Perham Investigation and Remediation


In the 1930s and 1940s, during the grasshopper infestation, the U.S. Department of Agriculture distributed lead arsenate as grasshopper bait in several Minnesota counties. The East Otter Tail County Fairgrounds in Perham served as a mixing station and depository for unused arsenic-based grasshopper bait, and an estimated 200 to 2,500 pounds of arsenic were buried there in 1947. The site was later redeveloped into warehouse and office space, including the installation of a drinking water well on-site. This ultimately led to health issues in 1972 due to arsenic-contaminated well water. Subsequently, the drinking water well was sealed, and the City of Perham’s water system extended to the contamination site.

Project Details

Since that time, multiple soil and groundwater investigations have been completed, including various attempts to excavate the contamination. These attempts were inhibited by the building location—directly on top of the majority of the contamination. To address groundwater arsenic contamination, a groundwater treatment system (GWTS) was installed in 1997. The pump and treat system relies on alumina adsorber units to effectively remove arsenic from the contaminated groundwater.

In 2018, after observing increasing arsenic concentrations in the groundwater beginning around 2011, Bay West completed site investigations, optimization studies, and groundwater modeling. The studies revealed that remaining soil contamination was contributing to increased arsenic concentrations. Additionally, the GWTS effectiveness was impacted by the placement of the infiltration gallery, which was short-circuiting extraction well capture.

The stagnation in effective groundwater treatment coupled with the aging out of the treatment system—which has been in operation for approximately 27 years—requires a site-wide treatment approach re-evaluation. Currently, Bay West is assisting the client in determining the next remedial steps—evaluating complete soils excavation or revamping the existing treatment system to provide effective site remediation.

Bay West remains dedicated to environmental stewardship and client-centric solutions, ensuring the ongoing protection of communities and the environment.


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