Skip to main content
Article thumbnail
Location of Repository

Site investigation techniques for DNAPL source and plume zone characterisation

By Rachel Dearden, Jonathan Chambers, Debbie Allen and Gary Wealthall


Establishing the location of the Source Area BioREmediation (SABRE)\ud research cell was a primary objective of the site characterisation\ud programme. This bulletin describes the development of a two-stage site\ud characterisation methodology that combined qualitative and\ud quantitative data to guide and inform an assessment of dense nonaqueous\ud phase liquid (DNAPL) distribution at the site.\ud DNAPL site characterisation has traditionally involved multiple phases of\ud site investigation, characterised by rigid sampling and analysis\ud programmes, expensive mobilisations and long decision-making\ud timeframes (Crumbling, 2001a) , resulting in site investigations that are\ud costly and long in duration. Here we follow the principles of an\ud innovative framework, termed Triad (Crumbling, 2001a, 2001b;\ud Crumbling et al., 2001, Crumbling et al. 2003), which describes a\ud systematic approach for the characterisation and remediation of\ud contaminated sites. The Triad approach to site characterisation focuses\ud on three main components: a) systematic planning which is\ud implemented with a preliminary conceptual site model from existing\ud data. The desired outcomes are planned and decision uncertainties are\ud evaluated; b) dynamic work strategies that focus on the need for\ud flexibility as site characterisation progresses so that new information can\ud guide the investigation in real-time and c) real-time measurement\ud technologies that are critical in making dynamic work strategies\ud possible.\ud Key to this approach is the selection of suitable measurement\ud technologies, of which there are two main categories (Crumbling et al.,\ud 2003). The first category provides qualitative, dense spatial data, often\ud with detection limits over a preset value. These methods are generally of\ud lower cost, produce real-time data and are primarily used to identify site\ud areas that require further investigation. Examples of such "decisionquality"\ud methods are laser induced fluorescence (Kram et al., 2001),\ud membrane interface probing (McAndrews et al., 2003) and cone\ud penetrometer testing (Robertson, 1990), all of which produce data in\ud continuous vertical profiles. Because these methods are rapid, many\ud profiles can be generated and hence the subsurface data density is\ud greatly improved. These qualitative results are used to guide the\ud sampling strategy for the application of the second category of\ud technologies that generate quantitative, precise data that have low\ud detection limits and are analyte-specific. These methods tend to be high\ud cost with long turnaround times that preclude on-site decision making,\ud hence applying them to quantify rather than produce a conceptual\ud model facilitates a key cost saving. Examples include instrumental\ud laboratory analyses such as soil solvent extractions (Parker et al., 2004)and water analyses (USEPA, 1996). Where these two categories of\ud measurement technologies are used in tandem, a more complete and\ud accurate dataset is achieved without additional site mobilisations.\ud The aim of the site characterisation programme at the SABRE site was to\ud delineate the DNAPL source zone rapidly and identify a location for the\ud in situ research cell. The site characterisation objectives were to; a) test\ud whether semi-quantitative measurement techniques could reliably\ud determine geological interfaces, contaminant mass distribution and\ud inform the initial site conceptual model; and b) quantitatively determine\ud DNAPL source zone distribution, guided by the qualitative site\ud conceptual model

Topics: Earth Sciences
Publisher: CL:AIRE
Year: 2010
OAI identifier:

Suggested articles


  1. (2002). 3D electrical imaging of known targets at a controlled environmental test site.
  2. (1991). A method for assessing residual NAPL based on organic-chemical concentrations in soil samples. doi
  3. (2009). A structured approach to the measurement of uncertainty in 3D geological models.
  4. (2001). Applying the concept of effective data to environmental analyses for contaminated sites, EPA 542-R-01-013, U.S. Environmental Protection Agency,
  5. (2001). Current perspectives in site remediation and monitoring: Using the Triad Approach to improve the costeffectiveness of hazardous waste site cleanups, EPA 542-R-01-016. U.S. Environmental Protection Agency,
  6. (2003). Defining TCE plume source areas using the Membrane Interface Probe (MIP). Soil and sediment contamination, doi
  7. (1993). DNAPL Site Characterization. Boca
  8. (2004). Field study of TCE diffusion profiles below DNAPL to assess aquitard integrity. doi
  9. (2003). Improving decision quality: Making the case for adopting next-generation site characterisation practices. doi
  10. (2001). Managing uncertainty in environmental decisions. doi
  11. (1996). Practical techniques for 3D resistivity surveys and data inversion. doi
  12. (1996). Rapid least-squares inversion of apparent resistivity pseudosections by a quasi-Newton method. doi
  13. (1990). Soil classification using the CPT.
  14. This document is printed on Era Silk recycled paper (FSC certified TT-COC-2109) using vegetable-based inks sabre bulletin
  15. (2001). Use of LIF for real-time in-situ mixed NAPL source zone detection. Groundwater Monitoring and Remediation, doi
  16. (1996). Volatile organic compounds by gas chromatography/mass spectrometry (GC/MS) doi
  17. (2002). Volatile organic compounds in water, soil, soil gas, and air by direct sampling ion trap mass spectrometry (DSITMS).

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.