Spotlight on Research: Environmental Chemist Monitors the Anacostia
Posted: June 2, 2003 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am
By Lynn Burke
This spring’s wet, wet weather has caused Washington area residents numerous problems, such as canceled sporting events and damp basements. Greg Foster, professor and chair of George Mason’s Chemistry Department, has been looking at another problem caused by wet weather: urban runoff. This refers to the debris and chemicals washed from streets, parking lots, and other impervious surfaces into local watersheds during storms. Foster has been studying and monitoring urban runoff in and around the Anacostia River for the past 10 years.
His latest project, funded by a grant from the Metropolitan Washington Council of Governments (MWCOG), involves looking at the health of the Anacostia River as it is affected by such runoff. “Particularly, we’re after polycyclic aromatic hydrocarbons [PAHs],” says Foster. “Those are of interest because they are carcinogenic, and there is so much of them.” PAHs are a whole assemblage of chemicals that come mainly from the combustion of fossil fuels and petroleum itself and are deposited on impervious surfaces, he explains, adding that combustion sources seem to be on the rise as more cars are on the highway and urban regions expand.
The Anacostia River is in a very urban watershed, says Foster. About 50 percent of the entire watershed and 80 percent of the lower watershed is developed, keeping rain and melted snow from soaking into the ground. Foster studies the inputs and transport of these chemicals through the estuary into the Atlantic Ocean. “We’re trying to quantify the transport of these things and look at the variables that relate to their input.”
During storm events, samples are taken from small streams and sewer outfalls that discharge into the river. “Washington, D.C., has a very interesting water flow,” says Foster. “When it rains, all the street sewers drain to a wastewater treatment plant, which is the normal protocol. Now, when it rains a lot, the treatment plant cannot handle all the water and it overflows. Actually, the Anacostia gets direct untreated sewage discharge on rain events that exceed a certain threshold.”
Foster quantifies the amount of contaminants entering the river, which are known as loadings, and looks at the effect on the water quality. Standards called total maximum daily loads (TMDLs) determined by the U.S. Environmental Protection Agency (EPA) regulate the amount of loadings that a body of water can receive and still meet water quality standards. The data on loadings that Foster is collecting are being used to help MWCOG and the EPA develop models to set the TMDLs for the river.
“They have to have actual data on how much gets into the river through these different pathways, different streams, different outfalls, different sewers,” says Foster. “That’s where I come in. I provide data that help them model the inputs, the sources. As an environmental chemist, I deal with sources and sinks, that is, where chemicals collect and where they are transported, how they move around in the environment.”
Along with MWCOG and the EPA, the project involves the Chesapeake Bay Program Office. For more information on the project, e-mail Foster. To find out more about the Anacostia in general, visit web sites here or here.