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Evaluation of an Acid Ammonium Oxalate Extraction to Determine Fluoride Resident Concentrations in Soils
Author(s) -
Bégin Louis,
Fortin Josée
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.6620
Subject(s) - fluoride , ammonium oxalate , chemistry , soil water , oxalate , extraction (chemistry) , environmental chemistry , carbonate , inorganic chemistry , soil science , chromatography , geology , organic chemistry
Fluoride depositions near aluminum smelters and other fluoride‐emitting plants can lead to fluoride accumulation in soils, which constitutes a risk for ground water contamination. This study was conducted to investigate the capacity of a 0.2 M acid ammonium oxalate solution to selectively and quantitatively extract fluoride accumulated in soils. The recovery of fluoride added to three soils was evaluated following 7‐ to 28‐d incubations. Oxalate extraction was also compared with a total fluoride extraction method, using oxalate‐extractable fluoride (F ox ) and total fluoride (F tot ) accumulation profiles derived from column percolation experiments. To determine low‐level fluoride concentrations without interference from high Al and Fe concentrations, an adapted ion chromatography method was used. Following soil incubations, oxalate extracted 42 to 86% of added fluoride. Recovery varied between soils and, in one soil, increased with added fluoride concentration. Recovery was unaffected by incubation time. Maximum recovery was obtained in a soil high in amorphous Fe and Al, low in clay, and free of carbonate. Lower recoveries were obtained in soils with higher clay or carbonate contents. Only 4 to 8% of F tot was extracted in untreated samples using F ox , which suggests a high selectivity of this method for added fluoride. In percolation experiments, the use of F ox reduced considerably the background noise associated with F tot for the evaluation of fluoride accumulation profiles. Because of its high selectivity and despite incomplete fluoride recovery, the use of F ox to determine fluoride resident concentrations in soils may improve environmental monitoring of fluoride accumulation and movement in contaminated soils.