Quantification of large-scale urban mass fluxes of xenobiotics and of the river–groundwater interaction in the city of Halle, Germany

Abstract

In order to quantify the fluxes of micropollutants like pharmaceuticals including endocrine disruptors, and fragrances in the environment modelling approaches in the area of the city of Halle/Saale, Germany were performed. The investigated micropollutants are Bisphenol A, t-Nonylphenol, Carbamazepine, Galaxolide ® and Tonalide ®. These substances were found ubiquitously in the urban groundwater and surface waters. The assessment of the concentration values of these substances in the urban waters showed no significant changes during the city passage. Therefore, a balance model for the whole city area was set up and the main water-bounded mass fluxes of the substances were estimated. The assessment of the mass fluxes shows increasing values of about 20 up to 400% for nearly all investigated micropollutants during the city passage of the urban waters. An exception is Bisphenol A with a constant mass flux. In order to investigate the surface water–groundwater interaction, a transient hydrodynamic river reach model of the Saale River and a groundwater transport model of the area connected to the reach were created by coupling two well known conventional compartment models for river hydraulic and groundwater transport. The inter-compartmental transport of Carbamazepine initiated through infiltration from the Saale River into the groundwater during a flooding event was simulated . A substance mass flux of 3.29 × 10 5 μg d −1 and a fluid flux of 9.95 × 10 3 m 3 d −1 was calculated.