PH and Concentration Dependent Heavy Metal Uptake by <i>Helianthus tuberosus</i> in Phytoremediation Experiments

Abstract

In the recent time, phytoremediation became an emerging remediation technology due to its low costs and high sustainability. For the remediation of a contaminated mining site with low to medium heavy metal (HM) concentrations, experiments for the phytoextraction and growth behaviour of Helianthus tuberosus were performed. pH and HM concentrations were identified as crucial factors for plant growth and success of phytoremediation. In these experiments, optimal conditions for the plant growth and for the success of phytoremediation were investigated. Plant experiments were carried out in a pH range stepwise from 4.0 – 6.0 and with a combination of different HM (Cd, Cu, Fe, Mn, Ni, Zn, Pb) in three different concentration ranges (slight/ middle/ high); experimental conditions were typical for mining sites with AMD and slight to medium heavy metal impact. Yields of roots, tubers, leaves and shoots under the appropriate conditions were investigated, and the HM accumulation of different plant parts was analyzed. High accumulation of Fe (up to 1.48 g/kg), Mn (up to 1.68 g/kg) and Zn (up to 853 mg/kg) was measured in roots; shoots accumulated up to 2.6 g/kg Ni, 11.4 g/kg Mn and 6.06g/kg Zn. The accumulation factors for main heavy metals are given in the paper. The further utilization of tubers by fermentation was not inhibited for field site HM concentrations. As results, H. tuberosus represents a suitable phytoremediation plant species for the phytoextraction of Fe, Mn, Zn, Cd and Ni.