28 

 The pure acid formulation of 2,4-D is prepared by combining 

 2,4-dichlorophenol and monochloroacetic acid. The salts are formulated 

 by addition of amines or inorganic hydroxide to the pure acid. Esters 

 are produced by reaction of 2,4-D with the appropriate alcohols. 



Toxicology 



Effects of various formulations of 2,4-D have been evaluated for 

 a wide range of organisms in both the aquatic and terrestrial food 

 chains. Studies have shown that toxicity of 2,4-D varies with the 

 formulation utilized in the evaluations (Davis, 1970; Duke, 1971; Weed 

 Science Society of America, 1979; Halter, 1980). Acute oral toxicity 

 (LDcq) of the various formulations of 2,4-D has been reported to be 

 300 to 1,000 mg/kg for rats, guinea pigs, and rabbits (Weed Science 

 Society of America, 1979). Hansen et al . (1971) reported that rats fed 

 from to 1250 mg/kg 2,4-D acid for two years exhibited no significant 

 effect on growth rate, survival rate, organ weights, or hematologic 

 values. Ninety-three percent of dogs fed from to 500 mg/kg 2,4-D acid 

 in their diet for two years were clinically normal with no 2,4-D related 

 effects noted (Hansen et al . , 1971). In a critical review of the 

 effects of 2,4-D on the aquatic environment, Halter (1980) reported no 

 effects of 2,4-D acid on phytoplankton at rates as high as 300 mg/1. 

 Following a large-scale application of the BEE formulation at a rate of 

 49.7 kg/ha (a.e.), Whitney et al . (1973) reported no difference in 

 plankton populations following herbicide treatment. A review of the 

 effects of both the DMA and BEE formulations on benthic invertebrates 

 following routine aquatic weed control operations indicates no adverse 

 effects due to the herbicide, other than those caused due to habitat 



