This much we know: Stormwater is nasty stuff. The state of Washington has called it one of the leading threats to the Puget Sound ecosystem. It can kill salmon within hours and it contributes to all kinds of health problems for species ranging from orcas to humans. What we don’t know, however, is exactly what’s in it.
Rain and snowmelt wash an untold number of toxics into our waterways, but there is no such thing as typical stormwater. Its chemical makeup varies from place to place and depends on local pollutants, from petroleum to PCBs.
That’s a problem for scientists who want to understand how the chemicals in stormwater affect area wildlife. Knowing what’s in a particular mix of stormwater could help explain exactly which chemicals are lethal, or why some species of salmon die after exposure and not others. It could also provide a better understanding of where the chemicals come from. How much do automobiles contribute to the problem? Do the nastiest chemicals then come from leaking oil or car tires, or the asphalt from the roads themselves? Or somewhere else? The questions are seemingly infinite.
To meet this challenge, several scientists at the Puget Sound Institute and the University of Washington Center for Urban Waters are developing new techniques for analyzing stormwater’s chemical composition.
They recently published a paper outlining some of these techniques in the journal Environmental Science: Processes & Impacts. The paper was co-authored with collaborators from NOAA and the Washington Stormwater Center. The authors used “time-of-flight” mass spectrometry to identify novel compounds in runoff and fish tissues that were present in amounts as small as the parts per billion. Work is still underway, but so far the authors have found compounds ranging from the usual suspects like petroleum products to DEET and caffeine. “Further characterization of highway runoff and fish tissues,” the paper reads, “suggests that many novel or poorly characterized organic contaminants exist in urban stormwater runoff and exposed biota.”
Du, B., Lofton, J. M., Peter, K., Gipe, A. D., James, C. A., McIntyre, J. K., Scholz, N.L., Baker, J.E. & Kolodziej, E. P. (2017). Development of Suspect and Non-Target Screening Methods for Detection of Organic Contaminants in Highway Runoff and Fish Tissue with High-Resolution Time-of-Flight Mass Spectrometry. Environmental Science: Processes & Impacts.