Evaluation of the phytotoxicity of contaminated sediments deposited “on soil”: II. Impact of water draining from deposits on the development and physiological status of neighbouring plants at growth stage

As part of a study of the phytotoxic risk of spreading contaminated sediments “on soil”, a laboratory experiment was carried out to assess the impact of water draining from sediments on peripheral vegetation. Drainage water was obtained in the laboratory by settling three sediments with different pollutants levels, and the supernatant solutions (respectively A1, B1, C1 drainage waters) were used as soaking water for maize (Zea maïs L.) and ryegrass (Lolium perenne L.). The physicochemical characteristics of the supernatant water, particularly metal contents, showed a pattern of contamination, with C1 > A1 > B1. The plants tested were grown on soil for 21 days, before being soaked for another 21-day period with drainage water (treatments) and distilled water (control). Biomass parameters (fresh weight, length, etc.), enzymatic activity [glutamine synthetase (GS), phosphoenolpyruvate carboxylase (PEPc)] and Zn, Cu, Cd and Cr contents were measured on both the shoots and roots of each plant.