Formation of N-nitrosamines from chlorination and chloramination of molecular weight fractions of natural organic matter

► Formation of eight N-nitrosamines from disinfection of size fractions of NOM. ► N-nitrosodimethylamine was the most frequently detected N-nitrosamine. ► Chloramination showed higher potential to form N-nitrosamines than chlorination. ► Precursor materials of N-nitrosamines are more abundant in low to medium MW fractions of NOM.