Publications

Abstract The transportation sector plays a vital role in managing urban solid waste (USW) and significantly contributes to greenhouse gas (GHG) emissions. This study assesses the carbon footprint of USW collection in Fornos de Algodres, a municipality of Portugal, by comparing diesel trucks and electric trucks under various electricity supply scenarios. The analysis utilizes real-world operational data, including fuel and electricity consumption, emission factors, and vehicle efficiency. The results indicate that electrifying the waste collection fleet can reduce CO₂ emissions by between 29.3% and 87.1%, depending on the electricity supplier and the energy consumption of the trucks. Currently, the municipality sources electricity from Suppliers A and B, with Supplier A resulting in lower emissions (4259–8845 kgCO₂eq per year) compared to Supplier B (9,363–19,445 kgCO₂eq per year). A cleaner option, Supplier C, has the potential to further reduce emissions (3549–7371 kgCO₂eq per year) due to its more favourable energy mix. The findings emphasize that electrification alone is insufficient to fully maximize environmental benefits—the carbon footprint of electric trucks largely depends on energy efficiency and the electricity mix used. To optimize GHG reductions, municipalities should combine fleet electrification with cleaner electricity sources. This study offers valuable insights for policymakers and waste management companies, supporting goals related to sustainable urban mobility and climate action. Future research should focus on the economic feasibility, operational costs, and integration of renewable energy sources to further enhance sustainability. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.

Abstract This study analyses the Portuguese Corporate Income Tax (CIT) exemption provided under Article 53 of the Tax Benefits Code (TBC). This exemption applies exclusively to entities responsible for managing integrated systems of specific waste flows, such as packaging, tyres, used oils and electronic equipment, batteries and accumulators, and end-of-life vehicles. Duly licensed under the General Waste Management Regime (WMR), these entities benefit from tax exemption on reinvested profits or those allocated to legally designated purposes. The results show that, between 2013 and 2022, this exemption was used by the eligible entities despite the amounts claimed annually being relatively modest compared to the total tax benefits granted by the Portuguese government. This may be attributed to the limited number of entities eligible, given the legal requirement for licensing under the WMR, and to the narrow scope of the benefit itself, which applies only to profits that are either reinvested or allocated to legally defined purposes. Nevertheless, this measure has the potential to contribute to the sector’s economic competitiveness, ensuring reinvestment in technology and more efficient processes, strengthening beneficiary entities’ role in promoting the circular economy and the implementation of the European Union directives for waste management. It will also specify the Portuguese tax system's ability to integrate environmental objectives into public policies, highlighting the relevance of extra-fiscal instruments in driving the green transition and supporting the achievement of the global Sustainable Development Goals (SDGs). © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.

Abstract Waste separation is a crucial step toward sustainable waste management. Understanding public perception and participation in this process is essential for its success. This study evaluates public perception and participation in the selective collection of general waste and biowaste in Guarda, Portugal, identifying key motivations, barriers, and areas for improvement. A cross-sectional analytical study was conducted using an online survey with 205 residents. Results indicate that 83.4% (95% CI: 77.9%-88.0%) of participants separate waste in the household, while workplace separation is lower (65.9%, 95% CI: 59.2%-72.1%). Paper and cardboard are the most frequently separated materials, whereas used cooking oil receives the least attention (95% CI: 16.5%-30.6%). Regarding biowaste, 92.2% (95% CI: 87.9%-95.3%) of respondents understand the concept, and all recognize its environmental benefits. However, 43.4% (95% CI: 36.8%-50.3%) are unaware of the municipal biowaste collection network, and 57.1% (95% CI: 50.2%-63.7%) find the existing infrastructure inadequate. Municipalities should expand and optimize waste collection systems to improve participation while strengthening public awareness campaigns. Social media is the preferred information channel (91.2%, 95% CI: 86.8%-94.5%), but traditional outreach methods, such as school initiatives and community meetings, could enhance engagement. Addressing infrastructure gaps and promoting consistent separation practices across different settings are key to optimizing waste management. This study highlights the need for improved public engagement and infrastructure to ensure the success of selective waste collection, particularly for biowaste, contributing to enhanced sustainability efforts in the region. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.

Abstract Micro- and nanoplastics (MNPs) are an important atmospheric aerosol constituent. However, there still needs to be a standard procedure for their sampling and size fractionation, which is an obstacle to the aggregation and critical analysis of results obtained by different research groups. This review focuses on the sampling and fractionation methodologies used for MNPs. Moreover, a streamlined, simplified methodology for sampling and fractionation is proposed.

Abstract Green carbon-based materials (GCM), i.e., carbon materials produced using renewable biomass or recycled waste, ought to be used to make processes sustainable and carbon-neutral. Carbon nanomaterials, like carbon dots and the nanobichar families, and carbon materials, like activated carbon and biochar substances, are sustainable materials with great potential to be used in different technological applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) were critically reviewed: agriculture, water treatment, energy management, and carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and played an important role in the sustainability of the processes, contributing to the mitigation of climate change, by reducing emissions and increasing the sequestration of CO<inf>2</inf>eq.

Abstract Green carbon-based materials (GCM), i.e., carbon materials produced using renewable biomass or recycled waste, ought to be used to make processes sustainable and carbon-neutral. Carbon nanomaterials, like carbon dots and the nanobichar families, and carbon materials, like activated carbon and biochar substances, are sustainable materials with great potential to be used in different technological applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) were critically reviewed: agriculture, water treatment, energy management, and carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and played an important role in the sustainability of the processes, contributing to the mitigation of climate change, by reducing emissions and increasing the sequestration of CO2eq.

Abstract In Portugal, Decree-Law no 102-D/2020 determines the establishment of networks for the selective collection of biowaste or the separation and recycling of biowaste at the source. The goal of this demanding is to decrease landfill deposition and ensure that, starting from 2030, landfills will not accept waste that can be recycled or recovered, such as biowaste from urban solid waste. This study determines the potential for energy generation through anaerobic digestion of biowaste collected from 14 Portuguese municipalities based on a previously published report on solutions for the separation, collection, and recycling at the source of biowaste. Assuming a population of 181,839 inhabitants and a selective collection of biowaste ranging from 11,659 to 17,808 tons by 2030, it is possible to generate up to 7.6 GWh of electricity. This electricity can meet the energy needs of up to 1650 people for a year and avoid until 1402 tons of CO2.

Abstract Directive 94/62/EC on packaging and packaging waste (PPWD) aimed at harmonizing regulations and coherence of the European Union (EU) internal market and preserving the environment and natural resources. Despite its economic importance, packaging production poses significant environmental challenges, including the generation of solid waste and the depletion of natural resources. This paper addresses the current policy framework that the EU intends to implement to minimize the growing generation of packaging waste, promote circularity, and integrate recycled materials in the EU. The proposed regulatory measures, including the transition from a directive to a Regulation, the establishment of mandatory targets for the reduction of solid waste and recycled content, and the strengthening of reuse systems, aim to promote a resilient value chain, mitigate environmental degradation, and stimulate economic growth. By adopting a circular economy approach, the EU strives to champion sustainable development in the internal market and improve social well-being in various sectors. © 2024 Cisa Publisher. All rights reserved.

Abstract Lithium mining driven by the growing demand for lithium-ion batteries, has environmental consequences linked to soil and water pollution. Nevertheless, research on the environmental impacts of lithium extraction still needs to be improved, highlighting the imperative for additional research. The article addresses the potential impact of the C57 lithiniferous feldspar mine on water quality, specifically focusing on surface, groundwater and spring water samples collected at the mining site and surrounding area in Gonçalo (Guarda, Portugal). The objective is to evaluate the environmental consequences of mining activities, with particular emphasis on mineral leaching. This study aims to evaluate the water quality around the C57 mine and the potential environmental impacts of mining operations. Water samples were collected from different sources, such as surface, underground, and spring waters, and chemical analyses were carried out to determine concentrations of different parameters, which were later compared with national and international reference guidelines. In addition to analysing the water samples, weathering tests were carried out using the Soxhlet extractor method to simulate the leaching of minerals over a shorter period (about 125 days). The concentrations of the analysed elements by atomic absorption spectroscopy (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb and Zn) in the weathering solutions were generally low and decreased throughout the testing period, with significant concentrations of aluminium and chromium exceed Canadian environmental quality guidelines for surface waters. The detected lithium concentrations are quite different, ranging from 8.7 to 19.8 μg/L in surface waters, from 6.9 to 74.1 μg/L in groundwater, and from 25.6 to 35.4 μg/L in spring waters, but are all below the US EPA (2021) recommendations threshold of 0.7 mg/L. Based on the findings, the article concludes that there is currently no clear evidence to indicate the environmental impact of mining activities on water quality in the analysed samples. However, weathering tests suggest potential long-term implications regarding the leaching of specific chemical elements, particularly aluminium and chromium. © The Author(s) 2024.