Mitigation efforts have been done in phases since discovery of chemical contamination at 29th and Grove in 1994 but largely without public notice
Officials at the Kansas Department of Health and Environment say efforts to clean up the contamination from a long-ago chemical spill that was discovered in 1994 have been ongoing for years, even though the public has not been aware of much of it.
“There was a lot of publicity about it at the time it was first discovered and traced to the Union Pacific rail yard at 29th and Grove,” geologist Mary Daily said in an interview with The Community Voice. “Then it got quite a bit of attention in 2003 when the EPA started an investigation.”
The EPA completed its investigation in 2006. A feasibility study to evaluate the best method of clean-up was completed in 2008.
Since then, there have been pilot projects, testing, and five Interim Remedial Measures have been implemented to reduce the contamination, but levels in the groundwater plume that runs 14 to 20 feet below the soil surface from 29th Street North to Murdock Ave and in the soil at the spill site remain too high.
A public hearing on Sept. 8 to outline further proposed action to clean up the soil at the site and remove the chemicals from the groundwater surprised residents and city officials. Although information about the spill was released in 1994, that was before the internet and even before The Community Voice, and limited effort was made by KDHE to make sure those impacted were made aware of the spill or, in the years since then, kept informed about efforts to clean up the contamination.
Daily said, the risk assessment dating back to the 1990s showed the contamination is unlikely to put residents of the area at high risk because the homes and business were already built and city water lines already installed long before the spill happened, which is estimated to have been in the 1970s or 1980s.
The soil at the spill site was heavily contaminated, Daily said, and the chemical in question, trichloroethene, or TCE, does not flow along the surface but instead sinks through the ground and gets trapped in the groundwater. It is very volatile, which means that when exposed to the air outside, it breaks down to harmless elements quickly.
However, as the chemical in the soil or the groundwater evaporates, it can move into the underground spaces under buildings and pollute indoor air, something called vapor intrusion.
Air tests were done at several locations including residential homes, schools including Gordon Parks Academy, The Opportunity Project, the Boys & Girls Club, and the Little Early Childhood Learning Center in 2004, 2009, 2012 and 2013.
Vapor intrusion was detected in some of the buildings, but at very low levels.
Potential Health Threats
Heavy or prolonged exposure to TCE is known to cause kidney and bladder cancer and is suspected to cause non-Hodgkins lymphoma, a blood cancer, and liver disease.
Temporary over-exposure to vapors, such as by workers using the chemical, can cause light-headedness, vision problems and even unconsciousness.
“That would be in cases of people who work with the chemical and have prolonged exposure,” Daily said. “It would definitely be a concern if people were drinking or bathing in well water, but all the homes and businesses have water from the city of Wichita. And all of those lines were already in place at the time of the spill.”
She said that means residents of the area are less likely to have been exposed to harmful levels of the chemical.
However, the area does have a number of wells used for watering lawns and gardens, which would increase the risk of exposure to people who came in contact with the water or the wet soil.
Daily said studies have shown that the chemical is not taken up by the roots of growing plants so food would be safe to eat and exposure to the air would cause the chemical to evaporate quickly.
Interim cleanup efforts
Four of the interim remedial or correction measures were done at the spill site while the fifth was implemented at the end of the groundwater plume which extends from 29th Street North southward to Murdock. A containment system was put at the south end of the contaminated area to prevent further movement of contaminated groundwater.
At the site, clean-up has involved using wells to pump the contaminated groundwater into a contained tank and bombarding it with air, injecting microbes into the soil to help break down the chemicals into harmless substances and digging up the soil and disposing of it in an Oklahoma landfill.
Five wells were installed along the railroad tracks in two phases in August 2004 and December of 2005. They were shut down in 2010.
The soil excavation took place in two rounds in 2010 and 2011, as did an injection of chemicals into both the soil and the groundwater to help break up the contaminants. A later evaluation determined that the treatment, while it helped, did not bring the level of contamination down enough to be considered safe.
Proposed remediation recommendations
KDHE completed a second feasibility study in 2020 and is now proposing a final clean-up plan. A second public hearing to explain that plan is set for Nov. 5, beginning at 3 p.m. at the Boys and Girls Club on Opportunity Drive.
KDHE studied options for what to do next – ranging from doing nothing to re-treating the most heavily contaminated spots at the spill site to excavating the soil at the spill site all the way to bedrock and came up with recommendations that its scientists believe will result in a full cleanup.
For the spill site, KDHE is recommending that more soil be removed from “hot spots” that are the most contaminated and repeating the addition of chemicals and biological cleanup remedies.
For the groundwater plume remediation, KDHE is recommending directed groundwater recirculation. That involves drilling wells to pump the groundwater into above ground tanks where it can be cleaned then injected back into the aquifer or discharged to Chisholm Creek or into storm sewers.
Daily said the multiple pumping and reinjection with clean water will “rinse” the aquifer multiple times.
“It’s kind of like rinsing soap out of a sponge,” she said. “It takes several rinses before you get all of it out.”
What isn’t known is how long it will take before the aquifer is cleaned to drinking water standards which is the goal. That level is 0.005 milligrams per liter. The worst of the contamination is 432 milligrams per liter.
Daily said most residents of the area won’t be affected by the cleanup efforts.
“Residents may notice some drilling equipment on the city right of way or the installation of piping, but any disruption of their daily lives should be minimal. It might mean closing a street for a short length of time pipes need to go under a street,” she said.
Residents who want to know more about the proposal can view documents that are available at the Maya Angelou Northeast Branch Library or at the Curtis State Office Building in Topeka. Documents related to the site are also available on the KDHE website at https://www.kdhe.ks.gov/1938/29th-and-Grove-Site.
The new proposed remediation project is expected to cost about $14 million and Union Pacific will be responsible for paying for it, Daily said.
Next hearing and steps
KDHE is also conducting a health study in the area at the city’s request, but it is unlikely to be done in time for the Nov. 5 public hearing, Daly said.
A final decision on which corrective action to take will be made after all the public comments submitted before Oct. 16 are evaluated.
After that, a final decision will be made and the public will be notified if any comments from the public caused a change in the preferred remedial decision.
Once the final decision is published, Union Pacific and its consultants will begin the design stage for the remedy and after that, necessary construction will begin.
To learn more about what to expect, residents should plan to attend the Nov. 5 public hearing from 3 to 5 p.m. at the Boys and Girls Club.