Fluoride in the Serra Geral Aquifer System: Source Evaluation Using Stable Isotopes and Principal Component Analysis

Table 3

δ ¹⁸O and δ ²H values of phreatic waters (a), GAS (a), and SGAS (b). Data from [28] (*) and [20] (**). TA is a code to Tres Arroios City (sampled by author). Fluoride content is exclusive to SGAS.

(a)

Sample code	Aquifer	δ ^18O (‰)	δ ^2H (‰)
PMT1*	Phreatic	−4.67	−23.4
PMT2*		−4.26	−20.8
PMCG3*		−5.05	−27.4
PMBF7*		−4.56	−22.9
Averages		−4.64	−23.7
TA	GAS	−5.1	−30.0
1-RS**		−5.2	−33.0
2-RS**		−4.9	−28.0
3-RS**		−4.8	−29.0
4-RS**		−5.3	−33.0
5-RS**		−5.3	−33.0
7-RS**		−5.5	−32.0
8-RS**		−5.4	−37.0
Averages		−5.28	−33.2

(b)

Sample code	SGAS water group	F^− (mg/L)	δ ^18O (‰)
35	CaMg	0.1	−5.2
33	CaMg	1.02	−5.2
29	CaMg	0.3	−4.5
16	CaMg	0.47	−4.2
416	F	0.45	−5.0
360	F	0.68	−4.8
235	F	0.95	−5.2
208	F	0.75	−5.5
173	F	0.9	−5.3
138	F	3.03	−4.5
57	F	0.35	−4.7
37	F	2.6	−5.7
244	Na	0.32	−5.1
238	Na	0.52	−5.2
212	Na	0.31	−5.0
144	Na	0.23	−5.2
18	Na	0.23	−4.6
14	Na	0.19	−4.6
10	Na	0.6	−4.5
251	NaF	1.96	−5.7
31	NaF	2.03	−5.6
279	SO4F	1.19	−4.7
261	SO4F	1.81	−4.9
71	SO4Na	0.07	−5.2
334	Meteoric	0.39	−5.2
97	Meteoric	0.3	−5.1
58	Meteoric	0.03	−5.0
Averages		0.81	−5.01