Toxic chemicals used for fire-retardant plastic materials can be absorbed into the body through the skin, through contact with microplastics, new research shows.
The study offers the first experimental evidence that chemicals present as additives in microplastics can leach into human sweat and then be absorbed through the skin into the bloodstream.
Many chemicals used as flame retardants and plasticizers have already been banned due to evidence of adverse health effects, including damage to the liver or nervous system, cancer, and reproductive health risks. However, these chemicals are still present in the environment in older electronics, furniture, carpets, and building materials.
While the harm caused by microplastics is not fully understood, there is growing concern about their role as conduits of human exposure to toxic chemicals.
The research team showed in a study published last year that chemicals from microplastics leached into human sweat. The current study now shows that those chemicals can also be absorbed through sweat through the skin barrier into the body.
In their experiments, the team used innovative 3D human skin models as alternatives to laboratory animals and excised human tissues. The models were exposed over a 24-hour period to two common forms of microplastics containing polybrominated diphenyl ethers (PBDEs), a chemical group commonly used to flame retardant plastics.
The results, published in International Environment, showed that up to 8% of the exposed chemical could be absorbed by the skin, and that more hydrated (or “sweatier”) skin absorbed higher levels of the chemical. The study provides the first experimental evidence on how this process contributes to the levels of toxic chemicals found in the body.
Dr Ovokeroye Abafe, now at Brunel University, carried out the research while at the University of Birmingham. He said: “Microplastics are everywhere in the environment and yet we still know relatively little about the health problems they can cause. Our research shows they play a role as ‘carriers’ of harmful chemicals, which can reach “These chemicals are persistent, so with continued or regular exposure to them, there will be a gradual buildup to the point where they begin to cause harm.”
Dr Mohamed Abdallah, Associate Professor of Environmental Sciences at the University of Birmingham and principal investigator on the project, said: “These findings provide important evidence for regulators and policymakers to improve legislation on microplastics and protect public health against harmful exposure”.
Professor Stuart Harrad, co-author of the paper, added: “The study provides an important step forward in understanding the risks of exposure to microplastics to our health. Based on our results, more research is required to fully understand the different routes of human exposure”. to microplastics and how to mitigate the risk of such exposure.
In future research, the team plans to investigate other routes through which microplastics could be responsible for the entry of toxic chemicals into the body, including inhalation and ingestion. The work is funded by a Marie Curie research grant, within the European Union’s Horizon 2020 Research and Innovation Programme.