What's in the Water

Gastrointestinal bugs could be coming from poorly disinfected public water systems

(RxWiki News) Sometimes there's nothing like an ice-cold glass of water on a hot day or after an intense workout, but watch where it's coming from.

Viruses in non-disinfected ground water or well water that flows through the US public water systems may be the cause of up to 1.1 million cases of acute gastrointestinal illness, a new study has found.

This means the water coming from your facets at home may not be good for you.

"Drink filtered water."

The nausea, diarrhea and vomiting characteristic of this stomach illness comes from pathogens that enter the pipe system.

These pathogens include enterovirus, hepatitis A, norovirus and rotavirus.

Researchers, led by Mark Borchardt, PhD, a research microbiologist with USDA's Agricultural Research Service unit, and colleagues said that more than 100 million people in the US rely on water piped into their homes, businesses and schools.

Water from these systems draw from rivers, wells and other aboveground sources rather than lakes.

In the study, researchers installed ultraviolet light disinfection systems on the active wellheads in 14 Wisconsin communities.

These wells feed into all the drinking water in these communities and are disinfected as they leave the ground.

Researchers took water samples from wells, household taps and downstream from UV reactors once a month during four 12-week periods in 2006 and 2007.

The researchers found viruses in the groundwater and tap water of all 14 communities they studied. 

Even after the UV treatment, a little more than 10 percent of samples still contained one or more virus types with concentrations of less than 1.1 gc/L.

Downstream from the UV disinfection in household taps, a little more than 20 percent of samples had the virus with a concentration of less than 8.0 gc/L.

The authors say that the viruses are entering the distribution systems themselves and that this could be a fraction of what's happening across the country.

Without treatment, 32.3 percent of samples had the virus, and those samples contained an even higher concentration at less than 24 gc/L.

The authors say that not enough financial investment has been made to improve the water systems, and small ones are particularly at risk.

"As most of the national water distribution infrastructure is reaching the end of its design life in the coming decades, the frequency and health impacts of distribution system deficiencies will likely worsen," the authors said in a press release.

The authors suggest in their report that the illness can be controlled by keeping a disinfectant throughout the whole water system and make sure that the hydraulics are kept up.

Maxwell Chait, MD, a gastroenterologist at ColumbiaDoctors Medical Group in Hartsdale, New York, says there is a variety of ways people can treat water at home.

"Methods that may remove pathogens from drinking water are boiling, filtration, disinfection with iodine or chlorine, and a combination filtration and disinfection," he said.

Women who are pregnant shouldn't disinfect their water with iodine. The best method, Dr. Chait says, is boiling it.

"Of course, once you’ve boiled it, you have to keep it safely stored or it can become re-contaminated," he said.

He says if boiling is not possible, consumers can buy and combine their own filtration system and chemical disinfectant.

The study was supported by the US Environmental Protection Agency's STAR.

The study was published July 27 in the journal Environmental Science and Technology by the American Chemical Society.

Review Date: 
September 19, 2012