The potential of micro- and nanoplastics to exacerbate the health impacts and global burden of non-communicable diseases

Abstract

Non-communicable diseases (NCD) constitute one of the highest burdens of disease globally and are associated with inflammatory responses in target organs. There is increasing evidence of significant human exposure to micro- and nanoplastics (MnPs). This review of environmental MnP exposure and health impacts indicates that MnP particles, directly and indirectly through their leachates, may exacerbate inflammation. Meanwhile, persistent inflammation associated with NCDs in gastrointestinal and respiratory systems potentially increases MnP uptake, thus influencing MnP access to distal organs. Consequently, a future increase in MnP exposure potentially augments the risk and severity of NCDs. There is a critical need for an integrated one-health approach to human health and environmental research for assessing the drivers of human MnP exposure and their bidirectional links with NCDs. Assessing these risks requires interdisciplinary efforts to identify and link drivers of environmental MnP exposure and organismal uptake to studies of impacted disease mechanisms and health outcomes.

Keywords: additives; exposure; global health; inflammation; inflammatory; microplastic; particle.

Graphical abstract

Figure 1

Environmental exposure routes, transport, and sources of MnPs Environmental exposure routes and sources of MnPs in indoor (top) and outdoor environments (middle). Human exposure rates are determined by the environmental fate and transport of MnPs that control the connectivity between spatially and temporally dynamic environmental pollution sources and human exposures (bottom). Together, these dynamic exposure controls determine the combined uptake of MnPs and their additives that may influence the risk and/or severity of NCDs. The text boxes provide some example exposure ranges associated with different MnP sources.

Figure 2

Hypothesized uptake mechanisms of MnPs through human body (A–D) (A) Hypothesized uptake mechanisms of MnPs through human biological barriers, including via (B) the olfactory bulb, (C) the lung-air barrier, and (D) the gastrointestinal tract, indicating also the systems and organs directly affected by MnPs and the associated MnP impacts and suspected adverse health outcomes including NCDs. The suspected particle-size fractionation caused by differences in the uptake mechanisms (A–D) is highlighted in (E), with larger particles being ingested (up to 130 μm) rather than inhaled (≤2.5 μm) and only the smallest (nanoscale) particles being able to penetrate the blood-brain barrier. MnP internalized by routes (C) and (D) reach the wider circulatory system and from there can reach all organs.

Figure 3

Hypothesized reciprocal interactions between MnPs in the human body and NCDs indicating the potential mechanisms of increased NCD prevalence and severity through MnP exposure as well as NCD linked increases in susceptibility to MnP uptake and thus toxicity This conceptual model synthesizes the links between the main exposure routes presented in Figure 1 (inhalation, ingestion, and dermal) and the impacts of MnPs including the systems and organs most affected by MnPs (respiratory system, gastrointestinal tract, cardiovascular system) as shown in Figure 2.