Steven Thornton, David Lerner and Ruth Davison, Groundwater Protection and Restoration Group, University of Sheffield. This note was first published in GE’s July 2000 edition.
Natural attenuation (NA) technology is increasingly being viewed as a cost-effective alternative to engineered schemes for remediation of contaminated aquifers (Kremer, 1998).Some key difficulties in the use of the approach are the complexity of the processes involved, the experience and technical understanding of landowners, practitioners and responsible parties, and the need for a coherent methodology for evaluating its performance.
Many technical protocols have been developed in recent years to provide guidance for implementing NA. These provide a framework for the investigation and monitoring of contaminated sites where natural attenuation is being considered as a remedial option. However, there are significant differences in the protocols in terms of the evidence required to demonstrate whether NA is appropriate and effective. This is the second of two articles about NA. The first (GE January 2000) reviewed the concepts, philosophy and needs of the UK for a formal protocol. Here the site investigation, sampling and monitoring strategies necessary to demonstrate NA and predict its performance are discussed.