What We Know 

Between 1967 and 1989, wastewater from the manufacturing facility at 221 Sunset Drive was discharged to City Lagoon #3 (formerly known as the Hulett Lagoon). The wastewater contained trichloroethyene (TCE), which resulted in subsurface contamination in the lagoon and surrounding area. See the City Lagoon #3 webpage for additional information. Wastewater from this facility was discharged to the Camdenton Treatment Plant Lagoon (CTPL), also known as the C.P. White Lagoon, for an 18-month period between December 1989, when Lagoon #3 was closed, and June 1989, when the city’s wastewater treatment plant was brought online. The CTPL is located approximately 1.3 miles southwest of Lagoon #3 on Ha Ha Tonka Road. The city’s wastewater treatment plant was later constructed over a portion of the former CTPL. The Camdenton Industrial TCE Contamination Advisory Team (CITCAT) identified this lagoon as a potential site of TCE contamination in Camdenton, and requested the department conduct an investigation.

Investigations

Pre-CERCLA Site Screening

The department initiated a Pre-Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) screening investigation on Feb. 1, 2018. Information gathered through former employee interviews, discussions with CITCAT members, and a review of city records indicated there was a potential for a release of TCE from the 221 Sunset Drive manufacturing facility to the CTPL over an 18-month period in the late 1980s. According to a past employee who worked at the facility during this period, floor drains throughout the facility connected to the wastewater pre-treatment system, and drippage of TCE from degreased parts onto the factory floor was not uncommon. In sufficient volume, this waste TCE could have found its way to floor drains. The facility had a newly installed wastewater pre-treatment system in place at this time; however, the system was designed primarily to review metals and would not likely have had a significant effect on TCE levels in the wastewater. Sundstrand conducted sampling of the pre-treatment system liquid waste between April 24, 1986 and June 27, 1986. In 12 samples collected, TCE levels ranged from non-detect to 2,230 ug/L or parts per billion (ppb). Based on this information, it is possible that TCE was released to the CTPL over an 18-month period in the mid-1980s. Based on this finding, the department initiated a CERCLA site inspection investigation (SI) on Aug. 18, 2018 to assess the potential release further.

SI Investigation

The department conducted two separate sampling events as part of the SI, one on Dec. 19, 2018, and another on April 17, 2019. The two potential exposure pathways of concern identified for the investigation were consumption of groundwater and vapor intrusion. Seventeen private wells near the CTPL were sampled previously as part of the nearby Dawson Metal Products Camdenton Facility #2 site. No TCE was detected in any of the wells, which indicated releases of TCE at neither the Dawson nor CTPL sites were significant enough to pose a threat to drinking water sources. Shallow groundwater was sampled from within the footprint of the former CTPL during both site investigation-sampling events; one sample was taken from approximately 20 feet below ground surface (bgs) near the treatment plant office building. Five samples were taken from between 8 and 17 feet bgs at locations within the former CTPL bermed cell located just north of the office building. No TCE was detected in any of the shallow groundwater samples. During the December 2018 sampling event, soil cores collected from the surface to 20 feet bgs at a location near the treatment plant office were screened for the presence of volatile organic compounds; none were detected. In addition, eight soil gas samples were collected from different depths at locations adjacent to the treatment plant office; no TCE was detected in any of these samples. Based on the results of the department’s investigations, no release of TCE was documented at the CTPL site.

Path Forward

No TCE was detected in shallow groundwater, soil, soil gas or private drinking water wells at or near the CTPL site. Based on this finding, the department has concluded there was not a significant release of TCE at the lagoon and is not recommending further assessment of the site.