N-Nitrosodimethylamine Formation from Treatment of Seasonally and Spatially Varying Source Water

Abstract

N-nitrosodimethylamine (NDMA) is a disinfection by-product (DBP) that has been classified as a probable human carcinogen in multiple risk assessments. NDMA presence in drinking water is widespread and dependent on source water, disinfectant type, precursors, and water treatment strategies. The objectives of this study were to investigate NDMA formation potential in a modeled monochloramine water treatment plant (WTP) fed by seasonally and spatially varying source water; and to optimize DBP precursor removal by combining conventional and additional treatment techniques. After NDMA analysis, it was found that NDMA formation was significantly dependent on source water type and monochloramine contact time (CT); e.g., at 24 h CT, Cork Brook produced 12.2 ng/L NDMA and Bailey Brook produced 4.2 ng/L NDMA, compared with 72 h CT, Cork Brook produced 4.1 ng/L NDMA and Bailey Brook produced 3.4 ng/L NDMA. No correlations were found between traditional DBP precursors such as total organic carbon and total nitrogen, and the formation of NDMA. The laboratory bench-top treatment system was highly effective at removing traditional DBP precursors, highlighting the need for WTPs to alter their current treatment methods to best accommodate the complex system of DBP control.

Spatiotemporal Variability in N-Nitrosodimethylamine Precursor Levels in a Watershed Impacted by Agricultural Activities and Municipal Wastewater Discharges and Effects of Lime Softening

“…Some researchers observed a positive correlation between DON and NDMA formation, 52−56 while others reported weak relationships between NDMA formation and nitrogen-related parameters. 11,23,57 In the present study, a positive correlation between NDMA UFC and DN concentration was observed, which suggests that the DN concentration is a potential surrogate for NDMA precursors released into the rivers sampled in this study. When high NDMA UFC concentrations were detected in July 2020, January 2021, and February 2021, high DN concentrations were also observed.…”

Contamination, Decomposition, and Formation of N-Nitrosodimethylamine in Water Samples at the ng/L Level of Determination

“…A validation study was also recently performed for this system for the determination NDMA in advanced-treated recycle water, drinking water, and waste water. 14 The usefulness of this system has been demonstrated in several recent studies, including surveys of tap water and its source water, 15,16 and evaluations of reverse osmosis membranes and disinfectants. [17][18][19][20][21] Since this system is currently the only method capable of directly detecting NDMA in water samples at ng/L levels, it has revealed that sample analyses are widely subject to contamination by N-nitrosamines and their decomposition.…”