The impact of fluoride on Al abundance and speciation in boreal streams
2015 (English)In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 409, 118-124 p.Article in journal (Refereed) Published
The impact of fluoride on the abundance and speciation of aluminium (Al) was investigated in three boreal streams characterised by overall high concentrations of fluoride and dissolved organic matter. Stream-water sampling was carried out several times a year for at least 4 years, and a chemical equilibrium model (Visual MINTEQ) was applied in order to model the proportion of colloidal and organically/inorganically complexed Al in the waters. The Al concentrations in filtered (0.45 μm) water samples were inversely correlated with pH, and reached values up to approximately 1. mg/L during low pH conditions (pH < 6.0). In a stream with high fluoride concentrations, as compared to a similar stream with only moderately elevated fluoride concentrations, the Al concentrations were consistently elevated. For the stream with high concentrations of fluoride and Al, the model predicted both high concentrations and proportions of Al-fluoride complexation. This prediction indicates that high fluoride levels contribute to raise both the Al abundance and the ratio of inorganic to organic Al complexation in stream water. In contrast, for another stream with high fluoride concentrations and consistently high (near neutral) pH, there was no evidence of fluoride affecting Al concentration or complexation. These results show that it is important to focus future studies on the role of high levels of dissolved fluoride on both the speciation and the toxicity of Al in stream water.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 409, 118-124 p.
Al speciation, Al toxicity, Aluminium, Boreal catchments, Chemical modelling, Fluoride
IdentifiersURN: urn:nbn:se:kth:diva-170197DOI: 10.1016/j.chemgeo.2015.05.013ISI: 000358525500012ScopusID: 2-s2.0-84930942419OAI: oai:DiVA.org:kth-170197DiVA: diva2:828219
QC 201506302015-06-302015-06-292015-08-27Bibliographically approved