1,721,061 research outputs found
Automatic pre-screening of outdoor airborne microplastics in micrographs using deep learning
Get PDFAirborne microplastics (AMPs) are prevalent in both indoor and outdoor environments, posing potential health risks to humans. Automating the process of spotting them in micrographs can significantly enhance research and monitoring. Although deep learning has shown substantial promise in microplastic analysis, existing studies have primarily focused on high-resolution images of samples collected from marine and freshwater environments. In contrast, this work introduces a novel approach by employing enhanced U-Net models (Attention U-Net and Dynamic RU-NEXT) along with the Mask Region Convolutional Neural Network (Mask R-CNN) to identify and classify AMPs in lower-resolution micrographs (256 × 256 pixels) obtained from outdoor environments. A key innovation involves integrating classification directly within the U-Net-based segmentation frameworks, thereby streamlining the workflow and improving computational efficiency which is an advancement over previous work where segmentation and classification were performed separately. The enhanced U-Net models attained average classification F1-scores exceeding 85% and segmentation scores above 77%. Additionally, the Mask R-CNN model achieved an average bounding box precision of 73.32% on the test set, a classification F1-score of 84.29%, and a mask precision of 71.31%, demonstrating robust performance. The proposed method provides a faster and more accurate means of identifying AMPs compared to thresholding techniques. It also functions effectively as a pre-screening tool, substantially reducing the number of particles requiring labour-intensive chemical analysis. By integrating advanced deep learning strategies into AMPs research, this study paves the way for more efficient monitoring and characterisation of microplastics
Ionizing radiation-induced DNA damage response identified in marine mussels, Mytilus sp
No full textThere is growing concern over the potential detrimental impact of ionizing radiation on natural biota. The mechanistic cause-and-effect impact of ionizing radiation has yet to be characterized in any aquatic species. Adopting an integrated approach, including radiochemical analysis of environmental samples, we evaluate molecular responses to ionizing radiation in the marine mussel, Mytilus edulis. These responses included analyses of RAD51 mRNA expression, a gene involved in the repair of DNA double strand breaks, and induction of DNA strand breaks using the comet assay, in samples collected from a site impacted by low level ionizing radiation discharges. Based on activities of the radionuclides measured in sediment and mussel tissue at the discharge site, external and internal dose rates were low, at ca. 0.61 ?Gyh?1 and significantly lower than the generic (all species) “no effect” dose rate of 10 uGyh?1, yet DNA strand breakage and RAD51 mRNA expression were both altered
Exploring the Impact of Microplastics (Polyethylene terephthalate) in Lung cells
Get PDFIntroductionMicroplastics (MPs) are plastic particles smaller than 5 millimetres that arise either from intentional production or the breakdown of larger plastics. They have been detected across diverse environments, including air, water, and soil, and more recently in human tissues such as the lungs. While their health impacts are not yet fully understood, evidence suggests that some particles can evade clearance mechanisms in the respiratory tract and trigger inflammatory responses, particularly in vulnerable individuals. Laboratory studies often use polystyrene beads as models, though airborne pollution is more commonly composed of fibres such as polypropylene (PP) and polyethylene terephthalate (PET). The detection of MPs in biological fluids like blood and urine further raises concern about their potential to move within the body and accumulate in organs.Based on this, we hypothesize that:MPs at environmentally relevant levels and sizes cause inflammation in lung cells associated with lung diseases.MethodsThis study investigated the effects of MPs on lung-related cell models and tissue. MPs in suspension were first characterized spectroscopically and dyed to distinguish them from environmental contamination. Their impact was assessed on A549 epithelial cells and alveolar macrophages (Daisy cells), focusing on cell viability (LDH and MTT assays), barrier integrity (TEER), and oxidative and cytokine responses. Silicon dioxide (SiO2) served as a positive control due to its known toxicity, while cellulose fibres (200–300 μm) were used as a negative control.ResultsExposure to PET MPs induced distinct oxidative and immune responses in A549 epithelial cells and Daisy macrophages. In A549 cells, low concentrations (0.02 mg/ml) reduced ROS, while higher doses (1 mg/ml) triggered oxidative stress; TEER reduction at 0.1 mg/ml indicated impaired barrier integrity. Cytokine analysis showed suppression of IL-15, TARC, and I-309. Daisy cells showed similar ROS trends, with increases at 1 mg/ml, and cytokine profiling revealed broad suppression (IL-12p40/p70, IL-13, IL-1β, IFN-γ, TNF-β) but strong induction of GRO-α, suggesting selective pro-inflammatory signalling.ConclusionPET MPs seem to exert dose-dependent effects on oxidative stress, barrier integrity, and cytokine signalling, with higher concentrations promoting cellular stress and immune disruption. Given their persistence and ubiquity, PET MPs pose risks to human health and ecosystems, underscoring the need for coordinated strategies to reduce plastic pollution
Atmospheric microplastics and the human lungs
Get PDFMicroplastics (MPs) are an emerging environmental contaminant (EEC), that have recently been isolated from samples collected from the atmosphere, and are considered ubiquitous on Earth. There is a lack of knowledge regarding the properties of atmospheric MPs (AMPs), in terms of location, concentrations, plastic types, sizes and shapes. There is also limited understanding of the potential for these MPs to be inhaled, and the consequences of such exposure. Standardised approaches throughout the AMP field are called for, because incomparable datasets and varying microplastic (MP) definitions are slowing down the progression of research. It is now necessary to thoroughly investigate AMPs, and gain knowledge of the location and MP types relevant to human exposure, as well as assessing MP inhalation as an exposure route for humans. This information can direct future investigations into the potential hazards associated with AMP inhalation.This thesis presents 3 publications, within this publication style thesis; investigating indoor AMPs, outdoor AMPs and a final investigation into the presence of MPs within human lung tissue samples, acquired from living patients.First, passive sampling of 20 households over a 6-month discontinuous duration, reported an average concentration of 1414 MP m− 2 day− 1 ± 1022 (mean ± SD). This high abundance of MPs within household environments supports the importance of indoor MP sampling locations. Fibrous and fragmented Polyethylene terephthalate (PET), Polypropylene (PP) and Nylon were also stated as relevant to human exposure, at head height.Secondly, passive sampling within a busy outdoor urban roadside location reported concentrations of MPs; 3055 ± 5072 MP m−2 day−1 (mean ± SD, 1164 median), over a yearlong investigation. Specific outdoor areas of high human activity were suggested to rival that of indoor concentrations. An additional snap-shot 2-week investigation, passively sampling 5 different areas of varying human activity, was also conducted. Roadside, commercial and industrial locations were reported with high concentration rates and relevance to human exposure. An abundance of film and fragmented particles, of Polyethylene (PE), Nylon and Resin composition, suggested these properties to be most relevant to human health studies.Finally, digested human lung tissue analysis provided evidence to support the human inhalation of MPs. 39 MPs were identified within 13 lung tissue samples, acquired from 11 living human patients. PP was reported within samples, after strict limit of detection and limit of quantification (LOD LOQ) adjustments were applied. PP, PET and Resin synthetic plastic types, and fibre and fragment shape categories were identified and suggested to be of relevance to human inhalation. The size of most MPs identified within lung tissue samples were larger than that thought possible to inhale, whilst some were smaller and traditionally more inhalable.These publications bridge environmental MP research and human MP health studies, providing much needed knowledge regarding the concentration and types of AMPs that humans are most likely exposed to on a daily basis, as well as supporting the potential for exposure to AMPs via inhalation. Uniquely, at the forefront of all publications, was the aim to provide novel, high quality methodologies, combatting methodological restrictions, and focusing considerably on improving the quality of research concerning AMPs and human exposure, with great emphasis on quality control. These chapters, alongside other AMP research, can form the foundations for future research improvements, leading to eventual standardised operating procedures (SOPs), policy formation, and to achieve guided, accurate and environmentally relevant MP exposure investigations
Atmospheric microplastics and the human lungs
No full textMicroplastics (MPs) are an emerging environmental contaminant (EEC), that have recently been isolated from samples collected from the atmosphere, and are considered ubiquitous on Earth. There is a lack of knowledge regarding the properties of atmospheric MPs (AMPs), in terms of location, concentrations, plastic types, sizes and shapes. There is also limited understanding of the potential for these MPs to be inhaled, and the consequences of such exposure. Standardised approaches throughout the AMP field are called for, because incomparable datasets and varying microplastic (MP) definitions are slowing down the progression of research. It is now necessary to thoroughly investigate AMPs, and gain knowledge of the location and MP types relevant to human exposure, as well as assessing MP inhalation as an exposure route for humans. This information can direct future investigations into the potential hazards associated with AMP inhalation.This thesis presents 3 publications, within this publication style thesis; investigating indoor AMPs, outdoor AMPs and a final investigation into the presence of MPs within human lung tissue samples, acquired from living patients.First, passive sampling of 20 households over a 6-month discontinuous duration, reported an average concentration of 1414 MP m− 2 day− 1 ± 1022 (mean ± SD). This high abundance of MPs within household environments supports the importance of indoor MP sampling locations. Fibrous and fragmented Polyethylene terephthalate (PET), Polypropylene (PP) and Nylon were also stated as relevant to human exposure, at head height.Secondly, passive sampling within a busy outdoor urban roadside location reported concentrations of MPs; 3055 ± 5072 MP m−2 day−1 (mean ± SD, 1164 median), over a yearlong investigation. Specific outdoor areas of high human activity were suggested to rival that of indoor concentrations. An additional snap-shot 2-week investigation, passively sampling 5 different areas of varying human activity, was also conducted. Roadside, commercial and industrial locations were reported with high concentration rates and relevance to human exposure. An abundance of film and fragmented particles, of Polyethylene (PE), Nylon and Resin composition, suggested these properties to be most relevant to human health studies.Finally, digested human lung tissue analysis provided evidence to support the human inhalation of MPs. 39 MPs were identified within 13 lung tissue samples, acquired from 11 living human patients. PP was reported within samples, after strict limit of detection and limit of quantification (LOD LOQ) adjustments were applied. PP, PET and Resin synthetic plastic types, and fibre and fragment shape categories were identified and suggested to be of relevance to human inhalation. The size of most MPs identified within lung tissue samples were larger than that thought possible to inhale, whilst some were smaller and traditionally more inhalable.These publications bridge environmental MP research and human MP health studies, providing much needed knowledge regarding the concentration and types of AMPs that humans are most likely exposed to on a daily basis, as well as supporting the potential for exposure to AMPs via inhalation. Uniquely, at the forefront of all publications, was the aim to provide novel, high quality methodologies, combatting methodological restrictions, and focusing considerably on improving the quality of research concerning AMPs and human exposure, with great emphasis on quality control. These chapters, alongside other AMP research, can form the foundations for future research improvements, leading to eventual standardised operating procedures (SOPs), policy formation, and to achieve guided, accurate and environmentally relevant MP exposure investigations
Exploring the Impact of Microplastics (Polyethylene terephthalate) in Lung cells
No full textIntroductionMicroplastics (MPs) are plastic particles smaller than 5 millimetres that arise either from intentional production or the breakdown of larger plastics. They have been detected across diverse environments, including air, water, and soil, and more recently in human tissues such as the lungs. While their health impacts are not yet fully understood, evidence suggests that some particles can evade clearance mechanisms in the respiratory tract and trigger inflammatory responses, particularly in vulnerable individuals. Laboratory studies often use polystyrene beads as models, though airborne pollution is more commonly composed of fibres such as polypropylene (PP) and polyethylene terephthalate (PET). The detection of MPs in biological fluids like blood and urine further raises concern about their potential to move within the body and accumulate in organs.Based on this, we hypothesize that:MPs at environmentally relevant levels and sizes cause inflammation in lung cells associated with lung diseases.MethodsThis study investigated the effects of MPs on lung-related cell models and tissue. MPs in suspension were first characterized spectroscopically and dyed to distinguish them from environmental contamination. Their impact was assessed on A549 epithelial cells and alveolar macrophages (Daisy cells), focusing on cell viability (LDH and MTT assays), barrier integrity (TEER), and oxidative and cytokine responses. Silicon dioxide (SiO2) served as a positive control due to its known toxicity, while cellulose fibres (200–300 μm) were used as a negative control.ResultsExposure to PET MPs induced distinct oxidative and immune responses in A549 epithelial cells and Daisy macrophages. In A549 cells, low concentrations (0.02 mg/ml) reduced ROS, while higher doses (1 mg/ml) triggered oxidative stress; TEER reduction at 0.1 mg/ml indicated impaired barrier integrity. Cytokine analysis showed suppression of IL-15, TARC, and I-309. Daisy cells showed similar ROS trends, with increases at 1 mg/ml, and cytokine profiling revealed broad suppression (IL-12p40/p70, IL-13, IL-1β, IFN-γ, TNF-β) but strong induction of GRO-α, suggesting selective pro-inflammatory signalling.ConclusionPET MPs seem to exert dose-dependent effects on oxidative stress, barrier integrity, and cytokine signalling, with higher concentrations promoting cellular stress and immune disruption. Given their persistence and ubiquity, PET MPs pose risks to human health and ecosystems, underscoring the need for coordinated strategies to reduce plastic pollution
Emerging environmental contaminants and human health : risk assessment of dietary exposure to microplastics
Get PDFMicroplastics (MPs) are an emerging contaminant ubiquitous in the environment. There is growing concern regarding potential human health effects. A major human exposure route is hypothesised to be the dietary pathway via ingestion of contaminated food. A risk assessment perspective was employed, which is the standard approach for human health protection regarding food safety. It is comprised of the four interconnected evidence-based steps of hazard identification, hazard characterization, exposure assessment and risk characterization. Existing scientific data were collected via the execution of scoping, systematic and rapid reviews, using state of the art, robust methodology. Quantitative meta- analysis and meta-regression analyses were also employed. Two bespoke novel risk-of-bias tools were developed and implemented in the execution of the reviews for the standardized quality appraisal of the studies.Seventy-two studies were included in the systematic reviews on food contamination from three categories. The majority of the samples were contaminated in varying levels: 0-4889 MPs/L in drinking water, 0–10.5 MPs/g in seafood and 0–1674 MPs/kg in salt, thus establishing the dietary ingestion route for MP human exposures. According to the exposure assessment modelling, the estimated levels for MP dietary aggregate exposures could be as high as 3.6 million MPs per year.Seventeen studies were included in a rapid review focusing on human cell in vitro MP toxicological effects. Four biological endpoints displayed MP-associated effects: cytotoxicity, immune response, oxidative stress and barrier attributes. Irregular shape was found to be the only MP characteristic predicting cell death, along with the duration of exposure and MP concentration (μg/mL). Minimum concentrations of 10 μg/mL (5– 200 μm), had an adverse effect on cell viability, and 20 μg/mL (0.4 μm) on cytokine release, effectively constituting thresholds of adverse effects. The preliminary comparison of the levels of the thresholds and the exposures reveals that human health could be at risk due to MP dietary exposures.Further high-quality research using standardized methods is needed to cement the scientific evidence on MP contamination and human exposures. On the other hand, serious data gaps exist regarding toxicodynamics and toxicokinetics which are necessary for a complete toxicological profile
Emerging environmental contaminants and human health : risk assessment of dietary exposure to microplastics
Get PDFMicroplastics (MPs) are an emerging contaminant ubiquitous in the environment. There is growing concern regarding potential human health effects. A major human exposure route is hypothesised to be the dietary pathway via ingestion of contaminated food. A risk assessment perspective was employed, which is the standard approach for human health protection regarding food safety. It is comprised of the four interconnected evidence-based steps of hazard identification, hazard characterization, exposure assessment and risk characterization. Existing scientific data were collected via the execution of scoping, systematic and rapid reviews, using state of the art, robust methodology. Quantitative meta- analysis and meta-regression analyses were also employed. Two bespoke novel risk-of-bias tools were developed and implemented in the execution of the reviews for the standardized quality appraisal of the studies.Seventy-two studies were included in the systematic reviews on food contamination from three categories. The majority of the samples were contaminated in varying levels: 0-4889 MPs/L in drinking water, 0–10.5 MPs/g in seafood and 0–1674 MPs/kg in salt, thus establishing the dietary ingestion route for MP human exposures. According to the exposure assessment modelling, the estimated levels for MP dietary aggregate exposures could be as high as 3.6 million MPs per year.Seventeen studies were included in a rapid review focusing on human cell in vitro MP toxicological effects. Four biological endpoints displayed MP-associated effects: cytotoxicity, immune response, oxidative stress and barrier attributes. Irregular shape was found to be the only MP characteristic predicting cell death, along with the duration of exposure and MP concentration (μg/mL). Minimum concentrations of 10 μg/mL (5– 200 μm), had an adverse effect on cell viability, and 20 μg/mL (0.4 μm) on cytokine release, effectively constituting thresholds of adverse effects. The preliminary comparison of the levels of the thresholds and the exposures reveals that human health could be at risk due to MP dietary exposures.Further high-quality research using standardized methods is needed to cement the scientific evidence on MP contamination and human exposures. On the other hand, serious data gaps exist regarding toxicodynamics and toxicokinetics which are necessary for a complete toxicological profile
An investigation of the uptake of estradiol in the bivalve Mytilus spp. corresponding biological implications and the effect of the addition of Sporopollenin on bioavailability
Get PDFThere has been concern over the past two decades over estrogenic hormones such as 17 α-ethinylestradiol and 17 β-estradiol (E2) in fresh water and marine ecosystems and the risk to aquatic organisms even with low exposure levels. This study is to access whether there is any bioaccumulation in mantle tissue of Mytilus edulis exposed to a known concentration of E2 in a controlled experiment and whether the introduction of sporopollenin, exposed to the same concentration of E2, has a similar effect with bioaccumulation in regard to the use of sporopollenin exine capsules (SECs) as a sequestering agent to remove estrogens from water systems.This study involved an experiment using M. edulis exposed over a week with a regular dose of 200 ng/L E2, SECs treated with the 200 ng/L of E2 and with untreated SECs and untreated Mytilus as controls. At the end of the experiment, tissue was preserved for histology purposes to ascertain the sex and stage of gametogenesis and to detect any presence of SECs. Portions of the mantle and digestive tract and gills were frozen for chemical analysis to ascertain if either free or conjugated E2 had been bioaccumulated. A portion of the mantle was frozen in RNAlater™ for qPCR determination of mRNA ER expression in either of the exposure groups. In parallel, analytical chemistry and extraction methods were optimised to determine the levels of E2 in tissues.Histological preparations of gonad tissue from all Mytilus indicated the presence of SECs in the gonad tissues of the Mytilus exposed to SECs only. The water filtrates from the tanks of those animals also indicated the presence of SECs in the water throughout the exposure experiment. Chemical analysis of the water indicated that E2 dissolved in the water was present. The Mytilus in the exposure experiment were in the mid to late development stage of gametogenesis. The results of mRNA ER 2 gene expression indicated no significant difference in ER gene expression in the E2 exposed Mytilus compared to the controls but there was a significant difference in ER gene expression compared to mussels that were exposed to SECs and SECs plus E2. There was no statistical significance in the ER gene expression between the SECs and E2 treated SECs. The chemical analysis of the gonad tissue from the exposure experiment was not undertaken due to time constraints but free E2 was extracted from gonad tissue and from the E2 treated SECs, in a similar experiment. As there is such a notable difference in fold change between both of the SECs treatments and the control, there is an unknown biological influence on the mRNA ER gene expression.In terms of wider implications of this work, the data shows that the SECs are very efficient at adsorbing or absorbing E2 and this property could be applied as a method to remove E2 from WWTPs. But it is not known if the SECs could be applied for this purpose until there is sufficient evidence of bioavailability
Sporopollenin : applications in water purification
Get PDFWater pollution from emerging contaminants is increasingly in the spotlight, as research on the impacts on the environment is revealing more about the dangers to both animals in the aquatic environment and human health. Pharmaceuticals, personal care products, surfactants and pesticides have been proven to have endocrine-disrupting properties, affecting not only the aquatic life but human life as well. Conventional wastewater treatment plants need to updated in order to deal with this family of chemicals, since they are currently incapable of removing them using traditional methods. New methods need to be developed since the current ones leave behind around 60 - 90% of the initial contaminant concentration and re-introduce it to the water cycle. Adsorption procedures have been proven to be very effective on water treatment, targeting emerging contaminants, with research focusing on developing new materials, that apart from being effective should also be environmentally friendly.Sporopollenin is the name of a bio-polymer found in nature, constructing the outer shell (exine) of the capsule of a pollen grain or spore. The capsule itself - sporopollenin exine capsule (SpEC) - evolved to protect the genetic material contained in each grain/spore, hence sporopollenin has been proven to be chemically stable and very resistant to harsh environmental conditions. SpECs can be extracted from pollen grains or spores producing empty capsules (devoid of their genetic material), presenting a variety of differently sized microcapsules and shapes depending on the plant species. These capsules are monodispersed, presenting great mechanical strength as well as permeability. The material has a high surface area due to the porous nature with many multi-directional channels leading to the core of the capsule, giving them features and properties that are ideal for contaminant adsorption.The focus of this thesis was the investigation of SpECs deriving from Lycopodium clavatum by multiple extraction methodologies for applications on emerging contaminant adsorption. Different extraction procedures were developed, as well as surface modification protocols, in order to optimise the material for the different pollutants. The resulting SpECs were tested against four different contaminants; diclofenac, triclosan, oestradiol and phosphates, under different experimental settings, either lab based or closer to real world conditions. The results revealed that SpECs offer a very promising natural material, presenting high efficiency against the tested contaminants, with low-cost production, offering an environmentally friendly approach to the problem of water purification.For diclofenac, the most efficient SpECs type was SpECs(3)AM, with a maximum adsorption capacity value of 27.4 mg/g under a packed-bed setup. For triclosan, SpECs(3) was the most efficient type, presenting a maximum adsorption capacity of 37 mg/g under packed-bed setup or a KF value of 35.14 mg(1−1/n)/gL−1/n for adsorption from a solution. For oestradiol adsorption, SpECs(1) worked the best, presenting a maximum adsorption capacity of 42.5 mg/g. For phosphates, all tested SpECs presented similar adsorption capacities, with the water/Fe loaded SpECs(3) presenting the highest, 2.1 mg/g.SpECs presented adsorption capacity values far beyond what would be required for treating hospital effluent or surface waters and very good adsorption rates, especially for diclofenac and triclosan. Although the oestradiol experiments resulted in excellent maximum adsorption capacity, the rate of adsorption was below what would be required for treating large bodies of flowing water. However all other materials exhibited very promising rates of adsorption, particularly SpECs(3)AM for diclofenac and SpECs(3) for triclosan, warranting scale-up experiments for the treatment of such volumes as hospital effluents (55 - 530 L/min).SpECs(3) and their aminated form, SpECs(3)AM were proven to be the best candidates for contaminant adsorption, with SpECs(3) ticking all the boxes for a successful adsorbent; apart from their excellent adsorption behaviour, their production is fast and low-cost, they are environmentally friendly since they derive from plant spores, the chemicals used are not harsh to the environment nor were high temperature treatments or long reaction times required and they also presented good reusability
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