Emerging contaminants uptake by an Ultisol and a Vertisol from Puerto Rico

Abstract

AbstractContaminants of emerging concern (CECs), including pharmaceutical compounds, have been found in irrigation waters and have found their way into crops through the uptake of contaminated water. Many farms in Puerto Rico are irrigated with water that might have considerable levels of CECs. The objective of this study was to determine the quantity of commonly detected CEC adsorbed onto soil particles of two contrasting tropical soils of Puerto Rico (Fraternidad, basic Vertisol [fine, smectitic, isohyperthermic Typic Haplusterts], and Mariana series, acid Ultisol [fine, mixed, active, isohyperthermic Typic Haplohumults]). A CECs single point and multicomponent adsorption experiments were carried out using the batch equilibrium technique. The CECs were naproxen (NPX), O‐desmethylnaproxen (O‐DesNPX), caffeine (CFN), paraxanthine (PX), carbamazepine (CBZ), carbamazepine‐10, 11‐epoxide (Ep‐CBZ), clofibric acid (ClofA), and salicylic acid (SA). The CEC concentrations in water before and after adsorption were determined using a triple quadrupole mass spectroscopy liquid chromatography. The results showed that SA was highly adsorbed by both soils, although in greater concentrations in Fraternidad than Mariana, probably because of greater cation‐bridging. Paraxanthine was adsorbed only in the multicomponent test, probably as a co‐adsorbate. Caffeine, CBZ, and their metabolites were adsorbed in both soils in lesser concentrations than SA and PX. However, NPX and ClofA were not adsorbed by either soil type. Thus, these CECs could potentially move more freely through the soil matrix and reach soil roots in greater quantities than other contaminants.