Transfer of Tritium Released into the Marine Environment by French Nuclear Facilities Bordering the English Channel

Abstract

Controlled amounts of liquid tritium are discharged as tritiated water (HTO) by the nuclear industry into the English Channel. Because the isotopic discrimination between 3H and H is small, organically bound tritium (OBT) and HTO should show the same T/H ratio under steady-state conditions. We report data collected from the environment in the English Channel. Tritium concentrations measured in seawater HTO, as well as in biota HTO and OBT, confirm that tritium transfers from HTO to OBT result in conservation of the T/H ratio (ca. 1 × 10(-16)). The kinetics of the turnover of tritium between seawater HTO, biota HTO, and OBT was investigated. HTO in two algae and a mollusk is shown to exchange rapidly with seawater HTO. However, the overall tritium turnover between HTO and the whole-organism OBT is a slow process with a tritium biological half-life on the order of months. Nonsteady-state conditions exist where there are sharp changes in seawater HTO. As a consequence, for kinetic reasons, the T/H ratio in OBT may deviate transiently from that observed in HTO of samples from the marine ecosystem. Dynamic modeling is thus more realistic for predicting tritium transfers to biota OBT under nonsteady-state conditions.

Modulation of Cosmogenic Tritium in Meteoric Precipitation by the 11-year Cycle of Solar Magnetic Field Activity

“…In fact, Kaitoke is known to be free of these sources. Even precipitation at coastal locations at the North Sea, like Cuxhaven, are not significantly affected by local or regional contamination sources 40 . The attenuation of the bomb peak is still visible in the 1980’s, however the decreasing trend is similar in each sites, being devoid of oscillations attributed to local contaminations.…”

“…The attenuation of the bomb peak is still visible in the 1980’s, however the decreasing trend is similar in each sites, being devoid of oscillations attributed to local contaminations. The Cuxhaven precipitation is slightly affected by the moisture evaporated from North Sea, which is contaminated by artificial tritium from the Le Hague reprocessing plant 40 . However, this local contamination is not co-varying with the solar cycle, rather this gives a constant tritium offset to the meteoric precipitation at the coastal region of northern France, Belgium, The Netherlands and Germany.…”

Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

“…Knowledge of dissolved transport (currents, advection and dispersion) is the basis of other oceanographic studies. It made possible pollutant transfer studies between seawater and living species [56,[80][81][82] or particulate matter and physical transport of sediments [83][84][85]. Radio-ecological models accounting together for biological and hydro sedimentary process are accessible.…”

The English Channel: Contamination status of its transitional and coastal waters

“…However, in seawater around La Hague the dissolved 3 H activity concentrations were typically <15 Bq L À1 , as compared with background values of 0.1-0.2 Bq L À1 (Fiévet et al, 2013). In the western English Channel and around the Channel Islands, dissolved 3 H activity concentrations were typically <2 Bq L À1 (CEFAS, 2013).…”