Persistence and vertical movement of 2,4-dichlorophenoxyacetic acid in two subarctic soils

Abstract

"The persistence of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in soils from two sub-arctic regions of Alaska. Study sites were established in Delta Junction, where the climate is cold and dry, and Valdez, a more temperate and humid climate. Soil samples were collected from three depth ranges (0-7.6 cm, 10-30 cm, and 36-60 cm) for roughly 360 days following the application of 2,4-D iso-octyl ester at both study sites. 2,4-D was extracted from the soil samples and analyzed using a gas chromatograph and mass selection detector (GC/MSD). Both study sites saw vertical movement of the herbicide, with 2,4-D concentrations detected to a depth of 60 cm in the soil column. The half-life calculated for the Delta Junction site during the growing season was comparable to those observed in studies conducted in temperate climates. However, 2,4-D exhibited longer persistence times at both study sites than the persistence observed in studies conducted in temperate climates, with 2,4-D concentrations present in surface soils one year after application"--Leaf iii