Plastic pollution is one of the most pressing environmental and social issues of the 21st century. Recent work has highlighted the atmosphere's role in transporting microplastics to remote locations ...S. Allen et al.,
12, 339 (2019) and J. Brahney, M. Hallerud, E. Heim, M. Hahnenberger, S. Sukumaran,
368, 1257-1260 (2020). Here, we use in situ observations of microplastic deposition combined with an atmospheric transport model and optimal estimation techniques to test hypotheses of the most likely sources of atmospheric plastic. Results suggest that atmospheric microplastics in the western United States are primarily derived from secondary re-emission sources including roads (84%), the ocean (11%), and agricultural soil dust (5%). Using our best estimate of plastic sources and modeled transport pathways, most continents were net importers of plastics from the marine environment, underscoring the cumulative role of legacy pollution in the atmospheric burden of plastic. This effort uses high-resolution spatial and temporal deposition data along with several hypothesized emission sources to constrain atmospheric plastic. Akin to global biogeochemical cycles, plastics now spiral around the globe with distinct atmospheric, oceanic, cryospheric, and terrestrial residence times. Though advancements have been made in the manufacture of biodegradable polymers, our data suggest that extant nonbiodegradable polymers will continue to cycle through the earth's systems. Due to limited observations and understanding of the source processes, there remain large uncertainties in the transport, deposition, and source attribution of microplastics. Thus, we prioritize future research directions for understanding the plastic cycle.
This study investigates microplastic (MPs) dynamics of a recently established surface flow 2100 population equivalent polishing constructed wetland (CW) receiving 1.4 ML per day of secondary treated ...wastewater. MPs type, size ranges and concentrations were measured along the CW at a 2-months sampling campaign. The CW received an average of 5·106 MPs per day (6 MPs per liter), mostly 100–1000 μm-sized synthetic fibers followed by fragments in the same size range. 95 % of MPs were retained, resulting in 0.30 ± 0.09 MPs per liter in CW effluent. Most MPs (97 %) were trapped within the first 20 % of the CW which consisted of a settling pond and shallow vegetated treatment cells and provided an areal removal rate > 4000 MP m−2 d−1. Data and microscopic analysis indicate MPs erosion and fragmentation in the CW. Turbidity and suspended solids were no indicator for MP removal due to water fowl activity, algal growth, and preferential flow conditions. This is the first study on MP dynamics in an independently operating full scale free water surface CW incorporated into a municipal wastewater treatment scheme. Surface flow CWs can retain MPs effectively but accumulation in CW sediments and substrate needs to be considered when further utilized or recycled.
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•Microplastic dynamics of an 8000 m2 full-scale polishing wetland investigated•Different wetland units have different effectiveness for retaining microplastics.•Areal removal rate >4000 plastic particles m−2 d−1 reduced downstream export >95 %.•Surface flow constructed wetlands are capable of effective microplastic retention.•Turbidity or suspended solids are no reliable indicator of microplastics retention.
Microplastics (<5 mm) are ubiquitous in the marine environment, occurring in both sediments and surface waters worldwide. However, few studies have documented the presence of microplastics and tire ...wear particles in coastal rivers. A survey of microplastics and low-density tire wear particles (≥63 μm) in the sediment and surface water of the three major tributaries within the Charleston Harbor estuary was conducted. Intertidal sediment, subtidal sediment, and sea surface microlayer concentrations ranged from 0 to 652 microplastics/m2, 3–4,375 microplastics/kg wet weight, and 3–36 microplastics/L, respectively. Blue fibers and tire wear particles were the two most abundant microplastic types observed, constituting 26.2% and 17.1%, respectively, of total microplastics. Tire wear particles were primarily identified by morphology, and ATR-FTIR analysis was conducted for a small subset (n = 5) of larger particles (≥500 μm). The present study provides the first microplastic field assessment of low-density tire wear particles in estuarine tributaries.
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•Microplastics were widely distributed in the water and sediments of each river.•Blue fibers and tire wear particles were the two most abundant microplastic types.•Morphological and analytical evidence of tire wear particles in the environment
After over 20 years of research on microplastic (MP) pollution, there are important areas of study which are still at the inception. In particular, between 2020 and 2023 new findings on MP have ...emerged, which open new sub-categories of MP research. These research areas include sea surface MP ejection, direct and indirect MP influence on climate and hydrological cycle, small and nano-sized MP analysis and the relationship between MP size and abundance. Not reported or barely mentioned in previous reviews, these globally-relevant findings are here highlighted and discussed with aim to promote their further research that will potentially result in new evidence of detrimental effects of MP pollution on the biosphere.
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Microplastics (MPs) are characterized by small particle sizes (<5 mm) and are widely distributed in the soil environment. To date, little research has been conducted on investigating the effects of ...MPs on the soil microbial community, which plays a vital role in biogeochemical cycling. In the present study, we investigate the influence of two particle sizes of MPs on dissolved organic carbon (DOC) and its relative functional groups, fluxes of greenhouse gases (GHGs), and the bacterial and fungal communities in fertilized soil. The results showed that a 5% concentration of MPs had no significant effect on soil DOC, whereas the formation of aromatic functional groups was accelerated. In fertilized soil, the existence of MPs decreased the global warming potential (GWP) as a result of a reduction in N2O emissions during the first three days. A potential mechanism for this reduction in N2O emissions might be that MPs inhibited the phylum Chloroflexi, Rhodoplanes genera, and increased the abundance of Thermoleophilia on day 3. An increase in N2O emissions was observed on day 30, mainly due to the acceleration of the NO3− reduction and a decrease in the abundance of Gemmatimonadacea. The CH4 uptake was significantly correlated with Hyphomicrobiaceae on day 3 and Rhodomicrobium on day 30. In soil with MPs, Actinobacteria replaced Proteobacteria as the dominant phylum. Larger MPs increased the richness (Chao1) and abundance-based coverage estimators (ACE) and diversity (Shannon) of the bacterial community on day 3, whereas these decreased on day 30. The richness and diversity of the fungal community were also reduced on days 3 and 30. Smaller MPs increased the community richness and diversity of both bacterial and fungal communities in fertilized soil. Our findings suggest that MPs have selective effects on microbes and can potentially have a serious impact on terrestrial biogeochemical cycles.
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•Smaller particle size microplastics could accelerate the aromatic matters’ formation.•Microplastics in fertilized soil could reduce N2O emission.•Actinobacteria replaced Proteobacteria as the Dominant phylum in microplastics soil.•Microplastic size effect was shown on alpha diversity.•Microplastics influenced the co-occurrence network among different microorganisms.
Main findings: Microplastics decreased the global warming potential of soil. Particle size affected alpha diversity, and Actinobacteria replaced Proteobacteria as the dominant phylum in soil with microplastics.
The ubiquitous prevalence of microplastics pollution has raised concerns about microplastics' potential risks and impacts on the global environment. However, the potential human health risks and ...impacts of microplastics remain largely unexplored. By providing an overview regarding the interaction of microplastics and human health, this review extends current knowledge on the potential impacts of microplastics pollution on humans from an environmental health perspective. The paper firstly presents the characteristics of microplastics as well as the status of global microplastics pollution. As for human health, the potential hazards of microplastics are reflected by toxic chemical components, vectors of contaminants, and physical damage. Extensive microplastic pollution on ecosystems due to human activities leads to inevitable human exposure, which may occur by dietary, inhalation and/or skin contact. Accordingly, microplastics exposure is closely associated with human health. This study explores the potential interactions of microplastics with the biological organization at various levels, including chemical, cellular, tissue, organ, and system levels. The review concludes by highlighting five urgent perspectives and implications for future research on microplastics: 1) Developing a standard terminology and research methods; 2) Reinforcing microplastics pollution governance; 3) Exploring innovative strategies and technologies; 4) Engaging the public and change behaviour; and 5) Adopting a transdisciplinary approach.
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•Evidence about potential human health risks of microplastics exposure•Interactions of microplastics with environmental health on different levels•Address the complex environmental health issues of microplastics pollution•Five urgent perspectives and implications for future research on microplastics
Conspectus The vast amount of plastic waste emitted into the environment and the increasing concern of potential harm to wildlife has made microplastic and nanoplastic pollution a growing ...environmental concern. Plastic pollution has the potential to cause both physical and chemical harm to wildlife directly or via sorption, concentration, and transfer of other environmental contaminants to the wildlife that ingest plastic. Small particles of plastic pollution, termed microplastics (>100 nm and <5 mm) or nanoplastics (<100 nm), can form through fragmentation of larger pieces of plastic. These small particles are especially concerning because of their high specific surface area for sorption of contaminants as well as their potential to translocate in the bodies of organisms. These same small particles are challenging to separate and identify in environmental samples because their size makes handling and observation difficult. As a result, our understanding of the environmental prevalence of nanoplastics and microplastics is limited. Generally, the smaller the size of the plastic particle, the more difficult it is to separate from environmental samples. Currently employed passive density and size separation techniques to isolate plastics from environmental samples are not well suited to separate microplastics and nanoplastics. Passive flotation is hindered by the low buoyancy of small particles as well as the difficulty of handling small particles on the surface of flotation media. Here we suggest exploring alternative techniques borrowed from other fields of research to improve separation of the smallest plastic particles. These techniques include adapting active density separation (centrifugation) from cell biology and taking advantage of surface-interaction-based separations from analytical chemistry. Furthermore, plastic pollution is often challenging to quantify in complex matrices such as biological tissues and wastewater. Biological and wastewater samples are important matrices that represent key points in the fate and sources of plastic pollution, respectively. In both kinds of samples, protocols need to be optimized to increase throughput, reduce contamination potential, and avoid destruction of plastics during sample processing. To this end, we recommend adapting digestion protocols to match the expected composition of the nonplastic material as well as taking measures to reduce and account for contamination. Once separated, plastics in an environmental sample should ideally be characterized both visually and chemically. With existing techniques, microplastics and nanoplastics are difficult to characterize or even detect. Their low mass and small size provide limited signal for visual, vibrational spectroscopic, and mass spectrometric analyses. Each of these techniques involves trade-offs in throughput, spatial resolution, and sensitivity. To accurately identify and completely quantify microplastics and nanoplastics in environmental samples, multiple analytical techniques applied in tandem are likely to be required.
Plastic waste is continuously introduced not only into marine, but also freshwater environments, where it fragments into microplastics. Organisms may be affected by the particles themselves due to ...ingestion and indirectly via incorporated additives such as plasticizers, since these substances have the ability to leach out of the polymer matrix. Although it has been indicated that the likelihood of additives leaching out into the gut lumen of organisms exposed to microplastics is low, studies distinguishing between the effects of the synthetic polymer itself and incorporated additives of the same polymer are scarce. Since this is obligatory for risk assessment, we analyzed the chronic effects of flexible polyvinylchloride (PVC), a widely used polymer, containing the plasticizer diisononylphthalate (DiNP) on morphology and life history of the freshwater crustacean Daphnia magna and compared these effects with the effects of rigid PVC, lacking DiNP, as well as a glass bead control. After up to 31 days of exposure, rigid PVC and glass beads did not affect body length and relative tail spine length of D. magna, whereas flexible PVC led to an increased body length and a reduced number of offspring. None of the treatments increased the mortality significantly. We were able to show that 2.67μg/L DiNP leached out of the flexible PVC into the surrounding medium using GC-MS. Yet, we were not able to measure leachate inside the gut lumen of D. magna. The effects emerged towards the end of the experiment, due to the time dependent process of leaching. Therefore, the results highlight the relevance of long-term chronic exposure experiments, especially as leaching of additives takes time. Further, our study shows the importance to distinguish between microplastics containing leachable additives and the raw polymer in ecotoxicological testing.
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•Flexible polyvinylchloride particles, containing diisononylphthalate affected Daphnia.•Flexible polyvinylchloride particles affected life history and morphology.•Rigid polyvinylchloride particles without diisononylphthalate did not affect Daphnia.•We measured a leached diisononylphthalate concentration of 2.67 μg/L medium.•Importance of long term exposition, as effects were visible at the end of the test.
Our study shows the importance to differentiate between microplastics containing additives and the raw polymer, thus exact composition of plastics used in toxicological testing is vital for risk assessment.
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•Polystyrene microplastics (PS-MPs) cause pulmonary cytotoxicity by inducing ROS.•PS-MPs is associated with impaired pulmonary barrier by depleting ZO proteins.•PS-MPs inhalation ...increases the risk for chronic obstructive pulmonary disease.
Microplastics (MPs) have become a global environmental concern. Recent studies have shown that MPs, of which the predominant type is often polystyrene (PS; known as PS-MPs), can extend to and affect remote, sparsely inhabited areas via atmospheric transport. Although exposure to inhaled MPs may induce lung dysfunction, further experimental verification of the pulmonary toxic potential of MPs and the mechanism underlying the toxicity is needed. Here we used normal human lung epithelial BEAS-2B cells to clarify the association between pulmonary toxicity and PS-MPs. Results revealed that PS-MPs can cause cytotoxic and inflammatory effects in BEAS-2B cells by inducing reactive oxygen species formation. PS-MPs can decrease transepithelial electrical resistance by depleting zonula occludens proteins. Indeed, decreased α1-antitrypsin levels in BEAS-2B cells suggest that exposure to PS-MPs increases the risk for chronic obstructive pulmonary disease, and high concentrations of PS-MPs can induce these adverse responses. While low PS-MP levels can only disrupt the protective pulmonary barrier, they may also increase the risk for lung disease. Collectively, our findings indicate that PS-MP inhalation may influence human respiratory health.
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