EGU23-1816, updated on 22 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Occurrence, fate, and risk assessment of N-nitrosamines in groundwater and river water in an agricultural area

Yingjie Chen1, Huanfang Huang2, Wenwen Chen3, Xuelian Huang1, Zhe Qian1, and Shihua Qi1
Yingjie Chen et al.
  • 1China University of Geosciences, China (
  • 2State Environmental Protection Key Laboratory of Water Environmental Simulation and Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment
  • 3College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China

N-nitrosamines have been frequently detected in natural waters as a kind of nitroso compound with significant carcinogenic effects on humans. In remote agricultural areas, groundwater is often consumed directly due to inadequate water supply systems, necessitating the investigation of the occurrence, sources, and cancer risk of N-nitrosamines in the groundwater of agricultural areas. This study identified eight N-nitrosamines in groundwater and river water in the Jianghan Plain, a popular agricultural area in central China. The total concentrations of N-nitrosamines in the groundwater and river water were <2.3~61 ng/L and 3.2~10 ng/L, respectively. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMOR), N-nitrosopyrrolidine (NPYR), and N-nitrosodi-n-butylamine (NDBA) were detected in groundwater, with the main compound being NDMA (up to 52 ng/L). These N-nitrosamines were also detected in river water at comparable concentrations. The significant negative correlations between N-nitrosamines and water temperature/DO indicated that aerobic biodegradation had an influence on the N-nitrosamine distribution. Ammonium (NH4+) was proven not to be a N-nitrosamine precursor, and it rarely reacts with the precursors to form N-nitrosamines. NH4+ and NDBA have similar sources in the JHP. Nitrite (NO2-) could consume active hydroxyl radicals, which played a decisive role in forming N-nitrosamines from the ozonation of secondary amines, rather than react with secondary amines when the concentration of NO2- was low. In the case of high NO2- concentrations, NO2- reacts with amines in the environment to form N-nitrosamines. The concentrations of NDMA, NDEA, and NDBA precursors were higher in groundwater than in river water, as suggested by the formation experiment. Redundancy analysis and multiple linear regression analysis results showed the primary source of N-nitrosamines by applying nitrogen fertilizer and specific N-nitrosamines such as NPYR carried by pesticides in groundwater. The average (1.08 × 10-5) and maximum (8.18 × 10-5) total cancer risk values of detected N-nitrosamines were higher than the accepted risk level (10-5), suggesting a potential carcinogenic risk of contaminated groundwater. To minimize N-nitrosamine contamination in the groundwater of agricultural areas, further research on selecting pesticides and fertilizers that are heavily used is urgently needed.

How to cite: Chen, Y., Huang, H., Chen, W., Huang, X., Qian, Z., and Qi, S.: Occurrence, fate, and risk assessment of N-nitrosamines in groundwater and river water in an agricultural area, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1816,, 2023.