Uptake and toxicity of micro-/nanoplastics derived from naturally weathered disposable face masks in developing zebrafish: Impact of COVID-19 pandemic on aquatic life

Accumulation and depuration of tire wear particles in zebrafish (Danio rerio) and toxic effects on gill, liver, and gut

The toxic effects of tire wear particles (TWPs) in the environment are a growing concern for a variety of aquatic organisms. However, studies about TWPs toxicity on aquatic organisms are limited. This study investigated the accumulation and depuration of TWPs in zebrafish at three different concentrations (5 mg/L, 10 mg/L, and 20 mg/L), as well as the toxic effects on the gill, liver, and gut. We found that TWPs could accumulate in the gill and gut for a long time, and the number of TWPs at the high-concentration (20 mg/L) was higher than at the low-concentration (5 mg/L). TWPs induced oxidative stress in the gill and liver. The liver transcriptome profiles indicated that the high concentration of TWPs tended to up-regulate metabolic processes, whereas the low concentration of TWPs was inclined to down-regulate cellular processes. The high-concentration treatment significantly increased xenobiotic biodegradation and metabolism, and lipid metabolism-related pathways, whereas the low-concentration treatment distinctly altered amino acid metabolism-related pathways. The expression of gstt1b, ugt1a1, mgst3b, miox, hsd17b3, and cyp8b1 gene was up-regulated in all TWPs treatments. In addition, Gemmobacter and Shinella enriched in the high-concentration treatment were closely correlated with the degradation of TWPs. These findings provided objective evidence for the toxicity evaluation of TWPs on zebrafish.

Cu-ZnO Embedded in a Polydopamine Shell for the Generation of Antibacterial Surgical Face Masks

A new easy protocol to functionalize the middle layer of commercial surgical face masks (FMs) with Zn and Cu oxides is proposed in order to obtain antibacterial personal protective equipment. Zinc and copper oxides were synthesized embedded in a polydopamine (PDA) shell as potential antibacterial agents; they were analyzed by XRD and TEM, revealing, in all the cases, the formation of metal oxide nanoparticles (NPs). PDA is a natural polymer appreciated for its simple and rapid synthesis, biocompatibility, and high functionalization; it is used in this work as an organic matrix that, in addition to stabilizing NPs, also acts as a diluent in the functionalization step, decreasing the metal loading on the polypropylene (PP) surface. The functionalized middle layers of the FMs were characterized by SEM, XRD, FTIR, and TXRF and tested in their bacterial-growth-inhibiting effect against Klebsiella pneumoniae and Staphylococcus aureus. Among all functionalizing agents, Cu2O-doped-ZnO NPs enclosed in PDA shell, prepared by an ultrasound-assisted method, showed the best antibacterial effect, even at low metal loading, without changing the hydrophobicity of the FM. This approach offers a sustainable solution by prolonging FM lifespan and reducing material waste.

An investigation into the aging mechanism of disposable face masks and the interaction between different influencing factors

In the natural environment, a symphony of environmental factors including sunlight exposure, current fluctuations, sodium chloride concentrations, and sediment dynamics intertwine, potentially magnifying the impacts on the aging process of disposable face masks (DFMs), thus escalating environmental risks. Employing Regular Two-Level Factorial Design, the study scrutinized interactive impacts of ultraviolet radiation, sand abrasion, acetic acid exposure, sodium chloride levels, and mechanical agitation on mask aging. Aging mechanisms and environmental risks linked with DFMs were elucidated through two-dimensional correlation analyses and risk index method. Following a simulated aging duration of three months, a single mask exhibited the propensity to release a substantial quantity of microplastics, ranging from 38,800 ± 360 to 938,400 ± 529 particles, and heavy metals, with concentrations from 0.06 ± 0.02 μg/g (Pb) to 29.01 ± 1.83 μg/g (Zn). Besides, specific contaminants such as zinc ions (24.24 μg/g), chromium (VI) (4.20 μg/g), thallium (I) (0.92 μg/g), tetracycline (0.51 μg/g), and acenaphthene (1.73 μg/g) can be adsorbed significantly by aged masks. The study elucidates pivotal role of interactions between ultraviolet radiation and acetic acid exposure in exacerbating the environmental risks associated with masks, while emphasizing the pronounced influence of many other interactions. The research provides a comprehensive understanding of the intricate aging processes and ensuing environmental risks posed by DFMs, offering valuable insights essential for developing sustainable management strategies in aquatic ecosystems.

The hidden threat: Unraveling the impact of microplastics on reproductive health

Microplastics, with intricate physical and chemical characteristics, infiltrate the food chain and extensively impact ecosystems. Despite acknowledging the link between environmental pollution and declining fertility, the specific mechanisms affecting reproductive health remain to be elucidated. This review emphasizes the global correlation between microplastics and subfertility, focusing on entry pathways and impacts on ecosystems. Research suggests that microplastics disrupt the neuroendocrine system, influencing sex hormone synthesis through the hypothalamic-pituitary-gonadal (HPG) axis. In the reproductive system, microplastics interfere with the blood-testis barrier, impairing spermatogenesis in males, and causing placental dysfunction, ovarian atrophy, endometrial hyperplasia, and fibrosis in females. Moreover, microplastics potentially affect offspring's lipid metabolism and reproductive functions. However, complex microplastic compositions and detection method limitations impede research progress. Mitigation strategies for reproductive effects, combined with addressing microplastic pollution through sustainable practices, are imperative. This review underscores the urgency of global initiatives and collaborative research to safeguard reproductive health amid escalating microplastic contamination.

Global daily mask use estimation in the pandemic and its post environmental health risks: Analysis based on a validated dynamic mathematical model

The outbreak of the COVID-19 pandemic led to a sharp increase in disposable surgical mask usage. Discarded masks can release microplastic and cause environmental pollution. Since masks have become a daily necessity for protection against virus infections, it is necessary to review the usage and disposal of masks during the pandemic for future management. In this study, we constructed a dynamic model by introducing related parameters to estimate daily mask usage in 214 countries from January 22, 2020 to July 31, 2022. And we validated the accuracy of our model by establishing a dataset based on published survey data. Our results show that the cumulative mask usage has reached 800 billion worldwide, and the microplastics released from discarded masks due to mismanagement account for 3.27% of global marine microplastic emissions in this period. Furthermore, we illustrated the response relationship between mask usage and the infection rates. We found a marginally significant negative correlation existing between the mean daily per capita mask usage and the rate of cumulative confirmed cases within the range of 25% to 50%. This indicates that if the rate reaches the specified threshold, the preventive effect of masks may become evident.

A metabolomics perspective on the effect of environmental micro and nanoplastics on living organisms: A review

The increasing trend regarding the use of plastics has arisen an exponential concern on the fate of their derived products to the environment. Among these derivatives, microplastics and nanoplastics (MNPs) have been featured for their associated environmental impact due to their low molecular size and high surface area, which has prompted their ubiquitous transference among all environmental interfaces. Due to the heterogenous chemical composition of MNPs, the study of these particles has focused a high number of studies, as a result of the myriad of associated physicochemical properties that contribute to the co-transference of a wide range of contaminants, thus becoming a major challenge for the scientific community. In this sense, both primary and secondary MNPs are well-known to be adscribed to industrial and urbanized areas, from which they are massively released to the environment through a multiscale level, involving the atmosphere, hydrosphere, and lithosphere. Consequently, much research has been conducted on the understanding of the interconnection between those interfaces, that motivate the spread of these contaminants to biological systems, being mostly represented by the biosphere, especially phytosphere and, finally, the anthroposphere. These findings have highlighted the potential hazardous risk for human health through different mechanisms from the environment, requiring a much deeper approach to define the real risk of MNPs exposure. As a result, there is a gap of knowledge regarding the environmental impact of MNPs from a high-throughput perspective. In this review, a metabolomics-based overview on the impact of MNPs to all environmental interfaces was proposed, considering this technology a highly valuable tool to decipher the real impact of MNPs on biological systems, thus opening a novel perspective on the study of these contaminants.

Exploring the release mechanism of micro/nanoplastics from different layers of masks in water: towards reduction of plastic contamination in masks

During the COVID-19 pandemic, a substantial quantity of disposable face masks was discarded, consisting of three layers of nonwoven fabric. However, their improper disposal led to the release of microplastics (MPs) and nanoplastics (NPs) when they ended up in aquatic environments. To analyze the release kinetics and size characteristics of these masks, release experiments were performed on commercially available disposable masks over a period of 7 days and micro- and nanoplastic releases were detected using fiber counting and nanoparticle tracking analysis. The study's findings revealed that there was no significant difference (p > 0.05) in the quantity of MPs released among the layers of the masks. However, the quantity of NPs released from the middle layer of the mask was 25.9 ± 1.3 × 108 to 81.3 ± 5.3 × 108 particles/piece, significantly higher than the inner and outer layers (p < 0.05). The release process of micro/nanoplastics (M/NPs) from each layer of the mask followed the Elovich equation and the power function equation, indicating that the release was divided into two stages. MPs in the range of 1-500 µm and NPs in the range of 100-300 nm dominated the release from each layer of the mask, accounting for an average of 93.81% and 67.52%, respectively. Based on these findings, recommendations are proposed to reduce the release of M/NPs from masks during subsequent use.

Disposable surgical/medical face masks and filtering face pieces: Source of microplastics and chemical additives in the environment

The production and consumption of disposable face masks (DFMs) increased intensely during the COVID-19 pandemic, leading to a high amount of them being found in the terrestrial and aquatic environment. The main goal of this research study is to conduct a comparative evaluation of the water-leachability of microplastics (MPs) and chemical additives from various types of disposable surgical/medical face masks (MM DFMs) and filtering face pieces (FFPs). Fourier-Transform Infrared Spectroscopy was used for MPs analysis. Liquid Chromatography/High Resolution Mass Spectrometry was used to analyse analytes presented in the water-leachates of DFMs. FFPs released 3-4 times more microplastic particles compared to MM DFMs. The release of MPs into water from all tested DFMs without mechanical stress suggests potential MP contamination originating from the DFM production process. Our study for the first time identified bisphenol B (0.25-0.42 μg/L) and 1,4-bis(2-ethylhexyl) sulfosuccinate (163.9-115.0 μg/L) as leachables from MM DFMs. MPs in the water-leachates vary in size, with predominant particles <100 μm, and the release order from DFMs is MMIIR > MMII > FFP3>FFP2>MMI. The main type of microplastics identified in the water leachates of the investigated face masks was polypropylene, accounting for 93-97% for MM DFMs and 82-83% for FFPs. Other polymers such as polyethylene, polycarbonate, polyester/polyethylene terephthalate, polyamide/Nylon, polyvinylchloride, and ethylene-propylene copolymer were also identified, but in smaller amounts. FFPs released a wider variety and a higher percentage (17-18%) of other polymers compared to MM DFMs (3-7%). Fragments and fibres were identified in all water-leachate samples, and fragments, particularly debris of polypropylene fibres, were the most common MP morphotype. The findings in this study are important in contributing additional data to develop science-based policy recommendations on the health and environmental impacts of MPs and associated chemical additives originated from DFMs.

Microplastics release from face masks: Characteristics, influential factors, and potential risks

Since the COVID-19 pandemic, face masks have been used popularly and disposed of improperly, leading to the generation of a large amount of microplastics. The objective of this review is to provide a comprehensive insight into the characteristics of mask-derived microplastics, the influential factors of microplastics release, and the potential risks of these microplastics to the environment and organisms. Mask-derived microplastics were predominantly transparent fibers, with a length of <1 mm. The release of microplastics from masks is mainly influenced by mask types, use habits, and weathering conditions. Under the same conditions, surgical masks release more microplastics than other types of masks. Long-term wearing of masks and the disinfection for reuse can promote the release of microplastics. Environmental media, UV irradiation, temperature, pH value, and mechanical shear can also influence the microplastics release. The risks of mask-derived microplastics to human health via inhalation cannot be neglected. Future studies should pay more attention to the release of microplastics from the masks with alternative materials and under more weathering conditions.