Hills Wells Tested Positive For Perchlorate. For 56 years, Vivian Knebel never thought twice when she filled a glass and took a drink of water. Until last year, she never thought to have her tap water tested for perchlorate.
In May 2002, a water test at Knebel’s home on Iowa Street indicated her water supply had 28.8 parts per billion concentration of perchlorate well above the recommended safety level. In May, it tested at 39.2 parts per billion.
“I’ve been drinking it all the years I’ve been here,” Knebel said, adding that she has not experienced any health problems. “I’m concerned about the future and anyone who might be living here.”
Knebel isn’t alone. She and more than 100 other Hills residents attended an informational meeting Wednesday with the U.S. Environmental Protection Agency to discuss water and soil test results.
In May, the EPA sampled 28 wells for perchlorate. Of those, 11 tested above 18 parts per billion – the provisional safety threshold. The highest level recorded was 51 parts per billion.
“The results that we got, I wouldn’t say they are worse or better than we expected,” EPA project manager Dan Garvey told the group. “I would suspect it’s been there for a long time.”
Perchlorate is both a naturally occurring and man-made chemical. It is the main ingredient in the production of solid rocket fuel and also is used in munitions, fireworks and fertilizers. For humans, it interferes with iodine intake by the thyroid gland, which can affect metabolism and could cause thyroid tumors.
Impairment of thyroid function during pregnancy could affect the fetus, resulting in neurological disorders in the newborn.
EPA Discovered Perchlorate In Groundwater
In 2001, the EPA discovered perchlorate in the groundwater, drinking water and soil from Main Street in Hills extending south of town. The discovery was made by accident as scientists were originally scouring for pesticide residues left behind by grain bins.
Hills is one of three sites in Iowa with significant amounts of perchlorate in the water.
Now, a plume at least 2,000 feet in length stretches across the southern portion of Hills and is apparently heading northeast for the Iowa River. What EPA officials do not know is what or where the source of the perchlorate is.
Garvey said one reason for Wednesday’s meeting was to question the group about any historical context or event that might have placed the perchlorate in the ground. Garvey said such information will help him devise the next round of sampling, expected to start one to two months from now.
Although 18 parts per billion still is considered safe, the EPA is offering bottled water to anyone whose well tested at 18 parts per billion or more. Those with wells that tested between four and 18 parts per billion should not be concerned.
“Nobody is falling over by drinking the water in this town,” Garvey said.
Johnson County Health Department Director Ralph Wilmoth said no cases of illness tied to perchlorate have been reported.
Bottled water may be a temporary solution, but Hills eventually will be faced with implementing a long-term solution. Some perchlorate sites in California and Texas have addressed the problem by physically removing the chemical from the groundwater. However, it is an expensive and time-consuming technique, said Ken Buchholz of the EPA.
A municipal water plant is one solution. Currently, Hills residents use wells to draw their drinking water.
“Generally speaking, the most effective way to address the problem is to tap into an existing water system,” he said.