Harmful chemical found in three Guam water wells

Three of the island’s water wells, which provide residents with drinking water, tested above the U.S. Environmental Protection Agency’s health advisory level for a contaminant that is used to make items waterproof and to extinguish fires that involve flammable liquids.

It could mean shutting down the contaminated wells or diluting the water from those wells using water from other sources.

Guam Waterworks Authority spokeswoman Heidi Ballendorf said two of the wells are located in Hagåtña and the third is located in Tiyan. The water agency currently is preparing a notice for affected residents, she said.

The chemical, Perfluorooctanesulfonic acid, or PFOS, is used to make carpets, clothing, fabrics for furniture, paper packaging for food and other cookware resistant to water or grease. It’s also used for fighting fires at airfields, according to a U.S. Environmental Protection Agency fact sheet.

The chemical, when present in high levels, has been linked to developmental defects in fetuses and breast-fed infants. Other health problems linked to PFOS exposure include cancer, liver and thyroid disease and problems with the immune system.

The levels of PFOS detected at five sampling sites, or wells, were measured at 41 to 110 parts per trillion. An EPA health advisory is required for levels above 70 parts per trillion, and three of the five wells exceeded that mark, according to U.S. EPA’s San Francisco Region 9 Drinking Water Management Section.

It is unclear how many customers and which villages are affected.

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Guam Waterworks Authority General Manager Miguel Bordallo didn't return a call for comment.

One of the three wells with high concentrations of the contaminant is located near the Guam International Airport, according to U.S. EPA.

“This is not surprising, since PFOS has been used to manufacture Aqueous Film Forming Foam, or AFFF, which is used to extinguish flammable liquid fires,” an email from the agency states. “Since PFOA/PFOS contamination is typically associated with a specific facility, for example, an airfield at which AFFF has been used for firefighting.”

The other four wells tested are located south and southwest of the airport, according to U.S. EPA.

Guam Waterworks Authority and Guam EPA have not yet identified the source of the contamination at these wells, U.S. EPA stated.

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According to a U.S. EPA PFOS Drinking Water Health Advisory, options are available to lower concentrations of the chemical in a drinking water supply.

The water agency currently pumps well water directly into the water supply system.

"In some cases, drinking water systems can reduce concentrations of the chemical by closing contaminated wells or changing rates of blending of water sources," the advisory states. 

To remove the chemical from drinking water, public water systems also can treat affected water with activated carbon or high pressure membrane systems, the advisory states.