Limiting factors for hydrocarbon biodegradation at low temperature in Arctic soils

Hydrocarbon fuel spills are common in the Arctic. But, little is known abou t hydrocarbon-degrading microflora in Arctic tundra soils or the potential for bioremediation of these soils. We examined mineralization of radiolabel ed hydrocarbons in microcosms containing soils collected from sites across the Canadian Arctic. The soils all contained psychrotolerant microorganisms which mineralized dodecane and substantially removed total petroleum hydro carbons (TPH) at 7 degrees C. Dodecane mineralization was severely limited by both N and P. Dodecane mineralization kinetics varied greatly among diff erent soils. Multiple regression analysis showed that soil N and TPH concen trations together accounted for 73% of the variability of the lag time prec eding dodecane mineralization. Soil characteristics were less effective as predictors of mineralization kinetic parameters other than lag time. High t otal C concentrations were associated with high mineralization rate constan ts, and high sand contents were associated with long times for half-maximal dodecane mineralization. Very high concentrations of TPH (100 mg g(-1) of dry soil) and heavy metals (e.g., 1.4 mg Pb g(-1) of dry soil) did not prev ent dodecane mineralization. Inoculation of soils with indigenous or non-in digenous hydrocarbon-degrading microorganisms stimulated dodecane mineraliz ation. Bioremediation of hydrocarbon-contaminated Arctic tundra soils appea rs to be feasible, and various engineering strategies, such as heating or i noculating the soil, can accelerate hydrocarbon biodegradation. (C) 2000 El sevier Science Ltd. All rights reserved.