New Research Exposes Skin’s Exposure to Flame Retardants from Microplastics

A study published in Environment International analyzed how certain flame retardants can be absorbed within the skin. Researchers also found that the skin absorbed 8% of the exposure dose. However, the amount of additives that became available to circulate in the bloodstream did not exceed 0.14% of what was initially present in the microplastics. 

Researchers noted that sweaty skin is more likely to absorb some flame retardants than dry skin. The study’s results suggest the need to address microplastic additives that people could be exposed to and the concern that skin absorption can be an exposure route. Microplastics are tiny plastic particles that are smaller than 5 mm. Humans are commonly exposed to microplastics. Therefore, researchers are seeking to understand the potential health dangers this poses to people. The authors note that many countries have banned the commercial formulation of PBDEs, but their environmental contamination could be a problem for decades. 

Researchers used the potential implications of such substances on human health along with three-dimensional human skin equivalent models. They examined how this exposure to microplastics, and related flame retardants affects absorption and if such chemicals could potentially pass through the skin to enter the bloodstream. Researchers also applied a special film liquid to the skin models to get an idea of how sweaty skin impacts absorption when compared to dry skin. They exposed the models to polyethene and polypropylene microplastics and, thus, several flame retardants. 

Researchers detected the presence of several flame-retardant chemicals within the skin and found that five of the flame retardants they tested (BDE 47, 99, 100, 153, and 183) got through the skin barrier to reach the equivalent of the human bloodstream. However, they also note that only a tiny amount made it into the bloodstream. 

The study authors found the microplastic type had a small but not significant effect on the amounts of flame-retardant chemicals in the skin. Exposure to polyethene microplastics led to more accumulation in the skin. By comparison, exposure to polypropylene microplastics led to slightly less accumulation. However, the microplastic type did not significantly impact the amounts of flame-retardant chemicals that made it into the bloodstream. 

Researchers also observed how skin hydration impacted the absorption of flame-retardant chemicals. In general, sweatier skin increased dermal bioavailability, except for BDE 47, where absorbed concentration was high in dry skin. 

Skin models might provide a helpful equivalent to human skin but cannot account for additional factors that can be involved in real-world exposures. Researchers also note they were only able to examine a small number of flame-retardant types. Future studies could look at other types of flame retardants and additional chemicals. 

Results of this study indicate a growing need to address the health implications of exposure to dangerous chemicals found in microplastics. Scientists and researchers could develop flame retardants that are not dangerous and explore how to address the buildup of microplastics.