Recent testing by the U.S. Army has detected elevated concentrations of the carcinogenic solvent Trichloroethylene (TCE) in groundwater at the far west boundary of the Badger Army Ammunition Plant. In March 2009, TCE levels were detected at 25 parts per billion (ppb) which exceeds the safe drinking water standard of 5 ppb. However state regulators said additional investigation or private well testing is not justified until there is a significant increasing trend in contaminant concentrations.
In response to a July 13 inquiry from CSWAB, the Wisconsin Department of Natural Resources (WDNR) confirmed that the most recent March 2009 increase to 25 ppb is similar to an early 2006 increase to approximately the same level. At that time, the WDNR collected samples from three private wells in the Maple Park area which is approximately ¼ mile to the south of monitoring well BGM-9103. No volatile organic compounds, including TCE, were detected in these wells.
WDNR officials said that they believe the Maple Park area is probably not in the direct path of contamination because groundwater flow appears to be more to the southeast. For this reason, WDNR officials believe that the source of the TCE may be located west of Badger.
“Because the trend of TCE concentrations in BGM-9103 of the last two years has been to be below or near the Enforcement Standard, no investigation action is justified at this time, and will not be until an upward and elevated trend is apparent in the BGM-9103 TCE data,” WDNR said. “Recent history implies that the TCE levels in this well are stable but can occasionally fluctuate.”
Tentative results from the Army’s June sampling round indicate that the TCE level in this monitoring well has decreased to approximately 6 ppb. WDNR said that it will continue to monitor TCE levels in this monitoring well as quarterly testing occurs.
CSWAB has asked regulators and the Army for groundwater studies that verify groundwater flow direction and has recommended testing additional groundwater monitoring wells in the vicinity. This information will help identify private wells that may be at risk. TCE has been consistently detected in BGM-9103 since 2002.