Search Results (73)

Microplastics, plastic particles smaller than 5 mm, are now ubiquitous and represent a form of pollution that threatens ecosystems and human health, infiltrating the environment, air, and food chain. The search for solutions to microplastics requires industrial policies that limit plastic production and technological innovations for removal and recycling. Specifically, this paper reports a sustainable and cost-effective method for the detection of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) microplastics using nitrogen-doped carbon dots (N-CD) synthesized from onion peel and L-cysteine via hydrothermal carbonization. Two precursor ratios (1:1 and 1:0.30 w/w) were evaluated. The resulting N-CDs exhibited bright yellow-green fluorescence (470–500 nm) and excitation-dependent photoluminescence under 365 nm UV light. FTIR and UV-Vis spectroscopy confirmed the presence of nitrogen-containing functional groups and effective graphitization, particularly in the 1:0.30 ratio. Fluorescence imaging revealed stronger intensity and greater stain uniformity in thermally softened MPs treated with 1:0.30 N-CDs, with a peak emission of 10,230.02 a.u. at 2 h and PMT 11—surpassing the 1:1 ratio. Bandgap and absorbance analyses supported the superior optical behavior of the lower-concentration formulation. Image analysis further indicated increased luminescent area over time, and two-way ANOVA confirmed statistically significant effects of heating time and PMT settings (p < 0.05). Compared to traditional filtration staining, thermal-assisted application offered enhanced and stable fluorescence. These findings demonstrate the efficacy of green-synthesized N-CDs for MP detection, with potential scalability and environmental applicability. Future work should explore alternative biomass sources and assess N-CD performance under field conditions to optimize environmental sensing strategies. Full article

Microplastic (MP) pollution in urban areas is a growing global concern due to its health risks and environmental effects. This study investigates the sources, spatial distribution, and health risks of MPs in road dust across industrial, capital city, and peri-urban areas of Bangladesh. Street dust samples were collected from 15 heavily congested traffic sites across Dhaka and its surrounding areas. The samples were analyzed using fluorescence microscopy and Fourier Transform Infrared (FTIR) spectroscopy to identify MP types and their morphological characteristics. We have identified six types of polymers, including Polyvinyl alcohol (PVA), Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE), with industrial areas exhibiting the highest levels of MPs followed by capital city and peri-urban zones. PP was the most prevalent MP polymer, with the highest level in industrial areas (14.1 ± 1.7 MPs/g), followed by capital city (9.6 ± 1.92 MPs/g) and peri-urban areas (7.2 ± 1.56 MPs/g). Principal Component Analysis (PCA) identified traffic emissions, industrial activities, and mismanaged plastic waste as the primary sources of MPs. Health risk evaluations indicated that children are more susceptible to MP exposure through ingestion and inhalation, with industrial areas posing the highest carcinogenic risk. The findings underscore the pressing demand for better waste management systems and stricter regulatory measures to mitigate MP pollution and safeguard public health in urban environments. Addressing these challenges is essential to reduce the growing threat of MPs and their long-term effects on ecosystems and human well-being. Full article

Microplastics (MPs) are a growing environmental concern due to their ability to adsorb hazardous chemicals, such as estrogens, and be ingested by marine organisms. This study focuses on low-density polyethylene (LDPE), a polymer widely used in Kuwait, to assess its role as a carrier of endocrine-disrupting chemicals (EDCs), specifically estrogens. Biological effects were evaluated using biomarkers such as cytochrome P450 1A (CYP1A) and vitellogenin (Vtg) gene expression. Virgin LDPE MPs were exposed to influent and effluent from a wastewater treatment plant (WWTP) for four weeks to facilitate estrogen absorption. The MPs were then incorporated into fish feed pellets for dietary exposure experiments. Fish were divided into three treatment groups—exposed to either virgin MPs, WWTP-influent MPs, or WWTP-effluent MPs—and monitored over four weeks. The results showed that WWTP-exposed MPs carried detectable levels of estrogen, leading to physiological effects on yellowfin bream. Fish in the control group, which received MP-enriched diets without estrogen, experienced significant weight loss due to nutrient deprivation. In contrast, weight patterns in the treatment groups were influenced by estrogen exposure. The condition factor (CF) decreased across groups during the experiment but remained within acceptable health ranges. A significant reduction in the hepatosomatic index (HSI) was observed in the effluent-exposed group, likely due to lower estrogen levels reducing physiological stress. The findings confirm that LDPE MPs can act as carriers for estrogens, impairing fish growth and metabolism while disrupting biological processes such as cytochrome oxidase function. These results highlight the potential risks of MPs in marine ecosystems and underscore the need for further research to understand their long-term effects. Full article

Greenhouses have positively impacted plant production by allowing the cultivation of different crops per year. However, the accumulation of agricultural plastics, potentially contaminated with agrochemicals, raises environmental concerns. This work evaluates the combined effect of Bordeaux mixture and low-density polyethylene (LDPE) microplastics (<5 mm) on the growth of lettuce (Lactuca sativa L.) and soil microbial communities. Different levels of Bordeaux mixture (0, 100 and 500 mg kg⁻¹), equivalent to Cu(II) concentrations (0, 17 and 83 mg kg⁻¹), LDPE microplastics (0, 1% and 5%) and their combination were selected. After 28 days of growth, biometric and photosynthetic parameters, Cu uptake, and soil microbial responses were evaluated. Plant germination and growth were not significantly affected by the combination of Cu and plastics. However, individual Cu treatments influenced root and shoot length and biomass. Chlorophyll and carotenoid concentrations increased with Cu addition, although the differences were not statistically significant. Phospholipid fatty acid (PLFA) analysis revealed a reduction in microbial biomass at the highest Cu dose, whereas LDPE alone showed limited effects and may reduce Cu bioavailability. These results suggest that even at the highest concentration added, Cu can act as a plant nutrient, while the combination of Cu–plastics showed varying effects on plant growth and soil microbial communities. Full article

Microplastic (MP) pollution is an emerging concern in ruminant production, as animals are exposed to MPs through air, water, and feeds. Ruminants play a key role in MP transmission to humans via animal products and contribute to MP return to agricultural soil through excreta. Identifying effective strategies to mitigate MP pollution in the ruminant sector is crucial. A promising yet understudied approach involves the potential ability of rumen microbiota to degrade MPs. This study investigated the in vitro ruminal degradation of three widely distributed MPs—low-density polyethylene (LDPE), polyethylene terephthalate (PET), and polyamide (PA)—over 24, 48, and 72 h. PET MP exhibited the highest degradation rates (24 h: 0.50 ± 0.070%; 48 h: 0.73 ± 0.057%; and 72 h: 0.96 ± 0.082%), followed by LDPE MP (24 h: 0.03 ± 0.020%; 48 h: 0.25 ± 0.053%; and 72 h: 0.56 ± 0.066%) and PA MP (24 h: 0.10 ± 0.045%; 48 h: 0.02 ± 0.015%; and 72 h: 0.14 ± 0.067%). These findings suggest that the ruminal environment could serve as a promising tool for LDPE, PET, and PA MPs degradation. Further research is needed to elucidate the mechanisms involved, potentially enhancing ruminants’ natural capacity to degrade MPs. Full article

Plastic pollution poses significant environmental challenges due to its persistence and contribution to the microplastic formation, with polyethylene being among the materials more abundantly found. Understanding how different artificial weathering protocols influence the degradation of plastics is crucial for assessing their environmental impact. This study investigates the effects of three distinct artificial weathering protocols—continuous UV-A irradiation (M_L), cyclic UV-dark exposure (M_C[L→D]), and sequential UV-dark phase (M_L→D)—on the physicochemical properties of plastics, using oxo-low-density polyethylene as the model material. Surface oxidation, measured by quantification of the carbonyl index, was most pronounced under the M_C[L→D] protocol despite the shortest time of overall UV exposure, indicating that oxidative reactions continue during the dark phases. Vinyl group formation, however, required continuous or cyclic UV exposure, highlighting the critical role of light in this chemical process. Alterations in the surface hydrophilicity, measured by contact angle, and changes in molecular weight were quantified and found to closely link to the weathering conditions, with increased oxidations enhancing the surface hydrophilicity and the chain scission balanced by crosslinking with extended UV durations. These findings emphasize the importance of weathering protocols when trying to simulate conditions in the lab that are closer to the ones in the environment to understand plastic degradation mechanisms. Biodegradation experiments with Rhodococcus rhodochrous demonstrated that weathered oxo-LDPE samples with higher surface oxidation levels (ΔCI > 1) supported an increased CO₂ production by Rhodococcus rhodochrous, with the M_C[L→D]—360 h protocol yielding the highest biodegradation rates—31–43% higher than the control. Full article

Microplastics have emerged as pervasive contaminants in various ecosystems, raising considerable concerns regarding their impact on environmental health and public safety. The degradation of microplastics is thus recognized as a pressing global challenge. Photocatalytic degradation has emerged as a promising approach due to its potential for efficiency and environmental sustainability. Nevertheless, there remains a need to investigate emerging trends and advancements to understand and fully optimize this technique. Consequently, PRISMA guidelines were employed to define the search parameters, enable the identification of pertinent scholarly articles, and systematically gather bibliographic data from the published literature from 2005 to October 2024. A bibliometric analysis of 204 research articles derived from merged Scopus and Web of Science datasets was conducted to map the field’s research landscape. The analysis showed a robust annual publication growth rate of 17.94%, with leading contributions from China, India, Mexico, and the United Kingdom. Keyword analysis revealed that the commonly applied photocatalysts are titanium dioxide and zinc oxide in the photocatalytic degradation of polyethylene terephthalate, polypropylene, polystyrene, polyvinyl chloride, high-density polyethylene, and low-density polyethylene. Advances in collaboration across Asia and Europe have bolstered the research landscape. However, challenges persist in achieving cost-effective scalability, ensuring the safety of degradation byproducts, and translating laboratory findings into real-world applications. Emerging trends include the development of visible-light-responsive catalysts, advanced nanocomposites, and sustainable photocatalytic technologies. This study underscores the utility of bibliometric tools in identifying knowledge gaps and guiding the development of innovative approaches for microplastic degradation as part of environmental remediation efforts. Full article

Microplastic (MP) particles are ubiquitous in the environment and pose a growing threat to ecosystem stability. As concern over their ecological impact increases, biotests and ecotoxicological approaches using plant species have become valuable tools for research. This study aimed to evaluate the effects of varying concentrations of low-density polyethylene (LDPE) MP on seed germination, root development, and shoot growth of white mustard (Sinapis alba L.) under controlled laboratory and pot experiment conditions. For the seven-day laboratory experiment, concentrations of 0.01% and 1% w/w were used, whereas concentrations of 1% and 5% w/w were applied in the ten-day pot experiment. Results indicated no statistically significant effects of LDPE MP on germination rate or germination speed index (GSI) in either setting. However, shoot length data suggest that the 5% LDPE treatment may have a slight stimulatory effect compared to the control, though this trend was marginally significant. These findings highlight the complex and context-dependent nature of MP–plant interactions. Further research is needed to better understand the mechanisms driving these responses and to support the development of mitigation strategies for MP contamination in terrestrial ecosystems. Full article

Microplastic (MPs) pollution has emerged as a critical environmental issue due to its persistent accumulation in ecosystems, posing risks to aquatic life, food safety, and human health. In this study, magnetic Fe₃O₄ nanoparticles functionalized with citric acid (Fe₃O₄@AC) were used to remove high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) MPs from an aqueous medium. Fe₃O₄@AC was synthesized via the coprecipitation method and characterized by morphology (SEM), crystalline phases (XRD), chemical aspects (FTIR), and surface area (nitrogen sorption isotherms). The MPs removal efficiency of Fe₃O₄@AC was evaluated based on the initial concentration, contact time, and pH. The adsorption isotherm and kinetics data were best described by the Sips and pseudo-second-order models, respectively. Fe₃O₄@AC removed 80% of the MPs at a pH of 6. Based on experimental observations (zeta potential, porosity, and SEM) and theoretical insights, it was concluded that hydrogen bonding, pore filling, and van der Waals forces governed the adsorption mechanism. Reusability tests showed that Fe₃O₄@AC could be reused up to five times, with a removal efficiency above 50%. These findings suggest that Fe₃O₄@AC is a sustainable and promising material for the efficient removal of microplastics from wastewater, offering a reusable and low-impact alternative that contributes to environmentally responsible wastewater treatment strategies. Full article

This study investigates the removal of microplastics (MPs) from simulated freshwater, brackish water, and seawater using a novel agglomeration–micro-flotation technique. This method combines particle size enlargement, facilitated by kerosene as a bridging agent, with bubble size reduction through column flotation to enhance the removal rate. Six common MP types—polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride (PVC)—were evaluated under varying salinity levels and kerosene dosages. Results showed that increasing kerosene dosage significantly improved removal rates, achieving up to ~99% recovery at 10 µL for low- and medium-density MPs (PP, PE, ABS, and PS), while a higher dosage of 30 µL was required for high-density MPs (PET and PVC). Elevated salinity levels (50–100%) promoted bubble stabilization and reduced coalescence, enhancing particle–bubble collisions and the overall flotation performance. This work addresses a key research gap in flotation-based MP removal under saline conditions and highlights the dual benefits of using kerosene—not only to enhance the removal rate but also to enable energy recovery, as both kerosene and plastics are combustible. The proposed technique presents a promising approach for microplastic remediation in aquatic environments, supporting sustainable water treatment and circular resource utilization. Full article

Microplastics (MP) are widespread pollutants that pose a risk to soil ecosystems globally, especially in agricultural soils. This study introduces a method to extract and identify MP in Brazilian tropical soils, targeting debris of low-density polyethylene (LDPE) and polyvinyl chloride (PVC) polymers, commonly present in agricultural settings. The method involves removing organic matter and extracting MP using density separation with three flotation solutions: distilled water, NaCl, and ZnCl₂. Extracted MP are then analyzed through optical microscopy and Fourier transform infrared spectroscopy. The organic matter removal efficiency ranged from 46% to 89%, depending on the initial organic matter content in the soil. Recovery rates for LDPE ranged from 81.0% to 98.8%, while PVC samples showed a range of 59.7% to 75.2%. Finally, this methodology was tested in four agricultural raw soil samples (i.e., without any polymer enrichment) The values found in the soil samples were 2517.5, 2245.0, 3867.5, and 1725.0 items kg⁻¹, for ferralsol, nitisol, gleysol, and cambisol samples, respectively, with MP having diverse shapes including fragments, granules, films, and fibers. This approach lays the groundwork for future studies on MP behavior in Brazilian tropical agricultural soils. Full article

The significant waste generated by the fashion industry necessitates sustainable textile recycling strategies. Polyester, made from poly(ethylene terephthalate) (PET), is abundant in post-consumer textiles. Technologies have been developed to convert low-density garment waste into flakes, but the role of color sorting in achieving uniform aesthetics in injection-moldable plastics remains underexplored. This study compares materials extruded from dark color-sorted polyester garment flakes with those from light-color flakes in terms of processability in extrusion and injection molding. The properties examined include melt fluidity, injection molding shrinkage, and mechanical and thermal properties. Commercial chain extenders with anhydride, oxazoline, or epoxide reactive groups were added during extrusion. Interestingly, only dark-colored extruded pellets showed significant degradation, but all the chain extenders allowed melt fluidity to be controlled during reprocessing. The bisoxazoline-based additive was the most promising, due to the highly improved ductility of the samples, regardless of whether they were dark-colored or light-colored. The results indicate significant potential for the industrial recycling of post-consumer textiles and highlight the industrial feasibility of repurposing post-consumer polyester garments. This approach not only supports initiatives of circular economy but also offers a viable solution for managing textile waste, particularly in the fashion industry. Additionally, the suggested recycling route combats the production of microplastics. Full article

Microplastics (MPs) have emerged as a significant environmental threat, infiltrating livestock systems. This study presents the first in vitro investigation of the effects of low-density polyethylene (LDPE) MP contamination on rumen fermentation dynamics and feed utilization in a simulated ruminal digestive system. Concentrate feed was incubated in buffered rumen fluid collected from lambs, supplemented with LDPE MPs at concentrations of 3.3 g/L and 6.6 g/L and compared to the concentrate incubated in the buffered rumen fluid without MP contamination. The results demonstrate that both levels of LDPE MPs significantly altered rumen fermentation dynamics by reducing asymptotic gas production by 11% and 15% and increasing the constant rate of gas production by 16% and 19% at low and high addition levels, respectively, compared to the control. However, the early-stage fermentation dynamics remained unaffected. Furthermore, both levels of LDPE MPs reduced rumen protozoal populations (20% and 23%) and ammonia-nitrogen levels by 11% at both of addition levels. Despite these disruptions, rumen pH remained unaffected. Increasing the addition level of LDPE from 3.3 to 6.6 g/L did not exacerbate the disruptions. The results of this study highlight the potential risks posed by LDPE MPs in ruminal nutrition. Further in vivo investigations are essential to validate these findings and assess their impact on animal performance. Full article

The widespread presence of microplastics (MPs) in agricultural soils raises concerns regarding their impact on crop health and productivity, particularly in legumes, which are known to have soil-enhancing properties. This study investigated the effects of low-density polyethylene (LDPE), polypropylene (PP), and polyamide (PA) MPs on white lupine (Lupinus albus L.). Plants were cultivated for 110 days in glass pots containing 700 g of volcanic soil mixed with 2% w/w MPs, with four treatments (control, LDPE, PP, and PA) and five replicates each. The results indicated that PP increased soil ammonium and available nitrogen by 71% and 60%, respectively, compared to the control. LDPE increased root length by 3% and decreased chlorophyll content by 2.7%, whereas PA increased chlorophyll levels by 3.5%. Oxidative stress markers were significantly elevated in the LDPE and PA treatments, with 12% and 5.4% increases, respectively, compared with the control. However, no significant differences were observed in enzyme activity or basal soil respiration. These findings contribute to the understanding of how short-term exposure to MPs affects agricultural soils and emphasize the necessity for long-term studies to elucidate their potential effects. Full article

Wastewater treatment processes can fragment microplastics (MPs), which may subsequently enter fertilizers applied in agricultural settings. This study aimed to quantify the occurrence of MPs in stabilized sewage sludge intended for fertilizer production. Matrix elimination was performed using an oxidative method to isolate MPs, followed by MPs separation with a saturated salt solution of appropriate density to enhance the accuracy of identification. The resulting samples were analyzed using spectroscopic and microscopic techniques to provide the detailed characterization of MPs content. The highest concentrations of MPs were recorded during the months of June, July, and May, with average values of 2942, 2341, and 1746 fragments per 100 g of dry weight, respectively. The analysis revealed that fragments were the dominant morphological form, and low-density polyethylene was the most common polymer type detected. These findings underscore a significant risk of MPs re-emission into the environment through the agricultural application of fertilizers derived from sewage sludge. Such practices may lead to the introduction of between 6110 and 13,889 MPs per square meter of soil, depending on the application rates, thereby posing potential risks to soil health and the broader ecosystem. This study highlights the importance of monitoring MPs content in fertilizers derived from wastewater treatment by-products. Full article