Characterization of Gardermoen airport soil contaminated by de-icing compounds and possible bioremediation strategies.

The new main airport of Norway, Gardermoen, located about 40 km north of Oslo, was inaugurated in 1998. It sits on the largest rain fed unconfined aquifer in Norway. The area is a glacial contact formation with sand and gravel dominating near the ground surface. The weather is characterized by about 800 mm/year of rain. The site is covered of snow from November to April every years. Thus, large amounts of de-icing chemicals are needed for the removal of snow and ice from airplanes (propyleneglycole) and from runways (potassium formate). Every winter, about 1200 tons of propyleneglycole and 630 m3 of potassium formate are dispersed on the site. Both contaminants are easily degradable. They still threaten the groundwater, however, due to overloading of the system since degradation rates are not sufficient, as compared to velocities in the unsaturated zone. Hence the airport is representative of contaminated sites where easily degradable and highly mobile contaminants are released to the soil in large amounts.