CHEMICAL AND MICROBIOLOGICAL ASSESSMENT OF PENDIMETHALIN-CONTAMINATEDSOIL AFTER TREATMENT WITH FENTONS REAGENT

This study assessed chemical effects and microbial response after Fent on's treatment of pendimethalin contaminated soils. The efficiency of the rapid chemical transformation of pendimethalin varied from 25% to greater than 90%. The highest efficiency was associated with a soil ha ving comparatively low organic matter and low acid neutralizing capaci ty. This is consistent with the role of organic matter as a free radic al scavenger and the optimum formation of free radicals at low pH. Pot ential heterotrophic activity, as measured by glucose mineralization, decreased with increasing pendimethalin concentration, but this inhibi tory effect was removed after Fenton's treatment. Treatment also relea sed BOD, COD, TOC, and nitrate into solution. The organic matter relea sed into solution was biodegradable and served as a substrate for subs equent microbial growth. Analysis of the microbial population growing in the Fenton's treated soil leachates showed an overall decrease in ( culturable) heterotrophic diversity, but an increase in the concentrat ion of Pseudomonas species. These results suggest that Fenton's treatm ent of pendimethalin contaminated soil created favorable conditions fo r microorganisms desirable for bioremediation. Copyright (C) 1996 Else vier Science Ltd