Pesticide metabolites as contaminants of groundwater resources: assessment of the leaching potential of endosulfan sulfate, 2,6-dichlorobenzoic acid, 3,4-dichloroaniline, 2,4-dichlorophenol and 4-chloro-2-methylphenol

This study reports the results of Koc and soil DT50 experiments used for the definition of the leaching potential through the GUS Index of five metabolites: endosulfan sulphate (ES) from endosulfan, 2,6-dichlorobenzoic acid (DBA) from dichlobenil, 3,4-dichloroaniline (DCA) from propanil, 2,4-dichlorophenol (DCP) from 2,4-d and 4-chloro-2-methylphenol (CMP) from MCPA. The Koc values for all the compounds were lower than 300, indicating high potential mobility in soil. Soil DT50 values were around 24 days for DBA and ES, and <3 days for the other three metabolites. The leaching potential expressed by the GUS Index was high for DBA and ES (>2.8) and low to negligible for CMP, DCA and DCP (<0.32). In short, the intrinsic characteristics of DBA and ES are typical of leachers, but their significance as groundwater contaminants should be further surveyed through leaching in soil columns treated with their parent compounds.