The aim of this study was to investigate the formation mechanisms and toxicity of emerging nitrogenous DBPs (e.g., haloacetamides) during disinfection of wastewater effluents. Cytotoxicity and genotoxicity of wastewater effluents were compared before and after monochloramine disinfection. The conditions of formation of target DBPs (haloacetamides) were studied. We also focused on the identification of unknown nitrogenous, brominated and iodinated DBPs using analytical tools such as GC-MS-MS and GC-ICP-MS.