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@PHDTHESIS{Shahid:810944,
      author       = {Shahid, Naeem},
      othercontributors = {Ließ, Matthias Erwin Fritz and Schäffer, Andreas},
      title        = {{A}ssessing pesticide effects on macroinvertebrates under
                      field relevant conditions},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2021-00825},
      pages        = {1 Online-Ressource : Illustrationen, Diagramme, Karten},
      year         = {2020},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University 2021; Dissertation, RWTH Aachen University, 2020},
      abstract     = {Exposure to pesticides may affect non-target aquatic
                      macroinvertebrates even below the regulatory acceptable
                      concentrations. Similar low pesticide concentrations can
                      force the organisms for adaptation. Aquatic organisms are
                      often exposed to multiple stressors acting simultaneously or
                      sequentially, including agrochemicals and suboptimal
                      environmental conditions. However, a little is known about
                      the pesticide effects on aquatic macroinvertebrates under
                      field relevant conditions. In order to improve the existing
                      risk assessment, this dissertation aims to assess important
                      factors for pesticide effects in the field that are still
                      not well understood. It contributes to the understanding of
                      adaptation to pesticides, assessment of toxic pressure,
                      interaction of mixtures, and the role of environmental
                      stressors for the eco-toxicological effects of pesticides.
                      To identify environmental parameters that govern the
                      development of increased pesticide tolerance, a field
                      investigation was conducted (Chapter 2). Gammarus pulex were
                      collected from 15 sites within the central Germany that
                      cover a wide range from un-contaminated to highly
                      contaminated streams. Populations from contaminated streams
                      showed almost 3-fold higher tolerance to the neonicotinoid
                      insecticide clothianidin as compared to non-exposed
                      populations. This tolerance of exposed populations increased
                      from 2- to 4-fold with increasing distance to the next
                      refuge area. Thus, distance from the refuge area and local
                      toxic pressure were important factors that drive the
                      development of pesticide resistance.In the second
                      investigation (Chapter 3), pesticide body burden was applied
                      to assess the pesticide exposure and potential effects in
                      freshwater organisms. Body burdens of a crustacean G. pulex
                      were converted into equivalent pesticide concentrations in
                      the water, and linked with the observed ecological effects
                      on freshwater macroinvertebrates. The toxic pressure derived
                      from body burden was reliable to explain the effect on the
                      macroinvertebrate community composition and the development
                      of insecticide tolerance in G. pulex. For better
                      understanding of multiple stressors in the environment
                      (Chapter 4), interaction between food stress and a mixture
                      of a pyrethroid esfenvalerate and prochloraz was
                      investigated. To predict the joint effects of multiple
                      stress, commonly applied models i.e. effect addition (EA),
                      concentration addition (CA), and stress addition model (SAM)
                      were compared. Results showed that the strength of
                      interaction between esfenvalerate and prochloraz was
                      increased with an increasing concentration of prochloraz.
                      The combination of both pesticides and food stress caused
                      highly synergistic effects even at 1 µg/L of prochloraz.
                      Moreover, synergistic effects of pesticides and food stress
                      were predicted best with the SAM model. The fourth
                      investigation contributed to understand the mechanisms
                      behind delayed effects at very low pesticide exposure in the
                      field (Chapter 5). The metabolic response of Daphnia magna
                      exposed to a pyrethroid esfenvalerate under suboptimal food
                      supply was investigated. Metabolomic effects were observed
                      at ultra-low concentrations, and were more pronounced under
                      low food conditions. Interaction between food- and chemical
                      stress was mainly responsible for extreme stress, and
                      thereby strong down-regulation of different metabolites.},
      cin          = {164120 / 160000},
      ddc          = {570},
      cid          = {$I:(DE-82)164120_20160614$ / $I:(DE-82)160000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2021-00825},
      url          = {https://publications.rwth-aachen.de/record/810944},
}