Dicofol residues in United States soils having a known history of its use as a miticide, 1974

Soil samples were collected from a total of 21 sites in California, Washington, Florida, Pennsylvania, and Michigan. Dicofol (Kelthane) miticide had been applied at various times over a 5-year period to 17 of the sites; four sites had received no applications. Samples were collected at 0-75-mm and 75-150-mm depths, and submitted to gas-liquid chromatographic analysis. Samples from only four of the 17 treated sites contained mean residues equal to or exceeding 2.00 ppm. Residues in all cases were only a small fraction of the total amount applied. Apparently, a mechanism for the dissipation of dicofol exists, but it is unidentified at this time.