| Definitions |
|---|
| meq/l |
milliequivalents per liter (meq/l) - meq/l is another method of
expressing concentration, when the analytes are dissolved and
disassociated in solution. meq/l is also equal to millimoles of
charge per liter (mM+/l or mM-/l depending on valence). To calculate
meq Ca/l from the reported value in mg/l, we must know something
about calcium.
- Calcium has a molecular weight of 40.08 grams/mole.
- Calcium has a valence of +2
- The equivalent weight = (40.08grams/mole)/(2 equivalents/mole) = 20.04 grams/eq
- To convert to mg/meq you simply multiply g/eq by 1000 mg/g
and divide by 1000 meq/eq, thus g/eq = mg/meq
- If your sample contains 30 mg Ca/L, what is the concentration
in meq/L?
Meq Ca/L = (30 mg Ca/L)/(20.04 mg/meq) = 1.50 meq Ca/L
|
| Stiff Diagram |
The Stiff diagram is usually plotted without the labeled axis and
is useful making visual comparison of waters with different
characteristics. The patterns tend to maintain its shape upon
concentration or dilution. |
| Collins Bar Diagram |
Collins diagrams (Collins 1923) present the relative major ion
composition in percent milliequivalent per liter. Both the cations
and anions have a total of 100 %. The bar diagram used in the Brine
Sample Plot, the cations are plotted on the left and the anions are
plotted on the right.
COLLINS, W.D. (1923): Graphic presentation of water analysis. Ind. Eng. Chem., 15: 394 p.
|
| References |
|---|
|
Wyoming Department of Agriculture Analytical Services.
Water Quality Mathematical Expressions & Relationships. |
|
Evaluation of graphical and multivariate
statistical methods for classification of water chemistry data.
(2002) 10:455-474,
Cüneyt Güler · Geoffrey D. Thyne · John E. McCray A. Keith Turner |
|
Freiberg On-line Geosciences Vol. 9 |