Mobility of 2,4‐D and 2,4,5‐T n‐Butyl Esters in Soils Following Massive Application to Field Mini‐Lysimeters

Abstract

Concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T) in soils and leachates from field mini‐lysimeters were monitored for up to 28 months to characterize the patterns of herbicide mobility in soils under climatic conditions of the Palouse region of the Pacific Northwest. The lysimeters contained soils from Washington, Wyoming, or Mississippi, and were treated with 1,120 or 5,600 kg/ha of a 1:1 mixture of 2,4‐D and 2,4,5‐T n‐butyl esters in 1976, 1977, or 1978. The winter of 1976–1977 was mild and relatively dry, and little leachate could be collected. However, subsequent winters were wet and the soil columns were saturated by the following springs. Less than 1 ppm of 2,4‐D was found in leachates from Washington and Wyoming soils receiving the herbicide application in 1976 or 1977, though over 30 ppm was found in leachates from Washington soil treated in 1978. Over 10 ppm of 2,4‐D could be found in leachates from the acidic Mississippi soil receiving the high rate of herbicide application in 1977 or 1978. Concentrations of 2,4,5‐T in the same leachates were higher for the Washington and Wyoming soils, but lower (than corresponding concentrations of 2,4‐D) for the Mississippi soil. In all cases, 96–99% of the undegraded herbicides in the lysimeters remained in the 0‐ to 10‐cm soil layer after two to three winters, and only 0.14–1.65% of the 2,4‐D and 0.33–3.7% of the 2,4,5‐T remaining in the lysimeters were present in the 10‐ to 30‐cm depths. Mobility characterization by soil thin‐layer chromatography showed that the ester form of both herbicides was relatively immobile, the acid form was less mobile in the Mississippi soil than in the Washington and Wyoming soils, and 2,4‐D was slightly more mobile than 2,4,5‐T under corresponding conditions.

Kinetic Study of Sorption of 2,4‐D and Atrazine on Rubber Granules

“…In one study, it was found that the maximum content of 2,4-D in water samples of rivers in the western United States sampled in 1968 was 0.35 ppb; 18 ppb of 2,4-D was found in irrigation return flow at Moses Lake, Washington. For drinking water, although the standard treatments in filtration plants reduce unduly high surges down to lower concentrations, they are in adequate to eliminate persistent lowlevel concentrations of 2,4-D. [2] Majka et al [3] reported that dissipation of 2,4-D and 2,4,5-T herbicides in the acidic Mississippi soils were extremely slow even at the lower application rate. Surface soil pH was lowered following herbicides' application.…”

Efficacy of Adsorbents of 2,4-D and Atrazine removal from water environment

“…Ricardo et al (1998) reported drifting loss during application of iso-octyl ester of 2,4-D in air. In a study carried out in 1978, it was found that when a 1:1 mixture of 2,4-D and 2,4,5-T (2,4,5 trichloro-phenoxy acetic acid) was applied to a field in Florida at 4,480 kg ha -1 , 54 % of the applied herbicides remained in the soil profile even after 414 days with 37 % being present in the top 15 cm soil layer; when the same was applied to a field in Washington, over 30 ppm was found in leachates (Majka et al, 1982). Toxic hazards caused by many herbicides like atrazine, simazine, 2,4-D, 2,4,5-T, etc.…”

Evaluation of thermodynamic properties of sorption of 2,4-D and atrazine by tire rubber granules

“…Considerable evidence has been accumulated to suggest that many water resources of India are polluted with organic pesticides [7,13,16]. 2,4-Dichloro-phenoxy-acetic acid (2,4-D) and 2-chloro-4-ethyalamino-6-isopropylaminos-traiazine (atrazine) are two widely used herbicides in the world as well as India and they were found in surface water and ground water in different countries of the world [3,10,11,12,15].…”