JBI: Janine Dizon, Timothy Barker, Ashley Whitehorn, Tania Marin, Danielle Pollock, Edoardo Aromataris*
Minderoo Foundation: Christos Symeonides*, Yannick Mulders*, Sarah Dunlop*

*Authors contributed equally to this report

What is the impact of plastic-associated chemical exposure on human health? Large-scale plastic production began in the 1950s and has since outpaced any other manufactured material (Geyer et al., 2017). Plastic is the signature material of our age which has transformed our everyday lives via, for example, food packaging, construction materials, household and personal goods, transport and medical applications (Landrigan et al., 2023). Plastic contamination of the environment, including air, water and soil, is ubiquitous, with plastics representing ‘a singular uncontrolled experiment on a global scale’ (Geyer et al., 2017) that are predicted to exceed planetary boundaries, defined as a ‘safe operating space for humanity’ (Persson et al., 2022).

During use, and once released into the environment, plastic fragments into smaller and smaller particles called micro- and nanoplastics (World Health Organization (WHO), 2022a). These plastic particles are beginning to be detected in human biospecimens (Kannan and Vimalkumar, 2021; Sripada et al., 2022). In addition, chemicals in plastics leach out of products during use and degradation, reflecting the complex nature of plastic materials (Hahladakis et al., 2018). Indeed, there are thousands of different known plastic-associated chemicals used to manufacture the polymer matrix of plastics, as well as added to the polymer matrix to give properties like flexibility (plasticisers) or fire resistance (flame retardants)(UNEP, 2023; Wagner et al., 2024; Wiesinger et al., 2021), with additional chemicals that are inadvertently included in the manufacture of plastics, or formed and released during the degradation of plastics (Kato and Conte-Junior, 2021). Only a limited number of these chemicals have been looked for in human research or bio-surveillance programs, but of these, there are some common plastic-associated chemicals that have routinely detected in many human studies over several decades (Woodruff et al., 2011) although we are, in fact, exposed to mixtures of multiple chemicals (Wang et al., 2021).

As part of its mission to eliminate the harmful effects of plastic on people and the planet, Minderoo Foundation formed a partnership with the JBI to examine the published evidence for the impacts of plastic exposure on human health. Evidence syntheses, such as pooled analyses and systematic reviews with meta-analysis, review the scientific literature both systematically and quantitatively, and provide a rigorous and transparent evaluation of the published evidence (Curtin University Library Services, 2022).

Here, we undertook an umbrella review to systematically evaluate this synthesised evidence. Umbrella reviews represent one of the highest levels of evidence synthesis currently available and are becoming increasingly influential for translating research into best practice as well as policy (FusarPoli and Radua, 2018).

Key findings

• There are no systematic reviews with meta-analyses of the health effects of plastic polymers, micro- and nanoplastics.
• We are exposed to plastic-associated chemicals from preconception onwards.
• Despite a multitude of plastic-associated chemicals in use, only a fraction has been researched more than once, and subsequently meta-analysed, to assess health effects in humans.
• Exposure to plastic-associated chemicals is linked to a wide range of adverse health outcomes from before birth (miscarriage), at birth (weight, genital development and appearance), in children (neurodevelopment, obesity, blood pressure, asthma and bronchitis, precocious puberty in girls, i.e. onset before eight years), and in adults (endometriosis, sperm concentration and quality, type 2 diabetes and insulin resistance, thyroid function, polycystic ovary syndrome, obesity, cardiovascular disease, hypertension, and cancer).
• None of the plastic-associated chemicals examined can be considered safe, with multiple harmful health effects linked to each chemical class.