27 results found
Jones LR, Wright SJ, Gant TW, 2023, A critical review of microplastics toxicity and potential adverse outcome pathway in human gastrointestinal tract following oral exposure., Toxicol Lett, Vol: 385, Pages: 51-60
Microplastics (MPs) are typically produced via environmental degradation of larger plastics, where they enter the human food chain. MPs are complex materials containing chemical and physical characteristics that can potentially affect their hazard and exposure. These physical properties can be altered by environmental exposure potentially altering any risk assessment conducted on the primary material. We conducted a literature review using an Adverse Outcome Pathway (AOP)-based approach from Molecular Initiating Event (MIE) to cell effect event to identify multiple knowledge gaps that affect MPs hazard assessment. There is some convergence of key biological events but could relate to most lying along well-established biological effector pathways such as apoptosis which can respond to many MIEs. In contrast, MIEs of chemicals will be via protein interaction. As MPs may occur in the lumen of the alimentary canal for example to the mucus, therefore, not requiring translocation of MPs across the epithelial membrane. At the other end of the AOP, currently it is not possible to identify a single adverse outcome at the organ level. This work did establish a clear need to understand both external and internal exposure (resulting from translocation) and develop hazard data at both levels to inform on risk assessments.
O'Brien S, Rauert C, Ribeiro F, et al., 2023, There's something in the air: A review of sources, prevalence and behaviour of microplastics in the atmosphere., Sci Total Environ, Vol: 874
Literature regarding microplastics in the atmosphere has advanced in recent years. However, studies have been undertaken in isolation with minimal collaboration and exploration of the relationships between air, deposition and dust. This review collates concentrations (particle count and mass-based), shape, size and polymetric characteristics for microplastics in ambient air (m3), deposition (m2/day), dust (microplastics/g) and snow (microplastics/L) from 124 peer-reviewed articles to provide a holistic overview and analysis of our current knowledge. In summary, ambient air featured concentrations between <1 to >1000 microplastics/m3 (outdoor) and <1 microplastic/m3 to 1583 ± 1181 (mean) microplastics/m3 (indoor), consisting of polyethylene terephthalate, polyethylene, polypropylene. No difference (p > 0.05) was observed between indoor and outdoor concentrations or the minimum size of microplastics (p > 0.5). Maximum microplastic sizes were larger indoors (p < 0.05). Deposition concentrations ranged between 0.5 and 1357 microplastics/m2/day (outdoor) and 475 to 19,600 microplastics/m2/day (indoor), including polyethylene, polystyrene, polypropylene, polyethylene terephthalate. Concentrations varied between indoor and outdoor deposition (p < 0.05), being more abundant indoors, potentially closer to sources/sinks. No difference was observed between the minimum or maximum reported microplastic sizes within indoor and outdoor deposition (p > 0.05). Road dust concentrations varied between 2 ± 2 and 477 microplastics/g (mean), consisting of polyvinyl chloride, polyethylene, polypropylene. Mean outdoor dust concentrations ranged from <1 microplastic/g (remote desert) to between 18 and 225 microplastics/g, comprised of polyethylene terephthalate, polyamide, polypropylene. Snow concentrations varied between 0.1 and 30,000 microplastics/L, containing polyethylene, pol
Tan Z, Berry A, Charalambides M, et al., 2023, Tyre wear particles are toxic for us and the environment
This briefing paper discusses the current knowledge on the effects of tyre wear particles on our health and environment, highlights the need for an ambitious research agenda to build further understanding of the impacts on people and nature and develop solutions, and includes recommendations for policymakers.
Napper IE, Parker-Jurd FNF, Wright SL, et al., 2023, Examining the release of synthetic microfibres to the environment via two major pathways: Atmospheric deposition and treated wastewater effluent., Sci Total Environ, Vol: 857
Research on the discharge of synthetic microfibres to aquatic environments has typically focused on laundering, where fibres can be discharged via wastewater effluent. However emerging research suggests that microfibres generated during the wear of textiles in normal use could present a major, additional, pathway for microfibre pollution to the environment. This study aimed to quantify and compare the quantities of microfibre entering the marine environment via both these pathways; wastewater discharge and atmospheric deposition. Areas of high and low population density were also evaluated. Samples were collected in and around two British cities (Bristol and Plymouth) both of which are located on tidal waters. Fibres originating from the atmosphere were deposited at an average rate of 81.6 fibres m2 d-1 across urban and rural areas. Treated wastewater effluent contained on an average 0.03 synthetic fibres L-1. Based on our results we predict ~20,000-500,000 microfibres could be discharged per day from the Wastewater Treatment Plants studied. When the two pathways were compared. Atmospheric deposition of synthetic microfibres appeared the dominant pathway, releasing fibres at a rate several orders of magnitude greater than via treated wastewater effluent. Potential options to reduce the release of microfibres to the environment are discussed and we conclude that intervention at the textile design stage presents the most effective approach. In order to guide policy intervention to inform the Plastics Treaty UNEA 5.2, future work should focus on understanding which permutations of textile design have the greatest influence fibre shedding, during both everyday use and laundering.
Tiernan H, Friedman S, Clube RKM, et al., 2022, Implementation of a structured decision-making framework to evaluate and advance understanding of airborne microplastics, Environmental Science and Policy, Vol: 135, Pages: 169-181, ISSN: 1462-9011
Microplastic pollution is increasingly recognised as a global environmental challenge which stems from the rapid growth of the use of petrochemical-derived plastic. As researchers and practitioners face a myriad of environmental challenges, oceanic microplastic pollution has so far dominated interest. However, airborne microplastics present an increasing environmental and public health concern. There is currently a need for research addressing this emerging challenge, and at the same time, the lack of knowledge and consensus regarding airborne microplastics presents an obstacle to action. The purpose of this study is to utilise a participatory Structured Decision-Making (SDM) approach to understand the perspectives of a range of stakeholders involved in the microplastics landscape, and subsequently refine common research priorities and knowledge gaps to advance the field. Through two participatory workshops, we first defined shared objectives of stakeholders and then negotiated best courses of action to achieve these objectives based on discussion between stakeholders and facilitators. The qualitative approach taken has enabled the full, complex and multidisciplinary aspects of the research into airborne microplastic pollution to be considered. Our findings highlight some important potential consequences of airborne microplastic pollution, including impacts on human health, and the need for more interdisciplinary research, and collaborative, integrated approaches in this area. As a result of the first workshop, five fundamental objectives on the theme of airborne microplastics were identified. As a direct consequence of this, participants identified 84 actions split across eight themes, which are outlined later in this paper.
Wright S, Borm PJA, 2022, Applying Existing Particle Paradigms to Inhaled Microplastic Particles, FRONTIERS IN PUBLIC HEALTH, Vol: 10
Allen D, Allen S, Abbasi S, et al., 2022, Microplastics and nanoplastics in the marine-atmosphere environment, NATURE REVIEWS EARTH & ENVIRONMENT, Vol: 3, Pages: 393-405
Gouin T, Ellis-Hutchings R, Thornton Hampton LM, et al., 2022, Screening and prioritization of nano- and microplastic particle toxicity studies for evaluating human health risks - development and application of a toxicity study assessment tool., Microplast nanoplast, Vol: 2
UNLABELLED: Concern regarding the human health implications that exposure to nano- and microplastic particles (NMPs) potentially represents is increasing. While there have been several years of research reporting on the ecotoxicological effects of NMPs, human health toxicology studies have only recently emerged. The available human health hazard data are thus limited, with potential concern regarding the relevance and reliability for understanding the potential human health implications. In this study we develop and apply a NMP toxicity screening assessment tool (NMP-TSAT) for evaluating human health effects studies against a suite of quality assurance and quality control (QA/QC) criteria for both in vivo and in vitro studies. A total of 74 studies representing either inhalation or oral exposure pathways were identified and evaluated. Assessment categories include particle characterization, experimental design, and applicability for risk assessment; with critical and non-critical criteria organized to allow screening and prioritization. It is observed that the majority of studies evaluated using the NMP-TSAT have been performed on monodisperse particles, predominately spheres (≈60%), consisting of polystyrene (≈46%). The majority of studies have tested particles < 5 μm, with a minimal particle size of 10 nm and a maximum particle size of about 200 μm. The total assessment score (TAS) possible for in vivo studies is 52, whereas for in vitro studies it is 46, which is based on receiving a maximum score of 2 against 26 and 23 criteria, respectively. The evaluated TAS ranged from between 12 and 44 and 16-34, for in vivo and in vitro studies, respectively. Given the challenges associated with prioritizing studies based on ranking them according to their TAS we propose a Tiered approach, whereby studies are initially screened based on how they score against various critical criteria, which have been defined for their releva
Coffin S, Bouwmeester H, Brander S, et al., 2022, Development and application of a health-based framework for informing regulatory action in relation to exposure of microplastic particles in California drinking water., Microplast nanoplast, Vol: 2
UNLABELLED: Microplastics have been documented in drinking water, but their effects on human health from ingestion, or the concentrations at which those effects begin to manifest, are not established. Here, we report on the outcome of a virtual expert workshop conducted between October 2020 and October 2021 in which a comprehensive review of mammalian hazard studies was conducted. A key objective of this assessment was to evaluate the feasibility and confidence in deriving a human health-based threshold value to inform development of the State of California's monitoring and management strategy for microplastics in drinking water. A tiered approach was adopted to evaluate the quality and reliability of studies identified from a review of the peer-reviewed scientific literature. A total of 41 in vitro and 31 in vivo studies using mammals were identified and subjected to a Tier 1 screening and prioritization exercise, which was based on an evaluation of how each of the studies addressed various quality criteria. Prioritized studies were identified largely based on their application and reporting of dose-response relationships. Given that methods for extrapolating between in vitro and in vivo systems are currently lacking, only oral exposure in vivo studies were identified as fit-for-purpose within the context of this workshop. Twelve mammalian toxicity studies were prioritized and subjected to a Tier 2 qualitative evaluation by external experts. Of the 12 studies, 7 report adverse effects on male and female reproductive systems, while 5 reported effects on various other physiological endpoints. It is notable that the majority of studies (83%) subjected to Tier 2 evaluation report results from exposure to a single polymer type (polystyrene spheres), representing a size range of 0.040 to 20 µm. No single study met all desired quality criteria, but collectively toxicological effects with respect to biomarkers of inflammation and oxidative stress represented a c
Turroni S, Wright S, Rampelli S, et al., 2021, Microplastics shape the ecology of the human gastrointestinal intestinal tract, Current Opinion in Toxicology, Vol: 28, Pages: 32-37, ISSN: 2468-2020
Microplastic particles are global pollutants which have been measured in drinking water, dust, and some food items. Concerns about population exposures and the resulting risks to human health are increasing. Because the gut can be considered one of the primary sites for microplastic exposure in the human body, here, we explore the possible impact of ingested microplastic particles on gastrointestinal ecology, providing some evidence for their active role as a driver of dysbiotic variation in the human gut microbiome. This further stresses the urgent need to quantitatively assess both oral exposure and hazards of microplastic in the human gut, enabling prediction of the levels of microplastic risk and outcomes of dysbiotic changes in the gut microbiome to be inferred.
Bank MS, Swarzenski PW, Duarte CM, et al., 2021, Global Plastic Pollution Observation System to Aid Policy, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 55, Pages: 7770-7775, ISSN: 0013-936X
O'Brien S, Okoffo ED, O'Brien JW, et al., 2020, Airborne emissions of microplastic fibres from domestic laundry dryers, Science of The Total Environment, Vol: 747, Pages: 1-6, ISSN: 0048-9697
An emission source of microplastics into the environment is laundering synthetic textiles and clothing. Mechanical drying as a pathway for emitting microplastics, however, is poorly understood. In this study, emissions of microplastic fibres were sampled from a domestic vented dryer to assess whether mechanical drying of synthetic textiles releases microplastic fibres into the surrounding air or are captured by the inbuilt filtration system. A blue polyester fleece blanket was repeatedly washed and dried using the ‘Normal Dry’ program of a common domestic dryer operated at temperatures between 56 and 59 °C for 20 min. Microfibres in the ambient air and during operation of the dryer were sampled and analysed using microscopy for particle quantification and characterisation followed by Fourier-Transform Infrared Spectroscopy (FTIR) and Pyrolysis Gas Chromatography-Mass Spectrometry (Pyr-GC/MS) for chemical characterisation. Blue fibres averaged 6.4 ± 9.2 fibres in the room blank (0.17 ± 0.27 fibres/m3), 8.8 ± 8.5 fibres (0.05 ± 0.05 fibres/m3) in the procedural blank and 58 ± 60 (1.6 ± 1.8 fibres/m3) in the sample. This is the first study to measure airborne emissions of microplastic fibres from mechanical drying, confirming that it is an emission source of microplastic fibres into air – particularly indoor air.
Lindeque PK, Cole M, Coppock RL, et al., 2020, Are we underestimating microplastic abundance in the marine environment? A comparison of microplastic capture with nets of different mesh-size, Environmental Pollution, Vol: 265, ISSN: 0269-7491
Microplastic debris is ubiquitous and yet sampling, classifying and enumerating this prolific pollutant in marine waters has proven challenging. Typically, waterborne microplastic sampling is undertaken using nets with a 333 μm mesh, which cannot account for smaller debris. In this study, we provide an estimate of the extent to which microplastic concentrations are underestimated with traditional sampling. Our efforts focus on coastal waters, where microplastics are predicted to have the greatest influence on marine life, on both sides of the North Atlantic Ocean. Microplastic debris was collected via surface trawls using 100, 333 and 500 μm nets. Our findings show that sampling using nets with a 100 μm mesh resulted in the collection of 2.5-fold and 10-fold greater microplastic concentrations compared with using 333 and 500 μm meshes respectively (P < 0.01). Based on the relationship between microplastic concentrations identified and extrapolation of our data using a power law, we estimate that microplastic concentrations could exceed 3700 microplastics m-3 if a net with a 1 μm mesh size is used. We further identified that use of finer nets resulted in the collection of significantly thinner and shorter microplastic fibres (P < 0.05). These results elucidate that estimates of marine microplastic concentrations could currently be underestimated.
Levermore JM, Smith TEL, Kelly FJ, et al., 2020, Detection of microplastics in ambient particulate matter using Raman spectral imaging and chemometric analysis, Analytical Chemistry, Vol: 92, Pages: 8732-8740, ISSN: 0003-2700
Microplastics have been observed in indoor and outdoor air. This raises concern for human exposure, especially should they occur in small enough sizes, which if inhaled, reach the central airway and distal lung. As yet, methods for their detection have not spectroscopically verified the chemical composition of microplastics in this size-range. One proposed method is an automated spectroscopic technique, Raman spectral imaging; however, this generates large and complex data sets. This study aims to optimize Raman spectral imaging for the identification of microplastics (≥2 μm) in ambient particulate matter, using different chemometric techniques. We show that Raman spectral images analyzed using chemometric statistical approaches are appropriate for the identification of both virgin and environmental microplastics ≥2 μm in size. On the basis of the sensitivity, we recommend using the developed Pearson’s correlation and agglomerative hierarchical cluster analysis for the identification of microplastics in spectral data sets. Finally, we show their applicability by identifying airborne microplastics >4.7 μm in an outdoor particulate matter sample obtained at an urban sampling site in London, United Kingdom. This semiquantitative method will enable the procurement of exposure concentrations of airborne microplastics guiding future toxicological assessments.
Wright SL, Ulke J, Font A, et al., 2020, Atmospheric microplastic deposition in an urban environment and an evaluation of transport, Environment International, Vol: 136, Pages: 105411-105411, ISSN: 0160-4120
Kelly FJ, Levermore J, Wright S, 2020, Inhalable Microplastics: A New Cause for Concern?, Editors: Cocca, DiPace, Errico, Gentile, Montarsolo, Mossotti, Avella, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 101-105, ISBN: 978-3-030-45908-6
Meng Y, Kelly FJ, Wright SL, 2020, Advances and challenges of microplastic pollution in freshwater ecosystems, A UK perspective, Vol: 256, ISSN: 0269-7491
Microplastics have been increasingly documented in freshwater ecosystems in recent years, and growing concerns have been raised about their potential environmental health risks. To assess the current state of knowledge, with a focus on the UK, a literature review of existing freshwater microplastics studies was conducted. Sampling and analytical methodologies currently used to detect, characterise and quantify microplastics were assessed and microplastic types, sources, occurrence, transport and fate, and microplastic-biota interactions in the UK's freshwater environments were examined. Just 32% of published microplastics studies in the UK have focused on freshwater environments. These papers cover microplastic contamination of sediments, water and biota via a range of methods, rendering comparisons difficult. However, secondary microplastics are the most common type, and there are point (e.g. effluent) and diffuse (non-point, e.g. sludge) sources. Microplastic transport over a range of spatial scales and with different residence times will be influenced by particle characteristics, external forces (e.g. flow regimes), physical site characteristics (e.g. bottom topography), the degree of biofouling, and anthropogenic activity (e.g. dam release), however, there is a lack of data on this. It is predicted that impacts on biota will mirror that of the marine environment. There are many important gaps in current knowledge; field data on the transport of microplastics from diffuse sources are less available, especially in England. We provide recommendations for future research to further our understanding of microplastics in the environment and their impacts on freshwater biota in the UK.
Wright S, Mudway I, 2019, The ins and outs of microplastics, Annals of Internal Medicine, Vol: 171, Pages: 514-516, ISSN: 0003-4819
Wright SL, Levermore JM, Kelly FJ, 2019, Raman spectral imaging for the detection of inhalable microplastics in ambient particulate matter samples, Environmental science & technology, Vol: 53, Pages: 8947-8956, ISSN: 0013-936X
Microplastics are ubiquitous contaminants, with preliminary evidence indicating they are a novel component of air pollution. This presents a plausible inhalation exposure pathway, should microplastics occur in the inhalable size range; however, this remains an analytical challenge. Here, we develop a filter-based sampling method compatible with both air quality monitoring and Raman spectral imaging (RSI) for the detection of inhalable-sized microplastics. Clean and particulate matter (PM) contaminated filters of a range of compositions were screened. RSI was validated using a plastic microbead suspension (poly(methyl methacrylate) (5-27 μm), polyethylene (10-27 μm), and polystyrene (4 and 10 μm)). Filters were loaded with the suspension before being analyzed. RSI analysis was conducted using a univariate analysis, fitting unique plastic bands to the spectral data sets, where high spatial intensity indicated the presence of microplastics. Inhalable microplastics were not visibly detectable against quartz or spectroscopically detectable against polytetrafluoroethylene (PTFE)- and alumina-based filters. While microplastics were detectable against cellulose, the PM-contaminated filters (4 and 24 h) burned during analysis. The greatest intensities for microplastics were observed against the silver membrane filter, and inhalable microplastics were still detectable in a 24 h PM sample. These findings will facilitate the acquisition of inhalable microplastic concentrations, which are necessary for understanding microplastic exposure and, ultimately, what their potential role in PM-associated health effects might be.
Bussolaro D, Wright SL, Schnell S, et al., 2019, Co-exposure to polystyrene plastic beads and polycyclic aromatic hydrocarbon contaminants in fish gill (RTgill-W1) and intestinal (RTgutGC) epithelial cells derived from rainbow trout (Oncorhynchus mykiss), Environmental Pollution, Vol: 248, Pages: 706-714, ISSN: 0269-7491
Microscopic plastic (MP) particles are a ubiquitous contaminant in aquatic environments, which may bind hydrophobic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), altering their environmental fate and interactions with biota. Using rainbow trout gill (RTgill-W1) and intestinal (RTgutGC) epithelial cells we investigated the effects of polystyrene microbeads (PS-MBs; 220 nm) on the cyto- and genotoxicity of the environmental pollutants benzo[a]pyrene (BaP) and 3-nitrobenzanthrone (3-NBA) over 48 h (0, 0.1, 1 and 10 μM). The Alamar Blue bioassay, used to assess cytotoxicity, showed that both pollutants significantly decreased cell viability by 10-20% at 10 μM in both cell lines after 48 h whereas PS-MBs (5 or 50 μg mL-1) were non-toxic. Cytotoxicity in cells treated with PS-MBs together with BaP or 3-NBA were similar to those observed after exposure to BaP or 3-NBA alone. Using the formamidopyrimidine-DNA glycosylase (FPG)-modified comet assay 3-NBA, but not BaP, induced DNA damage in RTgutGC cells at 10 μM (∼10% tail DNA in the absence and ∼15% tail DNA in the presence of FPG versus ∼1% in controls), whereas PS-MBs alone showed no detrimental effects. Interestingly, comet formation was substantially increased (∼4-fold) when RTgutGC cells were exposed to PS-MBs (50 μg mL-1) and 10 μM 3-NBA compared to cells treated with 3-NBA alone. Further, using 32P-postlabelling we observed strong DNA adduct formation in 3-NBA-exposed RTgutGC cells (∼900 adducts/108 nucleotides). 3-NBA-derived DNA adduct formation was significantly decreased (∼20%) when RTgutGC cells were exposed to MB and 3-NBA compared to cells treated with 3-NBA alone. Our results show that PS-MBs impact on the genotoxicity of 3-NBA, causing a significant increase in DNA damage as measured by the comet assay in the intestinal cell line, providing proof of principle that MPs may alter the genotoxic potential of PAHs in fish cells.
The annual production of plastic textile fibers has increased by more than 6% per year, reaching 60 million metric tons, about 16% of world plastic production. The degradation of these fibers produces fibrous microplastics (MPs). Such MPs have been observed in atmospheric fallouts, as well as in indoor and outdoor environments. Some fibrous MPs may be inhaled. Most of them are likely to be subjected to mucociliary clearance; however, some may persist in the lung causing localized biological responses, including inflammation, especially in individuals with compromised clearance mechanisms. Associated contaminants such as Polycyclic Aromatic Hydrocarbons (PAHs) could desorb and lead to genotoxicity while the plastic itself and its additives (dyes, plasticizers) could lead to health effects including reproductive toxicity, carcinogenicity and mutagenicity.
Wright SL, Kelly FJ, 2017, Threat to human health from environmental plastics, BMJ: British Medical Journal, Vol: 358, Pages: 1-2, ISSN: 0959-535X
Wright SL, Kelly FJ, 2017, Plastic and Human Health, A Micro Issue?, Vol: 51, Pages: 6634-6647, ISSN: 0013-936X
Microplastics are a pollutant of environmental concern. Their presence in food destined for human consumption and in air samples has been reported. Thus, microplastic exposure via diet or inhalation could occur, the human health effects of which are unknown. The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research. Key literature up to September 2016 relating to accumulation, particle toxicity, and chemical and microbial contaminants was critically examined. Although microplastics and human health is an emerging field, complementary existing fields indicate potential particle, chemical and microbial hazards. If inhaled or ingested, microplastics may accumulate and exert localized particle toxicity by inducing or enhancing an immune response. Chemical toxicity could occur due to the localized leaching of component monomers, endogenous additives, and adsorbed environmental pollutants. Chronic exposure is anticipated to be of greater concern due to the accumulative effect that could occur. This is expected to be dose-dependent, and a robust evidence-base of exposure levels is currently lacking. Although there is potential for microplastics to impact human health, assessing current exposure levels and burdens is key. This information will guide future research into the potential mechanisms of toxicity and hence therein possible health effects.
Wright SL, Rowe D, Reid MJ, et al., 2015, Bioaccumulation and biological effects of cigarette litter in marine worms, Scientific Reports, Vol: 5, ISSN: 2045-2322
Marine debris is a global environmental issue. Smoked cigarette filters are the predominant coastal litter item; 4.5 trillion are littered annually, presenting a source of bioplastic microfibres (cellulose acetate) and harmful toxicants to marine environments. Despite the human health risks associated with smoking, little is known of the hazards cigarette filters present to marine life. Here we studied the impacts of smoked cigarette filter toxicants and microfibres on the polychaete worm Hediste diversicolor (ragworm), a widespread inhabitant of coastal sediments. Ragworms exposed to smoked cigarette filter toxicants in seawater at concentrations 60 fold lower than those reported for urban run-off exhibited significantly longer burrowing times, >30% weight loss and >2-fold increase in DNA damage compared to ragworms maintained in control conditions. In contrast, ragworms exposed to smoked cigarette filter microfibres in marine sediment showed no significant effects. Bioconcentration factors for nicotine were 500 fold higher from seawater than from sediment. Our results illustrate the vulnerability of organisms in the water column to smoking debris and associated toxicants and highlight the risks posed by smoked cigarette filter debris to aquatic life.
Wright SL, Rowe D, Thompson RC, et al., 2013, Microplastic ingestion decreases energy reserves in marine worms, Current biology : CB, Vol: 23, Pages: R1031-R1033, ISSN: 0960-9822
Wright SL, Thompson RC, Galloway TS, 2013, The physical impacts of microplastics on marine organisms, a review., Vol: 178, Pages: 483-492, ISSN: 0269-7491
Plastic debris at the micro-, and potentially also the nano-scale, are widespread in the environment. Microplastics have accumulated in oceans and sediments worldwide in recent years, with maximum concentrations reaching 100 000 particles m(3). Due to their small size, microplastics may be ingested by low trophic fauna, with uncertain consequences for the health of the organism. This review focuses on marine invertebrates and their susceptibility to the physical impacts of microplastic uptake. Some of the main points discussed are (1) an evaluation of the factors contributing to the bioavailability of microplastics including size and density; (2) an assessment of the relative susceptibility of different feeding guilds; (3) an overview of the factors most likely to influence the physical impacts of microplastics such as accumulation and translocation; and (4) the trophic transfer of microplastics. These findings are important in guiding future marine litter research and management strategies.
Wright S, Caldwell GS, Clare AS, 2012, Sperm activation in acorn barnacles by elevation of seawater pH, Invertebrate Reproduction & Development, Vol: 56, Pages: 79-85, ISSN: 0792-4259
The sperm of most barnacle species show negligible motility unless exposed to oviducal gland fluid; a secretion associated with oviposition. Artificial activation has previously been induced in Semibalanus balanoides by elevating seawater pH using an ammonia buffer. To date, the information pertaining to barnacle sperm biology is rather limited. This study has investigated the activation of vesicular sperm from three species of acorn barnacles in response to the elevation of seawater pH using alkaline buffers, either sodium hydroxide (NaOH) or ammonium (). Elevation of seawater pH was observed to increase activation success, particularly for Balanus amphitrite and Elminius modestus. In all cases, there was a high degree of variability in the data. A median value of 20% sperm activation (mean ± SE = 20.65 ± 4.86%) was determined for E. modestus at pH 9 (). The lowest activation success was observed in S. balanoides which displayed maximal median activation of 1.79% at pH 8.4 (NaOH) (mean ± SE = 1.93 ± 0.44%). Balanus amphitrite and E. modestus showed greatest activation in seawater buffered with . This is the first study to artificially activate E. modestus and B. amphitrite sperm.
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