ANAEROBIC DDT BIOTRANSFORMATION - ENHANCEMENT BY APPLICATION OF SURFACTANTS AND LOW OXIDATION-REDUCTION POTENTIAL

Enhancement of anaerobic DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane) biotransformation by mixed cultures was studied with applicati on of surfactants and oxidation reduction potential reducing agents. W ithout amendments, DDT transformation resulted mainly in the productio n of DDD (1,1-dichloro-2,2-bis(p-chlorophenyl) ethane) upon removal of one aliphatic chlorine. The DDT transformation rate increased with th e addition of the nonionic surfactants Triton X-114 or Brij 35. The ad dition of either surfactant or reducing agents did not significantly e xtend the DDT transformation Addition of both surfactant and reducing agents extended DDT transformation by reducing the accumulation of DDD and increasing the accumulation of less chlorinated products. It is i mportant to minimize the accumulation of DDD because it is a regulated pesticide and is recalcitrant to aerobic transformation. Controlled e xperiments revealed that the transformation of DDT requires microbial culture, but the culture need not be biologically active. Transformati on results are presented for aqueous and soil phase contamination.