The origin of bromoform in seawater and atmosphere, as well as possible sinks and breakdown mechanisms, is discussed. A bromoform budget is calculated for the Kattegatt area between Sweden and Denmark, where the input of bromoform from a power plant is significant. Both anthropogenically (250 x 10(6) g yr-1) and biogenically (350 x 10(6) g yr-1, 0.016 g m-2 yr-1) produced bromoform is likely to have a great impact locally on the inventory and the release to the atmosphere. Using measured sur-face concentrations of bromoform, the total annual release from the Kattegatt to the atmosphere is estimated to 550 x 10(6) g (0.025 g m-2 yr-1).