Influence of natural organic matter and mineral colloids on arsenic (As) and uranium (U) transport in geological media

Abstract

Arsenic (As) and uranium (U) are two common groundwater contaminants that threaten human health. To assess the scope of As and U contamination in groundwater, it is important to characterize and quantify As and U migration in porous geo-media. This thesis research examined the influence of natural organic matter and mineral colloids on As and U transport. As and U transport was investigated by injecting As-spiked or U-spiked solution/suspension into water-saturated columns packed with natural sediments and quartz sand, and analyzing As or U concentration in column effluent. Column experiment results showed that natural organic matter substantially increased As and U transport, while mineral colloids had only minor effects on As and U transport. When natural organic matter and mineral colloids co-existed, As transport was lower, but U transport was higher compared to that in systems with HA but no illite.