By Sara Jerome
An analysis released this month by the Environmental Working Group (EWG) shows that dioxane is found in drinking water in 45 states, afflicting over 90 million people in the U.S.
Dioxane, a water pollutant that can be difficult for utilities to treat, makes its way into waterways from discharges at manufacturing plants, from leaks in underground storage tanks at hazardous waste sites, and from common consumer products such as shampoo and detergent. Some manufacturers, including Tide-maker Procter & Gamble, have made high-profile efforts to reduce 1,4-Dioxane in their products.
The environmental research and advocacy group EWG recently released a report and interactive map on dioxane contamination of water this month. The research reveals “that California, New York, and North Carolina had the highest numbers of people exposed to water that is contaminated above the U.S. EPA’s suggested standard,” Mother Jones reported.
“Samples from water systems serving those areas had average levels of 1,4-Dioxane ranging from four times to about 17 times the EPA's minimal cancer risk level of 0.35 parts per billion, which is about one drop of water in three Olympic-size swimming pools. That's the level expected to cause no more than one case of cancer for every million people who drink the water daily for a lifetime,” EWG said in a statement.
In EWG’s report, Detlef Knappe, part of a North Carolina State University research team studying 1,4-Dioxane contamination in the state's watersheds, noted how difficult it is for water utilities to treat dioxane.
“Source control would be protective of the surface water quality and would result in a lower societal cost than installing treatment processes for 1,4-Dioxane control at numerous downstream drinking water utilities,” Knappe said.
The EPA believes dioxane is a likely human carcinogen. The government also acknowledges that dioxane is difficult to treat. The EPA, in its handbook on how to handle the contaminant, notes that 1,4-Dioxane is “fully miscible in water.”
“As a hydrophilic contaminant, it is not, therefore, amenable to the conventional ex situ treatment technologies used for chlorinated solvents. Successful remedial technologies must take into account the challenging chemical and physical properties unique to 1,4-Dioxane,” it continued.
The handbook lists 15 projects where 1,4-Dioxane was treated in groundwater. Twelve of the project used ex situ advanced oxidation processes.
Dioxane contamination prompted Tucson Water to install an advanced oxidation process (AOP) facility.
Dioxane “is a contaminant not easily removed with conventional technologies, but TrojanUV’s oxidation systems destroy volatile organic compounds, breaking them down into their harmless components almost instantly. The process combines ultraviolet light with hydrogen peroxide to purify up to 8 million gallons of water a day,” according to a statement from TrojanUV.
For similar stories visit Water Online’s Source Water Contamination Solutions Center.
Image credit: "tide laundry detergent," mike mozart © 2014, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/