Natural Attenuation Training Courses
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The Natural Attenuation training courses provide a framework for thinking about natural attenuation based on science, focusing on the basic information needed to determine and document the conditions necessary for natural processes to be an effective part of remediating contaminants in groundwater.
Natural Attenuation of Chlorinated Solvents in Groundwater: Case Histories
In this special session of the ITRC Natural Attenuation of Chlorinated Solvents in Groundwater: Principles and Practices training course, the training class includes an additional two hours of content with information on historical case analysis of chlorinated volatile organic compound plumes.
The first two hours of this training class provide the Natural Attenuation of Chlorinated Solvents in Groundwater: Principles and Practices training course described above.
The second two hours of this training class describe the findings and conclusions from a study of nationwide chlorinated volatile organic compound (CVOC) plumes. It uses a statistical approach and data from multiple sites to evaluate hydrogeologic, biogeochemical, and physiochemical factors affecting the extent and growth behavior of CVOC plumes in groundwater. A number of specific questions of interest to managers of CVOC cleanup were addressed by this study:
- How often is a dense non-aqueous phase liquid (DNAPL) inferred to be present at sites within the CVOC historical data set and what is the relationship of inferred DNAPL presence to the plume length at a given site?
- How often is evidence of transformation processes in association with the CVOC plumes in the data set and what are the relationships between the indications of transformations and plume length?
- Do daughter product plumes behave differently compared to parent CVOC plumes?
- What is the relationship of fuel hydrocarbon co-contamination to CVOC plume behavior?
This study provides the first statistical analysis of data from a relatively large population of CVOC plumes. It demonstrates that broad trends in relationships between plume behavior and key site variables can be determined through the statistical analyses of historical field data from a large number of sites. This finding is important because it demonstrates that: (1) specific hydrogeologic conditions and contaminant release scenarios at individual sites are not so unique that expected overall trends in the data are completely obscured, and (2) useful average values for site variables such as hydraulic conductivity and groundwater velocity can be quantified in most situations. Such information is useful in bounding the uncertainty in CVOC plume behavior that is important in making risk and long-term resource management decisions. The possible application of the CVOC historical case data to individual site plume behavior uncertainty will be discussed and illustrated by examples. Important measurements that are frequently neglected will also be discussed.
Natural Attenuation of Chlorinated Solvents in Groundwater: Principles and Practices
This training introduces state regulators, environmental consultants, site owners, and community stakeholders to ITRC's Natural Attenuation of Chlorinated Solvents in Groundwater: Principles and Practices (ISB-3, 1999), created by ITRC's In Situ Bioremediation Team and the Remediation Technologies Development Forum (RTDF) Bioremediation Consortium. The manual and presentation are based on RTDF research activities and on experience and knowledge of the participating members. The course provides a framework for thinking about natural attenuation based on science, focusing on the basic information needed to determine and document the conditions necessary for natural processes to be an effective part of remediating chlorinated solvents in groundwater.