One of the most important components of natural attenuation is
biodegradation—the change in form of compounds carried out by
living creatures such as microorganisms. Under the right conditions,
microorganisms can cause or assist chemical reactions that change
the form of the contaminants so that little or no health risk remains.
Biodegradation is important because many chlorinated solvents can
be destroyed by biodegradation, microorganisms that are capable of
biodegrading contaminants are found almost everywhere, and
biodegradation can be very safe and effective. However, most
chlorinated solvents biodegrade only under very specific conditions,
which are not present at all sites.