Degradation behaviour of the Artificial sweetener-Acesulfame-K during riverbank infiltration system. A case study from Karany waterworks, Czech Republic.

Artificial sweeteners (ASs) are a class of low-level emerging organic contaminants (EOCs) that recently appeared in aquatic environment around the world due to its increased worldwide consumption. Once ingested by humans, the major amount of these artificial sweeteners excretes unchanged from the body and is transfered to the water environment through sewage systems. Consequently, artificial sweeteners are posing a new threat and a concern is growing over the contamination of a water environment.

Due to its stability and mobility, ASs have long been considered as ideal tracers for a detection of domestic wastewater in natural water bodies, particularly groundwater. However, other previously conducted studies show that ASs are vulnarable to degradation under certain conditions. Therefore, fate, behavior, and ecotoxicological side of artificial sweeteners within waterbodies still remain ambiguous.

Recently, ASs were also detected in the central part of the Czech Republic in the area of Káraný waterworks with a river bank filtration system. Considerable attention has been given to one of the widely used artificial sweetener - Acesulfame-K, which has been detected as a predominant contaminant in numerous pilot site across Europe and other worldwide countries.

In our research we focus to pilot site of Jizera river, Czechia, where Acesulfame-K was detected in ranges 72.0 to 591.0 ng/l. Although the systems of riverbank filtration eliminate the presence of many anthropogenic contaminants in water, Acesulfame-K was still detected in groundwater with concentrations up to 75 ng/l.

Based on available field and literature data, a two-dimensional large-scale hydraulic and transport model was developed using DRUtES software. For Acesulfame-K, the following first-order degradation rate was identified: λ = 0.0358 ± 0.0022 1/d. This result was further confirmed here by a small-scale laboratory experiment, where we mimicked conditions of our pilot site groundwater aquifer.