INVESTIGATION OF DIURON-AND LINURON-TREATED SOILS FOR 3,3',4,4'-TETRACHLOROAZOBENZENE

Soil samples from field plots, which had been treated for 12 consecutive years with 2 and 4 pounds per acre of 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (diuron) and soil samples from a field plot treated with a single application of 3-(3,4-dichlorophenyl)-lmethoxy-1-methylurea (linuron) at a rate of 2 pounds per acre, showed no detectable 3,3′,4,4′- tetrachloroazobenzene (TCAB). The laboratory results of Bartha and Pramer (1967) were confirmed in that the incubation of 3,4-dichloropropionanilide (propanil), at concentrations of 250 and 500 p.p.m. in soil, yielded substantial residual levels of 3,4-dichloroaniline (DCA) and TCAB after 31 and 42 days. The incubation of 500 p.p.m. of diuron and linuron in soil (equivalent to a field treatment of 500 pounds per acre to a depth of 3 inches), yielded minimal levels of DCA (approximately 1 p.p.m. or less) and no detectable amounts of TCAB, under the same laboratory conditions. Additional studies with DCA in soil up to concentrations of 500 p.p.m. showed, that despite the relatively high initial and residual DCA content, the soil content of TCAB was considerably less than anticipated. Therefore, it is believed that DCA is not the prime precursor for TCAB formed in the soil. © 1969, American Chemical Society. All rights reserved.