A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both, contains a fluid that includes a native reservoir fluid of the geological formation and a contaminant. The method also includes receiving a portion of the fluid into the downhole acquisition tool, obtaining a measured resistivity, a measured conductivity, or both of the portion of the fluid using the downhole acquisition tool, and using a processor of the downhole acquisition tool to obtain a temperature-corrected resistivity, a temperature-corrected conductivity, or both based on a downhole temperature of the portion of the fluid and the measured resistivity, the measured conductivity, or both.