Search Results (48)

Construction and demolition waste valorization as recycled aggregates remains largely underdeveloped in North African urban contexts. This study presents the first normatively referenced characterization of recycled aggregates from ten sites in Fez, Morocco, combined with experimental C25/30 concrete formulation using the Dreux-Gorisse method. Physical, mechanical, and chemical analyses reveal high water absorption (9.98 ± 0.94%), low particle density (2197 kg/m³), sub-standard sand equivalent (39.4%), and elevated methylene blue (3.06 g/kg), all governed by attached cementitious mortar content. Principal component analysis identifies three groups: Cluster A (E2, E6, E8), directly valorizable for structural use; Cluster B (E3, E4, E7, E10), requiring fine-fraction removal (<80 µm) prior to concrete incorporation; and an intermediate group (E1, E5, E9), suitable for non-structural applications. Concrete mixes from a composite blend of all ten samples were experimentally validated on cylindrical specimens. At 25% substitution, the 28-day compressive strength reaches 22–28 MPa, achieving marginal C25/30 compliance when superplasticizer and pre-wetting correction (9.98 L/100 kg recycled aggregate) are applied; substitution at 50% and above does not meet structural requirements (18–24 MPa). Durability assessments confirm increasing carbonation depth (7–11 mm at 25%) and moderate-to-high chloride permeability, underscoring the need for source-selective sampling and pre-treatment in urban construction and demolition waste valorization programs, particularly in North African and Maghreb contexts where construction materials and building practices are broadly similar and demolition waste is typically processed without prior sorting. Full article

Global urbanization is shifting from incremental expansion to stock optimization, and old residential communities have become important spatial units for low-carbon transition. However, in existing built environments, traditional process-based inventory methods face practical constraints, including missing original drawings, complex site conditions, and severe vegetation obstruction. As a result, systematic accounting of buildings, landscapes, and natural carbon sinks remains difficult. This study integrates life cycle assessment (LCA), BIM reverse modeling, 3D point clouds, DesignBuilder simulation, inventory-based accounting, and i-Tree Eco to construct a life cycle carbon emission accounting framework for old residential communities. The framework links current-condition data reconstruction, quantity take-off, operational energy simulation, landscape inventory accounting, and vegetation carbon sequestration assessment. It is applied to Nanyuan Xincun in Hefei to quantify the community-scale carbon source–sink structure. The results show that Nanyuan Xincun presents a clear operation-led emission pattern, with the operation and maintenance phase accounting for 82.52% of total positive emissions. Within architectural engineering, operation and maintenance accounts for 82.91%, while material production accounts for 13.28%. Landscape engineering shows a more mixed structure, with operation and maintenance accounting for 52.95% and material production accounting for 36.49%. Vegetation carbon sequestration analysis shows that mature trees and shrubs are the main ecological carbon assets. Annual sequestration reaches 16.95 t-CO₂e/a, and trees and shrubs contribute 92.85% of total vegetation carbon storage. Under current vegetation conditions, annual sequestration is equivalent to 32.99% of annual landscape operation emissions, indicating considerable ecological compensation potential. Based on these findings, this study proposes four optimization pathways: operational energy reduction, low-carbon material substitution, construction and demolition waste recycling, and mature tree protection. These pathways provide data support for refined carbon management and low-carbon renewal in existing communities. Full article

This study investigated the characteristics and interrelationships of polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs), and microbial communities in coastal river sediments and benthic mollusks collected from an e-waste recycling area in Taizhou, Zhejiang Province. In sediments, 16 PAHs and six PAEs were detected, with concentrations ranging from 2.66 to 379.99 μg/kg and 76.5 to 3426.57 μg/kg, respectively. Four-ring PAHs (particularly fluoranthene and pyrene) and Bis(2-ethylhexyl) phthalate (DEHP) were dominant, with DEHP posing a potential risk, especially at site 10, warranting further attention. In contrast, only eight PAHs and four PAEs were detected in mollusks, with concentrations of 60.14–523.10 μg/kg and 144.55–3005.71 μg/kg, respectively. Two-ring PAHs (particularly naphthalene) and Dibutyl phthalate (DBP) were dominant, likely derived directly from the overlying water. The PAHs in sediments primarily originated from fossil fuel combustion, biomass burning, and coal combustion, while PAEs were likely derived from the release of plastic waste from solid waste recycling. Lower concentrations and fewer PAH and PAE species were observed in the sediments near the ocean and at greater distances from the e-waste recycling sites. Significant differences were observed in microbial communities between sediment and mollusk samples. Dominant phyla shared by both sample types include proteobacteria, bacteroidetes, firmicutes, and acidobacteria. The concentration of low-ring PAHs was correlated with the microbial communities, particularly in mollusk samples. Relationships were also identified between microbial communities and DEHP concentrations in sediments or DBP concentrations in mollusks. Full article

The spatial configuration of Waste-to-Energy infrastructure plays a decisive role in determining the environmental and economic performance of municipal solid waste (MSW) management systems. This study applies a Life Cycle Assessment methodology to evaluate the environmental implications of centralized and decentralized siting strategies for Refuse-Derived Fuel utilization in Greece. Two alternative scenarios were modeled: (i) a centralized approach based on six large WtE plants as proposed by the Greek Ministry of Environment and Energy (gr. YPEN), and (ii) a decentralized approach involving smaller, regionally distributed units located closer to Recycling and Recovery Facilities. Using the SimaPro software and the ReCiPe method, environmental impacts were quantified across categories including global warming potential, acidification, eutrophication, and particulate matter formation. The results indicate that the decentralized scenario yields substantial environmental advantages, with reductions ranging from 33% to 45% across all impact categories and displaying a 35% decrease in CO₂-equivalent emissions compared to the centralized scenario. Economic analysis confirms these findings, showing a 31% reduction in total transport and emissions-related costs due primarily to minimized long-distance and maritime transport. The study concludes that decentralized RDF-to-energy systems offer a more balanced and sustainable pathway, enhancing operational flexibility, lowering environmental burdens, and improving social acceptance. These results underscore the importance of integrating spatial and logistical parameters in national WtE planning to align with EU waste hierarchy principles and circular economy objectives. Full article

Over 292 million tons of municipal solid waste (MSW) are generated annually in the United States, with more than half disposed of in landfills. Municipal solid waste landfills (MSWLFs) are stationary sources of air pollution and potential health risks for nearby communities. The Agency for Toxic Substances and Disease Registry (ATSDR) has completed over 300 public health assessments (PHAs) and related investigations at MSWLFs and open dumps since the 1980s. This paper reviews the ATSDR’s evaluations of air pathway concerns at 125 MSWLF sites assessed between 1988 and early 2025, with many being evaluated during the 1990s. Most sites were located in the Midwest and Northeast, and only 25% remained active. The ATSDR found no air-related public health hazard at 86% of sites. At sites where hazards were identified, common issues included elevated outdoor or indoor toxicants (e.g., hydrogen sulfide, benzene, trichloroethylene, and mercury) and unsafe methane accumulations. Contributing factors included older site designs, inadequate gas-collection, subsurface fires, and distance from nearby residences. Corrective actions effectively reduced exposures at the affected sites. Results suggest that well-located and maintained landfills minimize public health hazards, while aging or poorly managed sites pose risks. Continued monitoring and research are warranted as waste management shifts toward reducing, reusing, recycling, composting, and energy-recovery technologies to improve efficiency, advance technologies, and address systemic public health challenges. Full article

The increase in municipal solid waste (MSW) generation and its inefficient management have caused significant environmental impacts, particularly in developing countries such as Mexico. In the central region, final disposal in uncontrolled sites (UCSs) remains a common practice despite its negative effects on the environment and public health. These impacts have been underestimated due to the scarcity of studies and the lack of technological alternatives aimed at mitigating them. In response to this problem, Life Cycle Assessment (LCA) emerges as a strategic tool to quantify these effects and to guide decision-making toward more sustainable management. The objective of this study was to evaluate the environmental impacts of a UCS using LCA, considering four scenarios: a baseline (E0) representing the current system conditions and three alternative scenarios (E1, E2, and E3) designed to explore potential improvements in environmental performance and to identify a feasible option under the socioeconomic conditions of a municipality in central Mexico. The functional unit was defined as the treatment of one tonne of MSW. The system boundaries included the separation of recyclable inorganic waste (RIW), the treatment of organic waste (OW) through composting and anaerobic digestion (AD), and the final disposal of mixed waste (MW) in UCSs and sanitary landfills. The assessment was performed using SimaPro Analyst v9.6 software and the ReCiPe methodology. The E0 scenario exhibited the highest environmental burdens, whereas E2 and E3 reduced the disposal of MW from 85.92% to 52.57% and emissions by 78.9%. E3 showed the lowest overall impact by integrating mechanical separation, AD, and controlled landfill disposal. E2, which employed composting instead of AD, proved to be a viable alternative for resource-constrained contexts. The results support the closure of uncontrolled sites and encourage the transition toward integrated systems that incorporate valorization technologies, which are urgently needed to achieve the Sustainable Development Goals. Full article

Human activities have led to severe aquatic pollution and significant concerns about the ecological health of the Lianjiang River Basin (LRB). These concerns resulted in the implementation of comprehensive policies and treatments to improve the sediment and water quality. Herein, we explore the concentrations, sources, and degree of metal contamination in filtered water (FW), suspended solids (SSs), and surficial channel sediments (SCSs) in streams of the LRB. Calculated enrichment factors, an ecological risk index, and a principal component analysis were employed to understand the degree of elemental contamination, ecological risks, and their potential sources. Elements (e.g., Hg, Cd, Sn, Sb, Cu, and Mo) were mainly detected in FW, SSs, and SCSs in the Bergang, Hucheng, Xiashan, and Zhonggang rivers, and the mainstream of the LR. Four potential anthropogenic sources were identified, including electronic waste recycling (e.g., Cu, Sb, Pb, and Ni), mixed pollution (e.g., Se, Zn, Mn, and Mo), metal processing (e.g., Hg, Cr, Sn, and Cd), and battery manufacturing and recycling (e.g., Co, Ni, and Mn). Overall, Sn, Sb, Hg, Cu, and Cd were enriched by 37.5–79.2% and 34.8–91.3% at the SS and SCS sites, respectively. Mercury, Cd, Sn, Sb, Cu, and Mo posed the most risk both in the SSs and SCSs. Overall, the SS and SCS samples from the LRB remain severely contaminated with metals after recent environmental remediation. The implementation of pollution source control, sewage interception, and dredging operations should be further enhanced. Full article

In line with circular economy principles and the reduction of primary material exploitation, waste-to-energy (WtE) by-products such as bottom ash (BA) are increasingly being used as raw materials in cement and ceramics manufacturing. However, it is critical to verify that the final product presents not only adequate technical properties but also that it does not pose negative impacts to the environment and human health during its use. This study investigates the environmental compatibility of the use of ceramic porcelain stoneware tiles manufactured with BA as partial replacement of traditional raw materials, with a particular focus on the leaching behavior of the tiles during their use, and also after crushing to simulate their characteristics at their end of life. To evaluate the latter aspect, compliance leaching tests were performed on crushed samples and compared with Italian End-of-Waste (EoW) thresholds for the use of construction and demolition waste as recycled aggregates. Whereas, to assess the environmental compatibility of the tiles during the utilization phase, a methodology based on the application of monolithic leaching tests to intact tiles, and the evaluation of the results through multi-scenario human health risk assessment and the analysis of the main mechanisms governing leaching at different stages, was employed. The results of the study indicate that the analyzed BA-based tiles showed no significant increase in the release of potential contaminants compared to traditional formulations and fully complied with End-of-Waste criteria. The results of the monolith tests used as input for site-specific risk assessment, simulating worst-case scenarios involving the potential contamination of the groundwater, indicated negligible risks to human health for both types of tiles, even considering very conservative assumptions. As for differences in the release mechanisms, tiles containing BA exhibited a shift toward depletion-controlled leaching and some differences in early element release compared to the ones with a traditional formulation. Full article

In accordance with the EU Landfill Directive, by 2035, EU countries must reduce the amount of municipal waste sent to landfills to 10% or less of the total municipal waste generated. To achieve this, it is necessary to implement recycling measures, including composting organic waste. Another way to utilize organic waste generated in households is through anaerobic digestion, which produces biogas, a renewable energy source. Biogas production from biodegradable waste generated in households occurs in both industrial facilities and household biogas installations. Producing biogas in household installations offers the advantage of generating and using biogas at the same location where the waste is produced, reducing the need to transport bio-based materials to a storage site. This approach reduces costs and the environmental footprint associated with transporting waste to industrial facilities and subsequently transporting biogas to municipal (domestic) consumers. Although this solution appears optimal in many respects, the current technical and legal environment limits the development of the household biogas production market in EU countries. This article highlights the technical and legal aspects of safely using biogas from household installations (e.g., certification of gas equipment) and legal aspects (such as restrictions on the number of energy sources), which significantly limits the growth of this sector. Full article

Background: Electronic waste (e-waste) recycling in informal settings like Agbogbloshie in Accra, Ghana, releases toxic metals into the environment, posing serious health risks to nearby residents, particularly children. This study assessed the body burdens of lead (Pb), manganese (Mn), cadmium (Cd), chromium (Cr), nickel (Ni), and arsenic (As) and their association with cognitive function in schoolchildren living within 1 km of the Agbogbloshie site. Method: A cross-sectional study involving 56 pupils collected demographic data and blood and urine samples and administered the Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV). Blood was tested for Pb and Mn and urine for Cd, Cr, Ni, and As. Associations between metal levels and cognitive outcomes were examined using regression analyses, adjusting for confounders. Result: Children showed elevated metal levels, with mean blood Pb of 60.43 µg/L and urinary s of 21.50 µg/L. Symptoms of cognitive dysfunction were common: 75% reported confusion, 67.9% poor memory, and 66% poor concentration. Urinary Cr levels were significantly associated with lower Full-Scale IQ (β = −18.42, p < 0.05) and increased difficulty in decision-making (OR = 0.1, p < 0.05). Conclusion: These findings underscore the neurodevelopmental risks of heavy metal exposure from e-waste in low- and middle-income countries and call for urgent public health interventions and policy actions. Full article

Background: Informal electronic waste (e-waste) recycling practices release a complex mixture of pollutants, particularly heavy metals, into the environment. Chronic exposure to these contaminants has been linked to a range of health risks, but the molecular underpinnings remain poorly understood. In this study, we investigated the alterations in metabolic profiles due to e-waste exposure and linked these metabolites to systemic biological effects. Methods: We applied untargeted high-resolution metabolomics using dual-column LC-MS/MS and a multi-step analysis workflow combining MS1 feature detection, MS2 annotation, and chemical ontology classification, to characterize urinary metabolic alterations in 91 e-waste workers and 51 community controls associated with the Agbogbloshie site (Accra, Ghana). The impacts of heavy metal exposure in e-waste workers were assessed by establishing linear regression and four-parameter logistic (4PL) models between heavy metal levels and metabolite concentrations. Results: Significant metal-associated metabolomic changes were identified. Both linear and nonlinear models revealed distinct sets of exposure-responsive compounds, highlighting diverse biological responses. Ontology-informed annotation revealed systemic effects on lipid metabolism, oxidative stress pathways, and xenobiotic biotransformation. This study demonstrates how integrating chemical ontology and nonlinear modeling facilitates exposome interpretation in complex environments and provides a scalable template for environmental biomarker discovery. Conclusions: Integrating dose–response modeling and chemical ontology analysis enables robust interpretation of exposomics datasets when direct compound identification is limited. Our findings indicate that e-waste exposure induces systemic metabolic alterations that can underlie health risks and diseases. Full article

Effective municipal solid waste (MSW) management is crucial for urban sustainability, especially in fast-growing cities, like Hangzhou, China. This study examines residents’ willingness to pay (WTP) for the following five key MSW measures: differentiated waste charging, smart recycling points, on-site organic waste recovery, volunteer-based waste sorting supervision, and a community self-governance fund. Based on a survey of 521 residents across 13 districts, we use logistic and interval regression models to identify factors influencing WTP and payment amounts. Key findings include the following: Higher-income and more educated residents prefer cost-efficient, technology-driven solutions, like smart recycling and differentiated charging. Newcomers (≤5 years of residence) show higher WTP and greater sensitivity to environmental information, highlighting the need for targeted outreach. Providing explicit environmental benefits (e.g., waste reduction, increased recycling) significantly boosts WTP rates and payment levels. Community characteristics matter—residents in high-density areas favor waste charging, while those in older neighborhoods support volunteer programs and self-governance funds. Policy implications center on targeted outreach, transparent fee structures, and incentive programs to foster public trust and enhance participation. Although MSW management in Hangzhou remains predominantly government-led, select collaboration with private enterprises (e.g., in specialized recycling services) may offer additional efficiency gains. By aligning these measures with localized preferences and demographic patterns, Hangzhou—and other quickly urbanizing regions—can develop robust and inclusive MSW systems that contribute to broader sustainable development objectives. Full article

Informal e-waste recycling can cause serious heavy metal(loid) pollution to nearby bodies of water, thereby increasing the risk of heavy metal exposure to local residents. This study investigates metal(loid) pollution levels in the Lianjiang River, which flows through Guiyu, an e-waste recycling town in Shantou, Guangdong. In 2009 and 2020, water samples from the Lianjiang River were taken, and the levels of 12 metal(loid)s (V, Cr, Mn, Sr, Ni, Cu, Zn, As, Se, Cd, Ba, and Pb) were measured by ICP-MS. In total, 380 valid questionnaires from Guiyu kindergarten children were selected to assess child health. Exposure health risks for children were calculated using two forms of exposure (dermal and inhalation) and statistical methods (multiple linear regression and Bayesian kernel machine regression—BKMR). The concentrations of Mn, Ni, Pb, and Cd in 2009 were significantly higher than those in 2020. The concentration of heavy metal(loid)s had been decreasing in 2020. The non-carcinogenic risk levels of the 12 metal(loid)s in both exposure routes were at an acceptable risk level. The average carcinogenic risk levels for As, Cr, Ni, Pb, and Cd exceeded the ILCRi <10–6 acceptable range. According to MLR, it was found that daily oral intake doses of Pb [β(95% CI): −0.949 (−1.596, −0.863), p < 0.001 and Se [β(95% CI): −0.911 (−1.888, −0.092), p = 0.031] were negatively associated with body mass index. A BKMR model was developed, through which the synergistic effects of co-exposure to 12 heavy metal(loid)s on growth and development indicators in children were analyzed. Concentrations of heavy metal(loid)s in rivers near e-waste recycling sites have been decreasing for 10 years. It was found that the growth and development of children are affected by the intake of heavy metal(loid)s in water. The reduction in heavy metal(loid) contamination in e-waste recycling areas needs to be continued, and concern about its impact on children’s health must remain. Full article

Aqueous phase reforming (APR) is a promising method for producing hydrogen from biomass-derived feedstocks. In this study, carbon-supported Pt catalysts containing particles of different sizes (below 3 nm) were deposited on different commercially available carbons (i.e., Vulcan XC72 and Ketjenblack EC-600JD) using the metal vapor synthesis approach, and their catalytic efficiency and stability were evaluated in the aqueous phase reforming of ethylene glycol, the simplest polyol containing both C–C and C–O bonds. High-surface-area carbon supports were found to stabilize Pt nanoparticles with a mean diameter of 1.5 nm, preventing metal sintering. In contrast, Pt single atoms and clusters (below 0.5 nm) were not stable under the reaction conditions, contributing minimally to catalytic activity and promoting particle growth. The most effective catalyst Pt_A/C^K, containing a mean Pt NP size of 1.5 nm and highly dispersed on Ketjenblack carbon, demonstrated high hydrogen site time yield (8.92 min⁻¹ at 220 °C) and high stability under both high-temperature treatment conditions and over several recycling runs. The catalyst was also successfully applied to the APR of polyethylene terephthalate (PET), showing potential for hydrogen production from plastic waste. Full article

Given the current highest demand in history for raw materials, there is a growing demand for the recovery of key metals from secondary sources, in order to prevent metal depletion and to reduce the risk of toxic discharges into the environment. This paper focuses on the current nature-based solutions (i.e., biomining and bioleaching) applied to resource recovery (metals) from solid matrices. Biomining exploits the potential of microorganisms to facilitate the extraction and recovery of metals from a wide range of waste materials as an interesting alternative, replacing primary raw materials with secondary material resources (thus improving metal recycling rates in the context of the circular economy). Special attention was paid to the analysis of metal biomining from a process sustainability perspective. In this regard, several supporting tools (e.g., life cycle assessment, LCA), developed to assist decision-makers in the complex process of assessing and scaling-up remediation projects (including biomining), were discussed. The application of LCA in biomining is still evolving, and requires comprehensive case studies to improve the methodological approach. This review outlines the fact that few studies have focused on demonstrating the environmental performance of the biomining process. Also, further studies should be performed to promote the commercial opportunities of biomining, which can be used to recover and recycle metals from solid matrices and for site remediation. Despite some important disadvantages (poor process kinetics; metal toxicity), biomining is considered to be a cleaner approach than conventional mining processes. However, implementing it on a large scale requires improvements in regulatory issues and public acceptance. Full article