The transport of three emerging pollutants through an agricultural soil irrigated with untreated wastewater

Abstract

The aim of this work was to determine the mobility of naproxen, carbamazepine, and triclosan through a wastewater-irrigated agricultural soil. Transport experiments were carried out using undisturbed soil columns taken at 10 and 40 cm depths. The mobilization of the pollutants was evaluated using two hydrological regimes transient flow for superficial columns and steady-state conditions for the sub-superficial columns. Results demonstrated that preferential flows are present in the superficial soil, and transient flow conditions facilitate the movement of the pollutants through the soil. Conversely, displacement of the contaminants in the sub-superficial soil columns was slower than that observed in the superficial soil. Triclosan was not found in the leachates of the soil columns at the two depths, indicating the strong retention of the compound by the soils. Conversely, naproxen and carbamazepine were determined in leachates of the soil columns at both depths. Retardation in the transport of carbamazepine was higher than that observed for naproxen in the two tested soils. Naproxen and triclosan showed some degree of dissipation, while carbamazepine was recalcitrant. It was concluded that the natural depuration system studied is capable of retaining and removing the studied pollutants and thus the risk of groundwater pollution is minimized.