MCPA dimethylamine salt

Figure 3. Sunlight degradation products of commercial MCPA dimethylamine salt formulation in aqueous spray droplets.

Table 5 is a more comprehensive compilation of the DMN content of some herbicides formulated as the dimethylamine salts (53). Five out of six formulations of 2,4-D contained DMN at levels of between 60 and 370 Pg/l. All four formulations of MCPA contained DMN at levels of between 250 and 650 yg/1. DMN levels of between 187,000 and 640,00 yg/1 were found in formulations of 2,3, 6-trichlorobenzoic acid which had been stored in metal cans to which sodium nitrite had been added. Table 5 represents a comparative study between an EPA laboratory and Thermo Electron. The decrease of the DMN level for any one compound reflects the success of the manufacturers in decreasing the DMN contamination (60). 

Dicamba in the form of its dimethylamine salt is a translocatable auxin-type herbicide, which by pre- or postemergence treatment, usually combined with one or more phenoxyalkanoic acids, is used for the control of grasses, broad-leaved weeds and several shrubs. In combinations mainly 2,4-D, MCPA, and mecoprop are used. Its recommended rate is 80-130 g a.e./ha. 

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