6. Conclusion and outlook

After many years of experimentation in North America and various trials in Europe, natural attenuation now seems to be a mature management technique, with the release of the ATTENA project guides in particular. As pointed out in this article, but also in many other projects, the procedure for certifying that a site can be managed using natural attenuation is often quite complex. In fact, it is necessary to demonstrate that pollution will not reach site-specific receptors over a period of several decades.

The tools are necessarily multiple: they involve on-site measurements of electron donors and acceptors, monitoring of pollutant evolution and often the use of microcosms, analytical or numerical models and isotopic measurements. In other words, the aim is to eliminate most of the uncertainties surrounding the conceptual design, and to be able to certify that it...