POTENTIAL FOR INTRINSIC BIOREMEDIATION OF A DNT-CONTAMINATED AQUIFER

Microorganisms indigenous to a shallow aquifer, which underlies an exp losives-contaminated site, mineralized 28% of [U-ring-C-14] 2,4-dinitr otoluene to (CO2)-C-14 within 28 days under aerobic conditions. Approx imately 20% of added 2,4-dinitrotoluene remained undegraded at the end of the incubation while approximately 22% and 6% were transformed to 4-amino-2-nitrotoluene and 2-amino-4-nitrotoluene, respectively. In aq uifer microcosms containing 2,6-dinitrotoluene, approxinately 67% of t he substrate remained undegraded and approximately 14% was transformed to 2-amino-6-nitrotoluene. The radiolabeled study indicated that abou t 8% of the 2,6-dinotrotoluene was mineralized to CO2. The demonstrate d degradation and subsequent mineralization of dinitrotoluene compound s by aquifer microorganisms are consistent with the decline in dissolv ed dinitrotoluene concentrations observed along the general ground-wat er flowpath Pt the site. The results indicate that intrinsic bioremedi ation may be a viable alternative for remediating contaminated ground water at this site.