“We defined the extent of the plume when we did the original SI, installed monitoring wells throughout the area, and by monitoring those, the contamination has not spread,” Van Dyke said. “The figure used in the addendum RI is the same one used in 2003.”

This is a follow up report in regards to the Aug. 23, 2017 article published in the Lake Sun “New investigative report sheds light on Camdenton TCE plume.”

Officials with the Missouri Department of Natural Resources want to clarify a previous description published by the Lake Sun in regards to the extent of the trichloroethylene (TCE) plume in Camdenton based on a new graphic published in August.

The graphic was provided by Golder Associates Inc. as an addendum to a Supplemental Remedial Investigation contracted by the City of Camdenton through a Corrective Abatement and Consent Order agreed to in 2016. It depicts the drawdown of the TCE plume, which the Lake Sun described as “appearing to be more widespread than previous graphics have shown.”

Don Van Dyke, the contact for MDNR’s Mulberry Well and Hulett Lagoon investigations and remedial work plans, said that specific description is not accurate in regards to the TCE plume. In fact, Van Dyke said, Golder used the same data and graphics compiled in the 2003 Remedial Investigation Summary Report for Former Hulett Lagoon report.

“We defined the extent of the plume when we did the original SI, installed monitoring wells throughout the area, and by monitoring those, the contamination has not spread,” Van Dyke said. “The figure used in the addendum RI is the same one used in 2003.”

The difference between the two graphics is the size, scale and tool used to create the graphic, which contributed to the misleading description of the TCE plume. What the Golder report did determine was that the cone of depression in the underlying aquifer appears to be more “flat and broad” as opposed to “steep and aerially constrained.”

“Normally when you pump in well, it will create a cone of depression, in the case of the Mulberry Well, we don’t have that because flow is flat and horizontal. We identified exactly where the plume was to ensure the pumping we’re doing is containing and not allowing the contamination to spread,” Van Dyke said. “We basically determined the zones within the 400-600 feet and within those zones -- the water producing zones are containing TCE -- so what we wanted to know is if we pump just those zones contaminated with TCE, what pumping rate we could use to optimize the containment within the area of contamination.”

The Golder report ultimately concluded that the current pumping system and air-stripping method applied to the Mulberry Well, which is not connected to the municipal well system, is adequate in treating the TCE to be released at safe levels into the environment.

Van Dyke said the final plan is to install a charcoal filtration system in addition to the current set-up to completely remove the TCE from the Mulberry Well.

“The TCE vapors that come off (the air strip) will be sent through the charcoal filtration system, so no TCE is admitted in the atmosphere,” Van Dyke said. “This is what will be the final remedy for the Mulberry Well. Currently we’re doing the same thing, but we don’t have a system to capture it at this time. The TCE is just being discharged into the atmosphere, but the levels are not considered harmful.”