((in case of oil spill, is bioremediation feasible? This experiment on bioremediation of refined fuel-contaminated arctic soil can be taken as reference ?it is feasible for ?))

Introduction

-          soils in polar regions have unique properties, including numerous periglacial features, the presence of permafrost and lower microbial populations than other soils ?present challenges to classic bioremediation procedures developed for more temperate climates

-          REFINED FUELS ARE LESS RECALCITRANT THAN CRUDE OIL

-          Previous studies: the addition of nitrogen, phosphorus and potassium accelerated hydrocarbon removal in an experimental fuel spill in Antarctica

-          Removal of various hydrocarbons was stimulated by nutrient addition to fuel contaminated soil in mesocosm incubated on site at Point Barrow, Alaska

-          Summer season very short in polar regions, active soil layer above the permafrost typically thaws of a period of 1-2 months ?thus it might be practical and economical to use bioremediation

-          Summer season temperature and duration are likely to be limiting factors for bioremediation at polar sites

Experiment, results and discussion

-           biopiles for on-site bioremediation of soil contaminated with Arctic diesel fuel in two independent small-scale field experiments at different sites on the Arctic tundra

-          fertilization with N and P had the greatest stimulatory effect on hydrocarbon removal

-          drainage: low areas that were saturated with water: each soil was anoxic and therefore unfavorable for aerobic fuel biodegradation.  Permafrost probably interferes with the drainage of soil at each of the ties, therefore contributing to the persistence of fuel in the soil?evidence that drainage stimulated hydrocarbon biodegradation

-          inoculation (with cold-adapted, mixed microbial cultures) had a consistent, significant stimulatory effect on hydrocarbon removal (during the summer immediately following inoculation

-          the inocula only affected hydrocarbon removal during the first summer of treatment

-          clear plastic cover—increase temperature ?reduce removal time

-          Factors affecting efficacy of inocula:

o        Short summer season might have substantially limited the growth of indigenous hydrocarbon-degrading populations

o        Inocula used well adapted ?psychrotolerant, mixed microbial cultures, enriched from soil

-          Conclusion: fuel-contaminated arctic tundra soil can be effectively bioremediate on site in biopiles

-          Heating biopiles can also reduce clean-up time