Mobility of ibuprofen, a persistent active drug, in soils irrigated with reclaimed water

Abstract

Ibuprofen is not completely removed in wastewater treatment plants, and consequently, it may enter the soil through irrigation with reclaimed water. Subsequently, due to the reversible adsorption which takes place in the soil, this emerging pollutant can become bioavailable for plants. The adsorption reversibility of this anti-inflammatory compound on four agricultural soils was quantified with adsorption-desorption experiments. The adsorption was found to be almost linear, with a minimum n_ads of 0.76 and a maximum of 1.08. In contrast, desorption was nonlinear, with a n_des which ranged from 0.84 to 2.75. The hysteresis index values were low, ranging from 0.42 to 0.66; hence the process takes place reversibly. In addition, ibuprofen was found to be moderately fixed in the soils studied, with organic carbon distribution coefficient (K_OC) values which ranged between 139.75 and 238.17 L/kg. Therefore, we conclude that this pollutant could be bioavailable for soil microorganisms or plants exposed to it and may reach groundwater by leaching.