Traditionally this was expressed in units of milliequivalents, although if we are using SI units then the appropriate option would be in millimoles per kilogram ( N . B . 1 milliequivalents = 0.5 millimole; because 1 mEq of O2 = 1 mmol / 2 = 0.5 mmol of O2, where 2 is valence ).
12.
CaCO 3 . ( The conjunction " as " is appropriate in this case because the alkalinity results from a mixture of ions but is reported " as if " all of this is due to CaCO 3 . ) This can be converted into milliEquivalents per Liter ( mEq / L ) by dividing by 50 ( the approximate MW of CaCO 3 / 2 ).
