Fluoride uptake in conifers related to emissions from aluminium smelters in Norway

Fluoride concentrations in pine and spruce needles have been monitored for 15–25 years on permanent plots around eight aluminium smelters in Norway. A high correlation between fluoride emission levels and fluoride accumulation in needles is demonstrated. Emission levels above 20 kg Ftot h−1 will cause significant forest damage, especially in narrow fjords and valleys. At levels of 10 kg Ftot h−1 and less, the risk for forest damage is low. No long term effects from fluoride accumulation in soil was apparent in this study.