TOPEKA (KSNT) – The Kansas Department of Health and Environment (KDHE) announced Wednesday that results from recent water testing on Mill Creek show a decrease in the concentration of contaminants over time and a downward trend in contaminants on Little Blue River. KDHE has been sampling the water in Mill Creek, located in Washington County, following a massive crude oil spill that occurred last month.

According to the department, on Monday, a stream advisory was issued for Mill Creek downstream of the spill to the Little Blue River directing area residents not to come into contact or allow pets and livestock to contact the creek water. That advisory remains in effect.

Weather dependent, KDHE takes water samples weekly from multiple sites to measure levels of petroleum contaminants in the water. Additionally, KDHE staff review and analyze the daily water and soil sampling conducted by TC Energy’s contractors. The water is being analyzed for volatile organic compounds (VOCs) and semi-volatile organic compounds known to be present in this grade of crude oil known as diluted bitumen.

“Bitumen is a heavy grade of crude oil that is safely diluted for transportation down the pipeline,” Randy Carlson, PhD, Geologist and Director of Environmental Remediation at KDHE said. “Without dilution, it would not flow through a pipeline efficiently.”

TC Energy is temporarily diverting Mill Creek from a location upstream of the pipeline spill, to downstream of the containment dams. The diversion will assist in the clean-up and reclamation of the impacted zone of Mill Creek by limiting the quantity of unimpacted surface water that enters the containment area. 

Specially constructed earthen dams have been effective at containing spilled material. However, trace amounts of petroleum contaminants have been detected downstream. The diversion of surface water around the impacted area will reduce the chance of further impacts downstream.

No public water supply intakes are present on the Little Blue River. TC Energy is providing water testing for residents with private water wells close to Mill Creek, the Little Blue River, or with private surface water intake for livestock or recreational ponds located on either of those streams.