Persistence and effects of some chlorinated anilines on nitrification in soil

A study was made of the effects of aniline and monochlorine-substituted, and dichlorine-substituted anilines on nitrification in Guelph loam. These compounds were shown to be inhibitory against the oxidation of ammonium-nitrogen to nitrite-nitrogen, but not nitrite-nitrogen to nitrate-nitrogen. The chlorinated derivatives showed increased toxicity against Nitrosomonas in the following order, 4-chloroaniline, 3-CA, 2,6-DCA, 2-CA, 2,4-DCA, 3,5-DCA and 2,5-DCA. Two patterns of inhibition of the process of nitrification were noted in these experiments which were, in part, dependent on structure of the compound used.Decomposition studies of these compounds in soil indicated that the dichloroanilines were more persistent than aniline or the monochloroanilines. The disappearance of 3,4-DCA from soil was primarily due to chemical degradation, although bacterial participation was also involved.A discussion of the relationships of molecular configuration, lipophilic properties, and persistence of aniline and monoch...