Probabilistic Estimation of Airborne Micro- and Nanoplastic Intake in Humans

Assessment of suspended atmospheric microplastics in Tianjin Binhai New Area: characterization, human health risks, and correlation with weather conditions and Air Quality Index

Suspended atmospheric microplastics (SAMPs), as a critical component of environmental microplastic pollution, have garnered substantial scientific interest. The characterization of SAMPs in urban environments, as well as the potential risks on health, continues to be a topic of significant research interest. This study provides a comprehensive report on the presence of SAMPs in the Binhai New Area of Tianjin, China, based on samples collected during the autumn and winter of 2023-2024 using a medium-flow total suspended particulate (TSP) sampler at a monitoring station. Microplastics were detected in all samples, with concentrations ranging from 0.2 to 1.8 items/m3 in autumn and from 0.1 to 1.1 items/m3 in winter, and a total mean of 0.6 ± 0.4 items/m3. Particle sizes spanned 12.28-3248.58 µm, with fibrous shapes dominating the morphological composition. Observed colors included black, blue, yellow, transparent, red, and green, with black microplastics being the most prevalent. These SAMPs were composed of polyethylene terephthalate, polyethylene, rayon, polypropylene, and ethylene-ethyl acrylate copolymer. A risk assessment indicated that residents of Binhai New Area, Tianjin City, face a measurable health risk from microplastic exposure. Significant correlations were identified between SAMPs and dew point temperature as well as relative humidity in the autumn. In the winter, significant correlations were observed between the abundance of SAMPs and ground barometric pressure and wind velocity. Weak negative correlations were observed between SAMP abundances and the Air Quality Index (AQI) in both seasons Future research will utilize more advanced technologies and establish a global monitoring network to further explore the sources, distribution, and impacts of atmospheric microplastics.

Effects of micro- and nanoplastics on blood cells in vitro and cardiovascular parameters in vivo, considering their presence in the human bloodstream and potential impact on blood pressure

The adverse effects of plastics on the environment, wildlife, and human health have been extensively studied, yet their production remains unavoidable due to the lack of viable alternatives. Environmental fragmentation of larger plastic particles generates microplastics (MPs, 0.1-5000 μm) and nanoplastics (NPs, 1-100 nm), which can enter the bloodstream through inhalation or ingestion. This review examines whether MPs and NPs influence blood pressure. To address this question, relevant studies were analyzed based on predefined criteria. Due to anatomical barriers and microcirculatory dynamics, only NPs and small MPs are expected to enter the bloodstream under physiological conditions, although pathological states may alter this. In vitro research indicates that MPs and NPs negatively affect erythrocytes and endothelial cells, while rodent models suggest potential cardiovascular effects. Plastic particles and fibers have been detected in human blood, thrombi, atherosclerotic plaques, and various tissues. However, validated data on plastic particle-related blood pressure changes remain lacking. Despite limitations in their applicability to human physiology, preclinical models suggest that MPs and NPs circulate in the bloodstream, interact with blood cells, and contribute to vascular damage. Mechanisms such as endothelial injury, platelet activation, inflammation, and MPs/NPs accumulation in atherosclerotic plaques may contribute to blood pressure elevation but are unlikely to be the exclusive cause of hypertension. Further research is needed to clarify the role of plastic particles in blood pressure regulation. Standardized detection methods, real-world scenario-related models, and targeted human studies are essential to assessing cardiovascular risks associated with MP and NP exposure.

Dynamic non-coding RNA biomarker reveals lung injury and repair induced by polystyrene nanoplastics

Polystyrene nanoplastics (PS-NPs) are omnipresent in the air and can be inhaled by humans. However, their long-term adverse implications and toxicological mechanisms for human respiratory health are unclear. Therefore, this study aims to provide new insights into the pulmonary toxicity of PS-NPs using mice and organoid models. After subacute and subchronic inhalation of PS-NPs, mice showed pronounced lung injury characterized by respiratory rate changes, altered hematology, and histological evidence of tissue damage and oxidative stress. Similarly, repeated PS-NPs exposure also restricted organoid growth and cause oxidative damage. Notably, through BisqueRNA analysis for a single-cell dataset and canonical markers verification, it was found that PS-NPs induced the emergence and accumulation of transitional cells, suggesting impaired alveolar epithelial repair processes. Sequencing analyses revealed dynamic alterations in non-coding RNA (ncRNA) profiles, including circRNAs and lncRNAs, in response to PS-NPs exposure. Moreover, temporal profiling highlighted distinct sets of ncRNAs as early and progression-associated biomarkers of PS-NP-induced lung injury. These biomarkers correlated with aberrant transitional cells, implicating their roles in disrupted cellular differen tiation and repair mechanisms. Overall, this study observed the multifaceted toxicological responses of PS-NPs to the respiratory system, emphasizing the critical involvement of ncRNAs in mediating PS-NP-induce transitional cells, which was crucial for elucidating the pathophysiology of nanoplastic-induced lung injury and developing targeted therapeutic strategies.

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.

Micro/Nanoplastic Exposure on Placental Health and Adverse Pregnancy Risks: Novel Assessment System Based upon Targeted Risk Assessment Environmental Chemicals Strategy

Micro/nanoplastics (MNPs), as emerging pollutants, have been detected in both the maternal and fetal sides of the placenta in pregnant women, and their reproductive toxicity has been demonstrated in in vivo and in vitro experimental models. The Targeted Risk Assessment of Environmental Chemicals (TRAEC) strategy has been innovatively devised to facilitate valid risk assessment, encompassing a comprehensive evaluation of reliability, correlation, outcome fitness, and integrity across four dimensions based on the included published evidence and our own findings. This study serves as an application case of TRAEC, with 40 items of research evidence on the toxicity of MNPs to the placenta, which were rigorously screened and incorporated into the final scoring system. The final score for this TRAEC case study is 5.63, suggesting a moderate-to-low risk of reproductive toxicity associated with MNPs in the placenta, which may potentially increase with decreasing particle size. It is essential to emphasize that the findings also report original data from assays indicating that exposure to high-dose groups (100 μg/mL, 200 μg/mL) of 50 nm and 200 nm polystyrene nanoplastics (PS-NPs) induces HTR8/SVneo cell cycle arrest and cell apoptosis, which lead to reproductive toxicity in the placenta by disrupting mitochondrial function. Overall, this study employed the TRAEC strategy to provide comprehensive insight into the potential reproductive health effects of ubiquitous MNPs.