Newly Discovered Irbesartan Disinfection Byproducts via Chlorination: Investigating Potential Environmental Toxicity

Irbesartan belongs to the Sartan family, whose members are used in the treatment of arterial hypertension and kidney disease among patients with hypertension and type 2 diabetes mellitus as part of a treatment based on antihypertensive drugs. This drug has reached surface waters, accumulating to the extent of being considered an emerging pollutant, along with other substances from the same class. Wastewater treatment plants, which constitute the main environmental source of this compound, fail to completely reduce its presence in wastewater and generate additional toxic byproducts through the chlorine-based disinfection process. This study provides a comprehensive investigation into the chlorination mechanisms of irbesartan, revealing the identity of twelve new byproducts, which were characterized using NMR and mass spectrometry (MS-TOF). The other six byproducts were published in a previous study, allowing for the confirmation of some aspects of the supposed mechanisms of degradation, along with the identification of those that had only been hypothesized. An ecotoxicological assessment of a mixture and isolated byproducts was performed using Raphidocelis subcapitata for algal growth inhibition, Daphnia magna for immobility, and Aliivibrio fischeri for luminescence inhibition. The results revealed the variable toxicity of irbesartan and its byproducts. Different organisms exhibited varying sensitivities to the byproducts, with Aliivibrio fischeri being the most sensitive. The coexistence of multiple byproducts in the environment, their high toxicity, and their potential interactions highlight the significant environmental risks associated with chlorination and its derivates. Our study highlights the ongoing debate surrounding the generation of disinfection byproducts.