Evaluation of N-methylpyrrolidone and its oxidative products toxicity utilizing the microtox assay

N-Methylpyrrolidone (NMP) is a cyclic nitrogen-containing organic chemical used to replace more volatile and toxic organic solvents in paint coating a nd cleaning applications. The Marine Corps Multi-Commodity Maintenance Cent er was concerned that the high NMP and organic levels in process water woul d upset treatment processes at the industrial Process Water Plant (IWP). Th e NMP contaminated process water was oxidized by a semicontinuous advanced oxidation reactor to reduce the organic concentration. The oxidative byprod ucts of NMP were identified by GC/MS and tested for their toxicity. A toxic ity test, utilizing the Microtox toxicity assay, revealed that methylsuccin imide was the most toxic identifiable product of NMP oxidation. The toxicit y of the process water was reduced as methylsuccinimide and was further oxi dized to succinimide and other amine products. The results indicate that NM P contaminated process water should be oxidized past the N-methylsuccinimid e compound prior to standard industrial process water treatment procedures, so as to reduce toxicity concerns associated with NMP contaminated process water.