Specific conductivity sensor performance: I. Laboratory evaluation

The focus on specific conductivity in the Central Appalachian Coal Fields of the USA has highlighted the need to obtain accurate specific conductivity measurements, particularly in light of the US Environmental Protection Agency (USEPA) guidance that water discharged from mine sites in this region should have specific conductance levels less than 300-500 μS cm^-1. Being able to accurately determine the specific conductance levels of mine discharged waters has significant implications for the USEPA as well as mine operators particularly when specific conductance levels approach this designated threshold. Presently, a number of sensors are available on the market for recording specific conductance measurements; however, a detailed study comparing sensor performance under controlled conditions (e.g. temperature and specific conductance levels) has not been performed. This paper compares the performance of four commonly used sensors YSI 6600 V2-4 data sonde, HOBO U-24-001, Solinst Model 3001 LTC Levelogger Junior, and In-situ Aqua TROLL 100. Results of this laboratory study indicated that for conditions more frequently encountered in Kentucky streams, the HOBO and Solinst sensors were most accurate.