The effect of natural organic matter polarity and molecular weight on NDMA formation from two antibiotics containing dimethylamine functional groups

• Published in: The Science of the total environment 2016-12, Vol.572, p.1231-1237
• Main Authors: Leavey-Roback, Shannon L., Krasner, Stuart W., Suffet, Irwin H. (Mel)
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Chloramines - chemistry; Dimethylnitrosamine - chemistry; Disinfectants - chemistry; N-nitrosodimethylamine (NDMA); Natural organic matter; Spiramycin; Tetracycline; Water Pollutants, Chemical - chemistry; Water Purification
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2016.08.041

N-nitrosodimethylamine (NDMA) is a disinfection byproduct preferentially formed in chloraminated water. NDMA may be formed from certain chemicals containing dimethylamine (DMA) functional groups. This reaction may be slowed by the presence of natural organic matter (NOM). In this study, NOM fractionated by size or polarity was tested for its ability to slow or impede the formation of NDMA from two DMA-containing precursors, the antibiotics tetracycline and spiramycin. The high molecular weight NOM fractions (>10KDa) were shown to be the most effective in reducing the amount of NDMA formed from the precursor chemicals. The filtrate of a C-18 non-polar cartridge was also effective at reducing NDMA formation from tetracycline (spyramycin not tested). Therefore, polar and charged NOM components may be responsible for the reduction in NDMA formation. A possible mechanism for the reduction of NDMA formation from tetracycline is complexation due to the hydrogen bonding of the DMA functional group on tetracycline to polar phenolic functional groups in the NOM. [Display omitted] •Polar and charged natural organic matter reduce the formation of NDMA from tetracycline.•High molecular weight NOM (>0KDa) reduces NDMA formation from precursors.•Complexation of tetracycline to NOM via hydrogen bonding likely inhibits NDMA reaction.