GIS-based assessment of the agricultural land suitable for heavy metal phytoextraction: A case study of the Campine region (Belgium)

Abstract

The application of phytoextraction to agricultural soils that are moderately contaminated with heavy metals may be an effective way to achieve a double target. By selecting the appropriate plants the soil will be remediated to levels of contamination below threshold values, while simultaneously producing a considerable biomass flow for renewable energy purposes without taking in scarce agricultural land. However, since phytoextraction is a rather slow process, time frames have to be restricted to enhance adoption by farmers. This way, phytoextraction is only applicable within a limited range of soil pollutant concentrations. Using a Geographic Information System (GIS) allows us (1) to predict the soil contamination in the region and (2) to determine the agricultural area that can be committed to phytoextraction. Subsequently, the biomass potential and the resulting bioenergy potential can be assessed. In this study the Campine region in Belgium, a region diffusely contaminated with heavy metals like cadmium (Cd), is examined. It is illustrated that more than 2,000 hectares of agricultural land hold Cd concentrations exceeding guide values set by the Flemish Government (1.2 mg Cd kg-1). However, within the assumed time frames of 21 and 42 years, large quantities of these soils (i.e. 50% and 87%, respectively) can be remediated by means of phytoextraction. Concurrently, a significant amount of biomass is supplied for renewable energy production. After remediation, the reclaimed soil is fit for crops with a much higher income potential which were not allowed before.