Depth Control of an Underwater Sensor Platform: Comparison between Variable Buoyancy and Propeller Actuated Devices.

Underwater long-endurance platforms are crucial for continuous oceanic observation, allowing for sustained data collection from a multitude of sensors deployed across diverse underwater environments. They extend mission durations, reduce maintenance needs, and significantly improve the efficiency and cost-effectiveness of oceanographic research endeavors. This paper investigates the closed-loop depth control of actuation systems employed in underwater vehicles, focusing on the energy consumption of two different mechanisms: variable buoyancy and propeller actuated devices. Using a prototype previously developed by the authors, this paper presents a detailed model of the vehicle using both actuation solutions. The proposed model, although being a linear-based one, accounts for several nonlinearities that are present such as saturations, sensor quantization, and the actuator brake model. Also, it allows a simple estimation of the energy consumption of both actuation solutions. Based on the developed models, this study then explores the intricate interplay between energy consumption and control accuracy. To this end, several PID-based controllers are developed and tested in simulation. These controllers are used to evaluate the dynamic response and power requirements of variable buoyancy systems and propeller actuated devices under various operational conditions. Our findings contribute to the optimization of closed-loop depth control strategies, offering insights into the trade-offs between energy efficiency and system effectiveness in diverse underwater applications.

Nanoparticle-Based Treatment in Glioblastoma.

Glioblastoma (GB) is a malignant glioma associated with a mean overall survival of 12 to 18 months, even with optimal treatment, due to its high relapse rate and treatment resistance. The standardized first-line treatment consists of surgery, which allows for diagnosis and cytoreduction, followed by stereotactic fractionated radiotherapy and chemotherapy. Treatment failure can result from the poor passage of drugs through the blood-brain barrier (BBB). The development of novel and more effective therapeutic approaches is paramount to increasing the life expectancy of GB patients. Nanoparticle-based treatments include epitopes that are designed to interact with specialized transport systems, ultimately allowing the crossing of the BBB, increasing therapeutic efficacy, and reducing systemic toxicity and drug degradation. Polymeric nanoparticles have shown promising results in terms of precisely directing drugs to the brain with minimal systemic side effects. Various methods of drug delivery that pass through the BBB, such as the stereotactic injection of nanoparticles, are being actively tested in vitro and in vivo in animal models. A significant variety of pre-clinical studies with polymeric nanoparticles for the treatment of GB are being conducted, with only a few nanoparticle-based drug delivery systems to date having entered clinical trials. Pre-clinical studies are key to testing the safety and efficacy of these novel anticancer therapies and will hopefully facilitate the testing of the clinical validity of this promising treatment method. Here we review the recent literature concerning the most frequently reported types of nanoparticles for the treatment of GB.

Highlighted Advances in Therapies for Difficult-To-Treat Brain Tumours Such as Glioblastoma.

Glioblastoma multiforme (GBM) remains a challenging disease, as it is the most common and deadly brain tumour in adults and has no curative solution and an overall short survival time. This incurability and short survival time means that, despite its rarity (average incidence of 3.2 per 100,000 persons), there has been an increased effort to try to treat this disease. Standard of care in newly diagnosed glioblastoma is maximal tumour resection followed by initial concomitant radiotherapy and temozolomide (TMZ) and then further chemotherapy with TMZ. Imaging techniques are key not only to diagnose the extent of the affected tissue but also for surgery planning and even for intraoperative use. Eligible patients may combine TMZ with tumour treating fields (TTF) therapy, which delivers low-intensity and intermediate-frequency electric fields to arrest tumour growth. Nonetheless, the blood-brain barrier (BBB) and systemic side effects are obstacles to successful chemotherapy in GBM; thus, more targeted, custom therapies such as immunotherapy and nanotechnological drug delivery systems have been undergoing research with varying degrees of success. This review proposes an overview of the pathophysiology, possible treatments, and the most (not all) representative examples of the latest advancements.

Randomized clinical study of injectable dextrin-based hydrogel as a carrier of a synthetic bone substitute.

OBJECTIVES: This study aimed to improve the performance and mode of administration of a glass-reinforced hydroxyapatite synthetic bone substitute, Bonelike by Biosckin® (BL®), by association with a dextrin-based hydrogel, DEXGEL, to achieve an injectable and moldable device named DEXGEL Bone. METHODS: Twelve participants requiring pre-molar tooth extraction and implant placement were enrolled in this study. BL® granules (250-500 µm) were administered to 6 randomized participants whereas the other 6 received DEXGEL Bone. After 6 months, a bone biopsy of the grafted area was collected for histological and histomorphometric evaluation, prior to implant placement. The performance of DEXGEL Bone and BL® treatments on alveolar preservation were further analyzed by computed tomography and Hounsfield density analysis. Primary implant stability was analyzed by implant stability coefficient technique. RESULTS: The healing of defects was free of any local or systemic complications. Both treatments showed good osseointegration with no signs of adverse reaction. DEXGEL Bone exhibited increased granule resorption (p = 0.029) accompanied by a tendency for more new bone ingrowth (although not statistically significant) compared to the BL® group. The addition of DEXGEL to BL® granules did not compromise bone volume or density, being even beneficial for implant primary stability (p = 0.017). CONCLUSIONS: The hydrogel-reinforced biomaterial exhibited an easier handling, a better defect filling, and benefits in implant stability. CLINICAL RELEVANCE: This study validates DEXGEL Bone safety and performance as an injectable carrier of granular bone substitutes for alveolar ridge preservation. TRIAL REGISTRATION: European Databank on Medical Devices (EUDAMED) No. CIV-PT-18-01-02,705; Registo Nacional de Estudos Clínicos, RNEC, No. 30122.

Granulated biomass fly ash coupled with fenton process for pulp and paper wastewater treatment.

The work describes the combination of granulated biomass fly ash (GBFA) with Fenton process to enhance the removal of adsorbable organic halides (AOX) from pulp bleaching wastewater. At optimal operating conditions, wastewater's chemical and biochemical oxygen demand (COD and BOD5, respectively) and colour were also quantified, and operating cost of treatment assessed. For the first time, raw pulp bleaching wastewater was used to granulate BFA, instead of water, reducing the water footprint of the treatment. Five wastewater treatment setups were studied: (i) conventional Fenton process; (ii) GBFA application; (iii) simultaneous application of GBFA and Fenton process; (iv) sequential treatment by GBFA followed by Fenton process; (v) sequential treatment by Fenton process followed by GBFA. The latter yielded the highest AOX removal (60-70%), whilst COD was also reduced (≈15%) and wastewater biodegradability (BOD5/COD) was enhanced from 0.075 to a maximum of 0.134. Another positive feature of the proposed solution was that GBFA were successfully recovered and reused without regeneration, yielding similar AOX removal compared with fresh GBFA. The operating cost of removing 1 g of AOX from the pulp bleaching wastewater by the optimal treatment setup (60-70% removal of AOX) was 14-26% lower than the operating cost of conducting Fenton process alone (50% removal of AOX).

Genetic Algorithm to Solve Optimal Sensor Placement for Underwater Vehicle Localization with Range Dependent Noises.

In source localization problems, the relative geometry between sensors and source will influence the localization performance. The optimum configuration of sensors depends on the measurements used for the source location estimation, how these measurements are affected by noise, the positions of the source, and the criteria used to evaluate the localization performance. This paper addresses the problem of optimum sensor placement in a plane for the localization of an underwater vehicle moving in 3D. We consider sets of sensors that measure the distance to the vehicle and model the measurement noises with distance dependent covariances. We develop a genetic algorithm and analyze both single and multi-objective problems. In the former, we consider as the evaluation metric the arithmetic average along the vehicle trajectory of the maximum eigenvalue of the inverse of the Fisher information matrix. In the latter, we estimate the Pareto front of pairs of common criteria based on the Fisher information matrix and analyze the evolution of the sensor positioning for the different criteria. To validate the algorithm, we initially compare results with a case with a known optimal solution and constant measurement covariances, obtaining deviations from the optimal less than 0.1%. Posterior, we present results for an underwater vehicle performing a lawn-mower maneuver and a spiral descent maneuver. We also present results restricting the allowed positions for the sensors.

IoTMapper: A Metrics Aggregation System Architecture in Support of Smart City Solutions.

Smart cities are, nowadays, an unavoidable and growing reality, supported on software platforms that support city management, through the processing and presentation of a large number of data, obtained from sensors used throughout the cities. Low-power wide area networks (LPWAN) leverage the sensorization process; however, urban landscape, in turn, induces a high probability of change in the propagation conditions of the LPWAN network, thus requiring active monitoring solutions for assessing the city LPWAN network condition. Currently existing solutions usually consider the existence of only one type of LPWAN network to be monitored. In this paper, an architecture for aggregation of metrics from heterogeneous LPWAN networks is presented. The architecture, named IoTMapper, combines purpose build components with existing components from the FIWARE and Apache Kafka ecosystems. Implementation details for the LPWAN networks are abstracted by adapters so that new networks may be easily added. The validation was carried out using real data collected for long-range wide-area network (LoRaWAN) in Lisbon, and a simulated data set extrapolated from the collected data. The results indicate that the presented architecture is a viable solution for metrics aggregation that may be expanded to support multiple networks. However, some of the considered FIWARE components present performance bottlenecks that may hinder the scaling of the architecture while processing new message arrivals.

Optimization of Titanium Dental Mesh Surfaces for Biological Sealing and Prevention of Bacterial Colonization.

Titanium dental meshes have a wide application in order to ensure the retention of calcium phosphate-based biomaterials to regenerate bone tissue. These meshes are temporary and must grow a soft tissue to prevent bacterial colonization and provide stability. In this work, we aimed to optimize the roughness of the meshes to obtain a good biological seal while maintaining a behavior that did not favor bacterial colonization. To this end, six types of surfaces were studied: machined as a control, polished, sandblasted with three different alumina sizes and sintered. The roughness, contact angles and biological behavior of the samples using fibroblast cultures at 7, 24 and 72 h were determined as well as cytotoxicity studies. Cultures of two very common bacterial strains in the oral cavity were also carried out: Streptococcus sanguinis and Lactobacillus salivarius. The results showed that the samples treated with alumina particles by sandblasting at 200 micrometers were the ones that performed best with fibroblasts and also with the number of bacterial colonies in both strains. According to the results, we see in this treatment a candidate for the surface treatment of dental meshes with an excellent performance.

An update of advanced nanoplatforms for Glioblastoma Multiforme Management.

Glioblastoma multiforme (GBM) is a very aggressive and heterogeneous glioma. Currently, GBM is treated with a combination of surgery, radiotherapy, chemotherapy (e.g. temozolamide) and Tumour Treating Fields. Unfortunately, the mean survival is still around 15 months. This poor prognosis is associated with therapy resistance, tumor recurrence, and limited delivery of drugs due to the blood-brain barrier nature. Nanomedicine, the application of nanotechnology to medicine, has revolutionized many health fields, specifically cancer diagnosis and treatment. This review explores the particularities of different nanosystems (i.e., superparamagnetic, polymeric and gold nanoparticles, and liposomes) as well as how they can be applied to the treatment and diagnosis of GBM. As described, the most of the cited examples are on the preclinical phase; however, positive results were obtained and thus, the distance to achieve an effective treatment is shorter every day.

Biomass ash formulations as sustainable improvers for mining soil health recovery: Linking soil properties and ecotoxicity.

There is a growing need to recover degraded soils to restore their essential ecosystem services and limit damages of anthropic activities onto these systems. Safe and sustainable solutions for long-term recovery must be designed, ideally by recycling existing resources. Using ash from combustion of residual forest biomass at the pulp and paper industry is an interesting and sustainable strategy to recover mining soils. However, formulations must be found to limit the potential toxicity associated with soluble salts and chloride that ash contains. Here, we assessed the effectiveness of three field ash-based amendments for the recovery of three highly acidic soils from Portuguese abandoned mines. Three amendments were tested: an un-stabilized mixture of ash and biological sludge, granulated ash, and granulated ash mixed with composted sludge. One year after application in open field plots (in the scope of LIFE No_Waste project), soil health restoration was evaluated through (i) soil physico-chemical characterization and (ii) soil habitat functions though standardized ecotoxicological tests. This study highlights that stabilized materials provided nutrients, organic matter and alkalinity that corrected soil pH and decreased metal bioavailability, while controlling the release of soluble salts and chloride from ash. This soil improvement correlated with improved soil model organisms' reproduction and survival. For similar amendment, the native soil properties studied (as soil native electrical conductivity) affected the level of organism response. This work provides evidence that ash stabilization, formulation and supplementation with organic matter could be sustainable strategies to restore highly degraded mining soils and to recover their ecological functions. It further highlights the importance of analyzing combined effects on soil physico-chemical properties and ecological function recovery to assess restoration strategy efficiencies in complex multi-stressor environments.

LoRaWAN and Urban Waste Management-A Trial.

The city of Lisbon, as any other capital of a European country, has a large number of issues regarding managing waste and recycling containers spread throughout the city. This document presents the results of a study promoted by the Lisbon City Council for trialing LPWAN (Low-Power Wide-Area Network) technology for the waste management vertical under the Lisbon Smart City initiative. Current waste management is done using GSM (Global System for Mobile communications) sensors, and the municipality aims to use LPWAN in order to improve range and reduce costs and provisioning times when changing the communications provider. After an initial study, LoRa (Long Range) and LoRAWAN (LoRa Wide Area Network) as its network counterpart, were selected as the LPWAN technology for trials considering several use cases, exploring multiple distances, types of recycling waste containers, placements (underground or surface) and kinds of commercially available waste level measurement LoRa sensors. The results showed that the underground waste containers proved to be, as expected, the most difficult to operate correctly, where the container itself imposed attenuation levels of 26 dB on the LoRa link budget. The successful results were used to promote the deployment of a city-wide LoRa network, available to all the departments inside the Lisbon City Council. Considering the network capacity, the municipality also decided to make the network freely available to citizens.

Surface Comparison of Three Different Commercial Custom-Made Titanium Meshes Produced by SLM for Dental Applications.

The use of individualized titanium meshes has been referred to in scientific literature since 2011. There are many advantages to its use, however, the main complications are related to early or late exposures. As some aspects such as its surface properties have been pointed out to influence the soft tissue response, this study was designed to compare the surface characteristics of three commercially available individualized titanium meshes between them and according to the manufacturer's specifications. The results from the scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and the contact profilometry measurements were analyzed and cross-checked. It was discovered that, the BoneEasy's post-processing superficial treatment was more refined, as it delivers the mesh with the lowest Ra value, 0.61 ± 0.14 µm, due to the applied electropolishing. On the other hand, the Yxoss CBR® mesh from ReOss® was sandblasted, presenting an extremely rough surface with a Ra of 6.59 ± 0.76 µm.

A Novel Hybrid Nanosystem Integrating Cytotoxic and Magnetic Properties as a Tool to Potentiate Melanoma Therapy.

Cancer is a major health concern and the prognosis is often poor. Significant advances in nanotechnology are now driving a revolution in cancer detection and treatment. The goal of this study was to develop a novel hybrid nanosystem for melanoma treatment, integrating therapeutic and magnetic targeting modalities. Hence, we designed long circulating and pH-sensitive liposomes loading both dichloro(1,10-phenanthroline) copper (II) (Cuphen), a cytotoxic metallodrug, and iron oxide nanoparticles (IONPs). The synthetized IONPs were characterized by transmission electron microscopy and dynamic light scattering. Lipid-based nanoformulations were prepared by the dehydration rehydration method, followed by an extrusion step for reducing and homogenizing the mean size. Liposomes were characterized in terms of incorporation parameters and mean size. High Cuphen loadings were obtained and the presence of IONPs slightly reduced Cuphen incorporation parameters. Cuphen antiproliferative properties were preserved after association to liposomes and IONPs (at 2 mg/mL) did not interfere on cellular proliferation of murine and human melanoma cell lines. Moreover, the developed nanoformulations displayed magnetic properties. The absence of hemolytic activity for formulations under study demonstrated their safety for parenteral administration. In conclusion, a lipid-based nanosystem loading the cytotoxic metallodrug, Cuphen, and displaying magnetic properties was successfully designed.

Use of wastes from the pulp and paper industry for the remediation of soils degraded by mining activities: Chemical, biochemical and ecotoxicological effects.

Fly ash (FA) from biomass combustion and biological sludge (S), both wastes from the pulp and paper industry, were granulated in different proportions (90% FA+10% S, and 70% FA+30% S w/w, dry weight basis, dw) and used to recover the functionality of soils affected by mining activities (Aljustrel, Iberian Pyrite Belt), with and without the application of municipal solid waste compost (MSWC). Application doses of both mixtures were 2.5, 5.0 and 10% (w/w, dw). These materials corrected soil acidity to circumneutral values and increased extractable P and K concentrations. A significant increase in soil organic matter (from 0.6 to 0.8-1.5% w/w, dw) and N content (from 0.04 to 0.09-0.12% w/w, dw) was also observed, but only when MSWC was applied. The soil was already heavily contaminated with Cu, Pb and Zn and the application of amendments did not increase their pseudo-total concentrations. The CaCl2 extractable fractions of both Cu and Zn decreased to very low values. The improvement in soil quality, compared to fertilizer only treatment, was further evidenced by the increase in some soil enzymatic activities (dehydrogenase, ß-glucosidase and cellulase), with a better response for the granules with the higher proportion of biological sludge, as well as by the decrease in the soil-water extract toxicity towards different organisms (Daphnia magna, Thamnocephalus platyurus, and Pseudokirchneriella subcapitata). Agrostis tenuis germinated and grew during the first month only in the amended pots, but, after that, a considerable phytotoxic effect was evident. This was mainly attributed to salt stress or to some specific ionic toxicity. In conclusion, to establish a long-term plant cover in mining soils amended with biomass ash-based materials, the selection of plants with higher resistance to salinity and/or the stabilization of the amendments, to reduce their soluble salt content, is recommended.

Design of Finasteride-Loaded Nanoparticles for Potential Treatment of Alopecia.

BACKGROUND/AIMS: Androgenetic alopecia is an extremely common dermatological disorder affecting both men and women. Oral finasteride (FNS), a synthetic 4-aza-3-oxosteroid compound with poor aqueous solubility, blocks the peripheral conversion of testosterone to dihydrotestosterone (DHT) in a significant reduction in DHT concentration, achieving satisfactory results in alopecia treatment. However, its oral intake generally causes severe side effects. Considering that there is currently no scientifically proven treatment, new drug delivery systems able to improve alopecia therapy are urgently required. METHODS: In this study, polymeric nanoparticles have been proposed as a new carrier for topical delivery of FNS in hair follicles. RESULTS AND CONCLUSIONS: Polymeric nanoparticles, prepared by using a modified method of the emulsification/solvent diffusion, showed a mean particle size around 300 nm, which may be sufficient for reaching the dermis and hair follicles and negative zeta potential values. Scanning electron microscope measurements showed that all the polymeric nanoparticles exhibited a spherical shape and a smooth surface regardless of their composition. A high encapsulation efficiency was achieved for FNS (79.49 ± 0.47%). In vitro release assays in physiological conditions demonstrated that nanoparticles yielded a prolonged release of FNS for 3 h. Skin assays through an in vitro permeation study demonstrated that nanoparticles had low levels of penetration of FNS, improving its time residence onto the skin. All excipients used in nanoparticle composition and in 3 different vehicles were safe. These results suggest that the proposed novel formulation presents several good characteristics indicating its suitability for dermal delivery of FNS for alopecia treatment.

Ashes from fluidized bed combustion of residual forest biomass: recycling to soil as a viable management option.

Although bottom ash (BA) [or mixtures of bottom and fly ash (FA)] from clean biomass fuels is currently used as liming agent, additive for compost, and fertilizer on agricultural and forest soils in certain European countries, in several other countries most of the ashes are currently disposed in landfills. This is due to both a lack of a proper classification of the materials and of regulatory barriers.Chemical characterization including analysis of an array of potentially toxic elements (PTEs) proved that over 100,000 tons of BA currently landfilled every year in Portugal actually complied with legal limits for PTEs for soil fertilizers applied in other countries. Pot experiments were conducted, testing three dosages of BA and FA (1, 2.5, and 5%, in weight) in three mining soils with different properties. Additions of ash materials to soils led to an increase in the pore water pH relative to control pots (0% of ash added) and had a clear impact on DOC and on the solubilization of both macro- and micronutrients (notably Cu).The results from the case study using BA and FA from a Portuguese biomass thermal power plant demonstrate that it is imperative to further develop a regulatory framework to alleviate technological and environmental barriers for biomass ash utilization as raw material for fertilizers and/or soil liming agent, in accordance with the goals of the circular economy. A more harmonized view on how to assess the merits and risks of the re-use of these materials is also needed.

Análise econômica do sistema da reciclagem em Portugal / Economic analysis of the Portuguese recycling system

A reciclagem de resíduos de embalagens é um grande objetivo da União Europeia. A legislação comunitária impõe metas muito ambiciosas relativamente às taxas de reciclagem a atingir por todos os Estados-membros. Por conseguinte, a análise das operações e dos custos acrescidos que resultaram dessa política ambiental constitui um relevante tópico de investigação. Uma vez que cada Estado-membro tem seu próprio sistema de reciclagem, existe uma clara falta de informação acerca dos custos reais das várias etapas do ciclo de vida dos resíduos e de como esses custos têm sido distribuídos por todos os intervenientes. Este artigo caracteriza o caso português e discute as transferências financeiras feitas pela organização que gerencia o Sistema Ponto Verde. Essas transferências são posteriormente comparadas com os custos reais dos prestadores locais (operadores de resíduos), pelo que é possível discutir a eficiência e justiça do sistema. Conclui-se que cada tonelada de resíduos de embalagens triada custa cerca de 289€ aos prestadores de resíduos (custos de investimento, operação e manutenção com a coleta diferenciada e processo de triagem). Se os custos evitados com a coleta indiferenciada e a destinação final desses resíduos forem contabilizados como benefícios do sistema, então os benefícios correspondem a 127% dos custos totais. Contudo, se os custos evitados com a coleta indiferenciada e a destinação final não forem considerados, os benefícios dos prestadores de gestão de resíduos cobrem apenas 77% dos seus custos.

Recycling packaging waste is a major objective for the European Union. The European law sets clear targets for the recycling rates to be attained by all member states. Hence, to analyze the operations and added costs resulting from this environmental policy is an important research topic. Since every member state has its own recycling system, there is a clear lack of information regarding the true costs of the life cycle of packaging waste and how these costs have been allocated to the various participants. This study illustrates the Portuguese case and discusses the financial transfers made by the company that manages the Green Dot scheme. These transfers are compared with the true costs of the local authorities (waste management operators), which allow us to discuss the efficiency and justice of the national framework. Each ton of sorted packaging waste costs about 289€ to waste management operators (investment, operation and maintenance costs with selective collection and sorting). If the avoided costs with undifferentiated collection and final disposal of this waste are accounted for as benefits of the system, then the total benefits correspond to 127% of the total costs. However, if these “opportunity" costs are not considered, the benefits of the waste management operators only cover 77% of the costs.

Packaging waste recycling in Europe: is the industry paying for it?

This paper describes and examines the schemes established in five EU countries for the recycling of packaging waste. The changes in packaging waste management were mainly implemented since the Directive 94/62/EC on packaging and packaging waste entered into force. The analysis of the five systems allowed the authors to identify very different approaches to cope with the same problem: meet the recovery and recycling targets imposed by EU law. Packaging waste is a responsibility of the industry. However, local governments are generally in charge of waste management, particularly in countries with Green Dot schemes or similar extended producer responsibility systems. This leads to the need of establishing a system of financial transfers between the industry and the local governments (particularly regarding the extra costs involved with selective collection and sorting). Using the same methodological approach, the authors also compare the costs and benefits of recycling from the perspective of local public authorities for France, Portugal and Romania. Since the purpose of the current paper is to take note of who is paying for the incremental costs of recycling and whether the industry (i.e. the consumer) is paying for the net financial costs of packaging waste management, environmental impacts are not included in the analysis. The work carried out in this paper highlights some aspects that are prone to be improved and raises several questions that will require further research. In the three countries analyzed more closely in this paper the industry is not paying the net financial cost of packaging waste management. In fact, if the savings attained by diverting packaging waste from other treatment (e.g. landfilling) and the public subsidies to the investment on the "recycling system" are not considered, it seems that the industry should increase the financial support to local authorities (by 125% in France, 50% in Portugal and 170% in Romania). However, in France and Portugal the industry is paying local authorities more than just the incremental costs of recycling (full costs of selective collection and sorting minus the avoided costs). To provide a more definitive judgment on the fairness of the systems it will be necessary to assess the cost efficiency of waste management operators (and judge whether operators are claiming costs or eliciting "prices").

Eriophorum angustifolium and Lolium perenne metabolic adaptations to metals- and metalloids-induced anomalies in the vicinity of a chemical industrial complex.

As plants constitute the foundation of the food chain, concerns have been raised about the possibility of toxic concentrations of metals and metalloids being transported from plants to the higher food chain strata. In this perspective, the use of important phytotoxicity endpoints may be of utmost significance in assessing the hazardous nature of metals and metalloids and also in developing ecological soil screening levels. The current study aimed to investigate the role of glutathione (GSH) and its associated enzymes in the metabolic adaptation of two grass species namely Eriophorum angustifolium Honck. and Lolium perenne L. to metals and metalloids stress in the vicinity of a chemical industrial complex (Estarreja, Portugal). Soil and plant samples were collected from contaminated (C) and non-contaminated (reference, R) sites, respectively, near and away from the Estarreja Chemical Complex, Portugal. Soils (from 0 to 10 and 10 to 20 cm depths) were analyzed for pH, organic carbon, and metals and metalloids concentrations. Plant samples were processed fresh for physiological and biochemical estimations, while oven-dried plant samples were used for metals and metalloids determinations following standard methodologies. Both soils and plants from the industrial area exhibited differential concentrations of major metals and metalloids including As, Cu, Hg, Pb, and Zn. In particular, L. perenne shoot displayed significantly higher and lower concentrations of Pb and As, respectively at contaminated site (vs. E. angustifolium). Irrespective of sites, L. perenne shoot exhibited significantly higher total GSH pool, oxidized glutathione (GSSG) and oxidized protein (vs. E. angustifolium). Additionally, severe damages to photosynthetic pigments, proteins, cellular membrane integrity (in terms of electrolyte leakage), and lipid peroxidation were also perceptible in L. perenne shoot. Contrarily, irrespective of the sites, activities of catalase and GSH-regenerating enzyme, GSH reductase, and GSH-metabolizing enzymes such as GSH peroxidase and GSH sulfotransferase were significantly higher in shoot of E. angustifolium. Despite the higher total GSH content, L. perenne is vulnerable to multi-metals-induced stress in comparison to E. angustifolium as depicted by increased GSH- and protein oxidation, low reactive oxygen radical-processing potential (exhibited in terms of low catalase activity) and poor GSH pool utilization efficiency (in terms of lower GSH-associated enzymes activities). The outcome of the present study may be significant for understanding vital GSH-mediated metals and metalloids tolerance mechanisms in plants as well as their unsuitability for animal consumption due to higher metals and metalloids burdens.