Cassandra Rauert, an environmental chemist at the University of Queensland, has identified methodological challenges in the study of microplastics within the human body. In an interview with Yale Environment 360, Rauert reported that current analytical techniques are vulnerable to laboratory contamination and false positives. Specifically, her research indicates that lipids present in human blood can be mistaken for polyethylene, the most common type of plastic, because they share similar chemical building blocks.
To address these issues, Rauert and her team constructed a specialized laboratory designed to minimize plastic interference. The facility uses stainless steel surfaces and glass secured with low-phthalate silicon instead of standard construction materials. The lab maintains positive pressure to push outside air away from samples and has banned the use of plastic pipettes, Petri dishes, and cardboard. Rauert noted that these modifications resulted in air-borne plastic and phthalate levels approximately 100 times lower than those found in standard laboratories.
Regarding the health impacts of microplastics, Rauert stated that current scientific evidence has not yet established specific effects on human health. She also noted that a widely circulated claim—that humans consume an amount of plastic equivalent to a credit card per week—has been debunked by further study. Rauert's current research focuses on identifying primary exposure routes, such as indoor dust containing synthetic fibers and tire particles found on residential balconies.