A portable geometry-independent tomographic system for gamma-ray, a next generation of nuclear waste characterization

One of the main activities of the nuclear industry is the characterisation of radioactive waste based on the detection of gamma radiation. Large volumes of radioactive waste are classified according to their average activity, but often the radioactivity exceeds the maximum allowed by regulators in specific parts of the bulk. In addition, the detection of the radiation is currently based on static detection systems where the geometry of the bulk is fixed and well known. Furthermore, these systems are not portable and depend on the transport of waste to the places where the detection systems are located. However, there are situations where the geometry varies and where moving waste is complex. This is especially true in compromised situations.We present a new model for nuclear waste management based on a portable and geometry-independent tomographic system for three-dimensional image reconstruction for gamma radiation detection. The system relies on a combination of a gamma radiation camera and a visible camera that allows to visualise radioactivity using augmented reality and artificial computer vision techniques. This novel tomographic system has the potential to be a disruptive innovation in the nuclear industry for nuclear waste management

Secondary nanoplastics released from a biodegradable microplastic severely impact freshwater environments

This article is part of the themed collection: Environmental Science: Nano Recent HOT Articles https://pubs.rsc.org/en/journals/articlecollectionlanding?sercode=en&themeid=280a8 9ca-3eed-4abe-ae65-c856206f6c3c Article selected by the Editors in Chief of Environmental Science journals: DOI: 10.1039/D0EM90014A (Editorial)Over the last five decades, plastics production has increased as a consequence of their use in strategic sectors causing damage on aquatic ecosystems. In this context, biodegradable plastics have emerged as an ecological alternative because they are easily degradable in the environment. Despite the recent advances in the field of plastic ecotoxicology, the ecological impact of secondary nanoplastics (nanoplastics resulting from natural degradation of micro and macro plastics) in the environment remains poorly understood. Here, we have investigated the effects of secondary nanoplastics of polyhydroxybutyrate (PHB), a biodegradable plastic, on three representative organisms of aquatic ecosystems. Secondary PHB-nanoplastics were produced from PHB-microplastics by abiotic degradation under environmentally representative conditions. Secondary PHB-nanoplastics induced a significant decrease in cellular growth and altered relevant physiological parameters in all organisms. We investigated whether the observed toxicity was exerted by PHB-nanoplastics themselves or by other abiotic degradation products released from PHB-microplastics. An experiment was run in which PHB-nanoplastics were removed by ultrafiltration; the resulting supernatant was not toxic to the organisms, ruling out the presence of toxic chemicals in the PHB-microplastics. In addition, we have performed a complete physicochemical characterization confirming the presence of secondary PHB-nanoplastics in the 75-200 nm range. All results put together indicated that secondary PHB-nanoplastics released as a consequence of abiotic degradation of PHB-microplastics were harmful for the tested organisms, suggesting that biodegradable plastic does not mean safe for the environment in the case of PH

Time-course biofilm formation and presence of antibiotic resistance genes on everyday plastic items deployed in river waters

The plastisphere has been widely studied in the oceans; however, there is little information on how living organisms interact with the plastisphere in freshwater ecosystems, and particularly on how this interaction changes over time. We have characterized, over one year, the evolution of the eukaryotic and bacterial communities colonizing four everyday plastic items deployed in two sites of the same river with different anthropogenic impact. α-diversity analyses showed that site had a significant role in bacterial and eukaryotic diversity, with the most impacted site having higher values of the Shannon diversity index. β-diversity analyses showed that site explained most of the sample variation followed by substrate type (i.e., plastic item) and time since first colonization. In this regard, core microbiomes/biomes in each plastic at 1, 3, 6 and 12 months could be identified at genus level, giving a global overview of the evolution of the plastisphere over time. The measured concentration of antibiotics in the river water positively correlated with the abundance of antibiotic resistance genes (ARGs) on the plastics. These results provide relevant information on the temporal dynamics of the plastisphere in freshwater ecosystems and emphasize the potential contribution of plastic items to the global spread of antibiotic resistanceThe authors acknowledge the financial support provided by the Spanish Government (Ministerio de Ciencia e Innovacion, ´ MICIN): PID2020–113769RB-C21/22, PLEC2021–007693 (Funded by MCIN/ AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”), the IMPASSE project (PCIN-2017–06) belonging to the EU JPI-Water initiative, and the Thematic Network of Micro- and Nanoplastics in the Environment (RED2018–102345-T, EnviroPlaNet Network). SMC thanks the Universidad de Alcala ´ for the award of an FPI contract. A. Rico thanks the Talented Researcher Support Programme - Plan GenT (CIDEGENT/2020/043) of the Generalitat Valenciana. The authors gratefully acknowledge the Genomics Unit of the “Parque Científico de Madrid” for qPCR experiments and Illumina sequencin

Microplastics in sediments of artificially recharged lagoons: case study in a Biosphere Reserve

We studied the occurrence of microplastics in sediments of artificially and non-artificially recharged lagoons from the network of endorheic wetlands called “La Mancha Húmeda”, declared Biosphere Reserve by UNESCO. The particles sampled in this study covered the 25 μm–5 mm range. Films were the dominant microplastic typology in non-artificially recharged lagoons, while fibres and fragments were more abundant in those receiving wastewater. The concentration of microplastics in sediments reached up to 24.4 ± 5.2 microplastics/g, while plastic litter counts yielded <1 particle/g in non-wastewater receiving lagoons. Eleven types of plastic were identified using Micro-Fourier Transform Infrared Spectroscopy (micro-FTIR), the most abundant being the polyolefins polyethylene and polypropylene, and polyester and acrylic fibres. The statistical analysis of FTIR spectra confirmed the similarity between samples taken from recharged lagoons and wastewater treatment plant effluents. Overall, our results showed that endorheic lagoons are very sensitive to the accumulation of persistent pollutants, which include microplastics. The recharge of lagoons with wastewater effluents to maintain water levels, even if correctly treated according to current standards, is not a sustainable practice. Due to the closed character of endorheic basins, the continuous input of wastewater led to the accumulation of microplastics in sediments of wastewater receiving lagoons up to 40 times over non-recharged lagoon

Understanding nanoplastic toxicity and their interaction with engineered cationic nanopolymers in microalgae by physiological and proteomic approaches

The amount of plastics produced per year is in constant growth alongside their use in different sectors like the textile industry, agriculture or, more recently, in nanotechnology. Under certain environmental conditions, plastics break down into smaller pieces. Those plastics in the nanosize range are the most difficult to identify, quantify and remove and therefore probably prevail in aquatic ecosystems. Likewise, nanomaterial production has been increasing exponentially and therefore their potential release to the environment poses a threat. There is a lack of knowledge regarding the combined effects of co-occurring nanopolymers on biota. In this work, we have studied the individual toxicity of polystyrene nanoplastics (PS-NPs) as well as their combined effect with generation 7 PAMAM dendrimers (G7) on the filamentous cyanobacterium Anabaena sp. PCC7120, a relevant aquatic primary producer. Exposure to PS-NPs induced the overproduction of reactive oxygen species, lipid peroxidation, membrane disruptions, intracellular acidification and a decrease in photosynthetic activity. Internalization of the nanoplastics was also observed. Combined exposure to PS-NPs and G7 lowered PS-NP toxicity and precluded their internalization. This antagonistic interaction was due to the formation of heteroaggregates. Molecular biomarkers (differentially expressed proteins, DEPs) of the toxic effect of nanoplastics, G7 and their binary mixture were identified for the first time. These molecular biomarkers may be envisaged as a molecular signature of the toxic effect of the nanopolymers and could be predictors of cellular damage caused by exposure to nanopolymer

Ecotoxicity assessment of microcystins from freshwater samples using a bioluminescent cyanobacterial bioassay

The hepatotoxic cyanotoxins microcystins (MCs) are emerging contaminants naturally produced by cyanobacteria. Yet their ecological role remains unsolved, previous research suggests that MCs have allelopathic effects on competing photosynthetic microorganisms, even eliciting toxic effects on other freshwater cyanobacteria. In this context, the bioluminescent recombinant cyanobacterium Anabaena sp. PCC7120 CPB4337 (hereinafter Anabaena) was exposed to extracts of MCs. These were obtained from eight natural samples from freshwater reservoirs that contained MCs with a concentration range of 0.04–11.9 μg MCs L−1. MCs extracts included the three most common MCs variants (MC-LR, MC-RR, MC-YR) in different proportions (MC-LR: 100–0%; MC-RR: 100–0%; MC-YR: 14.2–0%). The Anabaena bioassay based on bioluminescence inhibition has been successfully used to test the toxicity of many emerging contaminants (e.g., pharmaceuticals) but never for cyanotoxins prior to this study. Exposure of Anabaena to MCs extracts induced a decrease in its bioluminescence with effective concentration decreasing bioluminescence by 50% ranging from 0.4 to 50.5 μg MC L−1 in the different samples. Bioluminescence responses suggested an interaction between MCs variants which was analyzed via the Additive Index method (AI), indicating an antagonistic effect (AI < 0) of MC-LR and MC-RR present in the samples. Additionally, MC extracts exposure triggered an increase of intracellular free Ca2+ in Anabaena. In short, this study supports the use of the Anabaena bioassay as a sensitive tool to assess the presence of MCs at environmentally relevant concentrations and opens interesting avenues regarding the interactions between MCs variants and the possible implication of Ca2+ in the mode of action of MCs towards cyanobacteri

Tracking nanoplastics in freshwater microcosms and their impacts to aquatic organisms

In this work, we used palladium-doped polystyrene NPLs (PS-NPLs with a primary size of 286 ± 4 nm) with an irregular surface morphology which allowed for particle tracking and evaluation of their toxicity on two primary producers (cyanobacterium, Anabaena sp. PCC7120 and green algae, Chlamydomonas reinhardtii) and one primary consumer (crustacean, Daphnia magna). the concentration range for Anabaena and C. reinhardtii was from 0.01 to 1000 mg/L and for D. magna, the range was from 7.5 to 120 mg/L.EC50 s ranged from 49 mg NPLs/L for D. magna (48hEC50 s) to 248 mg NPLs/L (72hEC50 s for C. reinhardtii). PS-NPLs induced dose-dependent reactive oxygen species overproduction, membrane damage and metabolic alterations. To shed light on the environmental fate of PS-NPLs, the short-term distribution of PS-NPLs under static (using lake water and sediments) and stirring (using river water and sediments) conditions was studied at laboratory scale. The results showed that most NPLs remained in the water column over the course of 48 h. The maximum percentage of settled particles (∼ 30 %) was found under stirring conditions in comparison with the ∼ 10 % observed under static ones. Natural organic matter increased the stability of the NPLs under colloidal state while organisms favored their settlement. This study expands the current knowledge of the biological effects and fate of NPLs in freshwater environment

Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote

This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1–5 mm mesh opening range. An average plastic density of 36.3 g/m2 was obtained with a large variability along the 90 m of the beach (from 8.5 g/m2 to 103.4 g/m2). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragment

Fibers spreading worldwide: Microplastics and other anthropogenic litter in an Arctic freshwater lake

We investigated the presence of microplastics and other anthropogenic litter in the sediments adhered to rocks of an Arctic freshwater lake at Ny-Ålesund (Svalbard Archipelago, 78°N; 11°E). Most of the sampled microparticles were fibers (>90%). The identification of polymer types and additives was performed by combining three spectroscopic techniques, namely Raman Microscopy, Fourier-Transform Infrared microspectroscopy (μFTIR) and Synchrotron Radiation μFTIR (SR-FTIR). SR-FTIR confirmed the presence of poly(ethylene terephthalate) fibers, while RAMAN spectroscopy provided evidence of fibers containing industrial additives. Our results estimated an average concentration of 400 microparticles/m2 of rocks identified as anthropogenic litter, which included an estimation of 90 microplastics/m2 identified as polyester fibers; the rest are mostly natural fibers with evidence of anthropogenic origin. Taken together, the results proved the occurrence of anthropogenic pollutants in remote polar areas. Their probable origin is the long range atmospheric transpor

Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote

This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1&#-5&amp;amp;amp;amp;amp;;8239#mm mesh opening range. An average plastic density of 36.3&#8239;g/m2 was obtained with a large variability along the 90&#8239;m of the beach (from 8.5&#8239;g/m2 to 103.4&#8239;g/m2). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragments