Bustling rivers such as the Mississippi and the Ohio are the source of drinking water for millions of Americans. But these rivers are likely to contain hazardous chemicals and pathogens that must be removed or neutralized before the water is safe for drinking.

New research suggests that the soil alongside these channels could help with the cleanup.

Drawing river water through the adjacent earth may strip away some unwanted pollutants, including harmful viruses, protozoa and bacteria, researchers at The Johns Hopkins University believe.

The idea is called river-bank filtration. Instead of pulling water directly from the river for subsequent treatment and distribution, utilities drill wells nearby. River water drawn from these wells must first pass through hundreds of feet of soil, which serves as a natural filter.

How effective are river banks as a cleansing agent? Scientists at Hopkins have launched a three-year study to find out. The researchers want to determine how well river-bank filtration removes pathogens, such as viruses, protozoa and bacteria. They also want to find out if this process removes other organic matter that reacts during disinfection in a treatment plant to form potentially harmful by-products.

"You can surmise that going through the ground should be a better method; that's your intuition," says Edward J. Bouwer, lead investigator in the study. "But we want to quantify how much better it is."

The work is important because dangerous microbes and cancer- causing chemicals sometimes slip past traditional water treatment. "We're worried about resistant pathogens created by the overuse of antibiotics," says Bouwer, a professor in Hopkins' Department of Geography and Environmental Engineering. "Some bacteria are becoming more resistant to disinfection. We're also worried about the by-products created during disinfection. Some of them may be car
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Contact: Phil Sneiderman
prs@jhu.edu
410-516-7160
Johns Hopkins University
7-Jul-1998