The site has been farmed since the 1890s. Row crops were grown in the earlier years and grass and grain crops in more recent years. Strawberries were grown on portions of the property in the 1950s and 1960s.
Dieldrin, banned for decades, is considered a legacy pesticide and remains in the environment long after its use. Dieldren was legal and widely used in the Willamette Valley and throughout the U.S. from the 1950s to the 1970s on many crops, including strawberries and corn. Due to how long it takes for dieldrin to break down in the environment, detection in agricultural soils in the valley is relatively common, but at very low levels as is the case here.
Detection of dieldrin and other legacy pesticides in soil is not new or unexpected. According to the Centers for Disease Control, “dieldrin is everywhere in the environment but at very low levels.”