Background groundwater concentrations of dissolved selenium in the Kamloops, BC area: Characterization, spatial distribution, and management

This study explores regional background groundwater concentrations of selenium in the Kamloops area, based on recent groundwater quality data collated as part of provincial contaminated site investigations, and determines if regional background concentrations for selenium in groundwater can be inferred based on statistical analysis and covariations with other groundwater characteristics. The objective was to quantify naturally-occurring concentrations of dissolved selenium for the purpose of supporting future groundwater management strategies and regulations. A review of the groundwater data, surrounding geology, and potential sources indicated that higher selenium concentrations are likely due to natural occurring geochemical processes and local geology, as the concentrations are widespread throughout the Kamloops area where anthropogenic sources were not identified. The higher selenium concentrations may be due to the leaching of subsurface soils in the saturated zones underlying alluvial fan deposits and sedimentary and volcanic rocks. The overall 95th percentile selenium concentration in groundwater was determined to be 160 mug/L.