Vegetation survey at Årdal, Sunndal and Mosjøen aluminium smelters in 2019-2020. Impact of fluoride emissions on local vegetation.

Abstract

The scope of this study was to provide an update on fluoride (F) emission effects on vegetation around three aluminium smelters. We visited Årdal and Sunndal smelters in 2019-2020 and Mosjøen in 2020, assessed and documented the visual symptoms of F-damage on vegetation and related these to detected values of F in plant tissue. The typical F-damage symptoms on vegetation were not immediately obvious, but at closer examination were present, especially in sensitive plant species. While at Årdal and Sunndal smelters, most of the sampled vegetation showed clear F-damage symptoms and higher F-concentrations in tissues, at Mosjøen the F-symptoms on vegetation were sparse and F-concentrations in sampled plants were low, never exceeding 30 mg F/kg. Four plant species showed qualities as useful indicators for various reasons: Rowan and pine were suitable both as bioindicators and biomonitors as they displayed clear visual F-damage symptoms and had a consistent F-accumulation pattern. St. John’s wort was suitable as bioindicator with “early warning”-qualities as it showed signature F-damage symptoms already at low F-emission levels. Because male-fern accumulated extreme F-values and showed clear grazing damage, the monitoring of this species may be warranted because of the potential health hazard for the grazing animals...