5. Cesium 137 volume and mass activities in continental aquatic environments

Outside the influence of nuclear facilities, caesium-137 activity levels in raw river water (dissolved and particulate fractions) are currently below or even well below 10 ^-3 Bq.L ^-1 . They are even lower in filtered water (dissolved fraction), because in freshwater, cesium-137 is mostly bound to suspended particles [BN 3 907] . Average caesium-137 volume activities in filtered water samples from the Orb and Hérault rivers, and in the Rhône upstream of the Creys-Malville nuclear site, are...