CHILLICOTHE, Ohio — Cancer-linked chemical byproducts, including chloroform, are showing up in Chillicothe’s drinking water at levels far above health guidelines set by a national environmental research group, even though the water utility remains in full compliance with federal law, according to data reviewed by the Scioto Valley Guardian.
The Environmental Working Group’s Tap Water Database found 10 contaminants in water supplied by Chillicothe City PWS that exceed the group’s health-based guidelines. The utility serves about 21,725 people and draws its supply from groundwater. EWG’s findings are based on state and federal testing data collected from 2014 through 2023.
The U.S. Environmental Protection Agency’s enforcement records show Chillicothe’s water was in compliance with federal health-based drinking water standards as of the most recent quarter assessed, April through June 2024.
But EWG’s report on the utility opens with a blunt caveat: “Legal does not necessarily equal safe.”
“Getting a passing grade from the federal government does not mean the water meets the latest health guidelines,” the group states. “Legal limits for contaminants in tap water have not been updated in almost 20 years.”
CHLOROFORM AND RELATED BYPRODUCTS
Chloroform was detected in Chillicothe’s water at 9.3 parts per billion — 23 times higher than EWG’s health guideline of 0.4 ppb. There is no federal legal limit for chloroform as an individual chemical. It is regulated only as part of a broader group of disinfection byproducts.
Chloroform belongs to a family of chemicals called trihalomethanes, which form when chlorine or other disinfectants react with organic matter during water treatment. EWG says these byproducts increase the risk of cancer and may cause complications during pregnancy.
Three related trihalomethanes were also detected above EWG guidelines:
— Dibromochloromethane: 9.57 ppb, 96 times the health guideline of 0.1 ppb.
— Bromodichloromethane: 10.3 ppb, 171 times the health guideline of 0.06 ppb.
— Bromoform: 3.62 ppb, 7.2 times the health guideline of 0.5 ppb.
Combined, the total trihalomethanes in Chillicothe’s water measured 32.8 ppb — below the federal legal limit of 80 ppb, but 218 times above EWG’s health guideline of 0.15 ppb.
OTHER CONTAMINANTS OF CONCERN
Haloacetic acids, another class of disinfection byproducts, were also found above EWG guidelines. The federally regulated group of five haloacetic acids, known as HAA5, measured 4.62 ppb, well under the legal limit of 60 ppb but 46 times above EWG’s guideline of 0.1 ppb. A broader group of nine haloacetic acids, which is not federally regulated, measured 7.54 ppb — 126 times EWG’s guideline.
Individual haloacetic acids detected above guidelines included dibromoacetic acid, at 63 times the guideline, and dichloroacetic acid, at 13 times the guideline. Both are classified by EWG as carcinogens.
Radium, a naturally occurring radioactive element linked to bone cancer, was detected at 1.0 picocurie per liter — 20 times EWG’s health guideline of 0.05 pCi/L, though still within the federal legal limit of 5 pCi/L.
In total, EWG’s database lists 24 contaminants detected in Chillicothe’s water system, including chlorate, fluoride, manganese, barium, nitrate and traces of industrial solvents such as 1,4-dioxane, though most of those substances were found at levels below EWG’s health thresholds.
CONTEXT ON THE GUIDELINES
EWG’s health guidelines are typically far stricter than federal legal limits. Many are modeled on public health goals set by the California Office of Environmental Health Hazard Assessment or on EWG’s own peer-reviewed cancer-risk modeling, which targets a one-in-a-million lifetime cancer risk — a far more conservative threshold than the U.S. EPA uses in setting enforceable limits.
The federal government has not updated most tap water contaminant limits in nearly two decades, according to EWG, even as scientific understanding of low-dose, long-term chemical exposure has evolved.
EWG recommends activated carbon or reverse osmosis filtration to reduce trihalomethane and haloacetic acid levels in tap water. Reverse osmosis is also effective at reducing radium.