Artificial sweeteners are used as sugar substitutes in numerous beverages and foodstuffs. Their properties are thoroughly investigated and the consumption of these substances was proved to be safe. Due to their application they might be introduced into the water cycle predominantly through sewage treatment plants, and therefore, serve as ideal tracers for municipal waste water.
In the TZW lab a new trace-analytical method for seven artificial sweeteners in water was developed. The results of the first measurements in two municipal waste water treatment plants (WWTPs) and several rivers were recently reported in M. Scheurer, H.-J. Brauch, F.T. Lange, Analysis and occurrence of several artificial sweeteners in German waste water and surface water and in soil aquifer treatment (SAT), Analytical & Bioanalytical Chemistry 394, 1585-1594 (2009).
Of the seven artificial sweeteners the four compounds acesulfame, cyclamate, saccharin and sucralose were detected in all investigated WWTP effluents and rivers. The observed levels in the WWTP influents ranged from several tens of µg/L to 190 µg/L for cyclamate. While cyclamate and saccharin were eliminated by more than 94% in the investigated WWTPs, acesulfame and sucralose were incompletely removed.
Acesulfame was the artificial sweetener, which occurred at the highest levels of all sweeteners in the WWTPs and in the analyzed river water samples (Rhine, Main, Danube, Neckar, up to 2.7 µg/L). Due to these comparatively high concentrations of acesulfame in the WWTP effluents, its persistence against microbial degradation, and its specificity for municipal waste water, it is a more appropriate tracer than e.g. pharmaceutical compounds such as carbamazepine. Thus, from now on, even marginal waste water influences on a certain water, either directly by leaking sewage systems or indirectly by infiltration of waste water impacted surface water can be reliably detected.
Since first results based on a few national and international research activities became known, further research on the occurrence and fate of artificial sweeteners in water treatment were initiated at TZW. Further results are expected within the next weeks and months. Due to the high aqueous solubility and the persistence of some of these compounds, it can be assumed that also in tap waters, which are produced from surface water or bank filtrates as raw water, traces of artificial sweeteners might be detected. The potential occurrence in tap water might cause some problems with consumer acceptance, which must be frankly discussed.
It has to be taken into account that similar to other trace-pollutants also the artificial sweeteners will start a public discussion. In order to face this, we should be prepared by gaining the necessary data on the occurrence of these compounds.
For requests on this issue and concerning analyses please contact:
Dr. F.T. Lange
Tel.: +49 721 9678-157
Fax: +49 721 9678-104
Mail: lange@tzw.de
