity and showed greater resistance to microbial degradation. The capability of Orbitrap MS to characterize P-containing molecules was superior to FT-ICR MS. Moreover, significant differences were found between FT-ICR and Orbitrap MS in weighted average carbon atom number, weighted average mass-to-charge ratio, carbohydrates, and P-containing compounds. LMW-DOM accounted for approximately 10% of Bulk-DOM. Compared to Bulk-DOM, LMW-DOM was more active than Bulk-DOM because of the reduced state and more N-containing compounds. This study provides a valuable perspective to reveal the molecular characteristics and behaviors of ADOM and MDOM, which has crucial implications for carbon cycling in aquatic ecosystems. Full article

Background/Objectives: Despite its growing application, life-cycle assessment (LCA) in the nutraceutical sector has not been systematically studied, leaving a gap in our understanding of the unique challenges of assessing its environmental footprint. The main objective of this study was to provide an overview of scientific publications related to nutraceuticals from the LCA perspective. Methods: This review combined bibliometric analysis, using VOSViewer as an analytic tool, with the search of the Web of Science database, aiming to identify the most relevant papers associated with nutraceuticals and life-cycle assessment. Results: The final selection of the most relevant publications was set at 65, analyzing 78 different nutraceuticals. Results reveal that the main sources of raw materials for extraction of nutraceuticals are marine-based, plant-based, and from agri-food waste. Polyphenols were analyzed 34 times and were predominantly sourced from plants, while carotenoids, analyzed 17 times, were mainly linked with marine-based and food waste-derived sources. The main environmental footprints were focused on climate change, covering most of the nutraceuticals analyzed (97.4%), followed by acidification (78.2%) and eutrophication (74.4%). SimaPro was the prevailing software used for 43.6% nutraceuticals, while the prevailing database was Ecoinvent, used in two thirds of the cases (66.7%). ReCiPe, as a life-cycle inventory assessment method, was used for calculating 34.6% of analyzed cases, followed by CML (33.3%). Conclusions: This systematic review highlights the main challenge in LCA studies, outlining great variability in study boundaries, functional units, and reported environmental footprints, and making it difficult to compare the environmental impacts of similar nutraceutical groups from a life-cycle perspective. This underscores the urgent need to improve input-data quality and develop standardized methodologies to validate sustainability claims using LCA. Full article

Peatlands store huge amounts of soil carbon and play an important role in the global carbon cycle. Drained peatlands stop accumulating carbon and become a source of carbon emissions. Rewetting is an effective method used to restore the ecological functions and carbon sequestration capacities of previously drained peatlands. The eutrophic Berkazan-Kamysh peatland, located in the forest–steppe zone of Bashkir Cis-Urals (the Republic of Bashkortostan), was drained in the 1970s, and since 2017, it has been undergoing rewetting. The aim of this work is to assess and quantify above- and belowground phytomass and its associated carbon pool, as well as to study the dynamics of the vegetation in the Berkazan-Kamysh peatland after rewetting. Vegetation mapping was performed and the areas of the main plant communities were calculated using the Random Forest method. It was found that, over the 7 years from the start of rewetting, the total area of hygro- and hydrophytic mire communities increased almost 3-fold (from 218 to 608 ha). During the same time, the area of meadow communities decreased by half (from 808.0 to 398.9 ha). The areas occupied by helophytic communities of tall graminoid plants (Phragmites australis and Typha angustifolia) have increased 10-fold and have begun to occupy more than 40% of the total area of the peatland. The aboveground phytomass of these types of plant communities can reach 1500–2000 g m⁻². Helophytization and other changes in vegetation composition led to a general increase in the above ground phytomass of the peatland of more than twofold. Full article

Cyanobacterial blooms in urban rivers present critical ecological threats worldwide, yet their mechanisms in fluvial systems remain inadequately explored compared to lacustrine environments. This study addresses this gap by investigating bloom dynamics in the eutrophic Majiagou River (Harbin, China) through phytoplankton resource use efficiency (RUE), calculated as chlorophyll-a per unit TN/TP. Seasonal sampling (2022–2024) across 25 rural-to-urban sites revealed distinct spatiotemporal patterns: urban sections exhibited 1.9× higher cyanobacterial relative abundance (RAC, peaking at 40.65% in autumn) but 28–30% lower RUE than rural areas. Generalized additive models identified nonlinear RAC–RUE relationships with critical thresholds: in rural sections, RAC peaked at TN-RUE 40–45 and TP-RUE 25–30, whereas urban sections showed lower TN-RUE triggers (20–25) and suppressed dominance above TP-RUE 10. Seasonal extremes drove RUE maxima in summer and minima during freezing/thawing periods. These findings demonstrate that hydrological stagnation (e.g., river mouths) and pulsed nutrient inputs reduce nutrient conversion efficiency while lowering bloom-triggering thresholds under urban eutrophication. The study establishes RUE as a predictive indicator for bloom risk, advocating optimized N/P ratios coupled with flow restoration rather than mere nutrient reduction. This approach provides a science-based framework for sustainable management of urban river ecosystems facing climate and anthropogenic pressures. Full article

Understanding plants’ productivity plasticity in response to environmental variations is crucial for evaluating their adaptive capacity and resilience in the face of rapid global changes. Phragmites australis, an important species in coastal wetlands, plays a vital role in ecosystem functions and wetland agriculture. Coastal areas are increasingly threatened by soil salinization due to rising sea levels and eutrophication driven by elevated nitrogen inputs. However, how P. australis adjusts its aboveground and belowground productivity under these environmental stresses remains poorly understood. We examined how P. australis alters its productivity in response to varying salinity and nitrogen enrichment levels through a mesocosm experiment. Our results showed that elevated salinity reduced both aboveground (by 2.7–13.7%) and belowground (by 15.3–24.7%) productivity, decreasing the belowground-to-aboveground biomass ratio of P. australis. In contrast, nitrogen enrichment promoted aboveground productivity (by 18.3–65.5%), but suppressed belowground biomass (by 11.7–29.7%), further reducing the biomass ratio. Nitrogen enrichment alleviated the negative impact of salinity on aboveground productivity, but exacerbated its effects on belowground biomass, further shifting resource allocation to aboveground growth. These findings underscore the adaptive plasticity of P. australis and suggest its potential role in supporting sustainable wetland agriculture, providing both ecological and economic benefits in the face of ongoing global environmental changes. Full article

Scientific conferences are invaluable for knowledge exchange, yet pose growing environmental concerns, especially through long-distance travel. This work quantifies and compares the environmental burdens of a national conference (30 delegates, Pisa, Italy) and an international conference (50 delegates, Athens, Greece) using ISO 14040/44-compliant Life-Cycle Assessment (LCA). A cradle-to-grave inventory combined primary data on participant travel, venue utilities, catering materials and waste handling with secondary datasets from Ecoinvent 3.8. Sixteen midpoint impact categories were calculated with the Environmental Footprint 3.1 method and normalized per delegate. The international meeting incurred 130 kg CO_2eq per delegate, compared with 11 kg CO_2eq per delegate for the domestic event, reflecting a ten-fold rise in fossil energy demand and comparable multiples across acidification, eutrophication and toxicity categories. Participant travel explained >85% of every global indicator in both cases, while venue energy and material flows together accounted for ≤12%. Further developments require harmonized functional units, improved digital-infrastructure inventories and integration of social impact metrics. The findings provide preliminary input for evidence-based guidelines for organizers and contribute to the standardization of LCA in the emerging field of event sustainability. Full article

Industrial processes like farming, food processing, petroleum refinery, and leather manufacturing produce a lot of high-salinity wastewater. This wastewater presents serious environmental risks, such as soil degradation, eutrophication, and water salinization, if it is released without adequate treatment. The sources and features of high-salinity wastewater are outlined in this review, along with the main methods for removing organic pollutants, such as physicochemical, biological, and combined treatment approaches. Membrane separation, coagulation–flocculation, and advanced oxidation processes are the primary physicochemical techniques. Anaerobic and aerobic technologies are the two categories into which biological treatments fall. Physicochemical–biological combinations and the fusion of several physicochemical techniques are examples of integrated technologies. In order to achieve sustainable and effective treatment and resource recovery of high-salinity wastewater, this review compares the effectiveness and drawbacks of each method and recommends that future research concentrate on the development of salt-tolerant catalysts, anti-fouling membrane materials, halophilic microbial consortia, and optimized hybrid treatment systems. Full article

Urban wastewater is composed of nutrients such as nitrogen and phosphorus, organic matter, heavy metals, pathogens, and micropollutants. If untreated, these contribute to eutrophication and environmental degradation. Microalgae-based bioremediation offers a sustainable solution, showing promise for pollutant removal and high-value bioproduct generation. This study evaluates the efficacy of Galdieria sulphuraria ACUF 427 in treating urban wastewater, with a focus on nutrient removal and phycocyanin production at different optical densities (OD 2, OD 4, and OD 6). Nutrient removal rates (RRs) were analysed for ammonium nitrogen (N-NH₄⁺), ammonia nitrogen (N-NH₃), phosphate phosphorus (P-PO₄³⁻), and chemical oxygen demand (COD). The RR for N-NH₄⁺ increased with optical density, reaching 7.49 mg/L/d at an optical density of 6. Similar trends were observed for N-NH₃ and P-PO₄³⁻, with peak removal at OD 6. COD removal remained high across all ODs, though differences between OD 4 and OD 6 were not statistically significant. Significant variations (p < 0.05) in nutrient removal were noted across the ODs, except for COD between OD 4 and OD 6. Biomass growth and phycocyanin production were significantly higher in the wastewater compared to the control (Allen Medium), with the most effective performance observed at an optical density (OD) of 6. Maximum growth rates were 0.241 g/L/d at OD 6, 0.178 g/L/d at OD 4, and 0.120 g/L/d at OD 2. These results highlight the potential of G. sulphuraria as an agent for wastewater bioremediation and the production of high-value compounds, particularly at elevated cell densities, where we achieved superior nutrient removal and biomass production. Full article

Phosphates are key pollutants involved in the eutrophication of water bodies, creating the need for efficient and low-cost strategies for their removal in order to meet environmental quality standards. This study presents a comparative thermodynamic evaluation of phosphate ion adsorption from aqueous solutions using two sustainable and readily available materials: autoclaved aerated concrete (AAC) and pumice stone (PS). Batch experiments were conducted under acidic (pH 3) and alkaline (pH 9) conditions to determine equilibrium adsorption capacities, and kinetic experiments were carried out for the best-performing adsorbent. Adsorption data were fitted to the Langmuir and the Freundlich isotherm models, while kinetic data were evaluated using pseudo-first-order and pseudo-second-order models. The Freundlich model showed the best correlation (R² = 0.90 − 0.97), indicating the heterogeneous nature of the adsorbent surfaces, whereas the Langmuir parameters suggested monolayer adsorption, with maximum capacities of 1006.69 mg/kg for PS and 859.20 mg/kg for AAC at pH 3. Kinetic results confirmed a pseudo-second-order behavior, indicating chemisorption as the main mechanism and the rate-limiting step in the adsorption process. To the best of our knowledge, this is the first study to compare the thermodynamic performance of AAC and PS for phosphate removal under identical experimental conditions. The findings demonstrate the potential of both materials as efficient, low-cost, and thermodynamically favorable adsorbents. Furthermore, the use of AAC, an industrial by-product, and PS, a naturally abundant volcanic material, supports resource recovery and waste valorization, aligning with the principles of the circular economy and sustainable water management. Full article

To address the problems of eutrophication exacerbation in water bodies caused by low carbon-to-nitrogen ratio (C/N) wastewater and the limited nitrogen removal efficiency of conventional constructed wetlands, this study proposes the use of biochar (Corncob biochar YBC, Walnut shell biochar HBC, and Manure biochar FBC) coupled with intermittent aeration technology to enhance nitrogen removal in constructed wetlands. Through the construction of vertical flow wetland systems, hydraulic retention time (HRT = 1–3 d) and influent C/N ratios (1, 3, 5) were regulated, before being combined with material characterization (FTIR/XPS) and microbial analysis (16S rRNA) to reveal the synergistic nitrogen removal mechanisms. HBC achieved efficient NH₄⁺-N adsorption (32.44 mg/L, Langmuir R² = 0.990) through its high porosity (containing Si-O bonds) and acidic functional groups. Under optimal operating conditions (HRT = 3 d, C/N = 5), the CW-HBC system achieved removal efficiencies of 97.8%, 98.8%, and 79.6% for NH₄⁺-N, TN, and COD, respectively. The addition of biochar shifted the dominant bacterial phylum toward Actinobacteriota (29.79%), with its slow-release carbon source (TOC = 18.5 mg/g) alleviating carbon limitation. Mechanistically, HBC synergistically optimized nitrogen removal pathways through “adsorption-biofilm (bacterial enrichment)-microzone oxygen regulation (pore oxygen gradient).” Based on technical validation, a dual-track institutionalization pathway of “standards-legislation” is proposed: incorporating biochar physicochemical parameters and aeration strategies into multi-level water environment technical standards; converting common mechanisms (such as Si-O adsorption) into legal requirements through legislative amendments; and innovating legislative techniques to balance precision and universality. This study provides an efficient technical solution for low C/N wastewater treatment while constructing an innovative framework for the synergy between technical specifications and legislation, supporting the improvement of watershed ecological restoration systems. Full article

The Sanniang Bay (SNB) and Dafeng River Estuary (DFR) in the Northern Beibu Gulf, China, are critical habitats for the Indo-Pacific humpback dolphin (Sousa chinensis). However, whether and how the decreased dissolved oxygen (DO) has happened in bottom seawater remains poorly understood. This study investigated DO depletion and microbial community responses using a multidisciplinary approach. High-resolution spatiotemporal sampling (16 stations across four seasons) was combined with functional annotation of prokaryotic taxa (FAPROTAX) to characterize anaerobic metabolic pathways and quantitative PCR (qPCR) targeting dsrA and dsrB genes to quantify sulfate-reducing bacteria. Partial least-squares path modeling (PLS-PM) was employed to statistically link environmental variables (seawater properties and nutrients) to microbial community structure. Results revealed pronounced bottom DO declining to 5.44 and 7.09 mg L⁻¹, a level approaching sub-optimal state (4.0–4.8 mg L⁻¹) in September. Elevated chlorophyll-a (Chl-a) near the SDH coincided with anaerobic microbial enrichment, including sulfate reducers (dsrA/dsrB abundance: SNB > DFR). PLS-PM identified seawater properties (turbidity, DO, pH) and nitrogen as key drivers of anaerobic taxa distribution. Co-occurrence network analysis further demonstrated distinct microbial modules in SNB (phytoplankton-associated denitrifiers) and DFR (autotrophic sulfur oxidizers, nitrogen fixation, and denitrification). These findings highlight how environmental factors drive decreased DO, reshaping microbial networks and threatening coastal ecosystems. This work underscores the need for regulating aquaculture/agricultural runoff to limit eutrophication-driven hypoxia and temporarily restrict human activities in SNB during peak hypoxia (September–October). Full article

Coastal ecosystems have faced escalating environmental degradation in recent years, with eutrophication and nutrient imbalances emerging as critical concerns, particularly in estuarine regions. Understanding the spatiotemporal dynamics of key nutrients, including dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and silicate (SiO₃-Si), is essential for effective coastal management. This study examines the spatial and seasonal variations in these nutrients across 36 sampling sites in the Yellow River estuary from 2016 to 2018. Results indicate that DIN was the primary contributor to water quality degradation, with more than 27% of sampling sites exceeding the Class II seawater quality standard in 2018. Nutrient concentrations were notably elevated near the estuary. The eutrophication index (EI) revealed predominantly mild-to-moderate eutrophication levels throughout the study area. The study area exhibited a widespread phosphorus (P) limitation, with 44.4–94.4% of coastal waters experiencing P-restricted eutrophication. The N/P ratio significantly exceeded the Redfield ratio (16), indicating a pronounced nutrient imbalance. Furthermore, SiO₃-Si concentrations displayed a declining trend, highlighting the need for balanced nutrient management alongside eutrophication mitigation. Full article