| Title: | Modeling short-term concentration fluctuations of semi-volatile pollutants in the soil-plant-atmosphere system |
| Author(s): | Bao Z; Haberer CM; Maier U; Beckingham B; Amos RT; Grathwohl P; |
| Address: | "Department of Geosciences, University of Tubingen, Holderlinstr. 12, 72074 Tubingen, Germany. Electronic address: zhongwen.bao@uni-tuebingen.de. Department of Geosciences, University of Tubingen, Holderlinstr. 12, 72074 Tubingen, Germany. Geoscience Centre, Georg-August-Universitat Gottingen, Goldschmidtstr. 3, 37077 Gottingen, Germany. Department of Geology and Environmental Geosciences, College of Charleston, 202 Calhoun Street, Charleston, SC 29041, United States. Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada" |
| DOI: | 10.1016/j.scitotenv.2016.06.117 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Temperature changes can drive cycling of semi-volatile pollutants between different environmental compartments (e.g. atmosphere, soil, plants). To evaluate the impact of daily temperature changes on atmospheric concentration fluctuations we employed a physically based model coupling soil, plants and the atmosphere, which accounts for heat transport, effective gas diffusion, sorption and biodegradation in the soil as well as eddy diffusion and photochemical oxidation in the atmospheric boundary layer of varying heights. The model results suggest that temperature-driven re-volatilization and uptake in soils cannot fully explain significant diurnal concentration fluctuations of atmospheric pollutants as for example observed for polychlorinated biphenyls (PCBs). This holds even for relatively low water contents (high gas diffusivity) and high sorption capacity of the topsoil (high organic carbon content and high pollutant concentration in the topsoil). Observed concentration fluctuations, however, can be easily matched if a rapidly-exchanging environmental compartment, such as a plant layer, is introduced. At elevated temperatures, plants release organic pollutants, which are rapidly distributed in the atmosphere by eddy diffusion. For photosensitive compounds, e.g. some polycyclic aromatic hydrocarbons (PAHs), decreasing atmospheric concentrations would be expected during daytime for the bare soil scenario. This decline is buffered by a plant layer, which acts as a ground-level reservoir. The modeling results emphasize the importance of a rapidly-exchanging compartment above ground to explain short-term atmospheric concentration fluctuations" |
| Keywords: | "Air Pollutants/*analysis Crops, Agricultural/*metabolism Environmental Monitoring Models, Chemical Models, Theoretical Soil Pollutants/*analysis Volatile Organic Compounds/*analysis Diurnal temperature changes Numerical modeling Photochemical transformati;" |
| Notes: | "MedlineBao, Zhongwen Haberer, Christina M Maier, Uli Beckingham, Barbara Amos, Richard T Grathwohl, Peter eng Netherlands 2016/06/25 Sci Total Environ. 2016 Nov 1; 569-570:159-167. doi: 10.1016/j.scitotenv.2016.06.117. Epub 2016 Jun 22" |
