Uranium Abatement-Can We Measure the Ions That May Interfere?

In the Four Corners area, toxic uranium was found in public water sources in concentrations greater than the allowable EPA safe drinking water limits (30 ppb). The exact amounts of uranium in the water sources are unknown but pose a potential health threat. Uranium toxicity is two-fold: radioactivity and heavy metal behavior. Uranium occurs naturally in soil and groundwater in low concentrations. Water sources usually contain other heavy metal contaminants and they may interfere with uranium measurements and solubility. During uranium abatement (the removal of uranium from an aqueous solution), the solution’s total matrix will affect abatement, especially because we use sorption as our abatement process. Therefore, we need a means to measure the total ionic matrix.  One method to measuring the matrix is conductivity. Conductivity measures currents in water due to solvated ions and it is a linear relationship to the ion concentration. Standard calibration measurements at 25 degrees Celsius were performed to report microsiemens or millisiemens. Conductivity is a function of temperature and concentration of the solution. The most common ions in a solution are sodium, potassium, calcium, and magnesium, Group 1 and Group 2 elements. These cations, along with lithium, were investigated. The Group 2 cation salts had greater conductivity. The conductivity of these salts was also compared to uranyl salts in a solution. An actual sample of water (266 microsiemens) from the Four Corners area caused a clay sample to flocc; this event did not occur in double distilled water. Supported by PHS Grant #R25 GM048998-13.