Excerpts:
Fluoride concentrations were determined also with an ion selective electrode, adding a TISAB solution for decomplexing and adjusting the ionic strength…
The Nevado de Toluca crater lake… Lithium, boron and fluoride were below the detection limits…
At El Chichon… Fluoride increased between 1983 and 1985 (0.16 mg/l in 1983 to 4.5 mg/l in 1985), decreasing afterwards up to less than 0.05 mg/l in January, 1997 (Table 1)… The decrease in the volcanic-related species like
sulfate, chloride, boron and fluoride since 1983 at El Chichon indicates a lowering of the magmatic contribution
in the crater lake, though its current general chemistry reflects that such contribution is still present.
At Popocatepetl.. Fluoride increased almost 30 fold between 1992 and 1994 (0.48 mg/l in 1992 to 11.5 mg/l in 1994) (Table 1)…