Climate change is intensifying hydrological extremes and degrading water quality in East Africa, increasing the vulnerability of communities and ecosystems in arid and semi-arid regions. To support evidence-based, climate-resilient water resources management in Ethiopia, the EU–AICS Integrated Water Resources Management programme (EU-IWRM) implemented a multi-level capacity development pathway across the Awash, Danakil and Webi Shebele basins. The programme strengthened institutional and technical competencies for integrated surface and groundwater quality monitoring through distance-learning, field-based training, and an advanced laboratory programme at CNR-IRSA in Italy, which also provided hands-on training in key analytical techniques for chemical and microbiological water characterization. Ethiopian staff from the Ministry of Water and Energy, Basin Administration Offices, and Regional Water Bureaus were trained in monitoring network design, sampling strategies, data standardization, and statistical reporting. Field campaigns across the Awash basin characterized water quality using physicochemical, inorganic, nutrient, trace-metal and microbiological indicators, following protocols aligned with the EU Water Framework Directive. Complementary laboratory training, both in Ethiopia and Italy, enhanced analytical capabilities and supported the co-development of standardized field forms, harmonized databases, and GIS-based reporting tools. Preliminary findings from the three sampling campaigns highlight turbidity, salinity and fluoride concentrations exceeding WHO standards as key challenges that jeopardize water use for both human consumption and irrigation purposes. The experience demonstrates how targeted international cooperation can translate research methodologies into operational monitoring frameworks, reinforcing institutional ownership and supporting long-term water quality governance under increasing climate pressures.

Phosphate-induced eutrophication of surface waters remains a major global environmental challenge, highlighting the need for efficient and sustainable phosphorus recovery technologies. This study evaluated alginate beads encapsulating iron oxyhydroxides (NXT), either alone or combined with zeolite (NXT+ZEO) or biochar (NXT+BIO), for selective phosphate removal from real wastewater and subsequent nutrient reuse. Batch experiments showed that NXT and NXT+ZEO beads removed up to 99% of phosphate from distilled water at an initial concentration of 10 mg P/L. Aging the beads in wastewater promoted biofilm formation, significantly enhancing adsorption kinetics. After only 1 h of contact time, aged NXT, NXT+ZEO, and NXT+BIO beads achieved phosphate removal efficiencies that were 44%, 40%, and 19% higher, respectively, than those of freshly prepared beads. Continuous-flow experiments with real wastewater confirmed the superior performance of NXT beads, which maintained phosphate removal efficiencies above 80% after treating approximately 5 L of wastewater. Adsorption capacities ranged from 19.5 to 44.7 mg P/g among the tested materials, with NXT beads exhibiting the highest capacity. The potential reuse of phosphate-enriched beads as slow-release fertilizers was assessed through growth trials with Lactuca sativa L. All phosphate-enriched treatments significantly increased plant biomass and tissue phosphorus content compared with the phosphate-free control. After three weeks, the NXT+BIO and NXT+ZEO treatments produced approximately ten-fold greater biomass than the control. Overall, these findings demonstrate that iron oxy-hydroxide-encapsulated alginate beads are promising materials for phosphate recovery from wastewater and subsequent reuse as slow-release fertilizers, supporting more circular and sustainable phosphorus management.

The wide application of graphene nanomaterials has led to their release into the environment, raising ecological risk concerns, especially when co-existing with other pollutants like copper (Cu), one of the most ubiquitous environmental metals. The impact of co-presence of these nanomaterials and Cu on woody plants remains unstudied and, in this regard, callus culture represents a reliable tool for toxicological studies. In this work, we investigated the effects of Cu in combination with two different graphene nanomaterials, graphene oxide (GO) and graphene nanoplatelets (GNP), on the cell ultrastructure, biochemical responses and nutrient uptake in callus culture of Populus nigra L., a pioneer tree species in the riparian ecosystem. GO and GNP alone showed an adverse impact on poplar cells, causing a significant reduction in dry weight and a notable increase in MDA levels, water and Ca uptake, and protein synthesis. Co-exposure to Cu and either GO or GNP increased dry weight while decreasing water content, MDA levels, antioxidant enzyme activities, and protein content. Furthermore, GO + Cu exposure promoted greater cellular metal uptake than the GNP + Cu treatment, indicating a greater effectiveness of GO as a Cu carrier, due to the higher presence of oxygen functional groups on its surface than GNP. Transmission Electron Microscopy (TEM) observations confirmed the cellular uptake of both GO and GNP, revealing distinct impacts on cell ultrastructure. These results provide useful information on the interaction between graphene nanomaterials and Cu for risk assessment and developing sustainable management strategies in agro-forestry.

The expanding development of graphene-based materials (GBMs) requires immediate and balanced environmental assessment balancing two key areas: investigating the risk of graphene oxide toxicity to ecosystems and evaluating GBMs’ potential to act as solutions for challenges like heavy metal stress mitigation. This study analyzed the effects of reduced graphene oxide (rGO) on copper (Cu) and nickel (Ni) toxicity in Lemna minor. Our findings reveal that rGO’s protective effects are metal-specific. L. minor demonstrated significant sensitivity to nickel, but rGO offered no mitigation; growth parameters, pigment content, and nickel accumulation showed no significant improvements with rGO co-exposure compared to Ni-plants. This suggests that rGO does not enhance L. minor’s ability to tolerate or absorb nickel, especially after 14 days (T14). In contrast, rGO showed a partially protective effect against copper toxicity. At T14, the presence of rGO significantly improved plant performance under copper stress, resulting in a 17% increase in biomass, a 19% increase in relative growth rate, and enhanced pigment content, including a 40% increase in chlorophyll when compared to Cu-plants. The protective effect of rGO was directly tied to a 37% reduction in copper accumulation, providing strong evidence that rGO reduces copper’s bioavailability, thereby limiting plant uptake. The divergent effects on Cu and Ni uptake suggest differing affinities of these metals for rGO. Future research, including large-scale experiments with various GBMs and Lemna clones, is crucial to fully assessing their phytoremediation potential.

The groundwater quality assessments are challenging in complex hydrogeological settings and highly anthropized areas where geogenic and anthropogenic pollution may coexist. The objective of this study was to elucidate groundwater quality patterns beneath an inactive landfill in a coastal region of central Italy by integrating chemical-physical and geochemical parameters with isotopic and microbiological analyses. The groundwater under the landfill, predating the EU Landfill Directive (1999/31/EC), is under pump-and-treat remediation. The site features a complex stratigraphy of fluvio-palustrine sediments, eolian sands, and volcanic deposits of Pleistocene age, with a water table aquifer overlying Pliocene clays. Sampling was performed from 13 piezometers within the landfill and two surface water sites between March and July 2024. Laboratory analyses were conducted to measure the concentrations of major, minor, and trace cations and anions (with a specific focus on Fe, Mn, and As), dissolved organic carbon (DOC), and isotopes (δ18O, δ2H, δ13C, tritium and 87Sr/86Sr). Microbiological analysis were performed by flow cytometry (microbial cell abundance) and spectrofluorimetry (microbial respiration rates).Upgradient of the landfill, the aquifer exhibits oxidizing conditions, with low concentrations of metals and bicarbonates. Electrical conductivity (EC, μS/cm) is higher near the most upstream piezometers, where chloride concentrations exceed 800 mg/L. In the downgradient zone, high concentrations of Fe (4.2 mg/L) and Mn (1.1 mg/L) – occasionally exceeding the legal limits for groundwater – are associated with the strongly reducing conditions of the aquifer, driven by the presence of fluvio-palustrine deposits rich in peat, as identified through available borehole logs. The presence of As (1.3-15.4 μg/L) was likely due to interaction of groundwater with the volcanic deposits in the area. The leachate-tracer tritium showed generally lower activity (0.4-5.5 U.T.) than previous measurements, implying that historical contamination is currently declining. DOC concentration has a range from 0.5 to 7.4 mg/L, higher downgradient. Surface water sampled in two sections in the nearby river is highly oxygenated and rich in organic matter. Microbial cell abundance ranged from 104 – 105 cells/mL in most of groundwater samples, with higher values downgradient (106 cells/mL). Microbial respiration showed an inverse relationship with DOC exclusively in downgradient piezometers.These data indicated a highly specific hydrogeological and geolithological context, further complicated by anthropogenic activities throughout the region. As suggested by the Na/Cl ratio and the 87Sr/86Sr ratio, high chloride seems linked to mixing with fossil seawater, likely associated with a geological history marked by marine incursions following the end of the last glaciation (Würm). Elevated metal levels were connected to anoxic conditions promoted by the occurrence of fluvio-palustrine sediments, where heterotrophic microbial communities consume oxygen for organic matter degradation.Our findings highlight the critical need for tailored monitoring strategies that consider the unique hydrogeological and geolithological characteristics of the site, ensuring effective long-term management and protection of groundwater resources in similarly complex environmental settings.

In an era marked by increasingly frequent extreme weather events, small inland reservoirs are emerging as crucial yet often overlooked water resources. This study investigates the potential of remote sensing techniques to efficiently monitor the water quality of those reservoirs and improve their management. Although many works in literature have tried to derive water quality parameters from different satellite platforms, micro satellites constellations like PlanetScope have never been investigated: they can be a promising tool for investigation of SRs thanks to their high spatial and temporal resolution. Focusing on Spina Reservoir, a small lake in the province of Perugia where a water quality survey has been conducted, the research combines on-site biochemical analyses with satellite imagery from Sentinel-2, well known and explored free Platform, and PlanetScope. The performances of images corrected with the default atmospheric correction and with a specific pre-processor (ACOLITE) for inland and coastal water are discussed.Water Quality Semi-empirical algorithms (indices) based on one or more spectral bands at different wavelengths are used to build correlation curves respect to in-situ measurements (e.g Chlorophyll-a, turbidity, Cyanobacteria), enabling the evaluation and comparison of the performance.PlanetScope images displayed higher reliability with respect to Sentinel-2 data and correction with ACOLITE lead to more accurate interpolations, except for chlorophyll-a, even if satellite images with lower spatial resolution (Sentinel-2) can also provide a well-distributed dataset.The findings underscore the significant potential of PlanetScope microsatellite constellation for real-time, cost-effective water quality assessment that could be easily applied on a larger scale, as regional assessment.

The aim of this research was to assess the sex-related responses to AgNPs stabilized with citrate (Cit) and glutathione (GSH), relative to silver ions supplied as AgNO3 in black poplar (Populus nigra L.), a dioecious, woody model species. The impact of the AgNPs-cit-GSH on male and female clones was evaluated by measuring key parameters of oxidative stress. The results showed that exposure to nanosilver resulted in lower Ag accumulation and reduced MDA levels in both genders compared to AgNO3. The female clone exhibited a dose-dependent response, characterized by an increase in dry weight (DW), along with a reduction in nutrient uptake, protein content, and ATPase activity, as well as an upregulation of glutathione-S-transferase (GST) activity compared to the control. The male clone displayed a specific treatment response. Exposure to AgNPs-cit-GSH caused a decrease in DW, water content, and nutrient uptake, accompanied by a rise in protein content as well as GST activity. In AgNO3-treated male cells, the increase in Ag content and MDA levels corresponded to a decrease in DW and a rise in protein, Cu, and Ca content. These findings offer valuable insights into sexual dimorphism in dioecious woody plants, a topic that has been largely understudied yet is critical for sustainable resource management strategies.

The application of graphene-related materials (GRMs) has increased considerably in various fields, posing a potential environmental risk. However, little is known about sex-related responses to GRMs in dioecious woody plants and in that regard, callus culture represents a reliable tool for toxicity and tolerance studies. In this work, the effects of different concentrations of graphene oxide (GO) and graphene nanoplatelets (GNP) on physiological traits of male and female clones of Populus nigra were investigated. After a 3-week treatment, at high concentrations, GO promoted in female calli, an increase in fresh weight and a reduction in protein content, accompanied by a remarkable enhancement of APX and CAT activity while no toxic effect was observed under GNP treatment. Instead, male cells displayed a greater sensitivity at lower GO concentration (25 mg/L), exhibiting a notable reduction in biomass, nutrient uptake and protein content, associated to an increase in APX and CAT activity. Similarly, at 25 mg/L, GNP caused a slight enhancement in lipid peroxidation (MDA) level and a significant decrease in protein content, accompanied by an increase in the production of flavonoids. These findings revealed sexually different responses to GO and GNP, with female clone exhibiting more tolerance compared to male one.

The complex structure and dynamics of geothermal ecosystems strongly affect the spatial distribution and activity of aquatic microbial communities. The interactions between groundwaters and thermal waters represent an additional selective factor. A deeper understanding of microbial diversity, metabolic potential, and ecological interactions in groundwater mixing zones is essential for evaluating their impact on biogeochemical cycles (such as sulfur, nitrogen, and carbon) and predicting the ecological consequences of water mixing on ecosystem functioning. In this study, the taxonomic diversity and metabolic potentialities of microbial communities in groundwater and thermal waters revealed the occurrence of novel thermophiles able to cope with extreme physical-chemical conditions and high concentrations of toxic elements, such as arsenic, characteristics of the studied area. Furthermore, a core microbiome composed of the families Burkholderiaceae, Caulobacteraceae, Halothiobacillaceae, and Sulfurovaceae was identified as markers of the interaction between the two water compartments. Our findings emphasize the key role of microbial communities in S-, As-, and N-related biogeochemical cycles of geothermal areas.

Plastic pollution represents a global environmental issue with relevant associated risks for ecosystem and human health. Fluorescence-based detection techniques allowed rapid tracking and identification of micro/nanoplastics (MNPs) in numerous studies by combining pre-treatment procedures, specific staining protocols, and advanced analytical instruments. However, despite an increasing scientific attention, the detection of plastic debris in the submicron and nano size range is still challenging when targeting environmental complex samples. In particular, the suitable approaches are not consistently harmonized and generally case/system-specific, with detrimental consequences on data reproducibility, accuracy, and reliability. This review is intended to provide state-of-the-art information on the existing and promising fluorescencebased approaches to assess the occurrence of MNPs in environmental samples of different origin. More specifically, we identified and discussed the most used fluorescent dyes, staining protocols, and analytical instruments for the fluorescence-based detection of MNPs. Advantages and disadvantages of the applied methodological approaches were critically presented, by highlighting their potentialities and challenges in view of future needs to improve the current scientific knowledge on spread and fate of MNPs in the environment. Overall, fluorescence-based techniques are offering promising results and unique analytical opportunities for the detection and quantification of MNPs in the environment.

In modern agricultural production, cattle manure waste recovery is considered as a sustainable approach to agricultural waste management, reducing environmental pollution and chemical fertilizer use. This study aimed to investigate the effects of manure and digestate derived from a pilot-scale livestock waste-recycling system, in combination with a low copper concentration as a fungicide, on the physiological response of lettuce cv Rufus (Lactuca sativa L.) plants and the associated soil microbiome. A five-week microcosm experiment was conducted in a greenhouse under environmental conditions. Lettuce plant performance was assessed in terms of biomass, leaf area index, photosynthetic activity, chlorophyll measurements, lipid peroxidation, total phenolic content, and nutrient uptake. The results suggested that incorporating digestate into the potting soil mix significantly enhanced crop yields compared to the control and manure treatments. The soil microbial activity increased in the presence of fertilizers, improving the soil chemical and biological properties. The addition of copper negatively affected the growth and physiological performance of the lettuce plants under both the control and manure-treated conditions, except for those grown in the presence of digestate, where copper accumulation was reduced. These findings highlight the potential of growing horticultural crops using organic fertilization through livestock waste anaerobic digestate, establishing a waste-to-food recycling system.

This study assesses the potential impacts on human health of volcanic ash emitted during the 2021 Tajogaite eruption (La Palma Island, Spain). Ash samples were physically and chemically characterized and leaching tests (with deionized water and acidic solution) were performed according to the IVHHN protocols to elucidate i) the leachable elements that may affect water quality and represent a potential threat for livestock and humans through drinking water supply; and ii) the bioaccessible fraction of toxicants able to be solubilized from ash surfaces if ashes are incidentally ingested by children. The most abundant readily water-soluble compounds were SO4, F, Cl, Na, Ca, Ba, Mg, and Zn. Fluoride and chloride (up to 1085 and 1347 mg/kg) showed higher values in distal ash samples than closer ones. The potential F availability assessed from water leachates may suggest important environmental and health implications. In addition, long-term health hazard due to a long-term weathering of tephra deposits should be possible as confirmed by the greater amount of F extracted by acidic solution. Concentration of other trace elements (e.g., As, V, Mn, Mo, Cr, Fe, Se, Ti, Pb) were low compared to global medians and within the range globally assessed. Indicative calculation of hazard for water supply showed that F concentration may exceed both the recommended value (1 mg/L) for irrigation purpose and the health based drinking water limits of 1.5 mg/L (for humans) and 2 mg/L (for livestock). If the predicted concentrations in water were compared with the toxicologically dose, F showed a potential health-risk for children through drinking water. The indicative health-risk characterization via accidental ash ingestion showed that the direct exposure does not represent a primary source of F daily intake for children. This important outcome confirmed F as element with the greatest health threat during Tajogaite 2021 eruption.

Owing to the unique physicochemical properties and the low manufacturing costs, silver nanoparticles (AgNPs) have gained growing interest and their application has expanded considerably in industrial and agricultural sectors. The large-scale production of these nanoparticles inevitably entails their direct or indirect release into the environment, raising some concerns about their hazardous aspects. Callus culture represents an important tool in toxicological studies to evaluate the impact of nanomaterials on plants and their potential environmental risk. In this study, we investigated the chronic phytotoxic effects of different concentrations of novel bifunctionalized silver nanoparticles (AgNPs-Cit-L-Cys) and silver nitrate (AgNO 3 ) on callus culture of Populus nigra L., a pioneer tree species in the riparian ecosystem. Our results showed that AgNPs-Cit-L-Cys were more toxic on poplar calli compared to AgNO 3 , especially at low concentration (2.5 mg/L), leading to a significant reduction in biomass production, accompanied by a decrease in protein content, a significant increase in both lipid peroxidation level, ascorbate peroxidase (APX), and catalase (CAT) enzymatic activities. In addition, these findings suggested that the harmful activity of AgNPs-Cit-L-Cys might be correlated with their physicochemical properties and not solely attributed to the released Ag + ions and confirmed that AgNPs-Cit-L-Cys phytoxicity is associated to oxidative stress.

Active hydrothermal travertine systems are ideal environments to investigate how abiotic and biotic processes affect mineralization mechanisms and mineral fabric formation. In this study, a biogeochemical characterization of waters, dissolved gases, and microbial mats was performed together with a mineralogical investigation on travertine encrustations occurring at the outflow channel of a thermal spring. The comprehensive model, compiled by means of TOUGHREACT computational tool from measured parameters, revealed that mineral phases were differently influenced by either abiotic conditions or microbially driven processes. Microbial mats are shaped by light availability and temperature gradient of waters flowing along the channel. Mineralogical features were homogeneous throughout the system, with euhedral calcite crystals, related to inorganic precipitation induced by CO2 degassing, and calcite shrubs associated with organomineralization processes, thus indicating an indirect microbial participation to the mineral deposition (microbially influenced calcite). The microbial activity played a role in driving calcite redissolution processes, resulting in circular pits on calcite crystal surfaces possibly related to the metabolic activity of sulfur-oxidizing bacteria found at a high relative abundance within the biofilm community. Sulfur oxidation might also explain the occurrence of gypsum crystals embedded in microbial mats, since gypsum precipitation could be induced by a local increase in sulfate concentration mediated by S-oxidizing bacteria, regardless of the overall undersaturated environmental conditions. Moreover, the absence of gypsum dissolution suggested the capability of microbial biofilm in modulating the mobility of chemical species by providing a protective envelope on gypsum crystals.

Arsenic is a potentially toxic element (PTE) that is widely present in groundwater, with concentrations often exceeding the WHO drinking water guideline value (10.0 μg/L), entailing a prominent risk to human health due to long-term exposure. We investigated its origin in groundwater in a study area located north of Rome (Italy) in a volcanic-sedimentary aquifer. Some possible mineralogical sources and main mechanisms governing As mobilization from a representative volcanic tuff have been investigated via laboratory experiments, such as selective sequential extraction and dissolution tests mimicking different release conditions. Arsenic in groundwater ranges from 0.2 to 50.6 μg/L. It does not exhibit a defined spatial distribution, and it shows positive correlations with other PTEs typical of a volcanic environment, such as F, U, and V. Various potential As-bearing phases, such as zeolites, iron oxyhydroxides, calcite, and pyrite are present in the tuff samples. Arsenic in the rocks shows concentrations in the range of 17–41 mg/kg and is mostly associated with a minor fraction of the rock constituted by FeOOH, in particular, low crystalline, containing up to 70% of total As. Secondary fractions include specifically adsorbed As, As-coprecipitated or bound to calcite and linked to sulfides. Results show that As in groundwater mainly originates from water-rock interaction processes. The release of As into groundwater most likely occurs through desorption phenomena in the presence of specific exchangers and, although locally, via the reductive dissolution of Fe oxy-hydroxides.

Duckweeds are aquatic plants often used in phytotoxic studies for their small size, simple structure, rapid growth, high sensitivity to pollutants and facility of maintaining under laboratory conditions. In this paper, induced phytotoxic effects were investigated in Lemna minor and Lemna minuta after exposition to silver nitrate (AgNO3) and silver nanoparticles stabilized with sodium citrate and L-Cysteine (AgNPs-Cit-L-Cys) at different concen-trations (0, 20 and 50 mg/L) and times (7 and 14 days). Lemna species responses were evaluated analyzing plant growth (mat thickness, fresh and dry biomass, relative growth rate - RGR) and physiological parameters (chlorophyll - Chl, malondialdehyde - MDA, ascorbate peroxidase - APX and catalase -CAT). Ag content was measured in the fronds of the two Lemna species by inductively coupled plasma optical emission spectrometry. AgNO3 and AgNPs-Cit-L-CYs produced phytotoxic effects on both duckweed species (plant growth and Chl reduction, MDA increase) that enhanced in response to increasing concentrations and exposure times. AgNPs-Cit-L-Cys caused much less alteration in the plants compared to AgNO3 suggesting that the presence of bifunc-tionalized AgNPs-Cit-L-Cys have a reduced phytotoxic effect as compared to Ag+ released in water. Based on the physiological performance, L. minuta plants showed a large growth reduction and higher levels of chlorosis and stress in respect to L. minor plants, probably due to greater Ag+ ions accumulation in the fronds. Albeit with some differences, both Lemna species were able to uptake Ag+ ions from the aqueous medium, especially over a period of 14 days, and could be considered adapt as phytoremediation agents for decontaminating silver ion-polluted water.

Polysulfone-graphene oxide hollow fiber membranes (PSU-GO HFs) with simultaneous adsorption and ultrafiltration capabilities are herein described and proposed for enhanced and simplified Point-of-Use (POU) drinking water purification. The PSU-GO HFs were prepared by phase inversion extrusion by a customized semi-industrial plant and their morphology, surface properties, and porosity were investigated by combined Scanning Electron Microscopy (SEM), contact angle and Raman confocal microscopy, in relation to different GO:PSU ratios (1-5% w/w GO vs PSU) and to the final adsorption-ultrafiltration properties. Filtration modules of PSU-GO HFs of filtering surface (FS) in the range 0,015-0,28 m2 showed same ultrafiltration capability of PSU-HF standard filters. Synergic adsorption properties were demonstrated by studying the adsorption maximum capacity of ciprofloxacin antibiotic (CIPRO) vs GO ratio in dead end in-out configuration, the standard configuration used for PSU HFs commercial modules. Loading of 3,5% GO vs PSU was selected as case study, representing the best compromise between performance and GO nanofiller amount. Heavy metals (Pb, Cu and Cr(III)) and polyfluoroalkyl substances (PFAS) removal capabilities from tap water were competitive and in some cases outperformed Granular Activated Carbon (GAC), the standard industrial sorbent. Ciprofloxacin removal from tap water was also under real operational conditions. Moreover, release of GO from working PSU-GO modules was excluded by Surface Enhanced Raman Spectroscopy (SERS) analysis of treated water having the state-of-the-art limit of quantification of 0.1 mu g/L for GO nanosheets.

Microwave (MW) accelerated synthesis combined with microfiltration (MF) on commercial hollow fiber modules enables fast and scalable preparation of highly pure modified graphene oxide nanosheets. The MW-MF procedure is demonstrated on polyethylenimine (PEI) modified GO, and the so-obtained GOPEI is used for simultaneous removal of arsenic and lead from water.

This study aims to assess the environmental impact of discarded face masks, that are a source of emerging concern as indicated by most recent literature, although still little investigated. Herein we evaluated micro- and nanoplastic particles that can be released from face mask once subject to environmental conditions. Exposure to simulated-low shear forces demonstrated to be effective in breaking and fragmenting face mask tissue into smaller debris. Even at low shear energy densities, a single mask could release in water thousands of microplastic fibers and up to 10^11 submicrometric particles. The latter were quantified using flow cytometry that was proven to be a promising technique for nanoplastic counting, thus improving our understanding on distribution and fate of NPs still representing a great analytical challenge in plastic pollution research.

Arsenic mobilization in groundwater systems is driven by a variety of functionally diverse microorganisms and complex interconnections between different physicochemical factors. In order to unravel this great ecosystem complexity, groundwaters with varying background concentrations and speciation of arsenic were considered in the Po Plain (Northern Italy), one of the most populated areas in Europe affected by metalloid contamination. High-throughput Illumina 16S rRNA gene sequencing, CARD-FISH and enrichment of arsenic-transforming consortia showed that among the analyzed groundwaters, diverse microbial communities were present, both in terms of diversity and functionality. Oxidized inorganic arsenic [arsenite, As(III)] was the main driver that shaped each community. Several uncharacterized members of the genus Pseudomonas, putatively involved in metalloid transformation, were revealed in situ in the most contaminated samples. With a cultivation approach, arsenic metabolisms potentially active at the site were evidenced. In chemolithoautotrophic conditions, As(III) oxidation rate linearly correlated to As(III) concentration measured at the parental sites, suggesting that local As(III) concentration was a relevant factor that selected for As(III)-oxidizing bacterial populations. In view of the exploitation of these As(III)-oxidizing consortia in biotechnology-based arsenic bioremediation actions, these results suggest that contaminated aquifers in Northern Italy host unexplored microbial populations that provide essential ecosystem services.