F1 - Transformation of environmentally relevant compounds in urban lakes by aquatic invasive ecosystem engineers
Doctoral student: Anna Lena Kronsbein 
Supervisors: PD Dr. Sabine Hilt , PD Dr. Jörg Lewandowski , Prof. Dr. Torsten Schmidt , Prof. Dr. Ferdi Hellweger 
Demographic changes and increasing urbanization lead to a higher contamination of surface water with trace organic compounds (TrOCs) such as pharmaceuticals or personal day care products. They enter surface waters with the effluents of waste water treatment plants and are detected in the range of ng/l to µg/l (Aus der Beek et al., 2016).
Bank filtration is a drinking water production technique where surface water infiltrates via the water bed of a lake or river into the aquitard due to a positive gradient between water level of the surface water and the groundwater (Schulte-Ebbert, 2004). Bank filtration is increasingly applied in urban areas where drinking water demands are high and surface water quality and groundwater availability are often low (Gillefalk et al., 2018; Hiscock and Grischek, 2002).
The increasing contamination of surface waters with TrOCs is a concern for the production of drinking water via bank filtration (Heberer et al., 2002). TrOCS are highly polar and persistent (Reemtsma and Jekel, 2006). Degradation and/or transformation of TrOCs can occur in the littoral sediments depending on the predominant redox conditions (Burke et al., 2014; Burke et al., 2017). Existing studies on the fate of TrOCs focus on simplified sediments while in reality, benthic organisms such as submerged plants and mussels cover littoral sediments and change physical and chemical sediment composition. Especially invasive benthic organisms, such as the quagga mussel (Dreissena bugensis rostriformis) or Nuttall’s waterweed (Elodea nutallii), play an important role due to their massive abundance and sediment coverage (Wegner et al., 2019).
- Figure 1: Quagga mussel (A) and Nuttall’s waterweed (B) in Lake Müggelsee (Wegner et al., 2019)
- © Kronsbein
The project aims at understanding how benthic organisms can affect oxygen concentration at the sediment water interface which in turn affects the redox zonation and consequently the fate of TrOCs during bank filtration.
To answer this research question field investigations are conducted in urban lakes used for bank filtration (e.g. Lakes Müggelsee and Tegel). Dialysis membrane samplers are used within the sandy littoral zone to sample pore water. Thus, depth profiles of redox parameters, e.g. concentrations of sulfate and manganese, and oxygen can be measured. Oxygen loggers installed above the sediment monitor oxygen concentration in the surface water and sediment cores are taken to determine sediment properties.
In a laboratory column study the effect of mussels and submerged plants on bank filtration is investigated. A selection of TrOCs is added in order to analyse their fate. Columns were designed and built for this research question. Oxygen concentration will be monitored under controlled conditions at the sediment water interface. Modern oxygen microsensors are used to measure depth profiles in the upper 3 cm of the sediment and oxygen optode foils are installed to observe oxygen concentration two-dimensionally. Sampling ports allow analysing the fate of TrOCs and redox parameters throughout the column.
- Figure 2: Schematic experimental set-up (A) and real columns (B) with sampling ports
- © Kronsbein
First results show that dialysis membrane samplers are a suitable tool to investigate the effects of benthic organisms on littoral sediments. Mussels seem to have an effect on the oxygen concentration in the overlying water column. Preliminary results show that maximum oxygen concentrations in the surface water are lower and have a different temporal pattern at sites covered by mussels as compared to uncovered control sites.
Other UWI projects: H1 , H2 , H3 
Common topic group: Interfaces in urban freshwater systems 
Aus der Beek, T. et al., 2016. Pharmaceuticals in the environment--Global occurrences and perspectives. Environ Toxicol Chem, 35(4): 823-35. DOI:10.1002/etc.3339
Burke, V. et al., 2014. Temperature dependent redox zonation and attenuation of wastewater-derived organic micropollutants in the hyporheic zone. Sci Total Environ, 482-483: 53-61. DOI:10.1016/j.scitotenv.2014.02.098
Burke, V., Greskowiak, J., Grunenbaum, N., Massmann, G., 2017. Redox and Temperature Dependent Attenuation of Twenty Organic Micropollutants - A Systematic Column Study. Water Environ Res, 89(2): 155-167. DOI:10.2175/106143016X14609975746000
Gillefalk, M., Massmann, G., Nützmann, G., Hilt, S., 2018. Potential Impacts of Induced Bank Filtration on Surface Water Quality: A Conceptual Framework for Future Research. Water, 10(9): 1240. DOI:10.3390/w10091240
Heberer, T., Reddersen, K., Mechlinski, A., 2002. From municipal sewage to drinking water: fate and removal of pharmaceutical residues in the aquatic environment in urban areas. Water Science and Technology, 46(3): 81-88. DOI:10.2166/wst.2002.0060
Hiscock, K.M., Grischek, T., 2002. Attenuation of groundwater pollution by bank filtration. Journal of Hydrology, 266(3-4): 139-144. DOI:10.1016/s0022-1694(02)00158-0
Reemtsma, T., Jekel, M., 2006. Organic Pollutants in the Water Cycle. Wiley‐VCH Verlag GmbH & Co. KGaA DOI:10.1002/352760877x
Schulte-Ebbert, U., 2004. Künstliche Grundwasseranreicherung und Untergrundpassage. In: e.V., D.D.V.d.G.-u.W. (Ed.), Wasseraufbereitung - Grundlagen und Verfahren. Oldenbourg Industrieverlag GmbH, München, pp. 403-432.
Wegner, B. et al., 2019. Mutual Facilitation Among Invading Nuttall's Waterweed and Quagga Mussels. Front Plant Sci, 10: 789. DOI:10.3389/fpls.2019.00789