Leaching of Fluoride from Biotite Mica in Soil: Implications for Fluoride in Shallow Groundwater

Table 4

Leachable ionic concentrations of treated highly weathered biotite: after one month and six months.

Ions	Medium
	Citric acid		Nitric acid		Distilled water
	1st month	6th month	1st month	6th month	1st month	6th month
F^−	1980	9000	2700	5750	300	3150
K^+	1091	1216	1277	390	68	65
Fe^2+	2008	5320	1031	1262	9	29
Mg^2+	170	613	225	369	75	73
Na^+	157	295	181	274	132	213