pH and Soil Additive-Depending Uptake of Various Metals and Metalloids by Helianthus tuberosus from a Uranium Containing Test Field Site

摘要

In the recent decades phytoremediation became an emerging technology for the stabilization and rehabilitation of slightly to medium heavy metal contaminated sites, as well as of mining sites. In previous own studies the general suitability of Helianthus tuberosus under slightly acidic soil pH and increased heavy metal (HM) concentrations was successfully tested. Phytoremediation was here investigated as a suitable remediation method for the stabilization of a U mining site near Ronneburg in Thuringia/Germany. In the experiments presented here, the uptake of heavy metals/radionuclides (HM/R) of H. tuberosus from test field substrate with different soil additives and mineral fertilizers under variation of soil pH was tested in pot and real field experiments. Compost was added in different masses (40 - 120 t/ha), and CaO was added in several experiments. The test field soil without additives (pH 4.65) was applied as control experiment. Good growth yields for tubers and shoot biomass were achieved for the addition of compost and CaO, but also for N-fertilization. The highest metal concentrations were achieved at the test field site for Al with 2.1 g/kg in roots at an N-fertilized soil of pH 4.6, furthermore 2.4 g/kg Fe, 0.66 g/kg Mn, 0.9 mg/kg U in the roots and 1.9 g/kg Mn in shoots (transfer factor 2.8). Good metal transfer factors were also achieved for Zn, Cd and Co. As a conclusion from these results, H. tuberosus is suited as a plant for phytostabilization and phytoextraction at such a site and for the subsequent winning of bioenergy. It was growing successful under the rough soil and climatic conditions at this test field site.