It may also be used as a plant growth regulator to control fruit drop, such as on tomatoes to cause all fruits to ripen at the same time for machine harvesting. 1991 data indicates only that production exceeded 5000 lbs. Patterns Major environmental releases of 2,4-D are due to agricultural applications of systemic herbicides. From 1987 to 1993, according to EPA's Toxic Chemical Release Inventory, 2,4-D releases to land and water totalled over 116,000 lbs., most of which was released to land. KOC values are 19.6 to 109.1.
Adsorption appears to increase with increasing organic content and decreasing pH of soil.
Leaching to groundwater will likely be a significant process in coarse-grained sandy soils with low organic content or with very basic soils. In general little runoff occurs with 2,4-D or its amine salts and runoff behavior is the inverse of adsorption behavior. Thus, 2,4-D can be desorbed from mineral soils, but not from those containing much organic matter. Percolating water appears to be the principal means of movement and diffusion is important only for transport over very small distance. Upward movement of 2,4-D occurs when the soil surface dries or if rapid evaporation occurs.