Measuring Microplastics in the Environment and the Body: Overcoming Background Contamination in a Plastic-Free Lab

Summary

Measuring microplastics in the environment and in the human body is more complex than it might first appear. In this interview, Dr. Cassandra Rout explains that background contamination from ubiquitous plastics in labs can inflate measurements, and her team built a minderoo clean lab made entirely of stainless steel to minimize plastic contact and false signals. She describes the dramatic drop in background concentrations when comparing the clean lab to a conventional lab, while noting that trace levels can still enter from the air and personal clothing. The conversation also covers how analyzing tissues and blood is difficult due to the complex biological matrix, and how signals from plastics can be confused with fats. Finally, Rout highlights global collaborations and her personal approach to reducing plastic exposure at home.
Key insights include the pervasiveness of plastics, the importance of contamination control, the challenges of complex biological samples, and the value of collaborative efforts to improve data quality in plastics and health.

• Background contamination is a major obstacle in microplastic measurements.
• A plastic-free, stainless steel lab dramatically reduces contamination signals.
• Biological samples like tissue and blood complicate detection due to complex matrices and signal overlaps.
• Global collaboration and improved methods aim to yield more reliable data on plastics and health.

Introduction and Context

The podcast features Flora Lichtman speaking with Dr. Cassandra Rout, a researcher at the University of Queensland studying microplastics exposure. Rout explains that the field of microplastics science is young, with plastics in the environment increasingly studied over the last decade and plastics in humans only in the last few years. A central theme is that measuring microplastics is fraught with challenges, the most significant being background contamination. In environments saturated with plastics, particles can shed from lab materials and enter samples during processing, artificially elevating apparent concentrations and clouding the true signal. The discussion emphasizes that reliable data depend not only on detection capabilities but also on controlling where and how samples are processed.

Building a Plastic-Free Lab

To address contamination, Rout describes the minderoo clean lab, a facility constructed completely from stainless steel to minimize plastic contact. Walls, flooring, ceilings and storage materials are chosen to avoid plastics, and even sample transport boxes are stainless steel. The lab uses glass syringes rather than plastic pipettes, and virtually no plastic touches the samples at any point. The environment is described as a large metal box, nicknamed the submarine, with a single window for viewing and acoustic panels to manage noise. This deliberately plastic-free setting is designed to reduce external and internal sources of contamination that could skew measurements.

Impact on Background Contamination and Data Quality

When the clean lab was commissioned, background testing showed concentrations of potential microplastics were reduced by about 100-fold compared with their normal lab. Rout notes that while background levels drop dramatically, trace plastics can still be detected, likely introduced by the researchers themselves from the air or clothing. They mitigate this by protocols such as changing into fresh lab coats and wearing pull-up cotton pants over existing clothes to reduce particle shedding. The key takeaway is that background contamination is so pervasive that even with strict lab controls, some tiny particles may still be introduced; nonetheless, the potential for contamination is greatly diminished in the clean lab, enabling more accurate assessments of microplastics in samples.

Challenges in Analyzing Human Tissues and Blood

The panel discusses the complexity of biological matrices. Tissues and blood contain fats, proteins, carbohydrates, cells and lipids, all of which complicate the isolation and identification of plastic particles. Rout explains that current analysis techniques can misattribute signals from plastics to other sample components, such as lipids. For example, polyethylene can produce signals similar to lipid components, making it hard to distinguish a plastic particle from a natural tissue component. The conversation stresses that this is a fundamental challenge in determining whether plastic particles are truly present in the body and in what quantities.

Collaborative Efforts and Methodological Advances

In response to these measurement challenges, Rout describes the Plastics Measurements Brains Trust, a global network of about 30 researchers from various disciplines who meet annually to discuss how to improve data quality and interpretation. The group published a paper in January that advocates using complementary techniques on the same sample to enhance confidence in results. The overarching message is that the field requires continued cooperation and methodological integration over the next five years to better understand plastics in human health and exposure.

Personal Exposure and Additive Chemicals

Rout shares personal actions she takes to reduce plastic exposure at home, illustrating how even scientists in the field take practical steps. She mentions swapping out kitchen utensils and chopping boards to minimize plastic contact. She also points to plastic additive chemicals such as phthalates and bisphenols, which are endocrine disruptors with established links to negative health effects. Even if the health implications of plastics themselves are not fully understood, these additive chemicals provide a strong motivation to reduce plastics exposure as a precautionary measure.

Concluding Thoughts

The discussion closes with Rout’s outlook: the combination of new analytical techniques, lab innovations, and collaborative networks will yield more reliable data about microplastics and health within the next five years. Rout is optimistic that the field will evolve toward better experimental design and data sharing that will clarify whether plastics influence health outcomes and, if so, to what extent. The podcast highlights the practical and theoretical steps being taken to improve the reliability of microplastic measurements and to translate findings into safer, healthier practices for everyday life.

Context and Affiliation

Dr. Cassandra Rout is a research fellow studying microplastics exposure at the University of Queensland in Australia. The episode is produced by Science Friday and features insights into current challenges and potential advances in the measurement of microplastics in the environment and human body.