Evaluate Quality of Water Analyses. Charge Balance

3 Evaluate Quality of Water Analyses. Charge Balance I 

The quality of field and laboratory measurements varies. A common criterion for determining the quality of water analyses is the charge balance among the reported cation and anion concentrations (Freeze and Cherry, 1979). The principle of electroneutrality 

Element Species Conversion factors Element Species Conversion factors  

The concentrations used in Equation (5.1) are in milliequivalents per liter (meq L-1), which can be calculated from milligrams per liter (mg L ) using conversion factors listed in Hem (1985). See Table 5.2. 

The cut-off value for acceptable charge imbalance is empirical and somewhat arbitrary. Freeze and Cherry (1979) reported that analytical laboratories usually consider a charge-balance error of 5% to be acceptable. However, for dilute solutions such as rain water, the errors are usually higher. 

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