Alpha emitters in the beach sands of the Mexican Pacific littoral

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.