By Aimen Farraj
Fine particulate matter (PM)—a tiny mass of solid and liquid matter floating in the air—comes from sources that emit air pollution including automobiles, power plants and forest fires, and is also formed by the interaction of other air pollutants. PM is everywhere and exposure levels are largely determined by how close one is to an emitting air pollution source.
Many studies have shown that PM’s health effects stem largely from its impact on the heart, driving people to the hospital and making diseases like heart failure worse. These health effects are caused by chemicals within particulate matter, which vary depending on the air pollution source. No two air sheds are alike, resulting in endless numbers of unique PM samples with little information on their potential to affect health. Traditional methods for assessment are just too slow and impractical.
In 2013, our team applied for a Pathfinder Innovation Project (PIP) to develop an approach to rapidly assess the cardiotoxicity potential of PM from different sources. The PIP program is an internal competition for EPA scientists to receive time to explore their biggest ideas in environmental research. The goal of this work is to identify PM sources and PM components that cause cardiovascular effects on a larger scale to expedite risk determinations associated with exposure to different air sheds.
To do this, we developed a zebrafish model to assess cardiotoxicity of PM from different sources. Zebrafish are tropical freshwater fish that have uncanny similarities in cardiac function with humans and their small size makes them ideal for rapid testing. The zebrafish model we developed is based on measurement of a simple health metric, i.e. heart rate, in hundreds of fish in a 96-well plate. Since the early days of the project, we have demonstrated that this model can be used to quickly assess cardiac impacts of PM exposure.
Now the team is working to refine all aspects of the model, including increased automation to permit rapid heart rate determinations and to expand the number of PM sources assessed. If successful, this effort may accelerate the pace at which PM toxicity information is acquired, link health effects to specific air pollution sources, and inform strategies to target and reduce PM sources linked to highest potency components.
Pathfinder Innovation Project Team: Aimen Farraj, Stephanie Padilla, Alan Tennant, Rory Conolly, David DeMarini, Ian Gilmour, Mike Hays, Najwa Haykal-Coates, Wayne Cascio, Mehdi Hazari, and Oak Ridge Institute for Science and Education student Kyle Martin
About the Author: Dr. Aimen K. Farraj is in his eleventh year as EPA’s Principal Investigator in the Environmental Public Health Division. His research interests include the study of the adverse cardiovascular effects of air pollution and development of better predictive tools for risk assessment.