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@PHDTHESIS{Linnemann:37446,
      author       = {Linnemann, Volker},
      title        = {{U}mweltverhalten von {MTBE} nach
                      {G}rundwasserkontamination},
      volume       = {40},
      school       = {Universität Bonn},
      type         = {Dr. (Univ.)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-37446},
      isbn         = {3-89336-339-4},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Umwelt /
                      Environment},
      year         = {2003},
      note         = {Record converted from VDB: 12.11.2012; Universität Bonn,
                      Diss., 2002},
      abstract     = {Since the late seventies, methyl-tert-butyl ether (MTBE)
                      has become one of the mort widely produced chemicals in
                      Europe and the USA due to its use as a fuel additive. MTBE
                      was first used as a substitute for the environmental poison
                      tetraethyl lead because of its anti-knock properties.
                      Statutory requirements for minimum volumes of
                      oxygen-containing additives in motor fuels, to protect the
                      atmosphere against the cl imate-relevant trace gases carbon
                      monoxide (CO) and ozone (Os), greatly increased the demand
                      for MTBE in the USA. One consequence was an increasing
                      number of groundwater and soil contaminations as well as
                      complaints of damage to health associated with MTBE. Since
                      the air had been kept clean at the expense of the
                      groundwater and the soil, the use of MTBE is prohibited in
                      the USA after 2003. In Europe increased numbers of
                      MTBE-contaminations in the groundwater and surface waters
                      have been reported. Goal of this PhD thesis was the
                      investigation of the MTBE mass transport into the atmosphere
                      after a contamination of the groundwater. For this studies a
                      tripartite experimental concept was selected: First of all,
                      a soil column experimental setup for studying mass transport
                      in undisturbed soil monoliths was designed, constructed and
                      validated. With this facility it was possible to create
                      under defined and reproducible experimental conditions an
                      aquifer below the soilcore, variable in height, in which a
                      contamination with MTBE had been simulated in a real
                      concentration range of 100 to 200 mg L$^{-1}$. A stream of
                      air flowed over the soil surface through the artificial
                      atmosphere, and was collected and analysed with respect to
                      the composition of volatile organic chemicals. Adsorption
                      onto multibed solid adsorbent material with subsequent
                      thermodesorption GC/MS analysis was developed for air
                      collection and displayed good sampling performance with
                      excellent detection limits. The groundwater samples were
                      analysed by radioactivity-HPLC, -GPC or a new direct
                      injection- GC/MS analytical technique. For this
                      liquid-injection-methods the detection limit still has to be
                      improved. In the first experiment, up to 47 ppb (170 ng
                      m$^{-3}$) of MTBE was detected in the air. MTBE was not
                      continuously recovered in the air but only occurred in
                      pulses. Maximum values were measured, in particular, in the
                      first few days. The mass transfer rates through the soil
                      into the atmosphere were in the region of 1.94 ± 1.88
                      $\mu$g m$^{-2}$ h$^{-1}$ in the first experiment with an
                      equilibrium value of approx . 0.45 ± 0.02 $\mu$g m$^{-2}$
                      h$^{-1}$. In the second experiment with
                      [$\alpha$,$\alpha$'-$^{14}$M] MTBE, only low volatilization
                      was measurable. At the same time, the water balance in the
                      experimental System was also recorded, which enabled a
                      qualitative relation to the MTBE loss to be established. The
                      simulated aquifer was redesigned for a scale-up experiment
                      and also the air sampler adapted for volatile hydrocarbons
                      at the fieldlike wind tunnel with a lysimeter. The new
                      sampling unit was validated in several preliminary
                      experiments and displayed good collecting efficiency for the
                      high volume flows applied. Analogously to the second column
                      experiment, over an experimental period of 4 weeks hardly
                      any mass transport of MTBE through the soil was determined.
                      The recovery rate in both experiments with $^{14}$C-MTBE was
                      in the region of 83 to 102 \% of the applied radioactivity
                      (AR). As described in the literature only slight adsorption
                      to the soil particles was found for MTBE. Since the soil
                      columns and the lysimeter represented a compartment of the
                      ecosystem with functioning microflora, the microbial aerobic
                      degradation in the soil was determined in two laboratory
                      studies. A maximum mineralization of 1.6 \% AR was detected
                      as a function of the previous contaminations of the soil and
                      the soil type. Moreover, rapid volatilization of the MTBE
                      from the surface took place perceptibly reducing the
                      bioavailability . The results obtained were readily
                      applicable to the transport studies.},
      cin          = {ICG-IV},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)VDB50},
      pnm          = {Chemie und Dynamik der Geo-Biosphäre},
      pid          = {G:(DE-Juel1)FUEK257},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/37446},
}