A Quick Look at Natural Attenuation Uses naturally occurring environmental processes to clean up sites. Is non-invasive and allows the site to be put to productive use while being cleaned up. Requires careful study of site conditions and monitoring of contaminant levels. The processes contributing to natural attenuation are typically acting at many sites, but at varying rates and degrees of effectiveness, depending on the types of contaminants present, and the physical, chemical and biological characteristics of the soil and ground water. Natural attenuation processes are often categorized as destructive or non-destructive.
Destructive processes destroy the contaminant.
Non-destructive processes do not destroy the contaminant but cause a reduction in contaminant concentrations. Microorganisms, like humans, eat and digest organic substances for nutrition and energy. Certain microorganisms can digest organic substances such as fuels or solvents that are hazardous to humans. In most subsurface environments, both aerobic and anaerobic biodegradation of contaminants occur. Once the contaminants are degraded, the microorganism populations decline because they have used their food sources.