Insecticide persistence and translocation: Residues of Aldrin and Heptachlor in Soils and Their Translocation into Various Crops

Abstract

Loam soils were treated with aldrin and heptachlor in five yearly dosages of 5 pounds per acre, one massive dose of 25 pounds per acre, or at "normal" rates of 1, 2, or 3 pounds per acre per year over a 3-year period. Various crops were grown on the insecticide-treated soils. The insecticidal applications in five yearly 5-pound dosages resulted in 1.7 to 2 times higher soil residues than in soils treated only once at 25 pounds per acre. Repeated applications resulted, after 3 or 5 years, in residue levels close to 20% of the total applied dosages. A dense cover crop of alfalfa prolonged the persistence of the insecticidal residues in soils. Certain crops grown in these soils did not absorb measurable amounts of insecticidal residues, while others translocated the chemicals in various amounts. Carrots absorbed more insecticidal residues than any other crop tested. Some quantitative relationship between soil residue levels and translocated insecticides was noticed. Potatoes, radishes, and carrots, grown on soil treated with aldrin at 1 pound per acre, either contained no measurable amounts of residues or residues at concentrations of 0.03 and 0.05 p.p.m., respectively. In general, more residues were found in crops grown on heptachlor-treated soils than in those from aldrin-contaminated soil plots. © 1965, American Chemical Society. All rights reserved.