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The Equivalent Weight field in the constituents table for geochemistry plots/diagrams is used to convert between the measured mass concentration and the concentration in equivalents or milliequivalents per liter. Equivalent weight is the mass per charge; more specifically, gram atomic weight (the mass, in grams, of one mole of atoms of that chemical) divided by valence, as shown in the equivalent weight values provided below. Charge concentration is the mass concentration of an ion in water divided by the equivalent weight. The equivalent weight field should be entered as positive for cations and negative for anions. If the concentration values are entered as milligrams per liter or parts per million, then the following values in the equivalent weight field will convert the concentrations to meq per liter.

 

 

Data Requirements

 

Concentrations of cations and anions are converted from mass to milliequivalents (meq) based on the entered values of equivalent weight in populated RT_ANALYTE_DETAIL.EQUIVALENT_WEIGHT fields (in an EQuIS database) or the Equivalent Weight field of the Constituent table/tab (in an EnviroInsite database). Only analytes for which the equivalent weight has been populated will be available for selection within the relevant report.

 

EnviroInsite expects that the equivalent weight of anions will be entered as negative quantities, while cations will carry positive equivalent weight values.