Comparative study of pre-treatment procedures for (3)H monitoring in water samples from environmental protection programs.

The determination of tritium activity in water samples is included in most environmental protection programs, and the recommended procedure consists of sample distillation and further measurement by liquid scintillation. Distillation is a simple but time consuming pre-treatment, especially in routine analysis. Here we evaluate alternative pre-treatments for tritium activity determination, such as filtration or the use of multiple selective ion exchange columns. 52 samples from different water sources (rain, surface, underground, sea and drinking water) in Spanish environmental protection programs, together with an IAEA reference material were analyzed. Results show that both pre-treatments can be applied as a preliminary tool to discriminate between tritium active and non active waters in environmental monitoring programs. In addition, filtration and multiple selective ion exchange column pre-treatments can be used as alternative procedures for tritium activity determination in the routine analyses of water samples with known and reproducible chemical and isotopic composition. Both methods are less time consuming than distillation and, in the case of filtration, extremely cheap. For waters with complex matrices, especially sea water, distillation is the recommended procedure due to the interference from salts contained in the sample.