Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.jenvrad.2021.106669
Document accepted manuscript
Title (Primary) Atmospheric washout of 35S during single rain events – Implications for 35S sampling schemes
Author Schubert, M.; Weise, S.M.; Knöller, K.
Journal Journal of Environmental Radioactivity
Year 2021
Department CATHYD
Volume 237
Page From art. 106669
Language englisch
Topic T5 Future Landscapes
Keywords 35S Input function; Short term variation; Groundwater residence time; Tracer

Cosmogenic radiosulfur (35S; half-life: 87.4 days) is transferred with the rain to the groundwater (as 35SO42−) and can be used as residence time tracer for the detection of sub-yearly groundwater residence times. Due to the distinct but non-regular annual 35S pattern in precipitation, related data evaluation requires consideration of a 35S input function that is based on representative rain samples. While minor rain events can easily be sampled quantitatively and hence representatively, a long-lasting rain event may get documented by a sample that represents only a certain sequence of the event, thus potentially resulting in a 35S activity concentration that might not be representative. With the aim to examine the magnitude of temporal variations of the 35S activity concentration in rain during long-lasting rain events, we present and discuss two related exemplary 35S time series. Furthermore, we evaluate the applicability of the parameters total sulfate and electrical conductivity (EC), both detected in rainwater as easily attainable 35S proxies. The results of the study show (i) that the 35S activity concentration may vary substantially during long-lasting rain events due to atmospheric migration processes and aerosol washout and (ii) that neither sulfate nor EC are suitable as 35S proxies due to the different origin of 35S on the one hand and sulfate/EC on the other. Hence, for the determination of a 35S activity concentration that is representative for a long-lasting rain event 35S analyses of an adequate number of sub-samples cannot be avoided.

Persistent UFZ Identifier
Schubert, M., Weise, S.M., Knöller, K. (2021):
Atmospheric washout of 35S during single rain events – Implications for 35S sampling schemes
J. Environ. Radioact. 237 , art. 106669