[en] Alpha emitters in Mexican Pacific beach sands were studied to calculate the ²³⁴U/²³⁸U activity ratio (AR) and the ^239+240Pu content. AR was related with the weathering conditions of the sands; AR = 1 means reduced weathering conditions, like those found in the end of the California peninsula, and AR < 1 suggest intense weathering effects as those found in the central coastline of the Mexican Pacific littoral. The plutonium activity of alpha emitters in the beach sands coming from the nuclear anthropogenic activity rises from north to south in the California peninsula, following the exchange of water with the ocean currents. (author)

[en] The interaction of salicylic acid with zirconium diphosphate surface and its reactivity toward uranium (VI) was investigated. The interaction of salicylic acid with zirconium diphosphate was firstly studied using several analytical techniques including atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The sorption of uranium (VI) onto surface-modified zirconium diphosphate was evaluated by the classical batch method at room temperature. This study showed that the uranium (VI) sorption onto zirconium diphosphate is influenced by the presence of salicylic acid. A fluorescence spectroscopy study revealed the presence of a uranyl specie onto the modified solid surface. The spectroscopy results were then used to restrain the modeling of experimental sorption data, which are interpreted in terms of a constant capacitance model using the FITEQL code. The results indicated that interaction between the uranium (VI) and the surface of zirconium diphosphate modified with salicylic acid leads to the formation of a ternary surface complex.