Formation of N-nitrosamines by chloramination or ozonation of amines listed in Pollutant Release and Transfer Registers (PRTRs)

Abstract

We determined whether or not the chloramination or ozonation of amines and hydrazines listed in Pollutant Release and Transfer Registers (PRTRs) results in the formation of N-nitrosamines when reacted in secondary wastewater effluent. We selected 12 primary, 2 secondary, 2 tertiary amines and 3 hydrazines from the PRTRs of Japan, the USA, and Korea. In this study, based on the assumption that there is a production of N-nitrosamines by not only the original selected amines and hydrazines but also the intermediate products in case of chloramination and ozonation, it was examined whether precursors were identified by selected amines and hydrazines based on the gap of the N-nitrosamines formation potential between day 0 and day 10 rather than analyzing the contribution depending on the concentration of selected amines and hydrazines. Many of the primary amines (notably 2,6-xylidine) and all of the secondary and tertiary amines produced N-nitrosodimethylamine (NDMA) by chloramination. Furthermore, the primary amines 2,6-xylidine, 3,3′-dimethylbenzidine, 4,4′-methylenebis(2-chloroaniline), 4-aminoazobenzene, p-chloroaniline, and p-cresidine produced more NDMA than did the secondary amines. The secondary amines produced mainly NDMA. Ozonation produced NDMA only from the hydrazine 1,1-dimethylhydrazine, and at a higher concentration than by chloramination. We identified 2,6-xylidine, 3,3′-dimethylbenzidine, 4,4′-methylenebis(2-chloroaniline), 4-aminoazobenzene, p-chloroaniline, p-cresidine, 1,1-dimethylhydrazine, diethylamine, 4,4′-methylenebis(N,N-dimethyl)benzenamine, and chinomethionat as warranting further study.