I'm working on my uranium bioremediation term paper and the evidence is piling up. Septic tanks effect uranium solubility in ground water.
The presence of oxygen in ground water leads to uranium solubility. Not just O2. Nitrates (NO3, NO2) and Sulfates (SO4) also have an effect on uranium solubility. Nitrogen and sulfur enter septic tanks in their reduced form attached to amino acids. Septic tanks are anoxic so nitrogen leaves the septic tank as NH4+ and sulfur as H2S. When they reach the leach field they are oxidized to nitrate and sulfate.
Some of the nitrate and sulfate get utilized in the biomat but for the most part, nitrate and sulfate leach out of soil fairly quickly. They have a negative charge and soil has a net negative charge so they repel each other. The end result is nitrate and sulfate in ground water interacting with the bound uranium in the aquifer and solubilizing it.
New Mexico has very high concentrations of uranium. We need to get off septic tanks. SHIT! (really).