In order to measure concentrations of mercury in moss, several nationwide surveys have been carried out since 1985. Concentrations remained more or less unchanged from 1985 to 1995, then generally dropped in 2000. In 2010 they were in line with or slightly higher than in 2000 and 2005, but lower than concentrations in 1985.
Concentrations of mercury
micrograms per gram moss
Source: Climate and Pollution Agency. The map is an animation that shows the reduction in acidification in Norway. If you cannot see the animation, you may need to change the settings of your web browser. In Internet Explorer, choose Tools -> Internet options -> Advanced, and tick the check box “Play animations in web pages”.