Characteristics, sources and influencing factors of atmospheric deposition of microplastics in three different ecosystems of Beijing, China

Atmospheric deposition of microplastics at a western China metropolis: Relationship with underlying surface types and human exposure

The issue of atmospheric microplastic (AMP) contamination is gaining increasing attention, yet the influencing factors and human exposure are not well-understood. In this study, atmospheric depositions were collected in the megacity of Chengdu, China, to investigate the pollution status and spatial disparities in AMP distribution. The relationship between AMP abundance and underlying surface types was then analyzed with the aid of back trajectory simulation. Additionally, a probabilistic estimation of human exposure to AMP deposition during outdoor picnics was provided, followed by the calculation of AMP loading into rivers. Results revealed that the mean deposition flux ranged within 207.1-364.0 N/m2/d (14.17-33.75 μg/m2/d), with significantly larger AMP abundance and sizes in urban compared to rural areas. Areas of compact buildings played an important role in contributing to both fibrous and non-fibrous AMP contamination from urban to rural areas, providing new insight into potential sources of pollution. This suggests that appropriate plastic waste disposal in compact building areas should be prioritized for controlling AMP pollution. Besides, the median ingestion of deposited AMPs during a single picnic was 34.9 N/capita/hour (3.03 × 10-3 μg/capita/hour) for urban areas and 17.8 N/capita/hour (7.74 × 10-4 μg/capita/hour) for suburbs. Furthermore, the worst-case scenario of AMPs loading into rivers was investigated, which could reach 170.7 kg in summertime Chengdu. This work could contribute to a better understanding of the status of AMP pollution and its sources, as well as the potential human exposure risk.

Inter-annual variation in the microplastics abundance in feces of the Baird's tapir (Tapirus bairdii) from the Selva Maya, México

Microplastics (MPs) are found in a wide range of ecosystems, from the Arctic to the deep ocean. However, there is no data on their presence in terrestrial mammals that inhabit the Selva Maya. The aim of this study is to detect the presence of MPs in the feces of the Baird's tapir (Tapirus bairdii) from the region of Calakmul, located in the Yucatan Peninsula, Mexico. We analyzed 129 fecal samples collected during 2017 and 2018, obtaining 57 and 72 samples during the rainy and dry seasons respectively. Sixty-eight percent of the samples contained 743 MPs with a mean of 19.3 ± 28.1 MPs/kg of dry weight (DW) feces in both years. An inter-annual variation in the average abundance of microplastic was observed during the two-year period (2017-2018), with a 72 % increase in these plastic particles in feces. Fourteen polymers were identified, with ethylene vinyl acetate (EVA), polypropylene (PP) and polyester (PES) being the most abundant during both years. Although the effects of MPs on the health of tapirs are not known, their presence is cause for concern. There is an urgent need for the implementation of appropriate plastic waste management programs in communities of the Selva Maya to diminish the consumption of MPs in species including humans where they pose a significant risk to health. ENVIRONMENTAL IMPLICATIONS: The use of plastics worldwide is increasing every day, so the presence of microplastics is and will continue to be a major environmental problem. It is known that contaminants can adhere to plastics, making them hazardous materials. Microplastics can contaminate remote areas such as Biosphere Reserves. Terrestrial species such as the tapir can ingest microplastics, putting their health at risk. Knowing the dispersion of microplastics is very important in order to manage them properly, taking into account their emission sources and type of polymer.

Probabilistic Estimation of Airborne Micro- and Nanoplastic Intake in Humans

Little research exists on the magnitude, variability, and uncertainty of human exposure to airborne micro- and nanoplastics (AMNPs), despite their critical role in human exposure to MNPs. We probabilistically estimate the global intake of AMNPs through three main pathways: indoor inhalation, outdoor inhalation, and ingestion during indoor meals, for both children and adults. The median inhalation of AMPs is 1,207.7 (90% CI, 42.5-8.48 × 104) and 1,354.7 (90% CI, 47.4-9.55 × 104) N/capita/day for children and adults, respectively. The annual intake of AMPs is 13.18 mg/capita/a for children and 19.10 mg/capita/a for adults, which is approximately one-fifth and one-third of the mass of a standard stamp, assuming a consistent daily intake of medians. The majority of AMP number intake occurs through inhalation, while the ingestion of deposited AMPs during meals contributes the most in terms of mass. Furthermore, the median ANP intake through outdoor inhalation is 9,638.1 N/day (8.23 × 10-6 μg/d) and 5,410.6 N/day (4.62 × 10-6 μg/d) for children and adults, respectively, compared to 5.30 × 105 N/day (5.79 × 10-4 μg/d) and 6.00 × 105 N/day (6.55 × 10-4 μg/d) via indoor inhalation. Considering the increased toxicity of smaller MNPs, the significant number of ANPs inhaled warrants great attention. Collaborative efforts are imperative to further elucidate and combat the current MPN risks.

Seasonal dynamics and typology of microplastic pollution in Huixian karst wetland groundwater: Implications for ecosystem health

This study offers an insightful and detailed examination of microplastic pollution in the Huixian karst wetland's groundwater, providing novel insights into the complex interplay of microplastic characteristics and their seasonal dynamics. We meticulously quantified microplastic concentrations, observing significant seasonal variation with values ranging from 4.9 to 13.4 n·L-1 in the wet season and 0.53-49.4 n·L-1 in the dry season. Our analysis pinpoints human activities and atmospheric deposition as key contributors to this contamination. A critical finding of our research is the pronounced disparity in microplastic levels between open wells and covered artesian wells, highlighting the vulnerability of open wells to higher pollution levels. Through correlation analysis, we unearthed the crucial influence of the karst region's unique hydrogeological characteristics on microplastic migration, distinctively different from non-karst areas. The karst terrain, characterized by its caves and subterranean rivers, facilitates the downward movement of microplastics from surface to groundwater, exacerbating pollution levels. Our investigation identifies agricultural runoff and domestic wastewater as primary pollution sources. These findings not only underscore the urgent need for environmental stewardship in karst regions but also provide a crucial foundation for formulating effective strategies to mitigate microplastic pollution in karst groundwater. The implications of this study extend beyond the Huixian karst wetland, offering a template for addressing microplastic pollution in similar ecosystems globally.

Human Exposure to Ambient Atmospheric Microplastics in a Megacity: Spatiotemporal Variation and Associated Microorganism-Related Health Risk

Microplastics are found in various human tissues and are considered harmful, raising concerns about human exposure to microplastics in the environment. Existing research has analyzed indoor and occupational scenarios, but long-term monitoring of ambient atmospheric microplastics (AMPs), especially in highly polluted urban regions, needs to be further investigated. This study estimated human environmental exposure to AMPs by considering inhalation, dust ingestion, and dermal exposure in three urban functional zones within a megacity. The annual exposure quantity was 7.37 × 104 items for children and 1.06 × 105 items for adults, comparable with the human microplastic consumption from food and water. Significant spatiotemporal differences were observed in the characteristics of AMPs that humans were exposed to, with wind speed and rainfall frequency mainly driving these changes. The annual human AMP exposure quantity in urban green land spaces, which were recognized as relatively low polluted zones, was comparable with that in public service zones and residential zones. Notably, significant positive correlations between the AMP characteristics and the pathogenicity of the airborne bacterial community were discovered. AMP size and immune-mediated disease risks brought by atmospheric microbes showed the most significant relationship, where Sphingomonas might act as the potential key mediator.

Occurrence, influencing factors and sources of atmospheric microplastics in peri-urban farmland ecosystems of Beijing, China

Atmosphere is an important component of the microplastics (MPs) cycle. However, studies on atmospheric MPs in peri-urban farmland ecosystems are limited. Herein, the occurrence, influencing factors and geographic sources of atmospheric MPs in peri-urban farmland ecosystems have been analyzed. The average deposition flux of atmospheric MPs was found to be 167.09 ± 92.03 item·m-2·d-1. Around 68 % MPs had particle size <1000 μm, while the main colors of MPs were black (40.71 %) and blue (20.64 %). Approximately 91 % MPs were fibers, while polyethylene terephthalate (49 %) and rayon (36.93 %) were observed as the major microplastic types. The main factors influencing the atmospheric deposition of MPs were gross domestic product (GDP), population density, air pressure, and wind direction. Deposition fluxes exhibited positive correlations with GDP, population density and air pressure, and negative correlations with wind direction. Combined with the backward trajectory model, MPs were mainly found to be originated from the southeast in September and from the northwest in October-February. The study of atmospheric MPs in farmland ecosystems in peri-urban areas is important for the protection of ecological environment, prevention of human diseases and control of MPs pollution.

Microplastics in the atmosphere: Adsorb on leaves and their effects on the phyllosphere bacterial community

Phyllosphere is the largest interface between the atmosphere and terrestrial ecosystems and serves as a major sink for atmospheric microplastics (MPs). It is also a unique habitat for microbiota with diverse ecological functions. This field study investigated the characteristics of atmospheric MPs adsorbed on leaves with automatic technology, and found their abundance was 3.62 ± 1.29 items cm-2. MPs on leaves were mainly below 80 µm, and dominated by polyamide, polyethene, and rubber. MPs on leaves correlated significantly with the structure and functions of the phyllosphere bacterial community (PBC). Both the MPs abundance and size distribution (MSD) were positively correlated with the α diversity and negatively correlated with the β diversity and network complexity of PBC. PBC functions of environmental and genetic information process were negatively correlated with MPs abundance, and functions related to human diseases and cellular process were positively correlated with MSD significantly. The relative abundance of Sphingomonas was significantly correlated with the MSD, suggesting that Sphingomonas might emerge as the key genus involved in the pathogenicity of PBC mediated by MPs. These results highlighted the ecological health risks of atmospheric MPs as they can be transferred anywhere and potentially increase the pathogenicity of local phyllosphere microflora.

A comprehensive review of micro- and nano-plastics in the atmosphere: Occurrence, fate, toxicity, and strategies for risk reduction

Micro- and nano-plastics (MNPs) have received considerable attention over the past 10 years due to their environmental prevalence and potential toxic effects. With the increase in global plastic production and disposal, MNP pollution has become a topic of emerging concern. In this review, we describe MNPs in the atmospheric environment, and potential toxicological effects of exposure to MNPs. Studies have reported the occurrence of MNPs in outdoor and indoor air at concentrations ranging from 0.0065 items m-3 to 1583 items m-3. Findings have identified plastic fragments, fibers, and films in sizes predominantly <1000 μm with polyamide (PA), polyester (PES), polyethylene terephthalate (PET), polypropylene (PP), rayon, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and ethyl vinyl acetate (EVA) as the major compounds. Exposure through indoor air and dust is an important pathway for humans. Airborne MNPs pose health risks to plants, animals, and humans. Atmospheric MNPs can enter organism bodies via inhalation and subsequent deposition in the lungs, which triggers inflammation and other adverse health effects. MNPs could be eliminated through source reduction, policy/regulation, environmental awareness and education, biodegradable materials, bioremediation, and efficient air-filtration systems. To achieve a sustainable society, it is crucial to implement effective strategies for reducing the usage of single-use plastics (SUPs). Further, governments play a pivotal role in addressing the pressing issue of MNPs pollution and must establish viable solutions to tackle this significant challenge.

Atmospheric microplastic transport and deposition to urban and pristine tropical locations in Southeast Asia

Atmospheric microplastic transport is an important delivery pathway with the deposition of microplastics to ecologically important regions raising environmental concerns. Investigating atmospheric delivery pathways and their deposition rates in different ecosystems is necessary to understanding its global impact. In this study, atmospheric deposition was collected at three sites in Malaysia, two urban and one pristine, covering the Northeast and Southwest monsoons to quantify the role of this pathway in Southeast Asia. Air mass back trajectories showed long-range atmospheric transport of microplastics to all sites with atmospheric deposition varying from 114 to 689 MP/m2/day. For the east coast of Peninsular Malaysia, monsoonal season influenced microplastic transport and deposition rate with peak microplastic deposition during the Northeast monsoon due to higher wind speed. MP morphology combined with size fractionation and plastic type at the coastal sites indicated a role for long-range marine transport of MPs that subsequently provided a local marine source to the atmosphere at the coastal sites.