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| Titel |
Extending the in situ microcosm approach (BACTRAP®) to field sites without groundwater wells - a new Direct-Push probe |
| VerfasserIn |
Christian Schurig, Anja Miltner, Ludwig Zschornack, Matthias Kaestner |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250045795
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| Zusammenfassung |
| Due to the large number of contaminated field sites in Europe, monitored natural
attenuation is in most cases the only financially feasible site remediation option.
However, only few methods are accepted by authorities as real proofs of natural
attenuation. One of those methods is the recently developed in situ microcosm approach
(BACTRAP®). These in situ microcosms consist of a perforated Teflon tube filled with an
activated carbon matrix and closed by glass wool stoppers. Afterwards, 13C labelled
contaminants are loaded on the activated carbon and the microcosms are then exposed in
groundwater wells. Based on this approach, natural attenuation was accepted by
authorities as a site remediation option for the BTEX polluted megasite Zeitz in
Germany.
Until now, the in situ microcosms are adapted to conditions in a groundwater well at the
level of the aquifer. Due to that, the system is only applicable on field sites with a network of
monitoring wells and only microbial activity inside the aquifer can be assessed. To overcome
these limitations, a new Direct-Push BACTRAP-probe was developed on basis of the
Geoprobe® infrastructure. With help of this new probe, the approach can be extended to field
sites without monitoring wells and microbial activity can also be measured in the vadose zone
above the aquifer.
Classical and Direct-Push BACTRAPs have been applied in the BTEX contaminated
aquifer at the ModelPROBE reference site Zeitz(Germany). Both types of BACTRAPs were
incubated in the centre and at the fringe of the BTEX plume. During microbial degradation of
the 13C labelled substrate, the 13C label was incorporated into bacterial biomass, which was
determined by phospholipid fatty acid (PLFA) analysis, and provided the proof of in situ
natural attenuation. In addition, the bacterial communities on classical and Direct-Push
microcosms were compared by analysing PLFA patterns.
Concluding, Direct-Push based BACTRAPs offer a promising and cost efficient way for
monitoring natural attenuation or remediation success at field sites currently inaccessible by
the technique. |
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