Organic analyses of an actual and simulated mixed waste: Hanford's organic complexant waste revisited

Abstract

Reanalysis of the organics in a mixed waste, an organic complexant waste from the U. S. Department of Energy's Hanford Site, has yielded an 80.4% accounting of the waste's total organic content. In addition to several complexing and chelating agents (citrate, EDTA, HEDTA and NTA), 38 chelator/complexor fragments have been identified, compared to only 11 in the orginal analysis, all presumably formed via organic degradation. Moreover, a misidentification, methanetricarboxylic acid, has been re-identified as the chelator fragment N-(methylamine)imino- diacetic acid (MAIDA). A nonradioactive simulant of the actual waste, containing the parent organics (citrate, EDTA, HEDTA and NTA), was formulated and stored in the dark at ambient temperature for 90 days. Twenty chelator and complexor fragments were identified in the simulant, along with several carboxylic acids, confirming that myriad chelator and complexor fragments are formed via degradation of the parent organics. Moreover, their abundance in the simulant (60.9% of the organics identified) argues that the harsh chemistries of mixed wastes like Hanford's organic complexant waste are more than enough to cause organic degradation, even in the absence of radiation.