About LIFE NARMENA
The LIFE project NARMENA (Nature-based Remediation of Metal pollutants in Nature Areas to increase water storage capacity), co-financed by the European Union, falls within the objective of remediating contaminated soils and sediments in rivers, on riverbanks and on flood plains. We seek to develop and implement sustainable and nature-based remediation methods that are both cost-effective and non-invasive. In Europe, these remediation techniques are not yet widely used in watercourses. It seems to be a major challenge to integrate this concept into remediation policy.
OVAM implements this project together with the Flemish Agency for Nature and Forests (ANB) and Natuurpunt, both owners and managers of the nature reserves. The Flemish Environment Agency (VMM), as the watercourse manager of Laak en Winterbeek and implementer of integrated water management, is also a partner in this project. Our experts in the field of soil research and remediation, ABO NV, phytoremediation, Bio2Clean and ecomodelling, ARCHE Consuling bvba, provide a high-quality partnership for this challenging project.
In LIFE NARMENA, demonstration projects are being established for two types of nature-based remediation methods, in which we align sediment and soil remediation with nature conservation and water storage: artificial wetlands and phytoremediation. In Flanders, sediments in up to 50% of watercourses are contaminated with heavy metals. While the source activities are often no longer present, the contamination remains in the sediment and on the banks of the stream. The sediment and banks act as secondary source zones. Therefore, a large number of natural floodplains are currently under risk. The 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 streams - the Grote Calie (Turnhout), the Winterbeek (Scherpenheuvel-Zichem) and the Laak (Geel – Laakdal) – are flowing through Natura2000 sites. By constructing phytoremediation fields and artificial wetlands, we aim to significantly reduce the bioavailability of the metals, to lower or eliminate possible risks to the ecosystem. Although mainly the reduction in availability of metals, such as chromium and cadmium, will be monitored, changes in nutrient concentrations will also be kept track of. This is expected to be an additional benefit of the implemented techniques.
In addition to these innovative soil remediation techniques, eco-modelling approaches will be developed and applied to predict the impact of these techniques. What is the toxicological impact on certain organisms of a concentration change? What is the availability of a particular harmful substance? These are important questions, which can help decision-makers to impose threshold values for pollutants in sediments of watercourses.
NARMENA's results and experiences will inspire us to develop a framework for the application of these nature-based remediation. These results will then be compared with conventional techniques. Not only the effectiveness and total cost of the remediation will be taken into account, but also the CO2 emission and contribution to ecosystem services. The findings will be disseminated within the European Union to encourage the competent authorities and relevant economic sectors to apply these techniques more often in vulnerable nature areas.