About LIFE NARMENA

LIFE NARMENA demonstration projects are being established for two types of nature-based remediation methods, which align sediment and soil remediation with nature conservation and water storage - artificial wetlands and phytoremediation. The sediments in almost 50% of Flanders watercourses are contaminated with heavy metals. While the source activities are often no longer present, contamination remains in the sediment and on river banks. The sediment and banks act as secondary source zones. A large number of natural floodplains are therefore currently at risk. This widespread water and sediment pollution poses a serious obstacle to the creation of retention areas, since pollution would spread even further. 

The demonstration projects will be rolled out in the valleys of three watercourses polluted by heavy metals. These three rivers - the Grote Calie (Turnhout), the Winterbeek (Scherpenheuvel-Zichem) and the Laak (Geel – Laakdal) – flow through Natura 2000 sites. By constructing phytoremediation fields and artificial wetlands, we aim to significantly reduce the bioavailability of the metals, in order to lower or eliminate potential risks to the ecosystem. Monitoring will mainly focus on the reduction of availability of metals such as chromium and cadmium, while changes in nutrient concentrations will also be kept track of, which is an expected, additional benefit of the techniques to be implemented.  

The CO2 emissions are also much lower, or virtually zero. There is no need, for example, for dozens of trucks to transport excavated soil and sludge. 

Unlike organic pollution, metals cannot be broken down. We therefore ensure that the metals are immobilised and can no longer migrate. This is done by means of biological processes. For example, by using certain plants that retain metals in their roots or convert metals into a non-harmful form.   

In monitoring the pilot projects, we make a distinction between total and bioavailable concentrations. Metals that are immobilised using nature-based techniques are therefore also no longer bioavailable. They can no longer be absorbed by organisms 

Eco modelling approaches will also be developed and applied to predict the impact of these innovative soil remediation techniques. What is the toxicological impact of a concentration change on certain organisms? What is the availability of a particular harmful substance? Answers to important questions like these can help decision-makers to impose threshold values for pollutants in sediments of watercourses.