Search Results (771)

The Sorgentina-RF project will use fusion neutrons to produce ⁹⁹Mo, a precursor of ^99mTc, by irradiating natural molybdenum. ⁹⁹Mo is produced by means of the inelastic reaction ¹⁰⁰Mo(n, 2n)⁹⁹Mo on ¹⁰⁰Mo, which is an isotope of natural Mo. From a functional point of view, the project consists of two parts: an irradiation neutron source at 14 MeV and a radiochemistry facility dedicated to the extraction of ⁹⁹Mo from the solid sample irradiated by the neutron source. Given the degree of complexity of such a facility, the risk management strategy is based on an integrated approach that combines the engineering method of safety with that of radiation protection. Therefore, design issues were studied and systems were planned according to both radiation protection and safety criteria already in the preliminary phase, allowing a general strengthening of the safety of the plant. This work discusses the preventive analysis and the related activities to identify the ways in which potential exposures to radiation may occur. In particular, the preliminary safety analysis is presented for the innovative rotating target, developed for the project, and, accordingly, some specific technical solutions are given to refine the initial design of the facility. Full article

Gas-permeable membrane (GPM) technology is a novel alternative to reduce N content in wastewater while recovering N in the form of an ammonium salt solution that can be used as fertilizer. This work aims to elucidate the effects of three operational conditions on the performance of GPM technology for ammonia recovery in batch conditions using synthetic wastewater that simulates livestock wastewater. Firstly, the effect of the ratio of the initial mass of total ammonia nitrogen (TAN) per membrane surface from 197 to 936 g N per m² of membrane was investigated. The highest ratio presented the highest TAN recovery rate (90 g N m⁻² d⁻¹). Secondly, the influence of the ratio of the volume of wastewater per volume of acidic trapping solution in the range from 7.8 to 33.3 L L⁻¹ was studied. In this case, the higher the ratio, the higher the N concentration in the trapping solution, achieving a N concentration of 43,773 mg N L⁻¹ with a ratio of 33.3 L L⁻¹. Finally, two different TAN concentrations (<0.1 and 30 g N L⁻¹) in the acidic trapping solution were evaluated. The use of a trapping solution with a TAN concentration of 30 g N L⁻¹ led to a reduction in the TAN recovery rate, which meant that the diffusion of ammonia through the membrane was more difficult as the trapping solution became saturated with TAN. Overall, the tested conditions highly influence the performance of GPM technology, and therefore, these conditions should be set to optimize the ammonia recovery and reduce nitrogen losses. Full article

Currently, people spend most of their time inside their homes. However, poor conditions in terms of comfort and quality of the indoor environment can pose high risks to the inhabitants’ health. Therefore, a good quality environment is essential, since, in addition to the hazards present in indoor air (e.g., particles, (S)VOCs, CO, radon and tobacco smoke), extreme temperatures, relative humidity levels, pests (e.g., mold, dust mites and bioaerosols), noise, airborne infectious agents (e.g., SARS-CoV-2) and contamination through water and soil can cause physical injuries, respiratory diseases, damage to multiple organ systems as well as harmful effects on the mental health of the occupants. Faced with this requirement, housing evaluation models were studied together with the main types of risk that could affect the health of the inhabitants, with the objective of proposing a new evaluation model for housing health and safety risks, fitted to the occupants, and especially suitable for Portuguese dwellings, although applicable in other geographical contexts. As a result of this analysis, this article proposes a new model for evaluating health and safety risks in housing, applicable in Portugal, supported by an inspection form and, as the main difference from the existing models, parameter measurements, providing complementary data for the evaluation. This model was created based on a set of functional and regulatory requirements that were identified for the healthy use of living spaces. Twenty-eight hazards were identified, and the respective risk factors were assessed using different processes and target demographics, including visual inspection, parameter measurements, occupants’ age and location and age of housing. In order to validate the model and determine its usefulness, it was applied to a set of houses with different construction dates, locations and occupants. This exercise enabled the identification of hazard classes and the calibration and fine tuning of the model application. Finally, proposals for future work are presented in order to create a base of evolution for the model. Full article

The study of the ²²²Rn terrestrial flux (Bq/(m²·s) or Bq/(m²·h)) is a complex issue involving both radiation-protection and environmental aspects. While the radiation-protection aspects are quite obvious—it has been well known for several decades that soil is the major source of indoor radon—environmental issues such as the correlation with conventional pollutants (PM_2.5, PM₁₀, NOX, etc.) and the use of radon for the esmation of the natural component of GHG (CO₂) emissions are relatively less discussed in spite of their growing relevance. In this work we present a method for the estimation of the average value of ²²²Rn flux from HPGe γ-spectrometry ²¹⁰Pb measurements performed on wet and dry deposition samples gathered monthly in the period 2006–2020. The results obtained with this technique give an average radon flux in the period Φ = 57 ± 27 Bq/(m²·h), the value of which is comparable with those coming from other methods and direct radon flux measurements as well. The method can thus be used to obtain a worldwide map of the radon flux. Full article

Road vehicles are a large contributor to nitrogen oxides (NOx) pollution. The routine roadside monitoring stations, however, may underrepresent the severity of personal exposure in urban areas because long-term average readings cannot capture the effects of momentary, high peaks of air pollution. While numerical modelling tools historically have been used to propose an improved distribution of monitoring stations, ultra-high resolution Computational Fluid Dynamics models can further assist the relevant stakeholders in understanding the important details of pollutant dispersion and exposure at a local level. This study deploys a 10-cm-resolution CFD model to evaluate actual high peaks of personal exposure to NOx from traffic by tracking the gases emitted from the tailpipe of moving vehicles being dispersed towards the roadside. The investigation shows that a set of four Euro 5-rated diesel vehicles travelling at a constant speed may generate momentary roadside concentrations of NOx as high as 1.25 mg/m³, with a 25% expected increase for doubling the number of vehicles and approximately 50% reduction when considering Euro 6-rated vehicles. The paper demonstrates how the numerical tool can be used to identify the impact of measures to reduce personal exposure, such as protective urban furniture, as traffic patterns and environmental conditions change. Full article

Gamma emitting radionuclides naturally present in the Earth’s crust and the radon exhaled by soil in the atmosphere with its short-lived progeny are two of the main contributors to the environmental gamma dose rate that typically characterizes an outdoor measurement site. The present work aims to investigate variations in the environmental dose-rate time series originated by different natural phenomena, such as weather and seismic events, which can modify the radon concentration in the air. The data analyzed here were acquired over a five-year period using a Reuter–Stokes high-pressure ionization chamber placed in the ENEA Casaccia Research Center (Rome, Italy), from November 2013 to December 2018. The detector was set to take a single measurement of the equivalent ambient dose $H^{*}\left(10\right)$ every 15 min, thereby collecting more than 184,000 values over the five-year period under consideration. The detector’s sensitivity to the short-lived radon progeny was verified in a preparatory study performed by means of simultaneous radon flux measurement on field. Variations induced by meteorological events as well as variations potentially induced by seismic events were investigated by implementing different data analysis techniques. In the latter case, a retrospective preliminary study was conducted, applying the ARFIMA class of models in order to test the method’s potential. The analysis techniques, results and potential applications are presented and discussed in this article. Full article

Insecticide testing facilities that evaluate a variety of vector control products may generate a large number of hazardous wastes from routine operations. These wastes originate from degraded technical grade materials, sprayed substrates with Indoor Residual Spraying (IRS), and redundant stock or working insecticidal solutions. The washing of Long-Lasting Insecticidal Nets (LLINs) during preparation for laboratory and experimental hut trials also contribute to wastewater with insecticide content. Human and environmental exposure to insecticidal waste can occur during transport, categorization, storage, and disposal, resulting in environmental pollution and potential health effects. Various national and international guidelines have been devised for safe disposal and should be strictly followed to avoid adverse effects on humans or environment. To facilitate proper insecticidal waste management, this paper outlines simple but safe practices derived from international and national guidelines that can be adopted by other similar facilities. National and international policies related to chemical management were reviewed and translated into Standard Operating Procedures (SOPs), training pathways, and manuals. National Environmental Management Council (NEMC) assessed the test facility and recommended disposal procedures. NEMC recommendations were followed to construct the soak pits for liquid waste disposal while chemical transporters and incinerators were contracted for solid waste disposal. An environmental expert was contracted for environmental audit and annual monitoring. Studies and activities at the facility were evaluated for their waste generation index. Safety manual and SOPs on risk assessment, waste management and disposal, handling hazardous materials, health and safety procedures, and chemical usage were written. At KCMUCo-PAMVERC, an annual average of 0.02 and 24.9 cubic meters of liquid waste, which mainly includes a mixture of water, insecticides, and solvents, were generated from laboratory experiments (phase I) and semi-field LLIN experiments (phase II), respectively, while the IRS semi-field experiments generated an annual average of 88 L of liquid waste and 6.3 tons of solid waste. An annual average of 0.18 cubic meters of liquid waste results from other sources, including expired laboratory reagents. Well-translated national and international policies/regulations may be adopted by insecticide test facilities for proper and effective waste disposal. Full article

Actions to control and eradicate Ailanthus altissima (Mill.) Swingle are essential to the prevention of uncontrolled growth and expansion of this species and its competition with native species. This competition leads to biodiversity and productivity losses in forests. The present study evaluated the potential to create value chains to maintain the sustainability of control actions through the energy recovery of collected A. altissima biomass. Other possibilities were also discussed, such as the extraction of allelopathic compounds. For this purpose, and to assess the potential for energy recovery, samples of A. altissima were collected and analyzed in the laboratory to discuss the potential of using extracted compounds in nature-based applications, and a literature review was carried out. It was found that, although there is potential for the use of these biomasses for energy production, the high levels of chlorine and heavy metals pose some obstacles to their large-scale use, mainly due to their corrosive potential. On the other hand, the extraction of allelopathic compounds was shown to be potentially interesting for use in the control of other invasive species. Used in this application, it may be possible to create value chains to sustain, control, and eradicate the actions of this invasive species. Full article

The growing environmental spreading of food synthetic dyes and bio-colors have the potential for altering organisms’ redox states. Here, three model species for aquatic pollution trials, Cucumis sativus seeds, Artemia salina cysts, and Danio rerio embryos, were short-term exposed to a fixed concentration of the artificial red E124, and two red bio-colors, cochineal E120, and vegan red (VEGR). In the animal models, we evaluated the total reactive oxygen species (ROS) and the susceptibility to in vitro oxidative stress, and in C. sativus, H₂O₂ production and antioxidant capacity. We also measured organismal performance indices (routine oxygen consumption in the animal models, dark oxygen consumption, and photosynthetic efficiency in C. sativus). In C. sativus, only E124 increased ROS and affected dark oxygen consumption and photosynthetic efficiency, while all dyes enhanced the antioxidant defenses. In the A. salina nauplii, all dyes increased ROS, while E120 and E124 reduced the susceptibility to oxidative stress. In D. rerio, treatments did not affect ROS content, and reduced oxidative stress susceptibility. Our data show that red food dyes affect the redox state of the developing organisms, in which ROS plays a significant role. We suggest a potentially toxic role for red food dyes with environmentally relevant consequences. Full article

Soils close to former mines or metallurgical facilities often contain extreme concentrations of potentially toxic elements (PTEs), and among soil remediation actions needed, enhanced phytoextraction techniques using chelating agents could be a very promising option. In this context, a pot experiment was conducted to evaluate the effect of Na₂-EDTA, olive mill wastewater (OMW), and their combination (EDTA + OMW) on As, Pb and Zn uptake by Helianthus annuus (sunflower), grown in a heavily contaminated soil from Lavrio, Greece. After harvest, aboveground and belowground biomass and the concentrations of As, Pb and Zn were determined. Additionally, composite soil samples of all treatments were subjected to appropriate sequential extraction procedures for each PTE. Results showed that although nonstatistically significant effects on plant growth and As concentration were observed, Pb and Zn plant concentrations increased by the EDTA addition, alone or combined with OMW. When the total bioavailability parameter was assessed, EDTA treatment was also found to significantly enhance As uptake (50% increase, p ≤ 0.05). These results were further supported by the respective sequential extraction schemes in which both Pb and As showed increased concentration in the corresponding more soluble soil fractions, probably as an outcome of partial Fe–Mn amorphous oxide dissolution. Our study thus suggests that the applied treatments of EDTA, OMW or their combined application could play a key role as reductive agents in enhancing the mobility of these PTEs in the soil environment, triggering their increased uptake by H. annuus. Full article

Coastal and marine ecosystems are supplying a wide range of services. With accelerated Sea Level Rise, intensification of waves and storm surge severity and increasing anthropogenic pressures, these areas are under multiple threats and society may not receive the same level of ecosystems services. This study aims at measuring the trend of beach erosion and at identifying and quantifying the role of some coastal and marine ecosystems in mitigating beach erosion in the region of Negril (Jamaica). In this location, the tourism industry provides the main source of economic revenue. Even at the national level, the two beaches are important assets linked with 5% of the national revenue as 25% of the hotel rooms are located around Negril. In Jamaica, the tourism industry is a significant component of national GDP. 25% of hotel rooms are located around the two beaches of Negril, which have lost an average of 23.4 m of width since 1968. Given the importance of Negril’s beaches to their economy, the Government of Jamaica asked UNEP to conduct a study to identify causes of beach erosion in Negril and potential solutions to address trends of beach erosion, in the context of future sea level rise scenarios induced by climate change. This paper addresses the current beach erosion status and future trends under different climate scenarios. We explain how, by using remote sensing, GIS, wave modelling and multiple regressions analysis associated with national, local and community consultations, we were able to identify and quantify the role of ecosystems for mitigating beach erosion. We show that larger widths of coral and seagrass meadows reduce beach erosion. Full article

Biochar (BC) has attracted attention due to its impacts on soil quality by enhancing soil fertility, carbon storage and contaminants immobilization. BC also induces changes in microbial community structure and enhances crop productivity in long term scenarios compared to many other organic amendments. However, information related to the role of modified BCs in altering the soil quality is still scarce. BC can be modified by using physical, chemical and microbial methods. Modified BC can change the functional groups, pore size, pore structure, surface area and chemical properties of soil, which plays a key role in changing the soil quality. The addition of modified BCs as soil amendment increased soil CEC (cation exchange capacity), EC (electron conductivity), pH, organic matter, hydraulic conductivity, soil porosity, infiltration rate, microbial activities (enzymes and community), nutrient profile and gas exchange properties, but it varies according to the soil structure and pervading environmental conditions. This study provides a basis for effective practical approaches to modifying BCs for improving soil quality. Full article

Although pig meat accounts for nearly half of total meat production in Europe, less attention has been focused on the greenhouse gas (GHG) emissions of pig farming. The aim of this study was to assess and compare the impact of pig livestock on GHG emissions during the period 2015–2020 in major European countries, including Greece, using different computational approaches (Tier 1, Tier 2, Gleam-i software v. 2.0 developed by FAO, Rome, Italy). A semi-extensive pig farm was also used as a small-scale scenario. The ranking of the countries related to GHG emissions was not affected by the applied methodology. Spain had the highest emissions due to the higher number of farming animals. The noted numeric differences in the estimations can be attributed to the elaborated and different equational approach that Tier 2 methodology and Gleam-i followed, considering many livestock parameters. Additionally, the semi-extensive farm had lower emissions/fewer animal compared to the average intensive pig farm in the Greek territory. The Tier 1 approach revealed that breeding animals produces more to the emissions, contrary to Tier 2, which showed that fattening pigs is responsible for the majority of GHG emissions. Therefore, specific animal categories could be targeted (i.e., fattening gilts) in a more specialized manner apart from general strategies (i.e., animal improvement). Full article

Non aqueous phase liquid (NAPL) pollution exists in porous media such as soil. SVE technology can be used to remove this pollution in soil. However, few domestic and international studies have paid attention to the changes of soil temperature in the field, which we believe can be useful information to optimize the layout of heating wells. In this research we established partial differential equations of soil heat transfer using the COMSOL multi-field coupling tool to simulate the field distribution of the change in soil internal temperature in the process of SVE to obtain the change of effective heating area with time under certain initial heating conditions. At the same time, we used liquid ethylbenzene to represent NAPL pollutants, and designed a simulation of soil temperature field distribution under the movement of liquid ethylbenzene under external pressure. It was found that under the action of Darcy’s velocity field, the utilization efficiency of the SVE system for the heat source was significantly improved, that is, the temperature distribution of the soil was more uniform. However, the temperature of the heated area increased slowly because the extraction well took away the heat energy. The heat source power should be increased or prolonged to improve the effect of Darcy’s field. Through a coupled simulation, we obtained a variation relationship of the soil temperature field in 1800 min under the action of one extraction well and four heating wells. These data will provide the basis for our next step in designing an algorithm to optimize the distribution of heating wells. Full article

The polymer processing industry is paying more attention to biodegradable materials synthesized from renewable sources. One of the most popular of them is polylactide (PLA). Except the material from which a given product is made, particularly important is the process of manufacturing a polymer material, processing, use by the consumer, and finally, recycling it. Neither of these steps is indifferent to the environment. The processing of polymers can often lead to material degradation, which affects the properties of the material and leads to the generation of substantial amounts of post-production waste that cannot be reused by processors. The aim of this work is to evaluate selected properties of PLA subjected to the extrusion process under variable extrusion conditions. This is important due to the large losses of material and energy resulting from the extrusion of biodegradable polymers under poorly selected processing conditions, which, apart from the economic effects, has a negative impact on the environment. The research proved that both the temperature and the structure of the plasticizing system as well as the rotational speed of the screws affect the mechanical properties of the final product. For PLA optimization, this process will directly contribute to the improvement of the PLA processing process, and indirectly help to act for the benefit of the environment by reducing the consumption of energy, raw materials, and the amount of post-production waste. The obtained results allowed for the selection of appropriate parameters depending on the expectations regarding the properties of the final product. The conducted research will help to optimize processing processes and reduce the consumption of raw materials, which in the future will also affect the environment. Full article