Toxicological assessment of dietary exposure of polyethylene microplastics on growth, nutrient digestibility, carcass and gut histology of Nile Tilapia (Oreochromis niloticus) fingerlings.

This study was conducted to ascertain the negative effects of dietary low-density polyethylene microplastics (LDPE-MPs) exposure on growth, nutrient digestibility, body composition and gut histology of Nile tilapia (Oreochromis niloticus). Six sunflower meal-based diets (protein 30.95%; fat 8.04%) were prepared; one was the control (0%) and five were incorporated with LDPE-MPs at levels of 2, 4, 6, 8 and 10% in sunflower meal-based diets. A total of eighteen experimental tanks, each with 15 fingerlings, were used in triplicates. Fish were fed at the rate of 5% biomass twice a day for 60 days. Results revealed that best values of growth, nutrient digestibility, body composition and gut histology were observed by control diet, while 10% exposure to LDPE-MPs significantly (P < 0.05) reduced weight gain (WG%, 85.04%), specific growth rate (SGR%, 0.68%), and increased FCR (3.92%). The findings showed that higher level of LDPE-MPs (10%) exposure in the diet of O. niloticus negatively affects nutrient digestibility. Furthermore, the results revealed that the higher concentration of LDPE-MPs (10%) had a detrimental impact on crude protein (11.92%) and crude fat (8.04%). A high number of histological lesions were seen in gut of fingerlings exposed to LDPE-MPs. Hence, LDPE-MPs potentially harm the aquatic health.

Sustainable use of plastic-derived nanocarbons as a promising larvicidal and growth inhibitor agent towards control of mosquitoes.

Nanoscale carbon was obtained from six widely used plastics (PET, HDPE, PVC, LDPE, PP and PP) via thermal degradation (600 °C) under inert atmosphere. The thermally degraded products were processed through bath sonication followed by lyophilisation and the same was characterized through proximate analysis, UV-Vis spectroscopy, Scanning electron micrograph (SEM) with energy dispersive X-ray (EDX) analysis, Transmission electron micrograph (TEM), Dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). A series of aqueous solution of nanoscale carbon (5-30 mg/L) were prepared and same were used as both mosquito growth inhibitor and larvicidal agent against 3rd and 4th instar larvae of Culex pipiens. The significant percent mortality results were recorded for LDPE (p < 0.007) with average particle size of 3.01 nm and 62.95 W% of carbon and PS (p < 0.002) with average particle size of 12.80 nm and 58.73 W% of carbon against 3rd instar larvae, respectively. Similarly, for 4th instar larvae, both significant pupicidal and adulticidal activity were also recorded for PET (F = 24.0, p < 0.0001 and F = 5.73, p < 0.006), and HDPE (F = 26.0, p < 0.0001) and F = 5.30, p < 0.008). However, significant pupicidal activity were observed for PVC (F = 6.90, p < 0.003), and PS (F = 21.30, p < 0.0001). Histological, bio-chemical and microscopic studies were revealed that nanoscale carbon causes mild to severe damage of external and internal cellular integrity of larvae. However, nanoscale carbon does not exhibit any chromosomal abnormality and anatomical irregularities in Allium cepa and Cicer arietinum, respectively. Similarly, non-significant results with respect to blood cell deformation were also recorded from blood smear of Poecilia reticulata. Therefore, it can be concluded that plastic origin nanoscale carbon could be a viable sustainable nano-weapon towards control of insects.

Polyethylene microplastic modulates lettuce root exudates and induces oxidative damage under prolonged hydroponic exposure.

Root exudates are pivotal in plant stress responses, however, the impact of microplastics (MPs) on their release and characteristics remains poorly understood. This study delves into the effects of 0.05 % and 0.1 % (w/w) additions of polyethylene (PE) MPs on the growth and physiological properties of lettuce (Lactuca sativa L.) following 28 days of exposure. The release characteristics of root exudates were assessed using UV-vis and 3D-EEM. The results indicated that PE increased leaf number but did not significantly affect other agronomic traits or pigment contents. Notably, 0.05 % PE increased the total root length and surface area compared to the 0.1 % addition, while a non-significant trend towards decreased root activity was observed with PE MPs. PE MPs with 0.1 % addition notably reduced the DOC concentration in root exudates by 37.5 %, while 0.05 % PE had no impact on DOC and DON concentrations. PE addition increased the SUVA254, SUVA260, and SUVA280 values of root exudates, with the most pronounced effect seen in the 0.05 % PE treatment. This suggests an increase of aromaticity and hydrophobic components induced by PE addition. Fluorescence Regional Integration (FRI) analysis of 3D-EEM revealed that aromatic proteins (region I and II) were dominant in root exudates, with a slight increase in fulvic acid-like substances (region III) under 0.1 % PE addition. Moreover, prolonged PE exposure induced ROS damage in lettuce leaves, evidenced by a significant increase in content and production rate of O2·-. The decrease in CAT and POD activities may account for the lettuce's response to environmental stress, potentially surpassing its tolerance threshold or undergoing adaptive regulation. These findings underscore the potential risk of prolonged exposure to PE MPs on lettuce growth.

Biodegradable PBAT microplastics adversely affect pakchoi (Brassica chinensis L.) growth and the rhizosphere ecology: Focusing on rhizosphere microbial community composition, element metabolic potential, and root exudates.

Biodegradable plastics (BPs) have gained increased attention as a promising solution to plastics pollution problem. However, BPs often exhibited limited in situ biodegradation in the soil environment, so they may also release microplastics (MPs) into soils just like conventional non-degradable plastics. Therefore, it is necessary to evaluate the impacts of biodegradable MPs (BMPs) on soil ecosystem. Here, we explored the effects of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) MPs and conventional polyethylene (PE) MPs on soil-plant (pakchoi) system at three doses (0.02 %, 0.2 %, and 2 %, w/w). Results showed that PBAT MPs reduced plant growth in a dose-dependent pattern, while PE MPs exhibited no significant phytotoxicity. High-dose PBAT MPs negatively affected the rhizosphere soil nutrient availability, e.g., decreased available phosphorus and available potassium. Metagenomics analysis revealed that PBAT MPs caused more serious interference with the rhizosphere microbial community composition and function than PE MPs. In particular, compared with PE MPs, PBAT MPs induced greater changes in functional potential of carbon, nitrogen, phosphorus, and sulfur cycles, which may lead to alterations in soil biogeochemical processes and ecological functions. Moreover, untargeted metabolomics showed that PBAT MPs and PE MPs differentially affect plant root exudates. Mantel tests, correlation analysis, and partial least squares path model analysis showed that changes in plant growth and root exudates were significantly correlated with soil properties and rhizosphere microbiome driven by the MPs-rhizosphere interactions. This work improves our knowledge of how biodegradable and conventional non-degradable MPs affect plant growth and the rhizosphere ecology, highlighting that BMPs might pose greater threat to soil ecosystems than non-degradable MPs.

Investigation on the effect of several parameters involved in the biodegradation of polyethylene (PE) and low-density polyethylene (LDPE) under various seawater environments.

This work investigates the biodegradation of polyethylene (PE) and low-density polyethylene (LDPE) and the leaching of their harmful additives. Micro/macro-plastics of both types were subjected to different laboratory-controlled conditions for 3 months. Gas Chromatography-Mass Spectroscopy (GC-MS) results revealed that leachate concentrations ranged from 0.40 ± 0.07 µg/L to 96.36 ± 0.11 µg/L. It was concluded that the additives' leaching process was promoted by light. However, light was not the only factor examined; microorganisms, pH, salinity, aeration/mixing and temperature influenced the biodegradation process, too. GC-MS results showed a prodigious impact on the biodegradation process when Pseudomonas aeruginosa was added to the artificial seawater compared to plastics exposed to light/air only. Scanning Electron Microscopy (SEM) micrographs demonstrated a significant alteration in the plastics' morphologies. Similarly, Fourier-Transform Infrared Spectroscopy (FTIR) spectra showed obvious changes in plastics characteristic peaks, especially microplastics. Furthermore, it was shown that PE was more susceptible to degradation/biodegradation than LDPE. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) findings showed that some toxic metals were present in water samples after experiments, with concentrations above the permissible limits. For instance, bio-augmentation/bio-stimulation experiments showed that the concentrations of Pb, Sr, and Zn were 0.59 mg/L, 70.09 mg/L, and 0.17 mg/L, respectively; values above the permissible limits. It is crucial to emphasise that plastics must be meticulously engineered to avoid environmental and human impacts, originated from their degradation by-products. Furthermore, a holistic approach engaging stakeholders, researchers, policymakers, industries and consumers, is essential to effectively tackle the global challenge of marine plastic pollution.

Vitexin-loaded poly(ethylene glycol) methyl ether-grafted chitosan/alginate nanoparticles: preparation, physicochemical properties and in vitro release behaviors.

BACKGROUND: Vitexin, a flavonoid in various foods and medicinal plants, has potential clinical, therapeutic and food applications due to its bioactive properties and beneficial health effects. However, its poor water solubility causes low oral bioavailability and poor absorption in the gastrointestinal tract, limiting its practical applications. Encapsulation is an efficient approach to overcome these limitations. This study demonstrates the encapsulation of vitexin into poly(ethylene glycol) methyl ether-grafted chitosan (mPEG-g-CTS)/alginate (ALG) polyelectrolyte complex nanoparticles. RESULTS: The vitexin-loaded mPEG-g-CTS/ALG nanoparticles were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy and X-ray diffraction. The vitexin-loaded mPEG-g-CTS/ALG nanoparticles had a spherical shape, 50-200 nm in diameter, and negatively charged surface (-27 to -38 mV). They possessed a loading capacity of 4-60%, encapsulation efficiency of 50-100% and antioxidant activity (30-52% 2,2-diphenyl-1-picrylhydrazyl decoloration) when their initial vitexin content was 0.02-0.64 g g-1 polymers. Successful vitexin loading into mPEG-g-CTS/ALG nanoparticles was also indirectly confirmed by the enhanced thermal stability of both polymers and the residual soybean oil used in the emulsion preparation step and delayed oxidative degradation of the residual soybean oil. Vitexin's in vitro release from the mPEG-g-CTS/ALG nanoparticles was very fast in phosphate buffer at pH 11, followed by pH 7, and very slow in acetate buffer at pH 3. The gastrointestinal digestion of vitexin increased by encapsulating into mPEG-g-CTS/ALG nanoparticles. CONCLUSIONS: Vitexin-loaded mPEG-g-CTS/ALG nanoparticles were successfully fabricated using a two-step process of oil-in-water emulsion and ionic gelation without the use of pungent odor acids and other crosslinkers. The obtained nanoparticles are suitable for oral intestinal-specific delivery systems. © 2023 Society of Chemical Industry.

Efficacy and Related Factors of Artificial Femoral Head Replacement for Femoral Intertrochanteric Fracture and Nonunion: A Systematic Review and Meta-Analysis.

Background: An intertrochanteric fracture can cause ischemic necrosis in the femoral head, leading to negative effects. There are many types of implants for this fracture procedure, including metal-on-metal, metal-on-polyethylene, ceramic-on-ceramic, and ceramic-on-polyethylene, that are currently in use. The current modification is a hybrid prosthetic implant with high functional capacity compared with predecessors. This study aims to determine the procedure's efficacy in recovery, function restoration, complications, and cost-effectiveness. Methods: Our study used a total of 200 patients undergoing total hip arthroplasty and 135 patients undergoing semi-hip arthroplasty to determine the effectiveness of total hip arthroplasty and femoral head arthroplasty From May 2022 to May 2023. Using the RAOSOFT sampling technique, 132 and 101 in the observation and control group, respectively, the sample is obtained with a confidence interval of 95%, an error margin of 1%, and response interval confidence of 50%. This is a descriptive type of research that relies on a meta-analysis of the available data from PubMed, scholarly articles, and the Chinese biomedical database to gather the fundamental data needed to conduct the research. Data obtained is analyzed using SSPS and STATA and presented in tables showing a summary of the objective measured value. Result: In this study, the Harris joint score of patients in the total hip arthroplasty group was significantly higher than that of the control group, indicating that total hip arthroplasty can restore femoral head function, but still lacks absolute strength like half hip arthroplasty. Conclusions: Femoral head replacement is a complex procedure, but the efficacy in restoring the function is better. In conclusion, despite slow healing and regeneration, the efficacy of complete artificial femoral head replacement is higher in restoring function for various fractures.

Alternative flexible plastic packaging for instant coffees.

Instant coffees are consumed worldwide and their packages must protect them mainly from moisture gain. Flexible packaging stand-up pouches made by PET/Al foil/LDPE are currently used but, the look for alternative materials is interesting to replace the aluminum foil with reducing costs and focusing on sustainability. Therefore, the aim of this study was to evaluate the quality loss of freeze-dried and spray-dried (agglomerated and powder) instant coffees during 365 days at 25 °C/75% RH, packaged in five plastic structures: PET (polyethylene terephthalate)/Al (aluminum) foil/LDPE (low density polyethylene), LDPE/HDPE (high density polyethylene)/LDPE, BOPP (biaxially oriented polypropylene)/BOPP met (metallized)/PP, PET/PET met/LDPE and PET/BOPP met/LDPE. The results were compared with the shelf-life estimated by modeling the moisture sorption isotherms of the products by mathematical models. Results indicated that the lower the barrier to water vapor of the packaging material, the greater the gains in moisture and water activity of the instant coffees and in addition to being thermally less stable. After 365 days of storage, the three soluble coffees still had acceptable characteristics in the five packaging structures, indicating that it is possible to replace the currently used laminate, which contains aluminum foil, with recyclable structures. However, the greatest stability for the coffees was obtained using the alternative structures: BOPP/BOPP met/PP and LDPE/HDPE/LDPE, a result that was in concordance with that obtained by mathematical modeling.

Blue 405 nm LED light effectively inactivates bacterial pathogens on substrates and packaging materials used in food processing.

This study investigates the antimicrobial effectiveness of 405 nm light emitting diodes (LEDs) against pathogenic Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus, in thin liquid films (TLF) and on solid surfaces. Stainless steel (SS), high density polyethylene (HDPE), low density polyethylene (LDPE), and borosilicate glass were used as materials typically encountered in food processing, food service, and clinical environments. Anodic aluminum oxide (AAO) coupons with nanoscale topography were used, to evaluate the effect of topography on inactivation. The impact of surface roughness, hydrophobicity, and reflectivity on inactivation was assessed. A 48 h exposure to 405 nm led to reductions ranging from 1.3 (E. coli) to 5.7 (S. aureus) log CFU in TLF and 3.1 to 6.3 log CFU on different solid contact surfaces and packaging materials. All inactivation curves were nonlinear and followed Weibull kinetics, with better inactivation predictions on surfaces (0.89 ≤ R2 ≤ 1.0) compared to TLF (0.76 ≤ R2 ≤ 0.99). The fastest inactivation rate was observed on small nanopore AAO coupons inoculated with L. monocytogenes and S. aureus, indicating inactivation enhancing potential of these surfaces. These results demonstrate significant promise of 405 nm LEDs for antimicrobial applications in food processing and handling and the healthcare industry.

Biodegradable mulch films improve yield of winter potatoes through effects on soil properties and nutrients.

Biodegradable mulch films are recognized as a promising substitute of polyethylene (PE) films to alleviate the "white pollution". Biodegradable mulch films with optimum degradation rates increase crop yield even compared to PE films. However, the mechanisms underlying this yield-increasing effect remains elusive. In this study, three biodegradable film treatments (BFM1, BFM2 and BFM3) and one PE film treatment (PFM) were used to evaluate their effects on soil and winter potatoes, and a partial least squares path model (PLS-PM) was constructed to investigate their relationships. The degradation rates of films under different treatments were ranked as BFM3 > BFM2 >BFM1 > PFM, and presented distinctive effects on soil properties and nutrients, structure of soil bacterial community, and yield traits of winter potatoes. The PLS-PM showed that mulch treatments affected potato yield through effects on soil properties (soil water and temperature) and soil nutrients (TOC, DOC, TN and NO3--N). The disintegration of the biodegradable films decreased soil water content and temperature, and reduced the loss of soil nutrients in the topsoil at the later growth stage of winter potatoes compared to PE films. Additionally, the elevated content of soil TN and NO3--N under treatment BFM1 may play a key role in its yield-increasing effect on potatoes compared to treatments PFM and BFM2. Thus, biodegradable mulch films with proper degradation rates regulate soil TN and NO3--N through their effects on soil water and temperature, and subsequently improve the yield of winter potatoes compared to PE mulch films.

Unique Raoultella species isolated from petroleum contaminated soil degrades polystyrene and polyethylene.

Polyolefin plastics, such as polyethylene (PE) and polystyrene (PS), are the most widely used synthetic plastics in our daily life. However, the chemical structure of polyolefin plastics is composed of carbon-carbon (C-C) bonds, which is extremely stable and makes polyolefin plastics recalcitrant to degradation. The growing accumulation of plastic waste has caused serious environmental pollution and has become a global environmental concern. In this study, we isolated a unique Raoultella sp. DY2415 strain from petroleum-contaminated soil that can degrade PE and PS film. After 60 d of incubation with strain DY2415, the weight of the UV-irradiated PE (UVPE) film and PS film decreased by 8% and 2%, respectively. Apparent microbial colonization and holes on the surface of the films were observed by scanning electron microscopy (SEM). Furthermore, the Fourier transform infrared spectrometer (FTIR) results showed that new oxygen-containing functional groups such as -OH and -CO were introduced into the polyolefin molecular structure. Potential enzymes that may be involved in the biodegradation of polyolefin plastics were analyzed. These results demonstrate that Raoultella sp. DY2415 has the ability to degrade polyolefin plastics and provide a basis for further investigating the biodegradation mechanism.

Biochemical and transcriptomic responses of buckwheat to polyethylene microplastics.

The ubiquity of microplastic is widely recognized as pollution. Microplastic can affect the growth performances of plants. Buckwheat is a potential model crop to investigate plant responses to hazardous materials. Still, little is known about the response of buckwheat to microplastics. Thus, this study investigated the effect and uptake of polyethylene (PE) in buckwheat plant growth by monitoring the morphological and photosynthetic merits, antioxidant systems and transcriptome analysis of gene expression. Results confirmed that the impacts of PE on buckwheat growth were dose-dependent, while the highest concentration (80 mg/L) exposure elicited significantly negative responses of buckwheat. PE can invade buckwheat roots and locate in the vascular tissues. PE exposure disturbed the processes of carbon fixation and the synthesis of ATP from ADP + Pi in buckwheat leaves. The promotion of photosynthesis under PE exposure could generate extra energy for buckwheat leaves to activate antioxidant systems by increasing the antioxidant enzyme activities at an expense of morphological merits under microplastic stresses. Further in-depth study is warranted about figuring out the interactions between microplastics and biochemical responses (i.e., photosynthesis and antioxidant systems), which have great implications for deciphering the defense mechanism of buckwheat to microplastic stresses.

Environmental life cycle assessment of nutraceuticals: A case study on methylcobalamin in different packaging types.

The growing production of pharmaceuticals and nutraceuticals, e.g., methylcobalamin supplements, improves the health of people. This study assesses the environmental footprint of chewable methylcobalamin supplements in four packaging types: blister packs or bottles made of HDPE, PET, or glass. A cradle-to-grave life cycle assessment is conducted to evaluate the supply to Belgian consumers of the recommended daily dose of methylcobalamin supplementation (1.2 mg) in case of deficiency. The impact of methylcobalamin manufacturing in major producing countries (China as baseline and France) is analyzed based on detailed synthesis modeling of data points coming from patents. The overall carbon footprint (CF) is dominated by the transport of consumers to the pharmacy and methylcobalamin powder manufacturing in China (while its mass share per supplement is only 1 %). The impact is the lowest for supplements in HDPE bottles (6.3 g CO2 eq) and 1 %, 8 %, and 35 % higher for those in PET bottles, glass bottles, and blister packs, respectively. Tablets in blister packs have for other investigated impact categories (fossil resource footprint (FRF); acidification; eutrophication: freshwater, marine, and terrestrial; freshwater ecotoxicity; land use; and water use) the highest footprint and those in HDPE and PET bottles for most the lowest. The CF of methylcobalamin powder manufacturing in France is 22 % lower than in China (2.7 g CO2 eq), while the FRF is similar in both locations (26-27 kJ). The FRF and the difference in the CF are chiefly due to energy use and solvent production emissions. Similar trends as the CF are found for other investigated impact categories. Valuable conclusions are drawn for environmental studies on pharmaceuticals and nutraceuticals: (i) including accurate data on consumer transport, (ii) using more environmentally-friendly active ingredients, (iii) choosing appropriate packaging types considering multiple aspects: convenience, environmental footprint, etc., and (iv) providing a holistic picture through assessing various impact categories.

Evaluation of bioactive low-density polyethylene (LDPE) nanocomposite films in combined treatment with irradiation on strawberry shelf-life extension.

A low-density polyethylene (LDPE) film reinforced with cellulose nanocrystals (CNCs) with an encapsulated bioactive formulation (cinnamon essential oil + silver nanoparticles) was developed for preservation of fresh strawberries. Antimicrobial activity of the active LDPE films was tested against Escherichia coli O157:H7, Salmonella typhimurium, Aspergillus niger, and Penicillium chrysogenum by agar volatilization assay. The optimal condition of the films showed ≥75% inhibitory capacity against the tested microbes. Strawberries were stored with different types of films: Group 1 (control): (LDPE + CNCs + Glycerol), Group 2: (LDPE + CNCs + Glycerol + AGPPH silver nanoparticles), Group 3: (LDPE + CNCs + Glycerol + cinnamon), Group 4: (LDPE + CNCs + Glycerol + active formulation), and Group 5: (LDPE + CNCs + Glycerol + active formulation + 0.5 kGy γ-radiation) at 4°C for 12 days. Weight loss (WL) (%), decay (%), firmness (N), color, and total phenolics and anthocyanin content of the strawberries were measured. Results showed that the most effective LDPE-nanocomposite film for reducing the microbial growth was LDPE + CNCs + Glycerol + active formulation film (Group 4). When combined with γ-irradiation (0.5 kGy), the LDPE + CNCs + Glycerol + active formulation (Group 5) significantly reduced both decay and WL by 94%, as compared to the control samples after 12 days of storage. Total phenols (from 952 to 1711 mg/kg) and anthocyanin content (from 185 to 287 mg/kg) increased with storage time under the different treatments. The mechanical properties, water vapor permeability (WVP), and surface color of the films were also tested. Though the WVP of the films were not influenced by the types of antimicrobial agents, they did significantly (p ≤ 0.05) change color and mechanical properties of the films. Therefore, combined treatment of active film and γ-irradiation has potential as an alternative method for extending the shelf-life of storage strawberries while maintaining fruit quality. PRACTICAL APPLICATION: Bioactive Low-density polyethylene (LDPE) nanocomposite film was developed in the study by incorporating active formulation (essential oil and silver nanoparticle) to extend the shelf life of stored strawberries. The bioactive LDPE-based nanocomposite film along with γ-irradiation could be used to preserve fruits for long-term storage by controlling the growth of foodborne pathogenic bacteria and spoilage fungi.

Sorbed environmental contaminants increase the harmful effects of microplastics in adult zebrafish, Danio rerio.

Aquatic animals ingest Microplastics (MPs) which have the potential to affect the uptake and bioavailability of sorbed co-contaminants. However, the effects on living organisms still need to be properly understood. The present study was designed to assess the combined effects of MPs and environmental contaminants on zebrafish (Danio rerio) health and behavior. Adult specimens were fed according to three different protocols: 1) untreated food (Control group); 2) food supplemented with 0.4 mg/L pristine polyethylene-MPs (PE-MPs; 0.1-0.3 mm diameter) (PEv group); 3) food supplemented with 0.4 mg/L PE-MPs previously incubated (PEi group) for 2 months in seawater. Analysis of contaminants in PEi detected trace elements, such as lead and copper. After 15 days of exposure, zebrafish underwent behavioral analysis and were then dissected to sample gills and intestine for histology, and the latter also for microbiome analysis. Occurrence of PEv and PEi in the intestine and contaminants in the fish carcass were analyzed. Both PEv- and PEi-administered fish differed from controls in the assays performed, but PEi produced more harmful effects in most instances. Overall, MPs after environmental exposure revealed higher potential to alter fish health through combined effects (e.g. proportion of microplastics, pollutants and/or microorganisms).

Effects of petroleum-based and biopolymer-based nanoplastics on aquatic organisms: A case study with mechanically degraded pristine polymers.

Mismanaged plastic litter submitted to environmental conditions may breakdown into smaller fragments, eventually reaching nano-scale particles (nanoplastics, NPLs). In this study, pristine beads of four different types of polymers, three oil-based (polypropylene, PP; polystyrene, PS; and low-density polyethylene, LDPE) and one bio-based (polylactic acid, PLA) were mechanically broken down to obtain more environmentally realistic NPLs and its toxicity to two freshwater secondary consumers was assessed. Thus, effects on the cnidarian Hydra viridissima (mortality, morphology, regeneration ability, and feeding behavior) and the fish Danio rerio (mortality, morphological alterations, and swimming behavior) were tested at NPLs concentrations in the 0.001 to 100 mg/L range. Mortality and several morphological alterations were observed on hydras exposed to 10 and 100 mg/L PP and 100 mg/L LDPE, whilst regeneration capacity was overall accelerated. The locomotory activity of D. rerio larvae was affected by NPLs (decreased swimming time, distance or turning frequency) at environmentally realistic concentrations (as low as 0.001 mg/L). Overall, petroleum- and bio-based NPLs elicited pernicious effects on tested model organisms, especially PP, LDPE and PLA. Data allowed the estimation of NPLs effective concentrations and showed that biopolymers may also induce relevant toxic effects.

Potential impact of polyethylene microplastics on the growth of water spinach (Ipomoea aquatica F.): Endophyte and rhizosphere effects.

Microplastic contamination has received much attention, especially in agroecosystems. However, since edible crops with different genetic backgrounds may present different responses to microplastics, more research should be conducted and focused on more edible crops. In the current study, pot experiments were conducted to investigate the potential impact of polyethylene microplastic (PE) (particle sizes: 0.5 µm and 1.0 µm, addition levels: 0 (control), 0.5% and 1.0% (w/w)) addition on the physiological and biochemical variations of I. aquatica F.. The results indicated that PE addition caused an increase in the soil pH and NH4+-N and soil organic matter contents, which increased by 10.1%, 29.9% and 50.1% when PE addition at A10P0.5 level (10 g (PE) kg-1 soil, particle size: 0.5 µm). While, PE exposure resulted in a decrease in soil available phosphorus and total phosphorus contents, which decreased by 53.9% and 10.5% when PE addition at A10P0.5 level. In addition, PE addition altered the soil enzyme activities. Two-way ANOVA indicated that particle size had a greater impact on the variations in soil properties and enzyme activities than the addition level. PE addition had a strong impact on the rhizosphere microbial and root endophyte community diversity and structure of I. aquatica F.. Two-way ANOVA results indicated that the particle size and addition level significantly altered the α-diversity indices of both rhizosphere microbial and root endophyte (P < 0.05, P < 0.01 or P < 0.001). Moreover, PE was adsorbed by I. aquatica F., which was clearly observed in the transverse roots and significantly increased the H2O2, ·O2-, malondialdehyde and ascorbic acid contents in both the roots and aerial parts of I. aquatica F., leading to a decrease in I. aquatica F. biomass. Overall, the current study enriches the understanding of the effect of microplastics on edible crops.

Assessment of barium diffusion from therapeutic mud wrapped in micro-perforated polyethylene bags towards the human organism.

Barium is present within the clay-derived therapeutic mud packs deposed on the patient's skin for treating some rheumatologic conditions. We studied in twenty-four young healthy volunteers the diffusion of Ba from mud wrapped in micro-perforated polyethylene bags and soaked in mineral water. No significant systematic increase in plasma or urine Ba levels was evidenced when comparing pre- and post-treatment samples using inductively-coupled plasma mass spectrometry. These levels were markedly inferior to the recommended thresholds in nearly all the participants. Noticeably variability in blood and especially urine Ba concentrations was large and mainly explained by environmental exposure (alimentation). Interestingly, we evidenced an intense Ba accumulation within the therapeutic mud at the end of the regimen. Because we chose a clay with one of the highest Ba content available in France for medical therapy and participants with an optimal transcutaneous diffusion capacity (young individuals with low-fat mass), we conclude unambiguously that there is no risk of Ba overexposure in patients receiving pelotherapy according to the procedure used in French medical spas.

Mean 16-Year Results of Total Hip Arthroplasty With Alumina Ceramic Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years or Less.

BACKGROUND: Highly cross-linked polyethylene (HXLPE) is a widely used bearing surface in total hip arthroplasty (THA); long-term results in young patients are limited. We previously demonstrated excellent results in HXPLE on cobalt-chrome femoral heads at 15-year mean follow-up. The purpose of the present study was to investigate polyethylene wear rates, implant survivorships, wear-related revisions, and patient-reported outcomes (PROs) in a young patient cohort who had alumina ceramic on HXPLE coupling at an average 16-year follow-up. METHODS: This was a retrospective study of 128 hips that underwent THA with HXLPE on alumina ceramic bearings between March 1, 2004, and April 15, 2007. The patient's mean age was 38 years (range, 13 to 50). All THAs utilized HXPLE liners with alumina ceramic heads. The University of California, Los Angeles activity score and modified Harris hip scores were collected preoperatively and at each follow-up. Martell hip analysis suite was used for wear calculations. RESULTS: At average 16 years (range, 13 to 18), aseptic revision survivorship was 93.3% and osteolysis/wear survivorship was 99.2%. The mean linear wear rate was 0.0191 mm/year and mean volumetric wear rate was 19.43 mm3/y, both of which were clinically undetectable. We observed excellent PROs with a significant increase in mean modified Harris hip scores (43.6 to 87.4, P < .0001) and the University of California, Los Angeles activity scores (4.0 to 6.0, P < .0001). There were no statistically significant differences in PROs or wear rates between ceramic and cobalt-chrome groups. CONCLUSION: At a mean 16-year follow-up, young patients who had HXLPE on ceramic coupling had excellent wear properties, PROs, and acceptable survivorships.

Tough Bioplastics from Babassu Oil-Based Acrylic Monomer, Hemicellulose Xylan, and Carnauba Wax.

We describe here the fabrication, characterization, and properties of tough bioplastics made of a babassu oil-based acrylic polymer (PBBM), hemicellulose xylan grafted with PBBM chains, and carnauba wax (CW). The plastic was primarily designed to obtain bioderived materials that can replace low-density polyethylene (LDPE) in certain food packaging applications. To obtain plastic, the radical polymerization of an original babassu oil-based acrylic monomer (BBM) in the presence of xylan macromolecules modified with maleic anhydride (X-MA) was conducted. The polymerization resulted in a material (PBBM-X) mostly consisting of highly branched PBBM/X-MA macromolecules. PBBM-X has a glass transition of 42 °C, a storage modulus of 130 MPa (at 25 °C, RT), and a Young's modulus of 30 MPa at RT. To increase the moduli, we blended PBBM-X with carnauba wax, a natural material with a high modulus and a melting temperature of ~80 °C. It was found that PBBM-X is compatible with the wax, as evidenced by the alternation of the material's thermal transitions and the co-crystallization of BBM side alkyl fragments with CW. As a result, the PBBM-X/CW blend containing 40% of the wax had a storage modulus of 475 MPa (RT) and a Young's modulus of 248 MPa (RT), which is close to that of LDPE. As polyethylene, the PBBM-X and PBBM-X/CW bioplastics have the typical stress-strain behavior demonstrated by ductile (tough) plastics. However, the bioplastic's yield strength and elongation-at-yield are considerably lower than those of LDPE. We evaluated the moisture barrier properties of the PBBM-X/(40%)CW material and found that the bioplastic's water vapor permeability (WVP) is quite close to that of LDPE. Our bioderived material demonstrates a WVP that is comparable to polyethylene terephthalate and lower than the WVP of nylon and polystyrene. Taking into account the obtained results, the fabricated materials can be considered as polyethylene alternatives to provide sustainability in plastics production in the packaging areas where LDPE currently dominates.