Expert on acidification, critical loads for sensitive organisms and countermeasures, especially with liming strategies for water and catchements. Environmental consultant for the large road construction on E18 from Grimstad to Kristiansand, and investigated and monitored the geochemical and envirnommental effects of blasting of sulphuric rock. From 2007 coordinated all NIVA-work on the eradiction of the salmon parasite Gyrodactylus salaris in rivers, both the treatment with sulphuric acid and aluminium and the method development.