Degradation behaviour of the artificial sweetener Acesulfame-K within a riverbank filtration system

Abstract

Artificial sweeteners are a class of low-level emerging organic contaminants that occur in the environment around the world. Once ingested by humans, major amounts of artificial sweeteners are excreted unchanged from the body and are added to the water environment via sewage systems. Consequently, artificial sweeteners pose a new threat to the aquatic environment, which is the primary recipient of these substances. Recently, they have been detected in the area of the Káraný waterworks, Czech Republic, where there is a riverbank filtration system. Considerable attention has been given to Acesulfame-K, which has proved to be the most frequently occurring contaminant in the Jizera river, with a concentration range from 72.0 to 591.0 ng/L. Although the riverbank filtration systems remove many anthropogenic contaminants in water, Acesulfame-K has continued to be detected in the groundwater, with a concentration range from <49.9 to 71.7 ng/L. Therefore, the main purpose of this study is to describe and quantify the attenuation behaviour within a riverbank filtration site by providing model-based estimates of the first-order degradation rate constant. For Acesulfame-K, the first-order degradation rate was identified: λ = 0.0358 ± 0.0022 1/d. This result was further confirmed by a small-scale laboratory experiment.