Ski sports like cross-country skiing, downhill skiing, and biathlon are popular winter sports. Applied ski waxes reduce the friction between snow and ski and therefore increase the ski gliding. Parts of the ski waxes can enter the soil due to snow melting.

• We hypothesize that ski wax increases the soil-water contact angle and consequently the water repellency of soils.

To test this hypothesis the contact angle is measured directly with the sessile drop measurement and indirectly by the Washburn method with the DCAT 11 advice. Two PFAs containing wax products (powder and liquid) are applied to sandy soil in various concentrations. The concentrations are based on their PFAs content and the PFAs concentrations measured directly in Nordic Skiing areas.  

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.

Volatile organic compounds (VOCs) produced by living organisms via biological processes, which are known as biogenic volatile organic compounds (BVOCs), are an important group of chemicals that has significant influences on atmospheric chemistry, climate system, as well as the bioactivities of plants and animals. Whereas plant-emitted BVOCs have been widely studied for the past decades, the understanding of soil related BVOCs remains inadequate.  A variety of abiotic and biotic processes taking place beneath the ground makes soil both a sink and a source for BVOCs.

Hypotheses

• BVOCs emission and/or uptake are highly affected by the percent of organic matter in the soil and the water content.
• The dynamics of BVOCs exchange are subject to memory effects, following the hysteretic water content vs matric potential relationship.

Methods

To test the two hypotheses, we conduct transient water drying and wetting experiments, and we quantify simultaneously BVOC sources and sinks, as well as soil water states and fluxes.