The case of "public congregation vs. COVID-19 PPE pollution": Evidence, lessons, and recommendations from the annual pilgrimage to the Catholic Holy Site in Mexico City, Mexico

Personal protective equipment (PPE) litter in terrestrial urban areas of Iligan City, Philippines

In recent years, many countries have relied on the massive use of personal protective equipment (PPE) following the recommendation of the World Health Organization (WHO) to combat COVID-19, an infectious disease caused by the SARS-CoV-2 virus. These PPEs include facemasks, face shields, disinfectant wipes, and disposable gloves. While PPE serves as protection, it can also be a source of pollution. This study is the first to establish a baseline monitoring and assessment of the spatial distribution of COVID-19-related PPE litter approaching the post-pandemic from the urban areas in Iligan City, Philippines. A total of 1632 COVID-19 PPE litter were gathered in all surveyed locations, predominantly facemasks (90.7%) and disinfectant wipes (8.8%). Among the surveyed areas, the location that recorded the highest count and density of PPE litter is in a residential zone (52.14%; n = 851; 0.0317 item m-2); the lowest was determined in recreational parks (2.57%; n = 42; 0.0016 item m-2). The significant difference in the total count of PPE items in each location could be traced to the varying land uses and ecosystems as well as the human behavior and activities. FTIR results reveal that all types of facemasks sampled are principally made of polypropylene, a material that threatens environmental sustainability and low recyclability. As the country is embracing the new normal and somewhat returning to pre-pandemic activities, this study calls for the prioritization of the government agendas on ecological solid waste management in the country.

Toxic effect of chronic exposure to polyethylene nano/microplastics on oxidative stress, neurotoxicity and gut microbiota of adult zebrafish (Danio rerio)

The rapid development of aquaculture industry has provided a large amount of high-quality animal protein, while the food safety caused by microplastics and nanoplastics (MP/NPs) has become a major concern. In addition, recent evidence has shown the potential toxic effect of PE-MP/NPs, highlighting the need for further research into their environmental and health impacts. Chronic exposure of polyethylene microplastics (PE-MPs) and nanoplastics (PE-NPs) on adult zebrafish were conducted in the present study for 21 d. Organ-dependent oxidative damage induced by MP/NPs was observed. Insignificant differences in neurotoxicity and dysbiosis of gut microbiota were found between MPs and NPs. Changes in glutathione S-transferase (GST), glutathione (GSH), catalase (CAT), lipid peroxidation (LPO), and superoxide dismutase (SOD) showed that MP/NPs induced oxidative damage in gill and intestinal cells of zebrafish. The inhibited AChE activity suggested the potential neurotoxicity of microplastics and nanoplastics (MP/NPs). In addition, chronic exposure increased the alpha-diversity of intestinal microbiota. At the phylum level, the average relative abundance of Proteobacteria increased from 29.73% (control group) to 66.10% (microplastics), 54.84% (nanoplastics) and 60.03% (combined exposure), respectively. Tenericutes decreased from 55.43% (control group) to 20.02% (microplastics), 22.44% (nanoplastics) and 31.77% (combined exposure), respectively. Overall, this study provides new insights and objective evidence for the toxicity assessment of PE-MPs.

Face masks: a COVID-19 protector or environmental contaminant?

Face masks, a prime component of personal protective equipment (PPE) items, have become an integral part of human beings to survive under the ongoing COVID-19 pandemic situation. The global population requires an estimated 130 billion face masks and 64 billion gloves/month, while the COVID-19 pandemic has led to the daily disposal of approximately 3.5 billion single-use face masks, resulting in a staggering 14,245,230.63 kg of face mask waste. The improper disposal of face mask wastes followed by its mismanagement is a challenge to the scientists as the wastes create pollution leading to environmental degradation, especially plastic pollution (macro/meso/micro/nano). Each year, an estimated 0.15-0.39 million tons of COVID-19 face mask waste, along with 173,000 microfibers released daily from discarded surgical masks, could enter the marine environment, while used masks have a significantly higher microplastic release capacity (1246.62 ± 403.50 particles/piece) compared to new masks (183.00 ± 78.42 particles/piece). Surgical face masks emit around 59 g CO2-eq greenhouse gas emissions per single use, cloth face masks emit approximately 60 g CO2-eq/single mask, and inhaling or ingesting microplastics (MPs) caused adverse health problems including chronic inflammation, granulomas or fibrosis, DNA damage, cellular damage, oxidative stress, and cytokine secretion. The present review critically addresses the role of face masks in reducing COVID-19 infections, their distribution pattern in diverse environments, the volume of waste produced, degradation in the natural environment, and adverse impacts on different environmental segments, and proposes sustainable remediation options to tackle environmental challenges posed by disposable COVID-19 face masks.

Personal protective equipment waste management behavior of undergraduates in Xi'an City based on extended theory of value-identity-personal norm model

The COVID-19 pandemic has changed people's lives, with the most prominent change being the use of Personal Protective Equipment (PPE). In this study, we used the extended Value-Identity-Personal (VIP) norm model to empirically analyze the influencing factors of Pro-Environmental Behavior (PEB) among college students in Xi 'an, China, while considering the usage of PPE as an example of PEB. We proposed nine hypothetical questions, and the VIP model was established through the SmartPLS software to test the valid questionnaires of 414 college students. The verification results indicated that all the nine hypotheses were supported statistically, with personal environmental social responsibility and personal norms showing the most significant direct impact on PEB; notably, personal norms were also strongly influenced by environmental personal social responsibility. Biosphere values affected PEB indirectly, through self-identity and individual norms. This study proposes viable countermeasures and suggestions for college students to improve PEB; our findings can serve as a reference for policymakers and stakeholders to ensure the effective waste management of personal safety equipment.

Chemical-analytical characterization and leaching of heavy metals associated with nanoparticles and microplastics from commercial face masks and the abundance of personal protective equipment (PPE) waste in three metropolitan cities of South America

In this study, we surveyed the presence of personal protective equipment (PPE) waste on the streets of Bogotá-Colombia, Lima-Perú, and Mar del Plata-Argentina. Furthermore, this work is also focused on the release capacity of Ag, Cu, and Zn metals associated with nanoparticles, and microplastics (MPs) from textile face masks (TFMs) and disposable face masks. According to our results, an association between low-income areas and PPE waste was found, which may be related to the periodicity of waste collection and economic activity. Polymers, like polypropylene, cotton-polyester, and additives, such as CaCO₃, MgO, and Ag/Cu as nanoparticles, were identified. TFMs released high levels of Cu (35,900-60,200 μg·L^-1), Zn (2340-2380 μg·L^-1), and MPs (4528-10,640 particles/piece). Metals associated with nanoparticles leached by face masks did not present any antimicrobial activity against P. aeruginosa. Our study suggests that TFMs may leach large amounts of polluting nano/micromaterials in aquatic environments with potential toxicological effects on organisms.

Current knowledge on the presence, biodegradation, and toxicity of discarded face masks in the environment

During the first year of the COVID-19 pandemic, facemasks became mandatory, with a great preference for disposable ones. However, the benefits of face masks for health safety are counteracted by the environmental burden related to their improper disposal. An unprecedented influx of disposable face masks entering the environment has been reported in the last two years of the pandemic, along with their implications in natural environments in terms of their biodegradability, released contaminants and ecotoxicological effects. This critical review addresses several aspects of the current literature regarding the (bio)degradation and (eco)toxicity of face masks related contaminants, identifying uncertainties and research needs that should be addressed in future studies. While it is indisputable that face mask contamination contributes to the already alarming plastic pollution, we are still far from determining its real environmental and ecotoxicological contribution to the issue. The paucity of studies on biodegradation and ecotoxicity of face masks and related contaminants, and the uncertainties and uncontrolled variables involved during experimental procedures, are compromising eventual comparison with conventional plastic debris. Studies on the abundance and composition of face mask-released contaminants (microplastics/fibres/ chemical compounds) under pre- and post-pandemic conditions should, therefore, be encouraged, along with (bio)degradation and ecotoxicity tests considering environmentally relevant settings. To achieve this, methodological strategies should be developed to overcome technical difficulties to quantify and characterise the smallest MPs and fibres, adsorbents, and leachates to increase the environmental relevancy of the experimental conditions.

Temporal considerations for an effective sampling of personal protective equipment litter derived from the COVID-19 pandemic

Personal protective equipment (PPE) has become a new pollutant derived from the COVID-19 pandemic. Much of the efforts to characterize PPE litter has focused on its spatial distribution (i.e., trying to identify hotspots of PPE litter), however, such efforts have been limited in the temporal domain, which might result in under- or overestimations in annual projections. Here, using 55 continuous days of sampling in an urban and tropical neighborhood in south east Mexico, I show that in order to have a robust and defensible average and variance values it is needed at least 22 days of random sampling. Nonetheless, this minimum number might change in different ecosystems and land use areas of the built environment due to the temporal variability of the human behavior and activities related to the surveyed areas, as well as the influence of weather conditions that might affect the mobility of people. Furthermore, I discuss how it is recommended to report the daily average density of PPE litter (items m^-2 day^-1) and its variability (i.e., 95 % confidence intervals), rather than only the density of PPE litter (items m^-2) in order to facilitate annual estimates of PPE litter disposal.

Strengthening citizen science partnerships with frontline sanitation personnel to study and tackle plastic pollution

The COVID-19 outbreak has boosted demand for and use of personal protective equipment (PPE) and other single-use plastics, adding to the environment's already high levels of plastic pollution and endangering biota. Estimating the relative abundance of PPE wastes that end up in the environment is crucial and has remained a challenge for COVID-19 researchers. Citizen science has been utilized in recent studies to monitor and collect data using volunteers, and it has proven to be a valuable approach even in difficult situations. The expansion of citizen scientific participation groups is important in light of the growing anthropogenic impacts of plastic pollution. To date, frontline sanitary personnel are often overlooked and underutilized in a citizen science perspective, yet they serve critical roles in maintaining cleanliness in key environmental settings (e.g., beaches and streets) both during and beyond the pandemic. This paper explores and emphasizes the advantages and need of including frontline sanitary personnel into citizen science for the benefit of both researchers and communities, as well as to encourage long-term goals in global plastic litter monitoring, thereby exemplifying citizen science opportunities. Recommendations are made to design in order to improve the future status of citizen science development.

Generation of environmental persistent free radicals (EPFRs) enhances ecotoxicological effects of the disposable face mask waste with the COVID-19 pandemic

A large amount of disposable plastic face masks (DPFs) is produced and used during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, which results in an inevitable consequence of the dramatic increase of DPFs waste. However, the impact of DPFs exposure to the environment on their toxicity is rarely considered. In this study, a range of 76-276 items/L microplastics (MPs) was detected in the DPFs leachates, and fibrous (> 80.3%) and polypropylene (PP, > 89.2%) MPs were dominant. Co, Cu, Ni, Sr, Ti and Zn, were commonly detected in all leachates of the tested DPFs. Organics, such as acetophenone, 2,4-Di-tert-butylphenol, benzothiazole, bisphenol-A and phthalide, were found in the DPFs leachate, which were including organic solvents and plasticizer. Besides, we first found an emerging environmental risk substance, namely environmentally persistent free radicals (EPFRs), was generated in the DPFs leachates. The characteristic g-factors of the EPFRs was in a range of 2.003-2.004, identified as mixture of carbon- and oxygen-centered radicals. By means of in vitro toxicity assay, the DPFs leachate were confirmed to cause cytotoxicity and oxidative stress. Significantly, it is found that the formed EPFRs could contribute more toxic effects. Furthermore, when compared to N95 respirators, the tested surgical masks tend to release more MPs, leach more metals and organics, and generate more EPFRs. Surgical masks were thus showed higher risk than N95 respirators after exposure to water. This work highlights the importance of understanding the chemical complexity and possible toxicity of DPFs for their risk assessment.