Geoscience Reference
In-Depth Information
Table 8.5 Carrying capacity of aqueous solution (CCAS) for hydrocarbons as a result of droplet
formation (Dror et al.
2003
)
Compound
Distilled water
solubility (mg/L)
Seawater
solubility (mg/L)
Freshwater
CCAS (mg/L)
Saline water
CCAS (mg/L)
Benzene (C
6
H
6
)
1,740
1,391
1,940
3,340
Toluene (C
7
H
8
)
535
379
1,345
7,461
Trichloroethylene (C
2
HCl
3
)
1,100
769
1,520
1,306
Effect of SAR and Na
+
concentration in water on the ESP of soils with different
Table 8.6
mineralogy
Location
Na
+
concentration,
mEq/L
Clay distribution
Clay mineralogy
SAR
ESP
\0.2 lm
0.2-2 lm \0.2 lm
0.2-2 lm
Burleson 71 29 M
1
Mi
3
K
3
M
2
MiK
2
Q
2
28 11.0 18.9
33.0 20.4
Houston black 78 22 M
1
M
2
K
2
Mi
2
Q
2
28 11.0 16.0
33.0 16.0
Miller 49 51 M
1
Mi
2
K
3
M
2
Mi
2
K
2
Q
2
F
3
28 11.0 25.8
33.0 37.9
Pullman 41 59 Mi
2
K
2
M
2
Mi
2
K
2
Q
2
F
3
28 11.0 31.7
33.0 32.5
Legend: Mi = mica, K = kaolinite, M = montmorillonite, Q = quartz, and F = feldspar.
Estimated quantities: 1: [40 %; 2: 10-40 %; and 3: \10 % (Thomas and Yaron
1968
)
chemical composition but also soil physical properties, such as porosity, aggre-
gation status, and water infiltration capacity.
When Na
+
from saline irrigation or wastewater disposal first flows through a
soil, there is no significant correlation between the sodium adsorption ratio (SAR)
of the water and the exchangeable sodium percentage (ESP) of soil. In a column
experiment by Thomas and Yaron (
1968
) on a series of Texas soils of differing
mineralogy, the total electrolyte concentration of the saline water was observed to
influence the rate of sodium adsorption. At equilibrium, the ESP in the soil was
influenced more by the soil mineralogy than by the cationic composition of the
water and the total electrolyte concentration (Table
8.6
).
Characteristic data for the adsorption of Na
+
are shown in Fig.
8.26
. Three
synthetic aqueous solutions with a total electrolyte concentration of 11 mEq/L and
SAR values of 7.5, 14.0, and 28.0 were passed through a Burleson soil column. At
equilibrium, a solution with SAR = 7.5 gave an ESP of 8.1, and a solution with
SAR = 28 exhibited an ESP of 18.0. We see from Fig.
8.26
that the quantity of
aqueous solution that had to be passed through the soil column to achieve a
constant Na
+
content in the entire profile increased with SAR. In other words, for a
given applied volume of solution, greater SAR values led to larger depths where a
constant ESP was achieved.
