The field experiment constituted a part of a more comprehensive MIDAS-project (Migration of Alternative De-icing Chemicals in Aquifers) that is carried out since year 1997 by the Finnish Environment Institute (SYKE) and Finnish Road Administration together with several other partners. Experiments with soil filters in the years 1998-2001 showed that potassium formate biodegraded rapidly in soil. Encouraged by these promising results, potassium formate was applied on a field site in south-eastern Finland during winter seasons 2002-2004 to study transport and biodegradation of potassium formate in shallow aquifers and weather conditions characteristic for Finland. The monitoring programme at the Kauriansalmi field site in Suomenniemi involved groundwater samples from a network of monitoring wells, privatedug wells and a water intake well. Furthermore, laboratory experiments using soil and groundwater samples were conducted to study the microbial degradation of potassium formate at a range of low temperatures. During the monitored winter seasons in the years 2002-2004, over 10 000 kg of potassium formate per kilometre was applied on the highway 13. By the end of the second monitoring season, use of potassium formate did not have any harmfuleffects on groundwater quality or vegetation near the road slopes. Laboratory microcosm experiments also demonstrated that biodegradation of formate initiated in less than 3 hours at temperatures of +6, +1 and -2 °C. Monitoring of groundwater quality for detecting the possible delayed effects will continue in 2009. For the covering abstract see ITRD E143097.
Samenvatting