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/26) Bioaugmentation of Lindane-contaminated soils with Rhodanobacter lindaniclasticus.

Phillips, Theresa¹, Seech, Alan², Lee, Hung¹, Trevors, Jack¹, ¹ University of Guelph, Guelph, Ontario, Canada² Adventus Remediation Technologies, Mississauga, Ontario, Canada

ABSTRACT- Lindane (gamma-hexachlorocyclohexane (HCH)) is a pesticide and widespread soil pollutant. The use of bioaugmentation for enhanced bioremediation of Lindane was tested using a pure culture of Lindane-degrading, rifampicin-resistant Rhodanobacter lindaniclasticus and mixed consortium of bacteria. The consortium was prepared by enrichment culture using soil obtained from a former Lindane manufacturing site. Two soils were tested. The first was the above-mentioned historically contaminated soil with a total HCH concentration of 6,692 mg/kg, of which 410 mg/kg was Lindane. The second was a pristine agricultural soil with no detectable HCHs, which was spiked with 505 mg/kg Lindane prior to the study. Bench-scale soil microcosms were spiked with ¹⁴C-Lindane and inoculated with 10⁶ CFU, of either culture, per gram of soil. Both soils exhibited the ability to mineralize ¹⁴C-Lindane in the absence of inoculation. Mineralization was enhanced by inoculation only in the pristine soil spiked with Lindane. The lag period prior to acclimation (10% cumulative recovery of ¹⁴C) and the onset of mineralization was significantly reduced by both inoculants. Acclimation was achieved after 14 days in the untreated soil, 4 days with consortium inoculation, and after 1 day when R.l. was used. After 35 days of treatment, GC-ECD analysis of soil extracts from the pristine soil indicated that Lindane concentrations were reduced from 505 mg/kg to 78, 89 and 7 mg/kg in the uninoculated, consortium and R.l.-inoculated microcosms, respectively. Survival of R.l. was detected by plating soil extracts on selective media. The identity of selected colonies was confirmed by PCR amplification and sequencing of the linA gene. The results indicated that R.l. survived in the pristine soil for up to 70 days. These data demonstrate the potential for enhanced bioremediation in soil not previously exposed to Lindane, by inoculation with previously acclimated microorganisms.

Key words: Lindane, Rhodanobacter lindaniclasticus, bioremediation, bioaugmentation