N-Nitrosamine Formation upon Chloramination and Chlorination of Cyanobacterial Strains

Other Titles


Blooms of blue-green algae (cyanobacteria) cause many water quality management issues. Water utilities oftentimes need to treat source waters laden with various cyanobacterial populations, which may contribute to the formation of harmful disinfection byproducts (DBPs), such as N-nitrosamines, in downstream drinking water treatment. This preliminary study investigated the formation of total and specific N-nitrosamines upon chloramination and chlorination of laboratory cultures of cyanobacteria. Two Microcystis aeruginosa strains (one confirmed microcystin producer and one non-toxin producing strain) were cultivated and harvested at different growth phases. Chloramination of cyanobacterial samples revealed that the toxin producing strain produced more N-nitrosamine precursors per dry cell weight than the non-toxin producing strain, and that the production of N-nitrosamine precursors from cyanobacteria was growth phase-dependent. Filtration of cyanobacterial samples through 0.7-μm glass fiber filters removed over 90% of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) precursors, which predominantly existed in the dissolved and/or colloidal phases. In contrast, filtration only removed around 50% of total N-nitrosamine (TONO) precursors, highlighting the importance of unknown precursors associated with cyanobacterial cells. Chlorination of cyanobacterial samples at varying chlorine doses led to enhanced TONO formation at and beyond the breakpoint, although the toxin producing strain released a significant amount of ammonium. The addition of ammonium chloride to non-toxin producing, low-ammonium cyanobacterial samples prior to chlorination did not result in statistically significant increases in TONO formation, suggesting that organic chloramines may play a role in the absence of in situ formation of inorganic chloramines during chlorination. Preliminary characterization of cyanobacterial samples using fluorescence spectroscopy and high resolution mass spectrometry revealed differences in optical and molecular properties of cyanobacterial organic matter derived at exponential and stationary growth phases.

Journal / Series

Volume & Issue


This report was prepared for the New York State Water Resources Institute (NYSWRI) with support from the U.S. Geological Survey under Grant/ Cooperative Agreement No. G21AP10626-01


Date Issued



New York State Water Resources Institute


USGS; Syracuse University; Wastewater; Nitrogen; Bacteria; Harmful Algal Blooms; Water Supply


Effective Date

Expiration Date




Union Local


Number of Workers

Committee Chair

Committee Co-Chair

Committee Member

Degree Discipline

Degree Name

Degree Level

Related Version

Related DOI

Related To

Related Part

Based on Related Item

Has Other Format(s)

Part of Related Item

Related To

Related Publication(s)

Link(s) to Related Publication(s)


Link(s) to Reference(s)

Previously Published As

Government Document




Other Identifiers


Attribution-NonCommercial 4.0 International



Accessibility Feature

Accessibility Hazard

Accessibility Summary

Link(s) to Catalog Record