When severe floods wash through the St. Louis region, what pollutants get swept into the waters? And where do those contaminants end up?
In the past, such episodes have been too rare or poorly studied to provide clear answers. But now, as the area copes with increasingly frequent major floods, researchers at the Missouri University of Science and Technology in Rolla are turning attention to those questions _ outfitted with new grant funding from the National Science Foundation.
"We usually don't collect data immediately after a flood to know what the impact is for contamination," said Ryan Smith, an assistant professor who studies groundwater resources and a co-leader of the study.
"It's important to see how these flood events are affecting us in different ways," he added. "With climate change and the way that global climate models are forecasting things, we're expecting to have more and more events."
As work shifts to analyzing the samples, the researchers will keep an eye out for some specific contaminants.
"We expect stuff like lead paints to be washed into water, or pesticides, or toxic runoff from construction areas," said Marek Locmelis, as assistant professor with expertise in analytical chemistry and the study's principal investigator.
"In the agricultural areas, of course, you'd expect lots of fertilizers to be flushed out," he added _ something that can cause algae blooms and other issues where nutrients get overloaded after they're redeposited elsewhere.
But the team is also casting a wide net for more unexpected findings and "emerging contaminants," such as traces of caffeine, ibuprofen or other drugs that can accumulate in water systems.
Beyond looking at what contaminants get moved around, the researchers are also seeking to understand how and where floods redistribute them _ and if they present public health risks in their new locations. To find out, the study covers a range of settings, from lakes and ponds to rivers, groundwater and depressions in farmland.
Some noted particular concerns in lakes and ponds, which can serve as natural repositories for contaminants to gather or settle. Others added that groundwater may be at risk, because aquifers in heavily agricultural areas can often face contamination issues. In fact, the researchers are still welcoming area volunteers open to having their groundwater wells tested.
"Or maybe, because there's so much water, (contaminants) are diluted so that there's no problem at all," added Locmelis.
