In geosciences and environmental research, small particles in the sub mm range are important actors. Due to their small size, the particles can be transported over long distances in both water and the atmosphere and they can deeply penetrate organisms. Besides, they often play a key role in sorption- and transformation processes of nutrients and contaminants as they have a large surface to volume ratio. In a variety of Projects (f.e. NacoTe, TRANS-LARA, USER II), the working group of Applied Geology investigates nanoparticles, (bio-)colloids and particulate matter using a multi-methodological approach in different environmental compartments, taking into account both natural and anthropogenic origins.
Fig.1. Application of imaging methods of bio(colloidal) phases; A) 3D Atomic Force Microscopy (AFM) image of flagellated microorganism B) Scanning Electron Microscopy image of a multimineral colloidal phase
Image: Marcus Böhm
The working group of Applied Geology addresses small particles in different environmental compartments, taking into account both natural and anthropogenic origins.
The quantitative description of the transport-controlling processes of natural and artificial nanoparticles via the soil zone into aquifers or from the groundwater over the soil zone into the biosphere is still poorly understood. Process understanding through a so-called "bottom-up" approach using small- and mesoscale column experiments or experiments with field-scale lysimeters. Here, targeted variation of individual parameters such as specific characteristics of the collector (e.g. hydrogeochemical properties of the aquifer or soil substrate as well as fracture surfaces) or of the nanoparticles is used. This is accompanied by further work focused on the co-transport of pollutants with natural and artificial inorganic and organic nanoparticles and (bio-)colloids and especially (a) the reasons for the observed trace element desorption kinetics (sorption or structural incorporation) and (b) the model-technical description of these transport processes. For this, laboratory experiments and field work are coupled with various analytical methods also in cooperation with other working groups such as Hydrogeology and Mineralogy.
As a result of industrialization and urbanization anthropogenic particulate matter has become an almost worldwide problem with adverse effects on health and environment. To substantially reduce the amount of particles in the atmosphere, corresponding sources need to be identified. Our work addresses the possibility to use data from sampling campaigns in combination with statistical methods (like principal component analysis or discriminant analysis) for this purpose. To generate the data, mainly non classical sampling methods are applied. This includes for example the sampling of spider webs, to whose adhesive surface dust particles attach, or the moss bag biomonitoring technique.
van Laaten N., von Tümpling W., Merten D., Bro R., Schäfer T., Pirrung M. (submitted). Spider web biomonitoring: A cost-effective source apportionment approach for urban particulate matter. Environmental Pollution.