A sensitive tool for detecting in situ degradation of contaminants.

BactrapsThe exposure of isotopically-labelled microcosms (BACTRAPs®) to the contaminant pool is a very sensitive tool for detection of in situ biodegradation. In the laboratory, contaminants are labelled with heavy isotopes (13C) and adsorbed to sediment particles. This material is placed into sediment cages and exposed to the contaminant plume for 4-12 weeks through monitoring wells at the polluted sites. During this time, metabolically-active bacteria within the microcosms will assimilate the contaminant (together with the isotope label) into their biomolecules (amino acids, fatty acids). After recovering the microcosms from the site, these biomolecules are extracted in the laboratory. Significant labelling of the bacterial cell components provides evidence that contaminant-degrading bacteria are present and active witin the site.

BACTRAPs in a groundwater wellCurrently, BACTRAPs have provided evidence for in situ bioderadation of BTEX, naphthalene, MTBE, chlorobenzene, acenaphthene and phenanthrene (1516). Generally, 2 - 6 BACTRAPs from a contaminated site will be sufficient to provide evidence for MNA.