Applying Existing Particle Paradigms to Inhaled Microplastic Particles

Abstract

Ambient particulate pollution originating from plastic contaminates air, including indoor and urban environments. The recent discovery of ambient microplastic (MP) particles of a size capable of depositing in the thoracic region of the airway, if inhaled, has raised concern for public exposure and health impacts following lessons learned from other particle domains. Current microplastic exposure estimates are relatively low compared to total ambient particulate matter, but optimal analytical techniques and therefore data for risk and health impact assessments are lacking. In the absence of such an evidence base, this paper explores paradigms, metrics and dose-response curves developed in other particle domains as a starting point for predicting whether microplastic are of concern. Bio-persistence, presence of reactive sites and soluble toxicants are likely key properties in microplastic toxicity, but these are not measured in environmental studies and hence are challenging to interpret in exposure. Data from a MP inhalation study in rats is available but the study was conducted using conditions that do not replicate the known human health effects of PM2.5 or surrogate exposures: compromised, aged animal models are recommended to investigate potential parallels between MPs and PM2.5. One of these parallels is provided by tire wear particles (TWP), which form part of current ambient PM and are sometimes regarded as microplastic. A connection to epidemiological studies where PM filters are still available is recommended and consequently analytical advances are required. In summary, established particle domains and existing paradigms provide valuable insight and data that can be used to predict MP toxicity, and direct study design and key properties to consider in this emerging field.

A Hidden Pathway for Human Exposure to Micro- and Nanoplastics—The Mechanical Fragmentation of Plastic Products during Daily Use

“…In the field of public health research, the study of MNPs exposure pathways is more diverse, in that, in addition to the oral exposure pathways such as eating food and drinking water, a considerable number of studies have been conducted on atmospheric MNPs concentration levels and respiratory exposure pathways [ 15 , 16 ]. In terms of abundances, MNPs in the atmosphere can reach up to four orders of magnitude higher in indoor and urban environments, far exceeding the levels at which they have been detected in the same volume of aqueous sediments and organisms [ 17 , 18 ].…”

Feasibility of Reverse Vending Machine for PET Bottle Recycling in Case of ABC Hypermarket

“…Furthermore, evidence demonstrates the presence of MPs in both outdoor and indoor air, and fibers have been detected in marine ecosystems and aquatic organisms. Consequently, the inhalation of MPs poses a potential risk to human health, particularly in young children who frequently engage in hand-to-mouth behaviors [8,14].…”

Environmental Microplastics in the Lower Airway of Shoe Manufacturing Workers

“… 1 , 2 Recent evidence shows that ambient MP particles, when inhaled, are capable of depositing in the human airway. 2 , 3 , 4 Following lessons learned from other particles, there have been concerns about the possible health impact of this exposition. 4 , 5 In fact, it has been shown that MPs induce chronic inflammation and DNA damage and oxidative stress, leading to carcinogenesis.…”

“… 2 , 3 , 4 Following lessons learned from other particles, there have been concerns about the possible health impact of this exposition. 4 , 5 In fact, it has been shown that MPs induce chronic inflammation and DNA damage and oxidative stress, leading to carcinogenesis. 6 Studies in humans have demonstrated that these products are more frequently detected in patients with worse pulmonary function and in lung cancer tissue.…”

“… 2 , 3 Some characteristics of MP toxicity in studies on rats include bio-persistence, presence of reactive sites and soluble toxicants. 4 …”