29th and Grove Site

Risk Assessment

A risk assessment determined the current and future effects of contaminants on human health and the environment if no cleanup action was taken. Results of the risk assessment indicated that exposure to contaminated soil at the UP rail yard does not present a significant health risk to workers or residents. There is some potential health risk to people who contact contaminated groundwater. Most of the risk was associated with ingestion of or dermal contact with contaminated groundwater. It should be noted that homes and businesses in and near the contaminated area have been provided with a safe drinking water supply and that current workers are not normally exposed to the contaminated groundwater. The risk assessment did not identify any significant ecological risk related to Chisholm Creek which runs south of the UP rail yard. 

Interim Remedial Measures

Several interim remedial measures (IRMs) for soil and groundwater have been implemented to reduce the mass of contamination at the UP rail yard and shorten the time to achieve overall cleanup goals. The list of IRMs implemented at the source area in chronological order include: accelerated remediation technology wells, soil excavation, in-situ chemical oxidation, and enhanced reductive dechlorination (also known as bioremediation). In addition, an IRM to establish hydraulic control of the groundwater plume was implemented in 2009 by installation and operation of six groundwater extraction wells along Murdock Avenue, south of Murdock Park. The groundwater extraction system was installed to prevent the contaminated groundwater plume from continuing to spread in the subsurface.

Feasibility Study

A Feasibility Study that includes the evaluation of remedial alternatives that could be used for cleanup was completed in December 2020. The Feasibility Study also summarizes supplemental investigations and pilot testing conducted in support of the evaluation of remedial alternatives. After investigation of the contamination and evaluation of remedial alternatives, KDHE identified the following actions as the best way to protect the public health and the environment:

•    At the source area, enhance the natural process of bioremediation of the contaminants by adding nutrients and other amendments to the soil and groundwater so that bacteria can degrade the contamination.   

•    At the source area, removing remaining shallow contaminated soil present under a concrete pad for a storage area. 

•    Pump contaminated groundwater to the surface and treat the water to remove contaminants. The water would be treated by air stripping technology and/or granular activated carbon technology. After contaminants are removed from the water, the treated water would be reinjected back into the subsurface and/or discharged to a nearby stream by permit.

•    Establish an environmental use control to restrict the use of the rail yard where the release of TCE occurred to prevent exposure to contaminated soil and groundwater.  

•    Evaluate the performance of the remedy by monitoring groundwater and surface water.  

•    Prevent installation of new domestic-use wells in areas with groundwater contamination. 

•    Conduct periodic reviews of receptors and potential exposure pathways to ensure that the remedy remains protective of human health.