Radiochemical analyses of the effluent obtained from the alum treatment of a simulated nuclear bomb blast mixture in an experimental water treatment plant showed that radioelements were removed in varying amounts. These data also indicated higher and lower removals than those that had been reported earlier when only single radioisotopes were subjected to similar treatment processes. Thus a series of jar test studies were made in which single isotopes and mixtures of isotopes were subjected to similar treatment processes to obtain data on removals. Such studies would show whether certain radioisotopes would be more easily removed when combined with other isotopes or whether such combinations would interfere with removals of the specific isotopes. (Author Modified Abstract)