Masterarbeit
Experimental and numerical investigation of the fate of insoluble pollutants in the rhizosphere
Betreuer: Frederic Leuther, Efstathios Diamantopoulos, Eva Lehndorff
Polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in terrestrial and aquatic ecosystems all around the world and are a group of chemicals among the so called “persistent organic pollutants” (POPs). PAHs comprise several hundred chemically related compounds and some of them are known to have toxic, mutagenic, and carcinogenic effects on humans and other living organisms Although PAHs are considered to be very poorly soluble in water, there appears to be transport of molecules in soil that allow them to be distributed, clog pores, or accumulate at the soil plant interface. Especially for high molecular weight PAHs, colloidal and particulate transport is assumed to be an important process. Little is known about the exact transport processes in soil and whether plants can influence this transport by suction
Hypotheses
- H1: PAHs bind to soil particles and can thus be transported in the soil despite their low water solubility.
- H2: Plants influence the distribution of the particle bound PAHs in the soil through their water uptake at the roots, which leads to the accumulation of these particles in the rhizosphere.
Methods
To test the first hypothesis an experiment is to be carried out with undisturbed soil columns without plants. An irrigation head with needles will be used to supply water to the columns, which will also contain any tracers and particles. Three steps are planned: i nvisible tracer (e.g., chloride) chloride), p articles + PAH s, inv isible and visible tracer (brilliant blue) blue). For each step, the drainage at the bottom of the column will be collected and analysed, and at the end the distribution of the particle bound PAHs in the column will be investigated. To test the second hypothesis, undisturbed soil columns with maize plants are to be used. Again, particle bound PAHs will be supplied via the irrigation system; then drying and rewetting phases will follow. The drainage will be collected and analysed and the distribution of particle bo und PAHs around the root will be studied.