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@ARTICLE{Engelhardt:136943,
      author       = {Engelhardt, I. and Barth, J. A. C. and Bol, R. and Schulz,
                      M. and Ternes, A. and Schüth, C. and van Geldern, R.},
      title        = {{Q}uantification of long-term wastewater fluxes at the
                      surface water/groundwater-interface: {A}n integrative model
                      perspective using stable isotopes and acesulfame},
      journal      = {The science of the total environment},
      volume       = {466-467},
      issn         = {0048-9697},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {FZJ-2013-03465},
      pages        = {16 - 25},
      year         = {2014},
      abstract     = {The suitability of acesulfame to trace wastewater-related
                      surface water fluxes from streams into the hyporheic and
                      riparian zones over long-term periods was investigated. The
                      transport behavior of acesulfame was compared with the
                      transport of water stable isotopes (δ18O or δ2H). A
                      calibrated model based on a joint inversion of temperature,
                      acesulfame, and piezometric pressure heads was employed in a
                      model validation using data sets of acesulfame and water
                      stable isotopes collected over 5 months in a stream and
                      groundwater. The spatial distribution of fresh water within
                      the groundwater resulting from surface water infiltration
                      was estimated by computing groundwater ages and compared
                      with the predicted acesulfame plume obtained after 153 day
                      simulation time. Both, surface water ratios calculated with
                      a mixing equation from water stable isotopes and simulated
                      acesulfame mass fluxes, were investigated for their ability
                      to estimate the contribution of wastewater-related surface
                      water inflow within groundwater. The results of this study
                      point to limitations for the application of acesulfame to
                      trace surface water–groundwater interactions properly.
                      Acesulfame completely missed the wastewater-related surface
                      water volumes that still remained in the hyporheic zone
                      under stream-gaining conditions. In contrast, under
                      stream-losing conditions, which developed after periods of
                      stagnating hydraulic exchange, acesulfame based predictions
                      lead to an overestimation of the surface water volume of up
                      to $25\%$ in the riparian zone. If slow seepage velocities
                      prevail a proportion of acesulfame might be stored in
                      smaller pores, while when released under fast flowing water
                      conditions it will travel further downstream with the
                      groundwater flow direction. Therefore, under such conditions
                      acesulfame can be a less-ideal tracer in the hyporheic and
                      riparian zones and additional monitoring with other
                      environmental tracers such as water stable isotopes is
                      highly recommended.},
      cin          = {IBG-3},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {246 - Modelling and Monitoring Terrestrial Systems: Methods
                      and Technologies (POF2-246)},
      pid          = {G:(DE-HGF)POF2-246},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000330491600003},
      doi          = {10.1016/j.scitotenv.2013.06.092},
      url          = {https://juser.fz-juelich.de/record/136943},
}