Erschienen:
[Erscheinungsort nicht ermittelbar]: [Verlag nicht ermittelbar], 2021
Sprache:
Englisch
Entstehung:
Hochschulschrift:
Dissertation, 2021
Anmerkungen:
Beschreibung:
According to estimates, 2.5 million sites in Europe are potentially contaminated. Contaminants, such as trace elements, can be introduced into the environment by human activities. Trace elements are persistent and not biodegradable, consequently they accumulate and threaten soil health and the food chain, in particular if they are bioavailable and occur at elevated concentrations. Common approaches for remediation of such soils include the removal of the polluted soil regions, in the most cases the topsoil, and the off-site clean-up by washing or incineration. However, those strategies are costly and result in a considerable loss of soil. Alternative on-site techniques imply immobilization by precipitation as indissoluble salts or adsorption, for example to organic residues such as compost as well as phytoremediation. Whereas the latter is limited by the tolerance of the plants to the trace element concentration and the respective conditions of the polluted soils (i.e. acidity), the first bears the danger of quick remobilization as a consequence of biodegradation of the amendment. In order to circumvent this problem, several recent studies propose the application of biochar, the solid product of the pyrolysis of biomass, for the remediation of soils polluted by heavy metals, since due to its high aromaticity is expected to resist quick mineralization. A further advantage of this material lays in its high porosity which is likely to support trace metal adsorption, thus their sequestration. It was further hypothized that their potential of trace element sequestration could be high enough to decrease their bioavailable fraction to concentration below the tolerance threshold of accumulating plants. In order to test the feasibility of such a strategy, in the present PhD thesis the remediation potential of biochars derived from agricultural residues was investigated in an area polluted with trace elements due to a mine spill in 1998 (The Guadiamar Green Corridor). The studied soils consisted of Fluvisols with two ...