PARENT SESSION

1B+C Abiotic Transformations + Biodegradation
Poster Hall
8:30 AM - Monday, 28 April 2003
Chair: Peijnenburg, W.¹, ¹
Co-chair: Jafvert, C.T.², Gombar, V.K.³, ^{2 3}

(MOP/31) Use of sodium to enhance DDT transformation in a long-term DDT-contaminated soil.

Singleton, Ian¹, Kantachote, Duangporn^{2, 5}, Naidu, Ravi³, Mallavarapu, Megharaj³, McClure, Nicholas⁴, Williams, Brian⁵, ¹ University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK² Prince of Songkla University, Hat Yai, Songklha, Thailand⁵ University of Adelaide, Adelaide, SA, Australia³ CSIRO, Adelaide, SA, Australia⁴ Flinders University of South Australia, Adelaide, SA, Australia

ABSTRACT- Bioremediation is an economically attractive option to remediate soil contaminated with DDT. However lack of DDT bioavailability in soil presents an obstacle to this technology particularly in soils that have been contaminated for long periods. In this work sodium was applied to a water saturated long-term DDT-contaminated soil as sodium is known to disperse clays. Such clay dispersal may potentially release and/or expose physically protected DDT thereby enhancing DDT bioavailability. Immediately after addition sodium significantly increased dissolved organic carbon (DOC) levels, and the amount of DDT residues (DDT, DDE and DDD) measured in soil solution. DDT transformation ranged between 95% (30 mg Na/kg soil) to 72% (no sodium added). At higher sodium levels (80 mg Na/kg soil) DDT transformation was reduced. The anaerobic incubation conditions employed (high water content) prevented DDE production and DDD was the major breakdown product formed. Overall it appears that sodium has potential as a cheap and safe alternative to surfactants as a method for increasing DDT transformation in contaminated soil.

Key words: soil, bioremediation, DDT, sodium