Resources

20 pages, 9222 KB

Open AccessArticle

Integrated Assessment of Potentially Toxic Elements in Soils and Irrigation Water and Human Health Risk in a Gold Mining-Impacted Area of Southern Ecuador

by Juan González-Menéndez, Carlos Hugo Bustamante-Torres, Bryan Salgado-Almeida, Giannella Muriel-Granda, Samantha Jiménez-Oyola and Kenny Escobar-Segovia

Resources 2026, 15(6), 81; https://doi.org/10.3390/resources15060081 (registering DOI) - 22 Jun 2026

Abstract

Areas where mining activities overlap with agricultural production may promote the mobilization of potentially toxic elements (PTEs) into soils and water resources, thereby creating exposure pathways for populations living or working in these environments. This study analyzes the concentration of PTEs in agricultural [...] Read more.

Areas where mining activities overlap with agricultural production may promote the mobilization of potentially toxic elements (PTEs) into soils and water resources, thereby creating exposure pathways for populations living or working in these environments. This study analyzes the concentration of PTEs in agricultural soils and irrigation water from Santa Rosa, southern Ecuador, and assesses the associated health risks for exposed agricultural workers. For this purpose, 35 soil samples were collected from farms and 12 water samples from the irrigation canal during the dry season of 2025. The concentration of PTEs in soil and water was determined using X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The PTE concentration in both matrices was compared with the maximum permissible limits (MPL) established by Ecuadorian regulations. Non-carcinogenic hazard indices (

H I

) and carcinogenic risk (

T C R

) were estimated following the U.S. EPA methodology. In soil, As and Cr were the PTEs of greatest concern, exceeding the MPL in 93% of the samples and by up to 4.4 and 2.4 times, respectively, while in water, all PTEs were below the MPL. Non-carcinogenic risk was below the recommended limit for soil and water (

H I_{s o i l}

= 3.00 × 10⁻² and

H I_{w a t e r}

= 2.00 × 10⁻³), with As as the dominant contributor. Cancer risk was tolerable in soil (

T C R_{s o i l}

= 4.34 × 10⁻⁵), while in water it remained at a low level (

T C R_{w a t e r}

= 1.65 × 10⁻⁶). These findings identify As and Cr as priority contaminants and support targeted monitoring and source-control measures in mining-influenced agricultural areas. Overall, by integrating agricultural soil and irrigation water quality with an occupational health risk assessment in Santa Rosa, this study contributes evidence to support future research in mining–agriculture coexistence areas. Full article

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18 pages, 1021 KB

Open AccessArticle

Sustainable Corrosion Inhibition of Admiralty Brass Using Plant Waste Extracts: Phytochemical and Electrochemical Screening with Techno-Economic Insights

by María Belén Canchig, Mateo Oleas, Ariel Miranda, Alfredo Viloria, Ruth Oropeza, Paola E. Ordóñez, Marvin Ricaurte and Alex Palma-Cando

Resources 2026, 15(6), 80; https://doi.org/10.3390/resources15060080 (registering DOI) - 22 Jun 2026

Abstract

Admiralty brass, commonly used in heat exchangers, is particularly susceptible to corrosion in acidic media such as those used in industrial cleaning. To mitigate this problem, the present study evaluated Musa acuminata (banana) peel and Lupinus mutabilis Sweet (Andean lupine) extracts as sustainable, [...] Read more.

Admiralty brass, commonly used in heat exchangers, is particularly susceptible to corrosion in acidic media such as those used in industrial cleaning. To mitigate this problem, the present study evaluated Musa acuminata (banana) peel and Lupinus mutabilis Sweet (Andean lupine) extracts as sustainable, low-toxicity corrosion inhibitors for admiralty brass in 0.5 M HCl. Six extracts were prepared using different solvents and characterized by qualitative and semi-quantitative phytochemical analyses (phenols, flavonoids, alkaloids). M. acuminata extracts were rich in phenolic compounds, while L. mutabilis extracts contained high levels of quinolizidine alkaloids. A comparative electrochemical screening of the agro-industrial waste-derived extracts revealed that the inhibition efficiency of M. acuminata extracts reached up to 43.6%, whereas the debittering wastewater extract of L. mutabilis (E6) achieved a maximum efficiency of 85.5% at 2000 ppm. A preliminary techno-economic analysis indicated the feasibility of industrial-scale production of the L. mutabilis-based inhibitor, yielding a net present value (NPV) of USD 9.48 million, an internal rate of return (IRR) of 27.3%, and a payback period of 6.7 years. These results demonstrate that agro-industrial residues can be valorized into effective and profitable green corrosion inhibitors, aligning with circular economy and sustainable chemistry principles. Full article

(This article belongs to the Special Issue Resource Recovery and Valorisation from Agricultural Products and Wastes)

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20 pages, 688 KB

Open AccessArticle

When Does Water Scarcity Become a Sovereign Financial Risk? International Threshold Evidence on Sovereign Borrowing Costs

by Ezer Ayadi

Resources 2026, 15(6), 79; https://doi.org/10.3390/resources15060079 - 16 Jun 2026

Abstract

Water scarcity is increasingly recognized as a macroeconomic challenge, yet its implications for sovereign financing conditions remain insufficiently understood. This study examines whether water scarcity is associated with sovereign borrowing costs and whether this relationship strengthens once hydrological pressure exceeds a critical threshold. [...] Read more.

Water scarcity is increasingly recognized as a macroeconomic challenge, yet its implications for sovereign financing conditions remain insufficiently understood. This study examines whether water scarcity is associated with sovereign borrowing costs and whether this relationship strengthens once hydrological pressure exceeds a critical threshold. Using an international panel of 105 countries over the period 2000–2024, the analysis combines second-generation panel diagnostics with nonlinear threshold estimation to examine long-run relationships and regime-dependent effects. The results indicate that water scarcity is positively associated with sovereign risk premiums, but the relationship is distinctly nonlinear. A critical threshold is identified at 61.37% water stress, beyond which the estimated association becomes substantially larger, with the coefficient increasing from 0.005 below the threshold to 0.024 above it. This pattern suggests that severe hydrological pressure is more strongly associated with higher sovereign borrowing costs than moderate water stress. The analysis further suggests that financial development, renewable energy deployment, and stronger institutional quality are associated with a weaker relationship between water scarcity and sovereign risk premiums, highlighting the potential importance of domestic resilience capacity. These findings remain broadly robust across alternative sovereign risk measures, alternative water scarcity proxies, dynamic specifications, and smooth-transition nonlinear models. This study contributes to the emerging literature on environmental macro-financial linkages by providing evidence that water scarcity may be increasingly relevant for sovereign financing conditions, particularly in economies facing severe and persistent hydrological stress. Full article

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23 pages, 2609 KB

Open AccessArticle

Energy Production Through Anaerobic Digestion of Typical Biodegradable Residues: LCA Comparison to Composting and Incineration in a Small and Larger Country

by Vasiliki P. Aravani, Shiya Wang, Wen Wang and Vagelis G. Papadakis

Resources 2026, 15(6), 78; https://doi.org/10.3390/resources15060078 - 12 Jun 2026

Abstract

The main sources of biodegradable waste come from agriculture and municipal waste, with animal manure and food waste (FW) being the most representative respectively. Most of this waste remains still unexploited, while there is skepticism regarding the environmental footprint of various methods of [...] Read more.

The main sources of biodegradable waste come from agriculture and municipal waste, with animal manure and food waste (FW) being the most representative respectively. Most of this waste remains still unexploited, while there is skepticism regarding the environmental footprint of various methods of their utilization. This work provides a reliable comparative environmental evaluation using life cycle assessment (LCA). In the present work, LCA applied to compare two alternative scenarios regarding the management of (a) sheep and goat manure and (b) FW. Alternative scenarios for sheep and goat manure include composting for fertilizer and energy production via anaerobic digestion (AD), while FW scenarios include incineration and energy production through AD. In both case studies, the AD scenario generates environmental benefits (expressed as negative damage) across all three damage categories namely resource scarcity, human health and ecosystem quality. Regarding sheep and goat manure, the most significant effect of AD is on human health (−0.016 Pt) while in the scenarios of FW the superior performance of AD is particularly evident in the ecosystem quality (−0.21 Pt). Both case studies reached the same conclusion pointing out that the use of sustainable technologies for managing agricultural and municipal waste mitigates the environmental impacts. Full article

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22 pages, 291 KB

Open AccessArticle

Oil Prices, Monetary Conditions, and Growth Dynamics in Saudi Arabia: Evidence from an ARDL–ECM and VAR Approach

by Ihsen Abid

Resources 2026, 15(6), 77; https://doi.org/10.3390/resources15060077 - 8 Jun 2026

Abstract

This study examines the dynamic relationships among oil prices, monetary conditions, and nominal GDP growth in Saudi Arabia, with particular attention to short-run adjustment and long-run equilibrium patterns in an oil-dependent economy operating under a fixed exchange-rate regime. Rather than identifying structural monetary [...] Read more.

This study examines the dynamic relationships among oil prices, monetary conditions, and nominal GDP growth in Saudi Arabia, with particular attention to short-run adjustment and long-run equilibrium patterns in an oil-dependent economy operating under a fixed exchange-rate regime. Rather than identifying structural monetary policy shocks, the study focuses on reduced-form dynamic associations between market-based monetary indicators, oil-price movements, and nominal economic activity. Using a high-frequency monthly dataset covering key macroeconomic variables, the analysis employs the Autoregressive Distributed Lag (ARDL) framework to estimate both short-run dynamics and long-run equilibrium relationships. An Error Correction Model (ECM) is used to capture the speed of adjustment toward equilibrium, while Granger causality tests assess short-term predictive linkages. The empirical results reveal that monetary indicators, particularly interest rates and money supply, exhibit lagged and non-monotonic associations with nominal GDP growth, reflecting delayed transmission under exchange-rate constraints. Oil-price movements emerge as a dominant driver, showing strong contemporaneous and lagged associations with growth, whereas inflation and exchange-rate movements display limited short-run predictive relevance. The ECM results indicate relatively rapid convergence toward long-run equilibrium, suggesting efficient adjustment dynamics. Granger causality findings further confirm the short-term predictive content of key macroeconomic variables. By integrating high-frequency data with ARDL–ECM estimation, VAR-based robustness checks, and sensitivity analysis, the study provides evidence on how oil-price movements, liquidity conditions, and interest-rate dynamics jointly shape growth fluctuations in Saudi Arabia. Full article

33 pages, 1713 KB

Open AccessArticle

Green Finance Energy Transition and Critical Raw Materials: An Integrated Framework for Resource Sustainability

by Nesrine Gafsi and Ines Belgacem

Resources 2026, 15(6), 76; https://doi.org/10.3390/resources15060076 - 4 Jun 2026

Abstract

The transition toward low-carbon economic systems has increased the strategic importance of green finance while simultaneously intensifying dependence on critical raw materials (CRMs) required for renewable energy technologies, energy storage systems, and electrification infrastructure. Despite the growing relevance of these interconnections, existing research [...] Read more.

The transition toward low-carbon economic systems has increased the strategic importance of green finance while simultaneously intensifying dependence on critical raw materials (CRMs) required for renewable energy technologies, energy storage systems, and electrification infrastructure. Despite the growing relevance of these interconnections, existing research has generally examined green finance, energy transition dynamics, and critical raw material sustainability separately, providing limited evidence on their combined interactions. This study develops an integrated finance–energy–resource framework to investigate the relationships among green finance, energy transition, and CRM sustainability. Using an unbalanced panel dataset covering 32 advanced and emerging economies over the period 2010–2022, the analysis employs the System Generalized Method of Moments (System GMM) estimator to address endogeneity, persistence effects, and unobserved heterogeneity. The empirical framework incorporates indicators of green finance, energy transition, CRM sustainability, and CRM supply risk, together with macroeconomic and institutional control variables. The results indicate that green finance contributes positively to CRM sustainability by supporting sustainable investment, resource efficiency, and environmentally responsible development. At the same time, the expansion of energy transition systems increases demand pressure on critical raw materials and may intensify supply-chain vulnerabilities. The findings further suggest the existence of feedback effects between resource constraints and financial systems through investment risk and capital allocation mechanisms. These results highlight the need for integrated policy approaches that align sustainable finance, energy transition objectives, and critical raw material governance to support long-term sustainability transitions. Full article

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33 pages, 1538 KB

Open AccessSystematic Review

Advances in the Green Extraction of Phytochemicals from Fruit Matrices Using Emerging Technologies and Natural Deep Eutectic Solvents: A Systematic Review

by Jhoseline Stayce Guillén Sánchez, Henry Javier-Ninahuaman, Rebeca Salvador-Reyes, Gary Rojas-Hurtado, Grimaldo Quispe, Brenda Yauri and Anhell Quispe-Calla

Resources 2026, 15(6), 75; https://doi.org/10.3390/resources15060075 - 3 Jun 2026

Abstract

In accordance with the PRISMA 2020 guidelines, a systematic review was conducted on the green extraction of bioactive compounds from fruit matrices through the integration of emerging technologies and natural deep eutectic solvents (NADES). Studies published between 2015 and 2025 were analyzed from [...] Read more.

In accordance with the PRISMA 2020 guidelines, a systematic review was conducted on the green extraction of bioactive compounds from fruit matrices through the integration of emerging technologies and natural deep eutectic solvents (NADES). Studies published between 2015 and 2025 were analyzed from databases such as Scopus and Web of Science, and 63 relevant studies were selected following a rigorous methodological evaluation process. The results demonstrate a growing scientific interest in the use of NADES due to their sustainable nature, low toxicity, and high extraction efficiency, particularly when combined with technologies such as ultrasound and microwaves. These synergies enhance yield, reduce energy consumption, and preserve the stability of polyphenols, flavonoids, and anthocyanins. Furthermore, the physicochemical properties of NADES, such as polarity and viscosity, together with operational factors, such as temperature and water content, significantly influence process efficiency, indicating that the combination of NADES with emerging technologies represents a promising alternative for agri-food valorization with potential application as functional ingredients and in clean-label systems. Moreover, it is established as a robust strategy for the development of sustainable extraction processes with industrial scale-up prospects. Full article

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21 pages, 2359 KB

Open AccessArticle

Contour-Based Trenches as a Nature-Based Solution for Soil Restoration and Potential Managed Aquifer Recharge in Guerrero, Mexico

by Javier Saldaña Almazán, Sirilo Suastegui Cruz, Marco Polo Calderón Arellanes, Enrique Moreno Mendoza and Ana Patricia Leyva Zuñiga

Resources 2026, 15(6), 74; https://doi.org/10.3390/resources15060074 - 1 Jun 2026

Abstract

Land degradation and declining groundwater availability threaten the sustainability of rural livelihoods across semi-arid regions. This study evaluates the hydrological performance of contour-based trenches as a low-cost and replicable nature-based solution (Nbs) for soil restoration, runoff regulation, and potential distributed managed aquifer recharge [...] Read more.

Land degradation and declining groundwater availability threaten the sustainability of rural livelihoods across semi-arid regions. This study evaluates the hydrological performance of contour-based trenches as a low-cost and replicable nature-based solution (Nbs) for soil restoration, runoff regulation, and potential distributed managed aquifer recharge (MAR) in Guerrero, Mexico. The structures were installed on 12% slopes and designed using a simplified water balance criterion based on trench storage capacity, runoff coefficient, and representative rainfall events. Each trench was constructed along contour lines with overflow notches and connecting micro-trenches to improve hydraulic continuity, reduce erosion, and enhance infiltration opportunities under degraded field conditions. After one year of field monitoring, the trenches reached an average filling efficiency of approximately 90% per effective rainfall event, with estimated infiltration rates ranging from 0.0069 to 0.011 L·s⁻¹. Soil moisture in the upper soil layer showed a relative increase of approximately 10–18% compared to adjacent untreated areas, while visible reductions in runoff velocity, sediment transport, and surface erosion were observed across the treated plot. Based on trench storage capacity, observed infiltration behavior, and assumed deep percolation fractions, the potential induced recharge was estimated between 216 and 360 m³·yr⁻¹ (43–72 mm·yr⁻¹). These values represent indicative plot-scale estimates rather than direct measurements of aquifer recharge, since no tracer studies or piezometric validation were performed. The results demonstrate that contour-based trenches contribute not only to infiltration enhancement and runoff control, but also to short-term soil restoration and improved water availability in rainfed agricultural systems. Their low-cost implementation, combined with community-based maintenance and adaptation to local environmental conditions, makes them a viable complementary strategy for strengthening decentralized water management, soil resilience, and climate adaptation in semi-arid rural landscapes. However, long-term effectiveness remains dependent on maintenance continuity, institutional support, and local governance conditions. Further multi-year monitoring and direct hydrogeological validation are recommended to improve the design and replicability of decentralized MAR systems. Full article

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26 pages, 1515 KB

Open AccessFeature PaperArticle

Probability Assessment of Strategic and Total Rare Earth Element Supply for the EU Under the EU Critical Raw Materials Act

by Melike Yildirim Ayyildiz, Jasemin Ayse Ölmez and Christoph Hilgers

Resources 2026, 15(6), 73; https://doi.org/10.3390/resources15060073 - 25 May 2026

Abstract

The European Union aims to reduce its dependency on imported critical and strategic raw materials. Therefore, the EU’s Critical Raw Materials Act defines benchmarks for strategic raw materials on domestic mining, recycling, refining, and the diversification of import sources to be achieved by [...] Read more.

The European Union aims to reduce its dependency on imported critical and strategic raw materials. Therefore, the EU’s Critical Raw Materials Act defines benchmarks for strategic raw materials on domestic mining, recycling, refining, and the diversification of import sources to be achieved by 2030. This study investigates the feasibility of the EU’s Critical Raw Materials Act mining benchmark for strategic rare earth elements, which aims for 10% of the EU’s annual demand to be met through domestic mining. We assess whether domestic rare earth element supply from mining within the EU can meet the projected future demand for 2030 and 2050. The study also examines the extent to which the total demand of rare earth elements for the EU could be met proportionally. An uncertainty estimation with Monte Carlo simulation with consideration of uniform and Gaussian distribution, based on individual project development stages, highlights that reaching the 10% benchmark for strategic rare earth elements is theoretically likely by 2030; however, with an incorporated nine-year lead time, meeting the 2030 benchmark is no longer feasible. Furthermore, obstacles such as social license to operate, mining permits and appeals in practice may additionally prolong procedures. The study concludes that in order to mine domestic rare earth elements and to reduce import dependency, the EU needs to invest in geological exploration and mining. Moreover, establishing a whole rare earth elements supply chain from mining to refining is highly complex and, as illustrated by the Japan–Australia partnership, which required 14 years without including the geological exploration phase. Full article

(This article belongs to the Special Issue Climate, Resources and Circular Economy (KLIREC)—Interdependencies, Synergies and Tradeoffs)

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26 pages, 734 KB

Open AccessReview

Bio-Based Construction Materials in the Context of the EU Bioeconomy: Overcoming Systemic Barriers to Mainstream Adoption

by Fernando Pacheco Torgal

Resources 2026, 15(6), 72; https://doi.org/10.3390/resources15060072 - 22 May 2026

Abstract

The construction sector must simultaneously meet rising global demand and cut embodied carbon deeply enough to satisfy European Green Deal and Bioeconomy Strategy targets—two pressures that conventional petrochemical-derived materials are poorly placed to resolve. Bio-based alternatives offer a credible path: they sequester carbon, [...] Read more.

The construction sector must simultaneously meet rising global demand and cut embodied carbon deeply enough to satisfy European Green Deal and Bioeconomy Strategy targets—two pressures that conventional petrochemical-derived materials are poorly placed to resolve. Bio-based alternatives offer a credible path: they sequester carbon, carry lower embodied emissions, improve indoor air quality, and fit naturally within circular economy models. Yet they remain marginal in specification practice. This paper reviews the evidence on bio-based construction materials and maps the barriers that keep them there. The analysis organises these barriers into four levels—structural, economic, technical, and enabling—and traces the conditional relationships between them, with direct consequences for how policy interventions should be sequenced. The strategic case for this transition extends beyond environmental policy: the 2026 Strait of Hormuz disruption is used here as a scenario to show how dependent European construction is on fossil-derived material inputs, and how exposed that dependence leaves the sector to geopolitical supply shocks. The principal obstacles to adoption prove to be institutional and economic rather than technical—regulatory fragmentation, absent harmonised standards, fragile supply chains, and market structures that systematically undervalue bio-based solutions. The paper concludes that meaningful scaling requires coordinated action across governance, market design, and industrial policy, and that material and performance advances alone will not deliver it. Full article

(This article belongs to the Special Issue Alternative Use of Biological Resources: 2nd Edition)

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28 pages, 351 KB

Open AccessArticle

Green Energy Finance and Agricultural Performance in MENA Region: Structural Pathways Toward Sustainability

by Ihsen Abid

Resources 2026, 15(6), 71; https://doi.org/10.3390/resources15060071 - 22 May 2026

Abstract

This study investigates the macroeconomic, institutional, and energy-related determinants of agricultural value added in Middle East and North Africa (MENA) countries over the period 2000–2023, with particular emphasis on whether international clean energy finance operates as a conditionally effective driver depending on energy [...] Read more.

This study investigates the macroeconomic, institutional, and energy-related determinants of agricultural value added in Middle East and North Africa (MENA) countries over the period 2000–2023, with particular emphasis on whether international clean energy finance operates as a conditionally effective driver depending on energy endowments. Using a panel fixed-effects framework with Driscoll–Kraay standard errors to address cross-sectional dependence, heteroskedasticity, and serial correlation, the analysis incorporates an interaction term between clean energy finance and an oil-exporting dummy to capture structural heterogeneity. Robustness is ensured through Panel-Corrected Standard Errors (PCSEs), Granger causality tests, and System GMM estimation. The findings reveal that GDP per capita and clean energy finance are positively and significantly associated with agricultural value added, while trade openness negatively affects the sector. Importantly, the interaction results indicate strong asymmetry: the positive contribution of clean energy finance is concentrated in non-oil economies but becomes weak or insignificant in oil-exporting countries, consistent with diminishing marginal returns in energy-abundant contexts. Inflation captures nominal price effects, while short-run dynamics suggest the presence of adjustment costs. Overall, the study highlights that clean energy finance acts as a structurally conditional mechanism, offering nuanced and policy-relevant insights for sustainable agricultural transformation in MENA economies. Full article

49 pages, 2894 KB

Open AccessArticle

Integrated Assessment of Photovoltaic Systems in Multi-Family Buildings as a Strategy for Climate Change Mitigation and Urban Energy Sustainability

by Cesar Yahir Canales Barrientos, Fredy Alberto Aliaga Yupanqui, Yoisdel Castillo Alvarez, Reinier Jiménez Borges, Luis Angel Iturralde Carrera, Berlan Rodríguez Pérez, José Manuel Álvarez-Alvarado and Juvenal Rodríguez-Reséndiz

Resources 2026, 15(5), 70; https://doi.org/10.3390/resources15050070 - 20 May 2026

Abstract

Decarbonizing the building sector requires integrating on-site renewable generation with systematic energy management. Among the most widely adopted alternatives are photovoltaic (PV) systems in buildings; however, they are often implemented as a standalone technological intervention (size–install–estimate savings), without being formally incorporated into an [...] Read more.

Decarbonizing the building sector requires integrating on-site renewable generation with systematic energy management. Among the most widely adopted alternatives are photovoltaic (PV) systems in buildings; however, they are often implemented as a standalone technological intervention (size–install–estimate savings), without being formally incorporated into an Energy Management System (EnMS) aimed at continuous improvement. In this context, this research addresses this gap through an integrated methodological framework aligned with ISO 50001, in which PV is explicitly included in energy performance management through energy review, the definition of an Energy Baseline (EnB), and the monitoring of Energy Performance Indicators (EnPIs) within the PDCA cycle. The approach articulates the analytical sizing of the PV system based on electricity demand and solar resources; its validation through simulation to ensure operational consistency and a technical, economic, and environmental assessment that translates PV generation into a verifiable reduction in energy imported from the grid and, consequently, into traceable improvements in EnPI under an audit-compatible scheme. The methodology is demonstrated in a multi-family building in Chorrillos, Lima (Peru), where a 14.5 kWp rooftop PV system (25 modules of 580 Wp) is designed to maximize self-consumption during daylight hours. The results show technical performance consistent with the demand profile, economic viability under the conditions of the case, and environmental benefits from replacing grid electricity, along with offsets associated mainly with the manufacture of PV components. The residual gap between the Post-PV EnPIs and the ISO 50001 target confirms that PV integration is a necessary but not sufficient first-cycle action within a comprehensive building decarbonization strategy, with demand-side management and envelope improvements identified as subsequent PDCA cycle priorities. In summary, the central contribution is not the PV sizing itself, but its operational and traceable integration within ISO 50001, making PV a quantifiable, verifiable, and scalable energy improvement action for residential buildings in emerging economies. Full article

(This article belongs to the Special Issue Assessment and Optimization of Energy Efficiency: 2nd Edition)

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22 pages, 489 KB

Open AccessArticle

Renewable Energy, Natural Resource Rents, and Environmental Quality in GCC Countries

by Noura Ben Mbarek

Resources 2026, 15(5), 69; https://doi.org/10.3390/resources15050069 - 18 May 2026

Cited by 1

Abstract

Environmental implications of resource dependence remain a central concern for hydrocarbon-based economies undergoing energy transition. Using panel data for GCC countries over 1990–2024 and second-generation econometric techniques that account for cross-sectional dependence and heterogeneity, this study identifies a stable long-run relationship between natural [...] Read more.

Environmental implications of resource dependence remain a central concern for hydrocarbon-based economies undergoing energy transition. Using panel data for GCC countries over 1990–2024 and second-generation econometric techniques that account for cross-sectional dependence and heterogeneity, this study identifies a stable long-run relationship between natural resource rents, renewable energy, and CO₂ emissions. The results show that a 1% increase in natural resource rents is linked to a 0.21% rise in CO₂ emissions, highlighting the persistence of carbon-intensive economic structures. By contrast, renewable energy is associated with a 0.15% reduction in emissions, although its environmental contribution remains modest. The interaction effect is negative (−0.048) but only partially robust, indicating that renewable energy weakens, but does not fully offset, the environmental pressure associated with resource dependence. These findings suggest that energy transition in GCC economies remains gradual and structurally constrained, requiring not only renewable expansion but also deeper transformation of hydrocarbon-based growth models. Full article

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20 pages, 824 KB

Open AccessArticle

Monetary Valuation of Life Cycle Impacts for Lithium Carbonate Extraction Pathways

by Abu Shahadat Md Ibrahim, Shivani Mathur and Roderick G. Eggert

Resources 2026, 15(5), 68; https://doi.org/10.3390/resources15050068 - 15 May 2026

Abstract

The rapid growth of battery energy storage and electric vehicles has increased lithium demand and intensified the attention given to the environmental performance of alternative extraction pathways. Conventional life cycle assessments (LCA) of lithium production typically report midpoint indicators in physical units, which [...] Read more.

The rapid growth of battery energy storage and electric vehicles has increased lithium demand and intensified the attention given to the environmental performance of alternative extraction pathways. Conventional life cycle assessments (LCA) of lithium production typically report midpoint indicators in physical units, which limits cross-category comparison and reduces their usefulness for economic and policy analysis. This study presents a comparative monetized LCA of lithium carbonate equivalent (LCE) production from three pathways: solar brine evaporation, hard-rock spodumene mining, and geothermal brine recovery. Using the TRACI 2.1 midpoint results reported in a prior LCA, six impact categories—global warming, smog formation, acidification, respiratory effects, carcinogenic toxicity, and non-carcinogenic toxicity—are converted into monetary values through a benefit-transfer, damage-cost approach. Total environmental external costs are estimated at USD 11.85/kg LCE for solar brine evaporation, USD 9.45/kg LCE for spodumene mining, and USD 4.11/kg LCE for geothermal brine recovery (all USD amounts are expressed in $2025 unless otherwise mentioned). Smog formation contributes more than 80% of the total monetized damages across all pathways, while toxicity-related impacts account for a smaller share than implied by the normalized midpoint results. Monetization changes the relative ranking of the solar brine and spodumene pathways, while indicating that geothermal brine recovery has the lowest monetized external cost among the impact categories evaluated. These findings show that monetized LCA can complement conventional midpoint assessment and provide more decision-relevant insights for policy and economic evaluation. Full article

(This article belongs to the Special Issue Critical Resources and Innovation for a Just and Sustainable Energy Transition)

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26 pages, 5786 KB

Open AccessArticle

Sustainable Fertilization with Iron-Enriched Montmorillonite and Sanitary Sludge Enhances Germination and Growth of Zea mays L.

by Wagner Alves Carvalho, Alessandro Lamarca Urzedo, Natalí Romero, Luciana Regaldo, Leticia Ferreira Lima Machado and Ana Maria Gagneten

Resources 2026, 15(5), 67; https://doi.org/10.3390/resources15050067 - 12 May 2026

Abstract

Sustainable fertilization strategies are required to reduce dependence on synthetic inputs, enhance waste recycling, and improve agricultural resilience under climate change. This study evaluates the effects of wastewater-derived sludge, particularly when modified with Fe-montmorillonite, on phosphorus availability and early development of Zea mays [...] Read more.

Sustainable fertilization strategies are required to reduce dependence on synthetic inputs, enhance waste recycling, and improve agricultural resilience under climate change. This study evaluates the effects of wastewater-derived sludge, particularly when modified with Fe-montmorillonite, on phosphorus availability and early development of Zea mays. Methods: Germination and early growth of Zea mays were assessed under four treatments: (i) untreated soil (Control); (ii) soil amended with sludge from the Cardeal Wastewater Treatment Plant (SC); (iii) soil amended with Fe-montmorillonite-modified sludge (TechPhos, ST); and (iv) soil amended with a commercial phosphorus salt (PS). Soil characterization was conducted using XRF, XRD, and FTIR. Plant responses were evaluated through laboratory (5 days) and pot (22 days) experiments. Results: ST showed the highest performance, with a germination index of 171.7 and improved biomass, leaf development, and chlorophyll content compared to Control and SC. ST also performed similarly to or better than the commercial fertilizer (PS), indicating high phosphorus efficiency. Conclusions: The integration of nanostructured modified montmorillonite with wastewater-derived sludge represents a promising alternative phosphorus source for early maize development. Its application supports waste valorization and circular economy approaches while contributing to improved soil fertility and more sustainable nutrient management under climate change scenarios. Full article

(This article belongs to the Topic Advances and Innovations in Waste Management)

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17 pages, 596 KB

Open AccessReview

Alkali-Activated and Geopolymer Systems Through the Lens of Resource Efficiency

by Nilofar Asim, Marzieh Badiei and Khadijehbeigom Ghoreishi

Resources 2026, 15(5), 66; https://doi.org/10.3390/resources15050066 - 8 May 2026

Abstract

Although geopolymer and alkali-activated binders are promoted as low-carbon OPC alternatives, their resource-centric performance remains complex and geographically dependent. This review examines these systems from a resource-efficiency perspective and evaluates alkaline activator demand; precursor availability, including fly ash, slag, calcined clays, and mining [...] Read more.

Although geopolymer and alkali-activated binders are promoted as low-carbon OPC alternatives, their resource-centric performance remains complex and geographically dependent. This review examines these systems from a resource-efficiency perspective and evaluates alkaline activator demand; precursor availability, including fly ash, slag, calcined clays, and mining residues; and embodied energy across mix designs and curing regimes. Recent mechanical and durability analyses, together with life cycle assessments, reveal important trade-offs in alkali-activated geopolymer systems. Customized precursors may unintentionally compromise their inherent resource efficiency, while the declining availability of industrial waste increasingly competes with alternative waste valorization processes. Developing one-part activator systems and implementing data- or machine-optimized mix designs capable of handling extremely highly variable waste streams will be necessary to achieve meaningful reductions in mineral consumption, energy demand, and emissions. The study reframes these binders as enablers of urban mining and industrial symbiosis. Policy changes toward resource-oriented governance, including performance-based standards, carbon-responsive procurement, and more transparent end-of-waste legislation, are also needed to promote a circular material economy. Strategic, large-scale deployment requires the integration of regional resource mapping with predictive performance modeling to navigate resource constraints in the construction sector. Full article

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31 pages, 1391 KB

Open AccessArticle

Asymmetric Growth–Energy–Emissions Dynamics in Large Emerging Economies Undergoing Energy Transition

by Ihsen Abid

Resources 2026, 15(5), 65; https://doi.org/10.3390/resources15050065 - 7 May 2026

Cited by 3

Abstract

Purpose: This study examines the asymmetric effects of economic growth, energy consumption, renewable energy, trade openness, and innovation on CO₂ emissions in China and India. It aims to determine whether positive and negative shocks in these variables generate different environmental responses across [...] Read more.

Purpose: This study examines the asymmetric effects of economic growth, energy consumption, renewable energy, trade openness, and innovation on CO₂ emissions in China and India. It aims to determine whether positive and negative shocks in these variables generate different environmental responses across economies undergoing energy transition. Design/methodology/approach: The analysis employs a Nonlinear Autoregressive Distributed Lag (NARDL) model using annual data from 1990 to 2023. The framework decomposes explanatory variables into positive and negative partial sums to estimate asymmetric long-run and short-run effects. Dynamic multipliers are used to trace adjustment paths, while a symmetric ARDL model serves as a robustness check. Findings: The results reveal strong and persistent asymmetries in China, particularly in energy use, renewable energy, and innovation. Positive energy shocks significantly increase emissions, while reductions produce limited environmental gains, reflecting structural rigidities. Renewable energy reduces emissions asymmetrically, and innovation exhibits direction-dependent effects. In contrast, India shows weaker and more selective asymmetries, with emissions primarily driven by short-run energy demand and limited long-run structural effects. The symmetric model fails to capture these dynamics, confirming the importance of nonlinear modeling. Conclusion: The findings demonstrate that emissions dynamics are nonlinear and country-specific. Asymmetry is more pronounced in structurally advanced economies undergoing energy transition, while developing economies remain demand-driven. These results highlight the need for differentiated and context-specific environmental policies. Full article

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35 pages, 1251 KB

Open AccessArticle

On the Economics of Low-Carbon Hydrogen Production for Large-Scale Industrial Facilities in Southeast Asia

by Alloysius Joko Purwanto, Ridwan Dewayanto Rusli, Citra Endah Nur Setyawati, Tanawat Papaeng, Nadiya Pranindita, Ryan Wiratama Bhaskara and Samantha Wibawa

Resources 2026, 15(5), 64; https://doi.org/10.3390/resources15050064 - 7 May 2026

Cited by 1

Abstract

This study examines the economics of blue and green hydrogen as feedstock for large industrial facilities in Southeast Asia. To understand how industries can adopt low-emission and renewable hydrogen, the levelised costs of blue and green hydrogen are calculated. Four pathways are examined, [...] Read more.

This study examines the economics of blue and green hydrogen as feedstock for large industrial facilities in Southeast Asia. To understand how industries can adopt low-emission and renewable hydrogen, the levelised costs of blue and green hydrogen are calculated. Four pathways are examined, including a large-scale carbon capture and sequestration facility located a distance away from an existing steam methane reforming hydrogen plant, a gigawatt-scale electrolysis facility adjacent to a large industrial site fed by an adjacent solar photovoltaic electricity source, as well as two pathways with either remote electrolyser and solar photovoltaic, necessitating hydrogen transport and storage, or a remote solar photovoltaic source with a dedicated power transmission line. The region’s transition to green hydrogen must overcome the challenges of high renewable electricity costs, the need for large land banks for solar photovoltaic farms and efficient long-distance hydrogen transport solutions or power transmission lines. Moreover, the region must improve its inconsistent track record in implementing billion-dollar public–private projects within budget and on time. Full article

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26 pages, 6054 KB

Open AccessReview

Natural Strategies for Increasing Yields: The Role of Plant Extracts and Micronutrients as Natural Resources in Sustainable Intensification

by Julia Chmiel, Krystian Wolski, Karolina Bakalorz, Emmanuel Manirafasha and Nikodem Kuźnik

Resources 2026, 15(5), 63; https://doi.org/10.3390/resources15050063 - 28 Apr 2026

Abstract

Natural resources play a fundamental role in ensuring global food security, while agricultural production itself strongly influences their demand, extraction, and availability. This article discusses natural strategies for increasing crop productivity within the framework of sustainable intensification, focusing on the integrated role of [...] Read more.

Natural resources play a fundamental role in ensuring global food security, while agricultural production itself strongly influences their demand, extraction, and availability. This article discusses natural strategies for increasing crop productivity within the framework of sustainable intensification, focusing on the integrated role of plant biostimulants and micronutrients. Both groups of substances are analyzed from a resource-oriented perspective, highlighting their potential to be derived from renewable sources, particularly agro-industrial by-products and plant biomass. Plant extracts obtained from fruit, vegetable, and cereal processing residues contain numerous bioactive compounds, including phenolics, amino acids, peptides, and organic acids, which can stimulate plant growth, improve nutrient uptake, and enhance tolerance to abiotic stress. Micronutrients such as Fe, Zn, Mn, Cu, and B are also strategic resources in crop production because they regulate key metabolic processes and influence the efficiency of macronutrient utilization. Their effectiveness, however, depends strongly on chemical form and bioavailability in soil–plant systems. The novelty of this work lies in integrating perspectives from plant physiology, coordination chemistry, and resource management to propose a conceptual framework in which plant-derived extracts and micronutrient complexes act as complementary tools supporting circular and resource-efficient agricultural systems. Full article

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