Aniwa, WI 50448
This Site is a former arsenic pesticide storage and disposal facility in a mixed residential and agricultural area in western Shawano County, WI. The Town of Aniwa purchased the property to use as a storage and distribution location for grasshopper pesticides in the 1930s. Arsenic-based pesticides were distributed by the United States Department of Agriculture and the Wisconsin Department of Agriculture at the time to control grasshopper infestation in potato crops. The pesticides were stored in a wooden shed at the Site and area farmers picked up a small supply for their use as needed. The farmers mixed the pesticides with molasses or sawdust and spread the mixture along the roadsides to attract grasshoppers from the fields. The government recalled the arsenic pesticides after World War II, however the pesticides stored at the Aniwa Site were somehow not returned to the Department of Agriculture. The US Government prohibited the use of arsenic in and around homes in 1967. In the 1970s, Town officials buried the pesticide in a pit adjacent to the shed.
A limited removal action was conducted in 1984 by WDNR to excavate and dispose of 19 metal and wooden drums of arsenic pesticide that were buried at the Site in the 1970s. Post-removal soil and groundwater monitoring conducted by the Town indicate that not all of the pesticide was successfully removed during the 1984 removal. Arsenic concentrations as high as 8,360 mg/kg have been identified in the upper four feet of soil and as high as 1,410 mg/kg in the surface soils where obvious recreational use is occurring. Groundwater monitoring indicates the contamination is migrating. The groundwater concentrations in the on-site monitoring wells within the historic source areas have been significantly increasing and the arsenic concentrations in the neighboring residential well are approaching concentrations that would exceed the 10ug/L WDNR Enforcement Standard (ES) and EPA Maximum Contaminant Level (MCL) for arsenic.
Post-removal soil and groundwater monitoring conducted by the Town indicate that not all of the pesticide was successfully removed. High levels of arsenic are present in the surface and sub-surface soils. The Site is unsecured and there is evidence of regular recreational use of the property by trespassers. The property is owned by the Town of Aniwa. The Town does not have the resources to conduct the needed clean-up. WDNR and the Town of Aniwa requested assistance from EPA’s Emergency Response Branch in September, 2014.
Aniwa will be excavated again starting June 1st, 2015.