Natural Attenuation

Natural attenuation is the risk-based management of contaminated land and groundwater using the combined effects of biological, chemical and physical processes, which occur naturally in the subsurface environment. This technology is increasingly becoming an important and environmentally sustainable strategy for the remediation and management of contaminated sites where engineered restoration is impractical, technically unfeasible or too costly. Key issues driving the development and application of this remediation technology are:

  • Understanding at a fundamental level the processes and related environmental factors which control the natural attenuation of contaminants. This focuses on deducing interactions between contaminants, indigenous microbial communities and the physical setting in contaminated subsurface media, which affect the nature, extent and kinetics of attenuation processes
  • Identifying appropriate monitoring techniques to discriminate processes and quantify attenuation at different scales. The challenge is to devise techniques which allow attenuation processes to be interpreted at the resolution of their operation and assess if these can be used to make realistic predictions of contaminant behaviour at the scale of the problem
  • The development of methodologies and robust modeling approaches for the accurate performance assessment of natural attenuation. These outputs need to be translated into simple engineering tools which can provide a robust prediction of natural attenuation potential at sites for end-users of the technology

Natural attenuation diagram