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The Science of the Total Environment Jul 2022Microplastics (MPs) are present in all environments, and concerns over their possible detrimental effects on flora and fauna have arisen. Density separation (DS) is...
Microplastics (MPs) are present in all environments, and concerns over their possible detrimental effects on flora and fauna have arisen. Density separation (DS) is commonly used to separate MPs from soils to allow MP quantification; however, it frequently fails to extract high-density MPs sufficiently, resulting in under-estimation of MP abundances. In this proof-of-concept study, a novel three-stage extraction method was developed, involving high-gradient magnetic separation and removal of magnetic soil (Stage 1), magnetic tagging of MPs using surface modified iron nanoparticles (Stage 2), and high-gradient magnetic recovery of surface-modified MPs (Stage 3). The method was optimised for four different soil types (loam, high‑carbon loamy sand, sandy loam and high-clay sandy loam) spiked with different MP types (polyethylene, polyethylene terephthalate, and polytetrafluoroethylene) of different particle sizes (63 μm to 2 mm) as well as polyethylene fibres (2-4 mm). The optimised method achieved average recoveries of 96% for fibres and 92% for particles in loam, 91% for fibres and 87% for particles in high‑carbon loamy sand, 96% for fibres and 89% for particles in sandy loam, and 97% for fibres and 94% for particles in high-clay sandy loam. These were significantly higher than recoveries achieved by DS, particularly for fibres and high-density MPs (p < 0.05). To demonstrate the practical application of the HGMS method, it was applied to a farm soil sample, and high-density MP particles were only recovered by HGMS. Furthermore, this study showed that HGMS can recover fibre-aggregate complexes. This improved extraction method will provide better estimates of MP quantities in future studies focused on monitoring the prevalence of MPs in soils.
Topics: Carbon; Clay; Magnetic Phenomena; Microplastics; Plastics; Polyethylene; Sand; Soil
PubMed: 35364148
DOI: 10.1016/j.scitotenv.2022.154912 -
PeerJ 2023This study aimed to examine the systemic effects of contemporary calcium silicate cements (CSC) contain different radiopacifiers in rats.
AIM
This study aimed to examine the systemic effects of contemporary calcium silicate cements (CSC) contain different radiopacifiers in rats.
MATERIALS & METHODS
Polyethylene tubes filled with BIOfactor MTA (BIO), Neo MTA Plus (NEO), MTA Repair HP (REP), Biodentine (DENT) and empty tubes (control group) were implanted into the subcutaneous tissues of 80 male Spraque Dawley rats for 7 and 30 days ( = 8). After 7 and 30 day, samples of liver and kidney tissues were submitted to histopathological analysis. Blood samples were collected to evaluate changes in hepatic and renal functions of rats. Wilcoxon and Dunn Bonferroni tests were used to compare between the 7th and 30th days in order to evaluate the histopathological data. Paired-sample t-test was used to compare laboratory values between the 7th and 30th days, ANOVA analysis and a Tukey test were used to compare values between groups ( < 0.05).
RESULTS
On the 7th day, REP, BIO and NEO groups were statistically similar in kidney tissue and the degree of inflammation was found to be significantly higher in these groups compared to the control and DENT groups. On the 30th day, the degree of inflammation of the REP and NEO groups in the kidney tissue was found to be significantly higher than the control, BIO and DENT groups. Although the inflammation in the liver was moderate and mild on the 7th and 30th days, no statistically significant difference was observed between the groups. Vascular congestion was evaluated as mild and moderate in kidney and liver in all groups, and no statistically significant difference was observed between the groups. While there was no statistically significant difference between the groups in the 7th day AST, ALT and urea values, when the creatinine values were compared, the DENT and NEO groups were found to be statistically similar and significantly lower than the control group. On the 30th day, ALT values were statistically similar between the groups. The AST values of the BIO group were found to be significantly higher than the DENT group. While BIO, DENT, NEO and control groups had statistically similar urea values, the REP group was found to be significantly higher than the other groups. The creatinine value of the REP group was significantly higher than the groups other than the control group ( < 0.05).
CONCLUSION
CSCs with different radiopacifiers had similar and acceptable effects on the histological examination of the kidneys and liver systemically, and serum ALT, AST, urea, creatinine levels.
Topics: Male; Animals; Rats; Creatinine; Inflammation; Polyethylene; Urea
PubMed: 37312877
DOI: 10.7717/peerj.15376 -
Current Biology : CB Aug 2017In their recent paper on the degradation of polyethylene by caterpillars of the wax moth Galleria melonella, Bombelli et al.[1] report various experiments, including...
In their recent paper on the degradation of polyethylene by caterpillars of the wax moth Galleria melonella, Bombelli et al.[1] report various experiments, including microscopic and spectroscopic data which the authors believe support the chemical digestion of the polymers by these insects. While the biodegradation of mostly inert artificial polymers is definitely a very interesting research field, we must respectfully disagree with the methodology and conclusions from this paper.
Topics: Animals; Biodegradation, Environmental; Insecta; Moths; Polyethylene; Polymers
PubMed: 28787599
DOI: 10.1016/j.cub.2017.07.004 -
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 -
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 -
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 -
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 -
Journal of Orthopaedic Surgery and... Feb 2023Adverse local tissue reactions have been problematic as an implant-related complication in total hip arthroplasty (THA). Despite the absence of significant metal wear...
BACKGROUND
Adverse local tissue reactions have been problematic as an implant-related complication in total hip arthroplasty (THA). Despite the absence of significant metal wear and corrosion, granulomatous pseudotumor has been reported to be caused by polyethylene wear. We performed a long-term follow-up study investigating the relationship between polyethylene wear and pseudotumor formation in THA.
METHODS
This study included 57 patients (64 hips) that underwent primary THA with metal-on-polyethylene or ceramic-on-polyethylene bearing over a minimum follow-up of 15 years. They were stratified into pseudotumor and non-pseudotumor groups and their linear wear rates of polyethylene liner and serum cobalt (Co) and chromium (Cr) ion levels were compared. Pseudotumor was diagnosed on metal artifact reduction sequence-MRI according to its composition and wall thickness using the Hauptfleisch classification.
RESULTS
The incidence of pseudotumor was 34% (22/64 hips) at the mean follow-up of 16.9 years. Metal ion levels did not differ between the pseudotumor and non-pseudotumor groups, and none of the patients exceeded the Co/Cr ratio of 2.0 μg/L. Moreover, the wear rate in the pseudotumor group was 1.8 times greater than in the non-pseudotumor group (0.14 vs. 0.08 mm/year, P < 0.001). According to an analysis of the receiver operating characteristic curves, the cutoff level of the wear rate to discriminate between pseudotumor and non-pseudotumor patients at 15 years was 0.11 mm/year (area under the curve = 91%; sensitivity = 95%; specificity = 78%; accuracy = 87%).
CONCLUSIONS
Our results might provide new insights into excessive polyethylene wear potentially leading to the future development of both pseudotumor and osteolysis. Further studies are needed to clarify the direct relationship between polyethylene wear and pseudotumor and the mutual effects of osteolysis and pseudotumor in particle reactions.
Topics: Humans; Polyethylene; Arthroplasty, Replacement, Hip; Follow-Up Studies; Osteolysis; Ceramics; Postoperative Complications
PubMed: 36849999
DOI: 10.1186/s13018-023-03634-7 -
Bulletin of Environmental Contamination... Apr 2022There is increasing evidence that microbial biofilms which form on the surface of marine plastics can increase plastics palatability, making it more attractive to...
There is increasing evidence that microbial biofilms which form on the surface of marine plastics can increase plastics palatability, making it more attractive to organisms. The same information, however, does not exist for freshwater systems. This study observed the response of the freshwater amphipod Gammarus pulex when exposed to 3 cm-diameter discs of biofilm-covered plastic, both alone and when presented alongside its natural food. G. pulex did not fragment or consume the plastic materials, and the presence of colonised plastic in the immediate environment did not alter the amount of time organisms spent interacting with their natural food. This study provides baseline information for virgin and microbially colonised low-density polyethylene and polylactic acid film. Further studies, with other types of plastic possessing different physical properties and with different microbial biofilm compositions are now required to build further understanding of interactions between plastic, microbial biofilms, and freshwater shredding invertebrates.
Topics: Amphipoda; Animals; Biofilms; Fresh Water; Plastics; Polyethylene
PubMed: 34993567
DOI: 10.1007/s00128-021-03448-5 -
Scientific Reports Nov 2022This study deals with the production of natural fiber plastic composites (NFPCs) to reduce environmental pollution with agricultural and plastic waste. Where the NFPCs...
This study deals with the production of natural fiber plastic composites (NFPCs) to reduce environmental pollution with agricultural and plastic waste. Where the NFPCs were prepared from waste/pure polyethylene (WPE) (pure polyethylene (50%)/recycled polyethylene (50%)) and modified sunflower waste via an eco-friendly and economic biological process. The sunflower fibers (SF) were treated via whole selective fungal isolate, namely, Rhizopus oryzae (acc no. OM912662) using two different incubation conditions; submerged (Sub), and solid-state fermentation (SSF) to enhance the fibers' compatibility with WPE. The treated and untreated fibers were added to WPE with various concentrations (10 and 20 wt%). The morphology and structure of fibers were characterised by a scanning electron microscope (SEM) and attenuated total reflection-Fourier transform infrared (ATR-FTIR). Furthermore, the mechanical properties, morphology, biodegradation and water vapour transmission rate (WVTR) for the prepared NFPCs were investigated. The results showed that compatibility, mechanical properties and biodegradation of NFPCs were improved by the addition of sunflower fibers treated by SSF conditions.
Topics: Plastics; Wood; Recycling; Agriculture; Polyethylene
PubMed: 36357465
DOI: 10.1038/s41598-022-21705-3