In order to measure concentrations of heavy metals in moss, several nationwide surveys have been carried out since 1977. The last survey was carried out in 2005. Inputs of lead from long-range atmospheric transport have been greatly reduced since the 1970s. Lead deposition in Southern Norway is now only 10 per cent of the level in 1977.
Concentrations of lead
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”.