Environmental Science and Pollution Research最新文献

{"title":"Microplastic contamination in the Karnaphuli River, Bangladesh: a PRISMA-guided critical appraisal of evidence reliability, source-attribution uncertainty, and receptor pathways.","authors":"Masuma Wahab, Abdul Hasib Mollah","doi":"10.1007/s11356-026-38317-3","DOIUrl":"https://doi.org/10.1007/s11356-026-38317-3","url":null,"abstract":"<p><p>Microplastic (MP) contamination in tropical river systems is increasingly reported, yet the reliability and comparability of available evidence remain uncertain. This review critically appraises MP contamination in the Karnaphuli River system, Bangladesh, using a PRISMA-guided systematic literature review and an expanded Source-Pathway-Receptor framework. Fifteen peer-reviewed studies were synthesized to evaluate environmental occurrence, methodological quality, reporting comparability, source-attribution certainty, physicochemical characteristics, ecological receptors, and human exposure plausibility. Because studies differed in sampling design, particle-size thresholds, analytical methods, QA/QC reporting, and measurement units, statistical meta-analysis was not appropriate. Available evidence reports MPs in water, sediment, fish, and fishery products, with fibres, fragments, and films frequently dominant. Industrial effluents, municipal wastewater, textile discharge, urban runoff, port activities, and unmanaged plastic waste are plausible contributors, but source attribution remains mainly inferential. Fish-ingestion evidence supports biological uptake and possible trophic transfer, although Karnaphuli-specific freshwater fish data remain limited. Aquatic plants, biofilms, plankton, and benthic organisms are important but understudied receptors. Human dietary exposure through fish and dried fish is plausible but locally unquantified. Overall, the Karnaphuli River should be treated as a high-concern MP system requiring standardized monitoring, source-specific sampling, polymer confirmation, QA/QC transparency, and receptor-based studies.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149206414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-situ magnetic nanocomposite of fluorite MO₂ and spinel M₃O₄ (where M = Mn, Fe, Co, Ni and Ce) for photocatalytic application.","authors":"Sanjula Pradhan, Kanhu Charan Barick, Bijaideep Dutta, Mutta Vasundhara, Nand Kishore Prasad","doi":"10.1007/s11356-026-38318-2","DOIUrl":"https://doi.org/10.1007/s11356-026-38318-2","url":null,"abstract":"<p><p>The fluorite structured CeO₂ is a well-known material for catalysis, sensors, fuel cells, and environmental remediation application due to rapid Ce⁴⁺/Ce³⁺ cycling. Similarly, the recently reported high entropy oxides (HEOs) have tailorable bandgaps, improved charge separation, and multiple redox-active sites, which make them an efficient catalyst for pollutant degradation. Herein, we report the catalytic property of in-situ nanocomposite of fluorite MO₂ and spinel structured high entropy oxide of M₃O₄ (where M = Mn, Fe_, Co, Ni and Ce). The composite was able to degrade around 92% of the methylene blue (MB) dye in 60 min during the photo-Fenton reaction. Further, the mass spectroscopy (MS) study of the solution obtained after complete degradation (in 90 min) of MB justified its total mineralisation. The magnetization value of ~ 25 emu/g of the composite endorses its ability for easy recovery and recycling. The structural and morphological studies via x-ray diffraction and transmission electron microscopy indicate the existence of both CeO₂ and M₃O₄ (spinel structure) phases. The valences of the respective cations were confirmed from x-ray photoelectron spectroscopy.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isocyanic acid measurements in Swedish industries and environments.","authors":"Gunilla Runström Eden, Tobias Storsjö, Anders Johansson, Lena Andersson, Håkan Tinnerberg","doi":"10.1007/s11356-026-38302-w","DOIUrl":"https://doi.org/10.1007/s11356-026-38302-w","url":null,"abstract":"<p><p>Isocyanic acid (ICA), the simplest monoisocyanate, is formed mainly as a by-product through thermal degradation of nitrogen-containing materials. Although ICA participates in protein carbamoylation, human health data remain limited. Existing studies have shown that certain industrial processes may generate substantial ICA emissions but other occupational settings have not been studied. Environmental concentrations are lower than industrial but have not been studied in Europe. This study aimed to survey ICA concentrations in a wide range of occupational and environmental settings in Sweden. In total, 173 air samples were collected in 16 environments. Both stationary and personal sampling were performed. Concentrations were compared to the only existing occupational exposure limit (OEL, 18 µg/m³ 8 h mean) to aid interpretation. High ICA concentrations were consistently observed in industries using urea-based binders at elevated temperatures, with maximum stationary levels exceeding 250 µg/m³. Newly installed mineral wool insulation during initial heating phases generated elevated emissions up to 64 µg/m³. Thermal processing of polyurethane produced lower but spatially widespread concentrations throughout large work areas. In contrast, ICA levels in newly investigated environments-including restaurants, food industries, linoleum welding, diathermy procedures, asphalt work and lawn mowing-were generally well below OEL or below detection limits. Outdoor air measurements in Gothenburg, Sweden, showed uniformly low concentrations (mean 0.12 µg/m³). Extremely high ICA levels were confirmed in direct cigarette smoke (4300 µg/m³), while side-stream exposure was considerably lower. Overall, the survey shows that higher ICA concentrations are mainly associated with industrial high-temperature handling of urea- or polyurethane-based materials, as well as cigarette smoke. Other investigated occupational settings showed low or negligible ICA levels under the conditions measured.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental Chemistry in higher education across Europe.","authors":"Ivana Ivančev-Tumbas, Ester Heath, Gerhard Lammel","doi":"10.1007/s11356-026-38307-5","DOIUrl":"https://doi.org/10.1007/s11356-026-38307-5","url":null,"abstract":"<p><p>In the academic year 2024/25, the EuChemS Division on Chemistry and the Environment (DCE) conducted a Europe-wide survey of higher education programmes that include Environmental Chemistry, either as the principal discipline or as embedded content in interdisciplinary and multidisciplinary curricula. Information on 300 programmes was collected from universities in 31 countries, i.e. 113 at the 1st, 156 at the 2nd and 31 at the 3rd study level. Respectively, 42%, 35% and 19% of the programmes shared details on the contents, teaching tools used, needs and future plans, while the rest of the responding programmes shared only basic information. With basic information on additional 159 1st and 2nd study level programmes based on web search by the authors (mostly for non-responsive countries), in total, 428 programmes at the 1st and the 2nd study level were identified. Since response rate varied dramatically across countries, the representativeness was severely undermined the findings for Europe as a whole. From the information collected from programmes which responded, it was found that multidisciplinary and/or environmental compartment-related approaches are present in programmes' design early, even from 1st level of education and more diverse at the 2nd level. Environmental Chemistry is taught in science programmes containing the terms 'environment(-al)', 'Chemistry', 'Geoscience' and 'Toxicology', but also quite frequently in engineering programmes. The water, climate, protection and sustainability themes are very common. A wide variety of programmes clearly reflects the importance of knowledge about the behaviour and effects of chemicals (including accompanying substances and waste products) in the environment for the training of experts in a variety of professions and occupational fields. The analysis of the contents of programmes with Environmental Chemistry as their principal discipline suggests that there is no uniform understanding of what exactly constitutes the discipline as a main or important topic within an interdisciplinary curriculum, most probably as a consequence of very broad discipline's boundaries. Greater consistency and better comparability of the content, skills and qualifications offered by degree programmes to be acquired therein could be achieved through a coordinated effort which would better define core contents.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gestational exposure to haloxyfop-R-methyl drives maternal and embryonic residue burden and hepatic biochemical injury in Wistar rats.","authors":"Abdurakhmonova Mashkhura Javdatovna, Mirkhamidova Parida, Pozilov Mamurjon Komiljonovich, Shakhmurova Gulnara Abdullayevna, Alimova Rano Abbasovna, Muhammad Waheed","doi":"10.1007/s11356-026-38308-4","DOIUrl":"https://doi.org/10.1007/s11356-026-38308-4","url":null,"abstract":"<p><p>Haloxyfop-R-methyl is a grass-selective aryloxyphenoxypropionate herbicide whose gestational exposure is toxicologically important because maternal xenobiotic burden can coincide with fetal organogenesis, placental transfer, and hepatic metabolic stress. The present investigation evaluated organ-specific accumulation of haloxyfop-R-methyl in pregnant Wistar rats and their fetuses following exposure on GD3, GD13, or GD17. It also assessed the corrective efficacy of narcissin and sophoroflavonoside (SFL) against pesticide-induced alterations in maternal hepatic biomarkers. Pregnant rats received haloxyfop-R-methyl orally at a sublethal dose equivalent to 1/10 LD₅₀ on gestational day (GD) 3, 13, or 17. Maternal and fetal liver, lung, spleen, and brain were collected on GD20-GD21 for LC-MS-based residue quantification. A parallel experiment measured maternal plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin. These biomarkers were assessed after haloxyfop-R-methyl exposure alone or combined with narcissin or SFL. LC-MS calibration showed strong linearity, with slopes of 93,384.20 and 97,181.37 and uncentered R² values of 0.99993 and 0.99978. Haloxyfop-R-methyl was absent from controls but was detected in all examined maternal and fetal tissues. Residue concentrations differed among exposure-timing groups at terminal sampling. Maternal liver and lung showed the highest concentrations in the GD17-dosed group, reaching 0.619 ± 0.050 and 0.529 ± 0.041 µg g⁻¹, respectively. Fetal liver and lung also showed the highest concentrations in the GD17-dosed group, reaching 0.419 ± 0.035 and 0.405 ± 0.020 µg g⁻¹. Fetal-to-maternal residue ratios were highest in several organs in the GD17-dosed group, particularly lung, liver, and brain. Haloxyfop-R-methyl increased maternal ALT, AST, and total bilirubin across all exposure windows. The highest values occurred in the GD17-dosed group at terminal sampling. However, all groups were sampled on GD20-GD21, resulting in different intervals between dosing and sampling. Therefore, the observed differences cannot distinguish gestational stage effects from effects of time elapsed since exposure. Narcissin and SFL reduced pesticide-induced biochemical alterations. SFL showed greater protective efficacy across most endpoints, particularly bilirubin on GD3 and AST on GD13. Standardized effect-size analysis confirmed large haloxyfop-R-methyl-associated effects and measurable biochemical correction following flavonoid treatment. The integrated residue-biomarker framework characterizes exposure window-associated maternal-fetal residue distribution and flavonoid-mediated biochemical correction during pregnancy.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Who is the patient of One Health?","authors":"Flavio Manoel Rodrigues da Silva Júnior, Livia da Silva Freitas, Camilla Thays Melquiades Tavares de Oliveira, Nair Albuquerque Gomes de Paula, Jefferson Phellippe Wanderley Florencio, Juliana de Lima Rodrigues, Alex Filipe Ramos de Sousa","doi":"10.1007/s11356-026-38312-8","DOIUrl":"https://doi.org/10.1007/s11356-026-38312-8","url":null,"abstract":"<p><p>The One Health approach has emerged as one of the most influential approaches for addressing contemporary challenges at the human-animal-environment interface. Although its conceptual foundation is based on the premise that human, animal, and environmental health are equally interconnected, concerns have recently been raised regarding persistent anthropocentric tendencies within its scientific and institutional implementation. This discussion article examines whether the three pillars of One Health are receiving equivalent attention within contemporary scientific production and governance structures. To explore this question, we combined a brief exploratory assessment of 490 articles indexed in the Web of Science containing the term \"One Health\" in their titles and published in 2026. Articles were evaluated according to research areas, Sustainable Development Goals (SDGs), and departmental affiliations and an article-level assessment of their substantive human, animal, and environmental health beneficiaries. We argue that the principal challenge facing One Health may no longer be conceptual, but institutional. Advancing the framework will require moving from conceptual integration toward governance systems capable of supporting balanced participation of human, animal, and environmental sectors. Without such transformation, One Health risks remaining conceptually integrated while structurally asymmetrical.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection, characterization, and quantification of microplastics in human biological matrices: a systematic review.","authors":"Israel Ríos-García, Andrea Carolina Machado-Sulbaran, Valentin Flores-Payan, Fernanda-Isadora Corona-Meraz, Carlos Vladimir Muro-Medina, Belkis Sulbaran-Rangel","doi":"10.1007/s11356-026-38311-9","DOIUrl":"https://doi.org/10.1007/s11356-026-38311-9","url":null,"abstract":"<p><p>The presence of microplastics (MPs) in the environment represents an emerging risk to human health, with growing evidence of detection in human biological matrices. This systematic review synthesizes evidence on the detection, quantification, and characterization of MPs in human biological matrices. A systematic search was conducted in PubMed, Web of Science, and Scopus databases. Original research articles published in English up to 2025 that involved human participants were included, specifically selecting observational studies. The 40 included studies confirmed MPs in multiple human biological matrices, including blood, urine, feces, placenta, breast milk, semen, lung, and heart tissue. The Newcastle-Ottawa Scale (NOS) was used to assess the quality and risk of bias of the individual studies. Substantial methodological heterogeneity was observed in analytical techniques, including Fourier-transform infrared microspectroscopy (μFTIR), micro-Raman spectroscopy (μ-Raman), laser direct infrared spectroscopy (LDIR), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), as well as in the reporting units and limits of detection. Most studies reported fragments and fibers, with a predominance of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). NOS assessment showed that 52.5% of studies were of moderate quality, indicating that while the frequent detection of these particles suggests widespread human contact, significant methodological shortcomings and potential analytical overestimations limit the accurate quantification of systemic exposure and the strength of causal inferences. The widespread detection of MPs raises public health concerns regarding chronic exposure and potential health implications. However, current evidence remains insufficient to establish causal relationships, underscoring the urgent need for rigorous epidemiological studies.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the effect of landfill leachate on soil and surface water quality: a case study of the Lamdeng landfill site, Manipur, Northeast India.","authors":"Ningombam Sharda Devi, Maibam Dhanaraj Meitei, Khoinaijam Sashikanta Meitei, Pallujam Rabina, Chuiyapem Shaiza","doi":"10.1007/s11356-026-38200-1","DOIUrl":"https://doi.org/10.1007/s11356-026-38200-1","url":null,"abstract":"<p><p>Environmental pollution due to leachate infiltration from Municipal Solid Waste (MSW) landfill is a grave problem in many developing countries. A pioneer study was undertaken to assess the impact of the Lamdeng Municipal Solid Waste Management Plant in Manipur, Northeast India on the soil and surface water quality of the surrounding areas and its associated human health risk. For the study, leachate, soil, and surface water physico-chemical characteristics were assessed during 2022-2023. Heavy metals such as Fe, Cu, Zn, and Cd concentrations in leachate, soil and surface water from the surrounding areas were quantified. The surface water characteristics such as EC, TDS, turbidity, DO, alkalinity, total hardness, Ca²⁺, Mg²⁺, Na⁺, NO₃^-, and PO₄^3- showed values beyond WHO thresholds. The Water Quality Index (WQI) values calculated for surface water in the surrounding areas ranged from 130.56 to 511.74, which is in the unsuitable category for drinking. Moreover, the crops cultivated in the agricultural fields near the facility are exposed to high EC, TDS, salinity, and magnesium ions. The health risk assessment of locals via metal exposure from the landfill leachate showed that the carcinogenic risk due to cadmium was 1.77 × 10^-6 for adults and 7.08 × 10^-6 for children, which is > 1 per 1,000,000 inhabitants, indicating an acceptable carcinogenic risk. However, the locals, oblivious of the current scenario, practice agriculture and fishing, extract wild edibles, and depend on the surface water from the surrounding areas of the waste management facility.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recovery of rare earth elements (Y, La, Ce, Eu and Tb) from waste fluorescent lamps via integrated leaching and EDTA-functionalized Chitosan adsorption.","authors":"Pallabi Roy, Musthaq Mohammad Syed, Arunabh Meshram, Krishanu Biswas","doi":"10.1007/s11356-026-38276-9","DOIUrl":"https://doi.org/10.1007/s11356-026-38276-9","url":null,"abstract":"<p><p>Rare earth elements (REEs) are critical for advanced technologies, and their demand is expected to exceed current supply in the coming years. This study presents an integrated enrichment-adsorption strategy for recovering Y, La, Ce, Eu, and Tb from waste fluorescent lamp phosphor powder containing ~6 wt% REEs. A three-cycle alkali roasting process at 800 °C transformed phosphate phases into oxides, facilitating subsequent hydrometallurgical treatment. Sequential two-stage leaching comprising 2 mol L^-1 H₂SO₄ at 40 °C followed by brine leaching (2.5 mol L^-1 NaCl, pH 5, 90 °C, 90 min) reduced Ca content from 36.74 to 8.06 wt%, corresponding to a 78.1% decrease and significant enrichment of the REEs. The enriched solution was treated with EDTA-functionalized chitosan under optimized conditions (pH 5, 50 °C, 24 h), achieving maximum adsorption efficiencies of 82.4% (Tb), 79.15% (Y), 74.10% (Ce), 60.13% (La), and 31.87% (Eu). Langmuir isotherm fitting demonstrated monolayer adsorption with maximum capacities (q_max) of 179.54 mg g^-1 (Tb), 106.45 mg g^-1 (Y), 115.35 mg g^-1 (Ce), 77.68 mg g^-1 (La), and 28.47 mg g^-1 (Eu). The integrated pre-concentration and bio-based adsorption strategy provides a technically efficient route for selective REE recovery, contributing to sustainable and circular economic development.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term monitoring of a full-scale parallel-unit downflow hanging sponge system with adaptive capacity for fluctuating wastewater flows in Japan.","authors":"Yasuyuki Takemura, Shinichi Yamazaki, Takashi Matsueda, Satoshi Ohmori, Akihiro Nagano, Motofumi Taniwaki, Noriko Tomioka, Masataka Aoki, Kazuaki Syutsubo","doi":"10.1007/s11356-026-38300-y","DOIUrl":"https://doi.org/10.1007/s11356-026-38300-y","url":null,"abstract":"<p><p>This study presents a 30-month full-scale evaluation of a parallel-unit downflow hanging sponge (DHS) system with adaptive downsizing capability at the Susaki Sewage Treatment Plant, Japan. The DHS reactor comprised ten identical units operated in parallel, allowing capacity adjustment by varying the number of active units. The system (primary sedimentation tank → DHS → moving bed biological filter) was monitored under normal, low-temperature (winter), partial downsizing, and sponge sheet installation (upper part of the sponge media-filled segment) conditions. Dichromate-based chemical oxygen demand (COD_Cr), biochemical oxygen demand (BOD), total suspended solids (TSS), NH₄⁺-N, NO₃⁻-N, total nitrogen, and Escherichia coli were analyzed weekly and monthly to evaluate organic removal, nitrification, and microbial reduction. DHS effluent (77-85% COD_Cr, BOD removal, and a 1.5 log₁₀ reduction in E. coli) consistently met Japanese discharge standards. Downsizing to nine units, that is, reducing the hydraulic retention time, maintained effluent quality, confirming the system's flexibility under declining inflows. Statistical comparison among operational periods showed no significant difference in NH₄⁺-N loading rate, whereas NH₄⁺-N removal efficiency was significantly higher after sponge sheet installation. The sponge sheet enhanced hydraulic dispersion and nitrification, reducing NH₄⁺-N from 16-19 to 9 mg N·L⁻¹ and promoting NO₃⁻-N accumulation. Compared to the conventional activated sludge process previously employed, DHS used 83% less power and reduced excess sludge generation, demonstrating its potential as a sustainable, energy-efficient alternative for small- to medium-scale sewage treatment facilities with aging infrastructure. These findings highlight DHS as a resilient and socially viable solution for regions with declining populations, ensuring reliable wastewater treatment despite demographic and economic challenges.</p>","PeriodicalId":545,"journal":{"name":"Environmental Science and Pollution Research","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}