Preliminary Characterization of a Post-Industrial Soil for Long-Term Remediation by Phytomanagement: Mesocosm Study of Its Phytotoxicity Before Field Application

The present study focused on the characterization of a multi-contaminated former industrial site, followed by an investigation into the suitability of a possible phytoremediation technique. This study area located in Issoudun (France) was contaminated with high concentrations of trace elements such as copper (Cu), lead (Pb), zinc (Zn), and arsenic (As). The site was divided into 18 blocks, and soil samples (46 samples taken from the 18 blocks) were analyzed for pH, total organic matter (TOC), electrical conductivity (EC), total concentrations in Cu, Pb, Zn and As and granulometry. In a mesocosm experiment soil pore waters (SPWs) were collected from potted soil using rhizon samplers, at both the beginning (T0) and the end of the experiment (TF), with pH, EC and dissolved organic carbon (DOC) being determined directly from the SPW solutions. Cu, Pb, Zn and As concentrations in SPW as well as aboveground and belowground organs of Phaseolus vulgaris were also analyzed. The two main results are shown in this study. Firstly, the physico-chemical properties of the soil revealed the heterogeneity of the area, in particular for blocks 1, 2, 17 and 18. Secondly, the mesocosm phytotoxicity test using Phaseolus vulgaris showed that metal(loid)s plant accumulation depended not only on the soil metal(loid) concentrations, but also on soil pH and sand content. Moreover, Phaseolus vulgaris plants presented a homogeneous growth indicating that the area was able to sustain plant growth. These results revealed that a phytoremediation technique could be applied in this contaminated site.