Behavior of [14c]-4-nitrophenol and [14c]-3,4-dichloroaniline in lab sediment-water systems. 1. Metabolic fate and partitioning of radioactivity

Using a standard screening procedure, the fate of [14C]-4-nitrophenol and [14C]-3,4-dichloroamline was studied in lab sediment-water systems; incubation intervals ranged from 4 h to 90 d. The sediments were collected from a creek, a pond, and a drainage ditch of a fruit-growing plantation, and were characterized. Both compounds and their transformation products were sorbed to the sediments in large quantities; radioactivity left in the water phase was below 11 % after termination of the experiments. Besides minor amounts of 14CO2, 3,4-dichloroaniline was converted to predominantly nonextractable residues, presumably without preceding microbial transformation of the 3,4-dichloroaniline moiety. Two main end products were observed in the 4-nitrophenol experiments, namely nonextractable residues and 14CO2. Data obtained from the sediment exhibiting highest microbial activity probably indicated a further mineralization of 4-nitrophenol-derived sediment-bound residues. On the whole, 4-nitrophenol presumably shows low persistence and accumulation in sediment-water systems, whereas due to its stability the toxicity of sediment-sorbed 3,4-dichloroaniline should be examined.