Humboldt Station Landfill has 7 groundwater monitoring wells, 6 of which have been polluted above federal advisory levels based on samples collected between September 20, 2010 and September 22, 2015. Groundwater at this site contains unsafe levels of manganese, boron, sulfate and cobalt.Site description
Humboldt Station's closed coal combustion residue (CCR) landfill is located along the north side of the Des Moines River near its junction with the East Fork Des Moines River. From 1950 to 1978, the 4.5 acre Humboldt Station landfill accepted approximately 2,241,000 cubic feet of coal ash from Humboldt Generating Station, which began operation in 1950. The landfill was capped in late 1999 with three feet of soil. Coal ash extends 11 feet beneath the capped surface. Annual water quality reports from 2008 to 2015 show a trend of manganese concentrations exceeding the Environmental Protection Agency's lifetime health advisory standard. The city of Humboldt operates a water well 3.4 miles north-north west of the landfill.