Tritium concentrations in Mediterranean precipitation event samples from the island of Corsica (France)

Event-based precipitation samples were collected between April 2017 and April 2018 in the city of Corte on the Mediterranean island of Corsica, France (42.300570° N, 9.148592° E; 415 m a.s.l.). The sampling location is located in central Corsica, on the eastern part of the island's main mountain ridge that reaches an elevation of up to 2706 m a.s.l. Corte lies on the west wind lee side of the main mountain ridge. The Castagniccia mountain range is situated east of Corte and reaches an elevation of up to 1767 m a.s.l. For tritium analyses, 1 L samples of precipitation were collected. Samples were transferred from the collector bucket into 1 L bottles directly after the rain event. Tritium analyses were performed at the Department of Oceanography of the Institute of Environmental Physics (IUP) at the University of Bremen (Germany) for analyses. Tritium concentrations were analyzed using the 3He-ingrowth method. Samples were divided into two aliquots of 500 mL, degassed, and stored in dedicated helium-free glass bulbs for the accumulation of the tritium decay product 3He. After a period of 2–3 months, the 3He content was analyzed by noble gas spectrometry. Details regarding the instrument setup can be found in Sültenfuß et al. (2009). All tritium concentration laboratory results were corrected for radioactive decay back to the time of the precipitation event. Concentration values are reported in tritium units (TU), where 1 TU equals a radioactivity concentration of 0.118 Bq L–1. This analytical setup allows for a precision of ±3 % and a detection limit of 0.02 TU