NATURAL ATTENUATION

The term natural attenuation refers to the combination of all natural degradation processes that take place in soil and groundwater, such as biodegradation, adsorption, dilution and chemical reactions with the soil itself. Over time, these natural processes reduce the concentration of contaminants to acceptable levels, in other words, levels that pose no risk for human health and for the health of the ecosystem. Free-floating, or mobile, pollutants can spread in liquid or vapour form and are thus easily captured by degradation processes. On the other hand, organic compounds that have a high molecular weight and many inorganic substances become trapped in the soil, which impedes their diffusion.
Source: Courtesy of Ambiente, an Eni Group Company