Specific conductance as an indicator of total dissolved solids in cold, dilute waters

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Abstract
Specific conductance is shown to bear a well-defined, linear relationship to total dissolved solids for cold, low ionic strength streams. Unless the water temperature is constant it is necessary first to correct the conductivity data to 25°C. This temperature correction may be taken as linear, even below 4°C, but not necessarily to be 2% per °C as is commonly used in many instruments. The error incurred by assuming the latter figure for cold streams could be large (>5%). Values of specific conductance calculated using data for the limiting equivalent conductivities of the individual ions are shown to be poor estimates of the actual specific conductances even for these dilute waters. Relationships between total dissolved solids and specific conductance may be impaired by the changing proportions of ionic species of the samples. In general, however, an empirical straight line was found to provide a good fit.