Matthew Rau is an assistant professor of mechanical engineering at George Washington University and studies microplastics and the effect of fluid flow on microplastic transport processes in aquatic systems. His fascination with physics and the unique intersection posed by the microplastic problem first drew him to the field. Dr. Rau notes that, in water systems, biology plays a significant role as particles and contaminants accumulate to impact the function of aquatic organisms. As human-made contaminants, microplastics, which are fragments of plastic less than five millimeters long, interact with microbiology in ways that are not fully understood yet. This gap in our knowledge compelled Dr. Rau to explore further.
As sustainability goals continue to shape modern agendas, Dr. Rau urges us to turn our attention to the microplastic problem as much remains unknown. He notes that existing studies have indicated that microplastics can act as stressors to plants and can interfere with the reproductive systems of certain organisms. Still, we have yet to fully understand their impact on entire ecosystems.
Dr. Rau points to how we recognize that plastics enter water sources through runoff, trash, and litter, which then break down into microplastics. Tiny microplastics have the ability to enter food webs at a base level, which happens globally on land and in aquatic systems. Dr. Rau notes that “implications are wide-ranging across many ecosystems,” underscoring our unfamiliarity with the precise organismal response and its potential as a prime area of research.
Dr. Rau’s research centers on fluid mechanics and how microplastics are moved around and find entry points into ecosystems. Specifically, he works with plastics smaller than 300 micrometers—a feat difficult for many given their trickiness to isolate—and assesses how they interact with other marine microorganisms, chiefly microalgae. When asked about his key findings, Dr. Rau was excited to share that his team observed that microalgae and microplastics very readily stick together, offering critical insight into understanding where the particles ultimately end up after entering the water. For instance, he explains that microplastics clumped within clusters of microalgae will behave very differently in a fluid flow compared to a free-floating microplastic. Ultimately, this clustering phenomenon determines where these contaminants go in the environment. Dr. Rau’s research endeavors continue to shape the broader discussions on microplastics, fluid mechanics, and the organism response to particulate matter.
When asked to reflect on public perceptions of microplastics, Dr. Rau was proud to note that the issue has been getting more press recently as interest in studying them increases. The field is less subject to misconceptions than most others in terms of pollutant effects and the importance of its study. But still, assumptions about plastic properties, such as buoyancy and density, downplay microplastics’ presence in marine ecosystems. Dr. Rau emphasizes the need to closely consider the evolution of microplastics in the environment to properly assess their abundance and properties as they degrade and interact with organisms.
“We’re at a point where wherever you look for microplastics, you’re probably going to find them,” Dr. Rau warns, posing questions about the larger health and environmental impacts of microplastics’ ubiquity. A recently published article by Harvard Medicine noted that tiny microplastics, known as nanoplastics, can enter animal cell nuclei, threatening oxidative damage, DNA damage, and gene activity changes. Unfortunately, the uncertainty surrounding microplastics fails to offer solid warnings of their long-term effects on humans. Although they are found everywhere, they are also fairly dilute in water, making it difficult to attribute them to disease as their accumulation is a long-term phenomenon. Still, Dr. Rau notes that we are beginning to uncover how microplastics might affect health.
Looking ahead, Dr. Rau is excited to expand upon his current research, specifically by explaining the precise adhesion mechanism between microalgae and microplastics. Similarly, he is interested in how microplastics disperse and how exactly small particles enter food webs to impact plant cell activity and behavior.
Setting his sights on a bigger picture and brighter future, Dr. Rau views GW as a uniquely positioned institution to combat plastic pollution. He takes pride in the diverse, collaborative, and scientific pool of GW faculty who already work closely together on issues involving plastics. Particularly within the School of Engineering and Applied Sciences, existing faculty are well-equipped to address this problem and mobilize common themes, research areas, and interests to promote further collaboration. “Whether it is through environmental engineers, mechanical engineers, like myself, chemists, or biologists, [collaboration among] these people is really what is needed to answer these questions,” Dr. Rau said.
Moving forward, he hopes to build larger pools of faculty with diverse backgrounds, each member offering a unique perspective and experience to demystify the open field of microplastics in a growingly receptive society. At the same time, Dr. Rau recognizes the strength of GW’s public health and policy programs and foresees a benefit in their collaboration with large organizations and initiatives nearby. GW’s unique position in the heart of Washington, D.C. invites endless possibilities for applying research findings to broader-scale publications and policy initiatives, all aiming to address the microplastic problem to safeguard environmental sustainability.