A dangerous toxin lurks in the sediments surrounding groundwater: uranium. Scientists have known this for a long time. But now, researchers at Stanford have identified a trigger that causes natural uranium to be forced out of sediments and seep into groundwater. New data will guide the movement of the toxin before it becomes a problem.
Uranium is one of the three main harmful natural pollutants in groundwater, along with arsenic and chromium. When consumed in large quantities, the radioactive metal element causes kidney damage and an increased risk of cancer. It is commonly found in semi-arid and arid environments around the world.
The study focuses on the chemical effects of groundwater recharge. The process of rainfall seeping into soils and moving downward into underlying aquifers as rainwater seeps down, its chemical composition changes as it interacts with the earth’s environment. Pumping water also affects the dynamics of the aquifer. This can change the chemical composition of soil and sedimentary rocks. And also how uranium is distributed between particulate matter (sediment) and water.
In their study, the scientists found that if water accumulates more calcium during its travel and becomes more alkaline, it can attract uranium and pollute aquifers.
However, according to researchers’ estimates, the factors influencing uranium release from sediments into groundwater arise within 1.8 m of the topsoil. The hazardous area can be bypassed when building and laying aquifers.
The new methodology gives water managers an easy way to understand and predict what will affect uranium concentrations in groundwater at scale.
Scientists emphasize that the study also solves the problem with uranium before its concentrations harm people, and the reconstruction of houses and entire settlements becomes too costly.