Mechanochemical Formation of Poly(melamine-formaldehyde) Microplastic Fibers During Abrasion of Cleaning Sponges

Size-dependent internalization of polystyrene microplastics as a key factor in macrophages and systemic toxicity

Microplastics are emerging pollutants with a wide range of ecological and biological effects, including the ability to accumulate in organisms and induce toxicity. Although numerous studies have investigated the distribution and toxicity of microplastics in murine models and cell lines, the conclusions are inconsistent owing to variations in experimental designs, particle sizes, exposure methods, and dose quantifications. To address these gaps, we systematically evaluated the size-dependent internalization and toxicity of polystyrene microplastics (PS-MPs) using in vitro and in vivo models. Fluorescently labeled PS-MPs were used to confirm the negligible toxicity of fluorophores on macrophages, demonstrating their suitability for tracking particle accumulation. In vitro experiments using RAW 264.7 cell lines and primary peritoneal macrophages revealed size-dependent phagocytosis and cytotoxicity, with smaller particles (0.5 µm) demonstrating higher internalization and causing greater mitochondrial depolarization, reactive oxygen species generation, and apoptosis compared to that with larger particles (5 µm). Acute in vivo experiments comparing oral administration and tail-vein injection revealed that the absorbed dose and toxicity were significantly influenced by particle size, with smaller PS-MPs showing higher organ retention and alterations in hematological and metabolic parameters. Additionally, a 28-day subacute oral exposure study highlighted systemic toxicity, including weight loss, disrupted food intake, elevated oxidative stress markers, and reduced antioxidant enzyme activity. By integrating multiple exposure routes, macrophage models, and fluorescence toxicity evaluations, this study provided a comprehensive and realistic assessment of microplastic toxicity, offering valuable insights for advancing toxicological evaluations and regulatory frameworks. However, this study did not address the influence of other plastic types, shapes, or environmental factors on toxicity. Future studies are thus needed to explore these variables and the long-term implications of real-world microplastic exposure.

Plastics of the Future? An Interdisciplinary Review on Biobased and Biodegradable Polymers: Progress in Chemistry, Societal Views, and Environmental Implications

Global demand to reduce polymer waste and microplastics pollution has increased in recent years, prompting further research, development, and wider use of biodegradable and biobased polymers (BBPs). BBPs have emerged as promising alternatives to conventional plastics, with the potential to mitigate the environmental burdens of persistent plastic waste. We provide an updated perspective on their impact, five years after our last article, featuring several recent advances, particularly in exploring broader variety of feedstock, applying novel chemical modifications, and developing new functionalities. Life-cycle assessments reveal that environmental performance of BBPs depends on several factors including feedstock selection, production efficiency, and end-of-life management. Furthermore, the introduction of BBPs in several everyday life products has also influenced consumer perception, market dynamics, and regulatory frameworks. Although offering environmental advantages in specific applications, BBPs also raise concerns regarding their biodegradability under varying environmental conditions, potential microplastic generation, and soil health impacts. We highlight the need for a circular approach considering the entire polymer life cycle, from feedstock sourcing, modification and use, to end-of-life options. Interdisciplinary research, collaborative initiatives, and informed policymaking are crucial to unlocking the full potential of BBPs and exploiting their contribution to create a circular economy and more sustainable future.

Unseen toxins: Exploring the human health consequences of micro and nanoplastics

Micro and nanoplastics (MNPs) contamination constitute a pressing global issue with considerable ramifications for human health. Particles originating from the decomposition of plastic waste permeate ecosystems and disturb biological systems, especially the gastrointestinal (GI) tract. MNPs compromise the intestinal barrier, provoke oxidative stress, inflammation, and immunological dysfunction, and modify gut microbiota, which is associated with metabolic problems, inflammatory bowel disease (IBD), and colorectal cancer. MNPs traverse biological barriers beyond the gastrointestinal system, including the blood-brain barrier, colonic mucus layer, and placental barrier, resulting in accumulation in essential organs such as the liver, kidneys, and brain. This results in inflammatory damage, metabolic abnormalities, and oxidative stress, specifically affecting liver disease due to microbiota metabolite alteration and nephrotoxicity in the kidneys. Airborne MNPs pose an additional risk to respiratory health, aggravating ailments such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. At-risk groups, such as pregnant women, newborns, and the elderly, encounter increased dangers, as MNPs traverse the placental barrier and may induce neurological and intergenerational health consequences. These particles function as vectors for environmental pollutants, exacerbating their cardiovascular and neurological effects. Addressing the long-term consequences of MNP exposure necessitates interdisciplinary collaboration to enhance comprehension and alleviate their growing risk to human health.

Characteristics and influencing factors of microplastics entering human blood through intravenous injection

The presence of microplastics in the human body and their potential health risks have drawn widespread attention in recent years. Microplastics have been detected in human blood, though their pathways of entry remain unclear. This study employed Raman spectroscopy and energy dispersive spectroscopy to evaluate the microplastic release characteristics of intravenous medical devices, aiming to investigate the influencing factors and the risk of microplastics entering the bloodstream. The results showed that microplastics were found in three widely-used medical devices, with abundances ranging from 0.44 to 2.00 items/n. Polyethylene, polypropylene (46.2 %), fragments (96.7 %), and white (86.8 %) were the predominant characteristics. Factors such as brand, specifications, and usage scenarios influence microplastic release, leading to differences in detection rates among different medical devices (0-100%). Repeated use significantly increases the risk of microplastic release (p < 0.05). Notably, built-in filtration membranes do not completely retain microplastics and may pose a risk of shedding fibers themselves. Using the exposure assessment model, the estimated microplastic release per person per year was 3.75 items for syringe, 6.22 items for infusion set, and 0.35 items for vein detained needle. Overall, although the amount of microplastics entering the human body through intravenous injection is significantly lower than that from dietary exposure and other pathways, the risk of direct entry into the bloodstream remains a concern. This research provides critical evidence for understanding the direct pathways and risks of microplastic exposure in human blood from plastic medical devices, offering significant scientific value for assessing exposure pathways and the safety of medical device use.

Ingestion of melamine cleaning sponges-derived microplastic fibers affects the survival and reproduction of Daphnia magna

The abrasion of melamine cleaning sponges release microplastic fibers (MPFs) into the environment, yet the potential risks remain unknown. Here, we evaluated the ingestion, elimination, and toxic effects of melamine MPFs on Daphnia magna through acute and chronic exposures. This new type of MPFs displayed different morphology (a combination of linear and branched fibers with a length ranging from 10 to 157 μm) from the widely-studied MPFs released from textiles (longer and thicker linear fibers but no branched fibers). Although the lethality of melamine MPFs to neonates was not observed upon a short-term exposure (24 h), such effect was detected when the animals were exposed for a longer period (21 d) and showed a concentration-dependent manner. The MPFs tended to aggregate in the gut of D. magna, leading to a slow elimination compared to polystyrene microspheres. The MPFs remaining in the gut triggered an elevation in the intracellular reactive oxygen species, which further induced oxidative damage and eventually death. The long-term exposure to MPFs also stimulated D. magna to produce more offspring. Our findings show the chronic toxicity of the sponges-derived MPFs to typical freshwater zooplankton and accentuate the environmental impacts related to the extensive use of the sponges.

Food packaging solutions in the post-per- and polyfluoroalkyl substances (PFAS) and microplastics era: A review of functions, materials, and bio-based alternatives

Food packaging (FP) is essential for preserving food quality, safety, and extending shelf-life. However, growing concerns about the environmental and health impacts of conventional packaging materials, particularly per- and polyfluoroalkyl substances (PFAS) and microplastics, are driving a major transformation in FP design. PFAS, synthetic compounds with dual hydro- and lipophobicity, have been widely employed in food packaging materials (FPMs) to impart desirable water and grease repellency. However, PFAS bioaccumulate in the human body and have been linked to multiple health effects, including immune system dysfunction, cancer, and developmental problems. The detection of microplastics in various FPMs has raised significant concerns regarding their potential migration into food and subsequent ingestion. This comprehensive review examines the current landscape of FPMs, their functions, and physicochemical properties to put into perspective why there is widespread use of PFAS and microplastics in FPMs. The review then addresses the challenges posed by PFAS and microplastics, emphasizing the urgent need for sustainable and bio-based alternatives. We highlight promising advancements in sustainable and renewable materials, including plant-derived polysaccharides, proteins, and waxes, as well as recycled and upcycled materials. The integration of these sustainable materials into active packaging systems is also examined, indicating innovations in oxygen scavengers, moisture absorbers, and antimicrobial packaging. The review concludes by identifying key research gaps and future directions, including the need for comprehensive life cycle assessments and strategies to improve scalability and cost-effectiveness. As the FP industry evolves, a holistic approach considering environmental impact, functionality, and consumer acceptance will be crucial in developing truly sustainable packaging solutions.