The emerging contaminants 1,4-dioxane and perfluoroalkyl substances (PFAS) were recently discovered in the groundwater at two of the Minnesota Pollution Control Agency’s closed landfills, the East Bethel and WDE landfills. Existing remediation systems have been in operation for many years to address volatile organic compounds in groundwater at these two landfills. Based on updated groundwater regulatory guidance for these emerging compounds, it was determined that the existing remediation systems have not fully captured the larger plumes associated with 1,4-dioxane and PFAS. The MPCA hired Barr to help understand the extent of the contamination by developing updated conceptual models for the two sites.
Barr conducted groundwater modeling and planned additional site investigation with the MPCA to create an updated conceptual model of the plumes. Based on this information, we expanded the groundwater monitoring network and identified potential remediation approaches and alternate treatment technologies to address the plumes and the emerging regulatory guidance for 1,4-dioxane and PFAS.