On-site studies toward a rational bioaugmentation strategy for Antarctic hydrocarbon contaminated soils

RUBERTO L; VAZQUEZ S; DIAS R; HERNANDEZ E; CORIA S; LEVIN G; MAC CORMACK W.P

Buenos Aires, Argentina

Congreso; XXXI SCAR and Open Science Conference; 2010

Scientific Committee on Antarctic Research

Bioremediation of hydrocarbon-contaminated soil applying bioaugmentation strategies is a controversial process. In this work, the effect of the inoculum size and the absence of natural microflora on the efficiency of hydrocarbon removal were studied. Two levels of inoculums (106 and 109 CFU g-1) were applied to flasks containing sterile (S6 and S9) and non-sterile (NS6 and NS9) fuel-contaminated Antarctic soil from Jubany Station. Community controls (CC) and biostimulated autochthonous microflora (BAM) were included. Total heterotrophic aerobic (THAB) and hydrocarbon degrading (HDB) bacteria as well as total petroleum hydrocarbons (TPH) were analyzed. Initially, THAB and HDB counts values (CFU g-1) were higher than those in CC only in systems inoculated with 109 CFU g-1. At day 60, three different levels of HDB were observed. The lower level was represented by CC (106 CFU g-1). A second group (¡Ö5x107 CFU g-1) was represented by BAM, NS6, NS9 and S6 and a third one by S9 (¡Ö1x109 CFU g-1). TPH values at day 60 decreased significantly in all systems excluding CC. However, NS6, NS9, S6 and S9 were not different from those corresponding to BAM. Results clearly showed that the cost-benefit balance for bioaugmentation of a diesel-fuel-contaminated Antarctic soil is not profitable using a single-stage process. Further studies should consider the efficiency of multiple-stages bioremediation processes involving an initial step involving biostimulation of the indigenous microflora (to remove the bulk of contaminants) and further stages of rational bioaugmentation or phytoremediation strategies to improve the removal of the more recalcitrant hydrocarbons.