Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2006
Publication Date: 7/15/2006
Citation: Williams, C.F., Williams, C.F., Adamsen, F.J. 2006. Sorption/desorption of carbamazepine from irrigated soils. Journal of Environmental Quality. 35(5):1779-1783.
Interpretive Summary: The reuse of sewage effluent for irrigation is an effective way to increase water supplies in the desert southwest. Contaminants such as human drugs, found in treated effluent, have been identified as a potential problem for use of this water for irrigation. Initial environmental fate parameters were determined for the drug carbamazepine in irrigated soils. It was found that carbamazepine is highly adsorbed to soils. Desorption of carbamazepine from the soil is also unlikely to lead to carbamazepine mobility in soil. This would indicate that the drug carbamazepine in treated effluent would initially be immobilized in the soil and remain bound preventing leaching from occurring.
Technical Abstract: The anti-seizure medication carbamazepine is often found in treated sewage effluent and environmental samples. Carbamazepine has been shown to be very persistent in sewage treatment as well as groundwater. Due to environmental persistence, irrigation with sewage effluent could result in carbamazepine contamination of surface and groundwater. To determine the potential for leaching of carbamazepine, a series of adsorption and desorption batch equilibrium experiments were conducted on irrigated soils. It was found that carbamazepine adsorption to biosolid amended (T) soils had a KD of 19.8 vs. 12.6 for unamended soil. Based on adsorption, carbamazepine leaching potential would be categorized as low. During desorption significant hysteresis was observed and KD increased for both soils. Desorption isotherms also indicate a potential for irreversibly bound carbamazepine in the T soil. Results indicate that initial removal of carbamazepine via adsorption from irrigation water is significant and that desorption characteristics would further limit the mobility of carbamazepine through the soil profile indicating that carbamazepine found in sewage effluent used for irrigation has a low leaching potential.