Document ID: EPA-HQ-OW-2003-0079-0020
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-11-18T05:00Z

D­
33
Appendix
D­
1.
Calculations
for
Ionic
Composition
of
Standard
Laboratory­
Reconstituted
Water
Molecular
Weights
Atomic
Weights
NaHCO3
=
84.03
CaSO4.2H2
O
=
172.12
MgSO4=
120.37
KCl
=
74.55
SO4
=
96.06
Na
=
22.98
Ca
=
40.08
Mg
=
24.31
K
=
39.10
Cl
=
35.45
Example
Calculation
[
Na]
in
very
soft
water:
12
mg
NaHCO3/
L
x
1
mmol
NaHCO3/
84.03
mg
NaHCO3
=
0.143
mmol
NaHCO3/
L.
0.143
mmol
NaHCO3/
L
x
(
1
mmol
Na/
1
mmol
NaHCO3)
x
22.98
mg
Na/
1
mmol
Na
=
3.3
mg
Na/
L.

[
Ca]
in
very
soft
water:
7.5
mg
CaSO4.2H2O/
L
x
1
mmol
CaSO4.2H2O/
172.12
mg
CaSO4.2H2O
=
0.044
mmol
CaSO4.2H2O/
L.
0.044
mmol
CaSO4.2H2O/
L
x
(
1
mmol
Ca/
1
mmol
CaSO4.2H2O)
x
40.08
mg
Ca/
1
mmol
Ca
=
1.8
mg
Ca/
L.

[
Mg]
in
very
soft
water:
7.5
mg
MgSO4/
L
x
1
mmol
MgSO4/
120.37
mg
MgSO4
=
0.062
mmol
MgSO4/
L.
0.062
mmol
MgSO4/
L
x
(
1
mmol
Mg/
1
mmol
MgSO4)
x
24.31
mg
Mg/
1
mmol
Mg
=
1.5
mg
Mg/
L.

[
K]
in
very
soft
water:
0.5
mg
KCl/
L
x
1
mmol
KCl/
74.55
mg
KCl
=
0.0067
mmol
KCl/
L.
0.0067
mmol
KCl/
L
x
(
1
mmol
K/
1
mmolKCl)
x
39.102
mg
K/
1
mmol
K
=
0.26
mg
K/
L.

[
Cl]
in
very
soft
water:
0.5
mg
KCl/
L
x
1
mmol
KCl/
74.55
mg
KCl
=
0.0067
mmol
KCl/
L.
0.0067
mmol
KCl/
L
x
(
1
mmol
Cl/
1
mmolKCl)
x
35.453
mg
Cl/
1
mmol
K
=
0.24
mg
Cl/
L.

[
SO4]
in
very
soft
water:
7.5
mg
CaSO4.2H2O/
L
x
1
mmol
CaSO4.2H2
O/
172.12
mg
CaSO4.2H2O
=
0.044
mmol
CaSO4.2H2O/
L.
0.044
mmol
CaSO4.2H2O/
L
x
(
1
mmol
SO4/
1
mmol
CaSO4.2H2O)
x
96.064
mg
Ca/
1
mmol
Ca
=
4.2
mg
Ca/
L.

[
SO4]
in
very
soft
water:
7.5
mg
MgSO4/
L
x
1
mmol
MgSO4/
120.37
mg
MgSO4
=
0.062
mmol
MgSO4/
L.
0.062
mmol
MgSO4/
L
x
(
1
mmol
SO4/
1
mmol
MgSO4)
x
96.064
mg
Mg/
1
mmol
Mg
=
6.0
mg
Mg/
L.

Total
SO
4
=
10.2
mg/
L
Conversion
Factors
to
calculate
water
hardness
(
as
CaCO3)
from
[
Ca]
and
[
Mg]:

[
Ca]
x
2.497
[
Mg]
x
4.116