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Chemphyschem : a European Journal of... Jan 2020Whilst the formation of plastic nanoparticles (nanoplastics) from plastic wastes has been unequivocally evidenced, little is known about the effects of these materials...
Whilst the formation of plastic nanoparticles (nanoplastics) from plastic wastes has been unequivocally evidenced, little is known about the effects of these materials on living organisms at the subcellular or molecular levels. In the present contribution we show through molecular dynamics simulations that polyethylene nanoparticles dissolve in the hydrophobic core of lipid bilayers into a network of disentangled, single polymeric chains. The thereby induced structural and dynamic changes in the bilayer alter vital functions of the cell membrane, which if lacking a mechanism to decompose the polymer chains may result in the death of the cell.
Topics: Cell Membrane; Hydrophobic and Hydrophilic Interactions; Lipid Bilayers; Molecular Dynamics Simulation; Nanoparticles; Polyethylene
PubMed: 31483076
DOI: 10.1002/cphc.201900481 -
Chemosphere Aug 2023The sorption and vector effect of microplastics on the transfer of pesticides and polycyclic aromatic hydrocarbons (PAHs), as well as its impact on agriculture remain...
The sorption and vector effect of microplastics on the transfer of pesticides and polycyclic aromatic hydrocarbons (PAHs), as well as its impact on agriculture remain largely unexplored. This comparative study is first to investigate the sorption behavior of different pesticides and PAHs at environmentally realistic concentrations by model microplastics and microplastics derived from polyethylene mulch films. Sorption was found to be up to 90% higher in the case of microplastics derived from mulch films as opposed to pure polyethylene microspheres. For microplastics from mulch films, the sorption percentages for pesticides in media containing CaCl were reported to be: pyridate (75.68% and 52.44%), fenazaquin (48.54% and 32.02%), pyridaben (45.04% and 56.70%), bifenthrin (74.27% and 25.88%), etofenprox (82.16% and 54.16%) and pyridalyl (97.00% and 29.74%) at 5 μg/L and 200 μg/L pesticide concentration levels respectively. For PAHs, the sorption amounts were: naphthalene (22.03% and 48.00%), fluorene (38.99% and 39.00%), anthracene (64.62% and 68.02%) and pyrene (75.65% and 86.38%) at 5 μg/L and 200 μg/L PAH concentration levels respectively. Sorption was influenced by the octanol-water partition coefficient (log K) and ionic strength. Kinetics of the process in the case of sorption of pesticides were best explained by pseudo-first order kinetic model (R between 0.90 and 0.98) while the best fitting isotherm model was Dubinin-Radushkevich (R between 0.92 and 0.99). Results suggest the presence of surface level physi-sorption through a micropore volume filling mechanism and the role of hydrophobic and electrostatic forces. Pesticide desorption data in polyethylene mulch films indicate that pesticides with high log K were almost completely retained in mulch films, while those with lower log K were desorbed rapidly into the surrounding media. Our study highlights the role of microplastics from plastic mulch films as vectors for pesticide and PAH transport at environmentally realistic concentrations and the factors that influence it.
Topics: Plastics; Polycyclic Aromatic Hydrocarbons; Microplastics; Pesticides; Agriculture; Polyethylene; Adsorption; Water Pollutants, Chemical
PubMed: 37209851
DOI: 10.1016/j.chemosphere.2023.138959 -
Scientific Reports Jun 2022250 µm particle size of wood and polyethylene (PE) materials were compounded at mixing proportions of 60/40, 70/30, and 80/20 (with an increase in polymer to decrease...
250 µm particle size of wood and polyethylene (PE) materials were compounded at mixing proportions of 60/40, 70/30, and 80/20 (with an increase in polymer to decrease in wood content) and extruded using a single screw extruder at a temperature range of 110-135 °C. The particles of Gmelina Arborea, Tectona grandis, Cordia milleni, and Nauclea diderichii with recycled Polyethylene were compounded and compressed at 175 N/mm to produce biopolymer composites. The biopolymer composites were subjected to dimensional stability test at 24 h of the water soak method and the ability to withstand load-bearing capacity was investigated. The outcome of the results shows that extruded-compressive biopolymer composites had values ranging from 0.06-1.43 g/cm, 0.38-3.41%, and 0.82-6.85% for observed density, water absorption, and thickness swelling at 24 h of a water soak test. The mechanical properties values ranged from 0.28 Nmm-21.35 Nmm and 0.44-550.06 Nmm for flexural modulus and strength; and 191.43 Nmm-1857.24 Nmm and 0.35 Nmm-243.75 Nmm for tensile modulus and strength respectively. It was observed that moisture uptake and strength displayed by the composites vary accordingly in values obtained for wood species at different mixing proportions. As observed that the more polyethylene content is compounded to wood, the better its dimensional stability, and flexural and tensile properties. The wood particles of Cordia milleni compounded at a proportion of 60 to 40 (polyethylene/wood) performed best in dimensional stability and load-bearing capacity. This study confirmed the effect of methods on wood species and recycled PE for manufacturing wood polymer-based composite for both indoor and outdoor applications.
Topics: Biopolymers; Nigeria; Polyethylene; Polymers; Water; Wood
PubMed: 35732701
DOI: 10.1038/s41598-022-14691-z -
Ecotoxicology and Environmental Safety Oct 2022Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity....
Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels.
Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.
Topics: ATP-Binding Cassette Transporters; Chlorella vulgaris; Citrates; Microplastics; Petroleum; Plastics; Polyethylene; Water Pollutants, Chemical
PubMed: 36152431
DOI: 10.1016/j.ecoenv.2022.114102 -
Journal of Pharmaceutical Sciences Jul 2020Semifluorinated alkanes (SFAs) are aprotic solvents, which may be used as drug solvents for topical ocular applications, for instance, in dry eye syndrome. Their...
Semifluorinated alkanes (SFAs) are aprotic solvents, which may be used as drug solvents for topical ocular applications, for instance, in dry eye syndrome. Their physical properties suggest that they might be prone to interaction with plastic materials, such as, polyethylene (PE) and polypropylene (PP), which are commonly used as packaging materials for pharmaceutical products. In this study, we investigate interactions of PE and PP with a liquid SFA perfluorohexyloctane (PFHO) using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross-polarized light microscopy. Binary phase diagrams of PFHO-PE and PFHO-PP systems demonstrating interactions of PFHO with the polymeric materials were constructed based on DSC data. According to this data, PFHO tends to lower the melting temperatures of PE and PP. The equilibrium values of solubilities of the polymers in PFHO and PFHO in the polymers were obtained by extrapolation of melting enthalpy data. Absorption of PFHO by PE and PP materials at ambient conditions after 4 weeks of equilibration was also studied by TGA. From the presented results, it may be concluded that thorough studies of interactions of PE or PP with SFAs are required when these materials are used as packaging components in SFA-based formulations.
Topics: Fluorocarbons; Pharmaceutical Preparations; Polyethylene; Polypropylenes
PubMed: 32240694
DOI: 10.1016/j.xphs.2020.03.026 -
Scientific Reports Sep 2023Microplastic (MP) pollution in agricultural soils, resulting from the use of plastic mulch, compost, and sewage sludge, jeopardizes the soil microbial populations....
Microplastic (MP) pollution in agricultural soils, resulting from the use of plastic mulch, compost, and sewage sludge, jeopardizes the soil microbial populations. However, the effects of MPs on soil chemical properties and microbial communities remain largely unknown. Here, we investigated the effects of different concentration levels (0, 0.1, 1, 3, 5, and 7%; w:w) of low-density polyethylene (LDPE) MPs on the chemical properties and bacterial communities of agricultural soil in an incubation study. The addition of LDPE MPs did not drastically change soil pH (ranging from 8.22 to 8.42). Electrical conductivity increased significantly when the LDPE MP concentrations were between 1 and 7%, whereas the total exchangeable cations (Na, K, Mg, and Ca) decreased significantly at higher LDPE MP concentrations (3-7%). The highest available phosphorus content (2.13 mg kg) was observed in 0.1% LDPE MP. Bacterial richness (Chao1 and Ace indices) was the lowest at 0.1% LDPE MP, and diversity indices (Shannon and Invsimpson) were higher at 0 and 1% LDPE MP than at other concentrations. The effect of LDPE MP concentrations on bacterial phyla remained unchanged, but the bacterial abundance varied. The relative abundance of Proteobacteria (25.8-33.0%) was the highest in all treatments. The abundance of Acidobacteria (15.8-17.2%) was also high, particularly in the 0, 0.1, and 1% LDPE MPs. With the increase in LDPE MP concentration, the abundance of Actinobacteria gradually increased from 7.80 to 31.8%. Our findings suggest that different MP concentration levels considerably alter soil chemical properties and microbial composition, which may potentially change the ecological functions of soil ecosystems.
Topics: Microplastics; Soil; Plastics; Polyethylene; Microbiota; Bacteria
PubMed: 37770500
DOI: 10.1038/s41598-023-42285-w -
Scientific Reports Mar 2023Microplastic fragments (microfragments) are among the most abundant microplastic shapes found in marine ecosystems throughout the world. Due to their limited commercial...
Microplastic fragments (microfragments) are among the most abundant microplastic shapes found in marine ecosystems throughout the world. Due to their limited commercial availability, microfragments are rarely used in laboratory experiments. Here a novel method of microfragment production has been developed and validated. Polyethylene and polypropylene plastic stock (2 and 3 mm thick respectively) was ground using a cryomill, washed, and rinsed through a stack of sieves. Microfragments were prepared at three distinct size classes (53-150, 150-300, 300-1000 μm) and were confirmed to be accurate and consistent in size. Employing a novel ice cap dosing technique, microfragments were accurately dosed into experimental vials while excluding headspace, facilitating particle suspension without the aid of chemical surfactants. A proof of principle ingestion experiment confirmed the bioavailability of 53-150 μm polyethylene microfragments to brine shrimp Artemia sp. Together, these methods provide a controlled way to produce and dose microplastic fragments for experimental and analytical research.
Topics: Animals; Plastics; Microplastics; Ecosystem; Polyethylene; Artemia; Biological Assay; Water Pollutants, Chemical; Environmental Monitoring
PubMed: 36997607
DOI: 10.1038/s41598-023-32250-y -
MSystems Apr 2022Polyethylene (PE) is one of the most abundant plastics in the ocean. The development of a biofilm on PE in the ocean has been reported, yet whether some of the...
Polyethylene (PE) is one of the most abundant plastics in the ocean. The development of a biofilm on PE in the ocean has been reported, yet whether some of the biofilm-forming organisms can biodegrade this plastic in the environment remains unknown. Via metagenomics analysis, we taxonomically and functionally analyzed three biofilm communities using low-density polyethylene (LDPE) as their sole carbon source for 2 years. Several of the taxa that increased in relative abundance over time were closely related to known degraders of alkane and other hydrocarbons. Alkane degradation has been proposed to be involved in PE degradation, and most of the organisms increasing in relative abundance over time harbored genes encoding proteins essential in alkane degradation, such as the genes and CYP153, encoding an alkane monooxygenase and a cytochrome P450 alkane hydroxylase, respectively. Weight loss of PE sheets when incubated with these communities and chemical and electron microscopic analyses provided evidence for alteration of the PE surface over time. Taken together, these results provide evidence for the utilization of LDPE-associated compounds by the prokaryotic communities. This report identifies a group of genes potentially involved in the degradation of the LDPE polymeric structure and/or associated plastic additives in the ocean and describes a phylogenetically diverse community of plastic biofilm-dwelling microbes with the potential for utilizing LDPE-associated compounds as carbon and energy source. Low-density polyethylene (LDPE) is one of the most used plastics worldwide, and a large portion of it ends up in the ocean. Very little is known about its fate in the ocean and whether it can be biodegraded by microorganisms. By combining 2-year incubations with metagenomics, respiration measurements, and LDPE surface analysis, we identified bacteria and associated genes and metabolic pathways potentially involved in LDPE biodegradation. After 2 years of incubation, two of the microbial communities exhibited very similar taxonomic compositions mediating changes to the LDPE pieces they were incubated with. We provide evidence that there are plastic-biofilm dwelling bacteria in the ocean that might have the potential to degrade LDPE-associated compounds and that alkane degradation pathways might be involved.
Topics: Polyethylene; Microbial Consortia; Bacteria; Plastics; Oceans and Seas
PubMed: 35229650
DOI: 10.1128/msystems.01415-21 -
The Science of the Total Environment Jul 2022The occurrence of microplastics (MPs) was investigated in the Arvand River (Iran). The Arvand River (200 Km) is a major water body that flows through land with diverse...
The occurrence of microplastics (MPs) was investigated in the Arvand River (Iran). The Arvand River (200 Km) is a major water body that flows through land with diverse use and it meets the Persian Gulf. This study constitutes the first assessment of MP pollution (prevalence and physico-chemical characteristics) in the Arvand river, both in the sediment and in the water. MP monitoring has been carried out in 24 stations located along the river. The MP pollution found ranged between 1 and 291 items·L and 70 to 15,620 items·kg (dw), in water and sediment, respectively. The majority of MPs were fibres, black/grey and yellow/orange in colour, and mainly 250-500 μm and >1000 μm in size. Polyethylene terephthalate (PET), polypropylene (PP), nylon (NYL), high-density polyethylene (HDPE), and polystyrene (PS) were found in sediment samples. All these polymers, except HDPE, were also identified in the water samples. PET and PP were dominant in the water samples; whereas PET and PS were the most abundant in the sediments. The vicinity of urban wastewater effluents could be behind MP pollution in both water and sediments. Significant differences (p < 0.05) of MP concentrations were affected by different land uses when comparing MP levels in undisturbed natural area with urban areas. A strong correlation between MP fibres and fragments found with PCA biplots revealed their similar distribution in water. In the sediment samples, fibre and fragment MP particles were significantly correlated with colloidal particles (e.g., clay and organic matter) suggesting a relevant role of colloidal particles in the aquatic ecosystem of the Arvand River in transporting MPs. This study contributes to the better understanding of the presence of MP in major rivers, which are systems that have been scarcely investigated for this type of pollution, and it can inform interventions to reduce MP inputs to the river and sea.
Topics: Ecosystem; Environmental Monitoring; Microplastics; Plastics; Polyethylene; Polypropylenes; Polystyrenes; Rivers; Water; Water Pollutants, Chemical
PubMed: 35331773
DOI: 10.1016/j.scitotenv.2022.154728 -
Marine Pollution Bulletin Dec 2022The northern fulmar Fulmarus glacialis ingests a larger number of (micro)plastics than many other seabirds due to its feeding habits and gut morphology. Since 2002, they...
The northern fulmar Fulmarus glacialis ingests a larger number of (micro)plastics than many other seabirds due to its feeding habits and gut morphology. Since 2002, they are bioindicators of marine plastics in the North Sea region, and data are needed to extend the programme to other parts of their distribution areas, such as the Arctic. In this study, we provide data on ingested plastics by fulmars collected in 1997 in Kongsfjorden, Svalbard. An extraction protocol with KOH was used and for half of the birds, the gizzard and the proventricular contents were analysed separately. Ninety-one percent of the birds had ingested at least one piece of plastic with an average of 10.3 (±11.9 SD) pieces. The gizzards contained significantly more plastics than the proventriculus. Hard fragments and polyethylene were the most common characteristics. Twelve percent of the birds exceeded the EcoQO value of 0.1 g.
Topics: Animals; Plastics; Gastrointestinal Contents; Environmental Monitoring; Svalbard; Birds; Arctic Regions; Polyethylene
PubMed: 36372049
DOI: 10.1016/j.marpolbul.2022.114333