Hydrogeochemical characterization of reservoir waters undergoing salinization processes in Northeastern Brazil

José do Patrocinio Hora Alves: Contributed to date analysis, statistical processing of date, interpretation of results and writing of the article. Maria Hortência Rodrigues Lima: Contributed to the realization of geochemical modeling and interpretation of hydrogeochemical processes. Josefa Raimunda Dória: Contributed to the interpretation of hydrogeochemical processes using ionic ratios. Igor Santos Silva: Contributed to the use of PHREEQC software to perform geochemical modeling. Adnivia Santos Costa Monteiro: Contributed to the use of PHREEQC software to perform geochemical modeling and to the interpretation of hydrogeochemical processes using geochemical modeling.

Reservoir/	Jacarecica I		Macela		Ribeirópolis
Reservoir/	N = 8		N = 8		N = 8
Parameter	Min-Max	Means ± sd	Min-Max	Means ± sd	Min-Max	Means ± sd
pH	7.1-9.1	8.0±0.7	7.3-8.4	7.7±0.4	7.9-8.8	8.2±0.3
T (°C)	25.0-29.0	26.7±1.7	21.1-28.0	26.0±2.2	23.8-30.4	26.6±2.0
EC (µS cm^-1)	219.6-536.9	399.6±110.0	972.2-2000	1166±342	1411-1866	1595±151
TDS (mg L^-1)	123.0-332.0	245.3±76.0	594.2-1380	753.3±263.6	972.8-1150	1059±59
Na⁺ (mg L^-1)	28.73-63.47	44.20±11.90	82.60-138.0	116.7±17.7	119.0-182.2	154.7±19.4
K⁺ (mg L^-1)	1.30-34.29	9.30±10.30	11.68-31.55	17.67±6.24	11.00-18.50	15.23±3.33
Ca²⁺ (mg L^-1)	1.66-45.81	23.20±14.90	26.97-93.90	39.92±22.20	35.84-67.92	54.86±14.06
Mg²⁺ (mg L^-1)	3.84-19.45	9.80±5.50	17.72-34.30	26.83±6.48	34.68-79.00	54.57±16.29
SO₄^2- (mg L^-1)	1.60-71.09	16.40±23.00	24.02-43.11	34.69±6.80	6.38-21.10	14.29±4.35
Cl^- (mg L^-1)	38.46-91.18	68.20±19.10	114.2-259.7	168.0±43.1	275.4-404.3	328.5±57.8
HCO₃^- (mg L^-1)	57.95-170.6	101.4±35.8	192.7-289.7	229.9±34.2	182.8-224.1	199.7±13.1

Correlation	pH	EC	TDS	Na⁺	K⁺	Ca²⁺	Mg²⁺	SO₄^2-	Cl^-	HCO₃^-
pH	1
CE	0.321	1
TDS	0.320	0.990	1
Na⁺	0.221	0.830	0.820	1
K⁺	-0.077	0.672	0.687	0.655	1
Ca²⁺	0.198	0.696	0.722	0.473	0.460	1
Mg²⁺	0.191	0.871	0.880	0.832	0.629	0.697	1
SO₄^2-	-0.296	0.302	0.280	0.154	0.497	0.206	0.191	1
Cl^-	0.189	0.908	0.901	0.901	0.665	0.697	0.950	0.133	1
HCO₃^-	-0.092	0.585	0.605	0.604	0.777	0.400	0.531	0.612	0.546	1

Mineral phases	SI Jacarecica I		SI Macela		SI Ribeirópolis
Mineral phases	Nov.13	Nov.18	Jun.13	Ago.18	Jun.14	Mai.18
Calcite	-1.13	0.49	-0.34	0.79	0.67	0.75
Dolomite	-1.54	1.45	-0.35	1.73	1.58	1.85
Gypsum	-4.76	-3.98	-2.49	-2.40	-2.57	-2.53
Halite	-7.35	-6.81	-6.34	-6.30	-6.03	-5.79

Mineral phases	Jacarecica I		Macela			Ribeirópolis
	Model (mol L^-1)		Model (mol L^-1)			Model (mol L^-1)
	A	B	A	B	C	A	B	C
Calcite	+1.9x10^-4	+6.8x10¹	+7.2x10¹	+4.6x10^-2	+8.4x10^-4	-	-1.7x10²	+8.2x10¹
Dolomite	+1.4x10^-4	-6.8x10¹	-7.2x10¹	-	-3.8x10^-4	+4.4x10¹	-	-8.2x10¹
Gypsum	-1.4x10^-6	+6.1x10^-6	+1.8x10^-4	+5.0x10^-4	+5.0x10^-5	-5.6x10^-5	+1.9x10^-4	+1.1x10^-4
Halite	+1.5x10^-3	+1.9x10^-3	+1.8x10^-3	+3.2x10^-4	+3.2x10^-4	-	+1.2x10^-2	+8.0x10^-3
Biotite	+1.7x10^-4	+2.3x10¹	+2.4x10^-1	-1.5x10^-5	-1.7x10^-5	-3.0x10¹	+5.6x10¹	+2.7x10¹
K-feldspar	+1.4x10^-5	-2.3x10¹	+2.4x10^-1	-2.1x10^-4	-3.3x10^-4	+3.0x10¹	-5.6x10¹	+2.7x10¹
CaX₂	+1.4x10^-4	-	-4.2x10^-4	-3.4x10^-4	-3.4x10^-4	-4.4x10⁺¹	+1.7x10²	+2.0x10^-3
NaX	-2.8x10^-4	-	+8.3x10^-4	+6.8x10^-4	+6.8x10^-4	-2.7x10^-3	-4.7x10^-3	-4.0x10^-3

\begin{array}{l} 177 N a_{0.62} C a_{0.38} A l_{1.38} S i_{2.62} O_{8} + 7.3 K M g_{3} A l S i_{3} O_{10} {(O H)}_{2} + \\ 13 K A l S i_{3} O_{8} + 412.5 H_{2} O + 310 C O_{2} = 133 A l_{2} S i_{2} O_{5} {(O H)}_{4} + \\ 110 N a^{+} + 68 C a^{2 +} + 22 M g^{2 +} + 20 K^{+} + 270 S i O_{2} + 310 H C O_{3}^{-} \end{array}

\begin{array}{l} 175 N a_{0.62} C a_{0.38} A l_{1.38} S i_{2.62} O_{8} + \\ 14 K M g_{3} A l S i_{3} O_{10} {(O H)}_{2} + 115 C a C O_{3} + \\ 404 H_{2} O + 427 C O_{2} = 81 C a_{0.17} A l_{2.33} S i_{3.67} O_{10} {(O H)}_{2} + \\ 33 A l_{2} S i_{2} O_{5} {(O H)}_{4} + 109 N a^{+} + 167 C a^{2 +} + 42 M g^{2 +} + \\ 12 K^{+} + 137 S i O_{2} + 539 H C O_{3}^{-} \end{array}

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