The nation's primary source of waterborne disease outbreak is the exposure of a tap water supply to pathogens residing in building plumbing systems, according to the Centers for Disease Control. Exposure can occur through aerosol inhalation, skin contact, or ingestion.

Legionella bacteria, which cause deadly Legionnaire's lung disease, serve as a prime example of a contaminant that can invade water systems. How this occurs is largely unknown.

Amy Pruden, an associate professor in Virginia Tech's Charles E. Via, Jr. Department of Civil and Environmental Engineering, has been awarded $250,000 by the Alfred P. Sloan Foundation to lead a project to determine the effects of pipe material, water flow, and chemistry on the building plumbing microbiome. The research will determine if the "right" microbes are being selected in the built environment.

Pruden's co-investigators on the project are: Marc Edwards, professor of civil and environmental engineering and building plumbing systems expert; Annie Pearce, associate professor of building construction; Husen Zhang, research assistant professor; all from Virginia Tech; and Anisha Patel, assistant professor at the University of California, San Francisco.

The researchers will sample distinct building plumbing field observatories installed at five potable water utilities across the eastern region of the U.S. and examine the effects of a range of water usage (frequency and flow velocity) and temperature scenarios in parallel laboratory systems. Both methods will enable broad comparison of water chemistry and pipe materials under controlled, replicated conditions.

Previous research was based on the distributed water before it reached the home whereas this unprecedented study will analyze the water after it enters the home, travels through the pipes, through the faucet tap, and into a drinking glass or out of a shower head.

"Home plumbing systems are very complex -- pipes can be made up of materials such as copper, iron, or PVC and receive intermittent water flow. Water sits in the pipes in a home while the inhabitants are at work or asleep during the night. Factors such as corrosion combined with specific pipe material, will directly affect the "good" and "bad" microbe growth in the water," said Pruden, an expert in applied environmental microbiology.

The focus of the project is on the "green" built environment -- buildings and schools. Both experience extreme water temperature and flow. While "green" plumbing systems are designed to be more efficient due to the usage of water conserving devices, this factor combined with low water usage during summer months and low temperatures to prevent burning of the skin, the water is more likely to be stagnant and have an undesirable impact on the microbiota.

New technology, next generation DNA sequencing, and metagenomic analysis will be used to investigate the relationships between these factors.

The project is expected to conclude October 2014.

Results from the research may offer guidance regarding plumbing materials, water conservation devices, and disinfection, and the ability to select materials most appropriate for water chemistry and to control flow conditions to desirably control the microbiota, thus improving public health and preventing disease.

Founded in 1934 by Alfred P. Sloan Jr., the Sloan Foundation is unique in its focus on science, technology, and economic institutions and considers the scholars and specialists who work in these fields are chief drivers of the nation's health and prosperity. Past recipients of Sloan research fellowships have gone on to win 38 Nobel prizes, 14 Fields Medals (mathematics), and eight John Bates Clark awards (economics).

"The Sloan Foundation's cutting edge support allows us as researchers to be at the forefront in leading groundbreaking research on water safety. And using new technology with DNA sequencing capabilities can teach us how we might correct some of the built environment's infrastructure challenges," said Pruden.

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