Evaluation of the halogenation and photofate of the blood pressure regulator losartan in water: reactivity and mechanisms

Highlights

	● Losartan showed distinct reactivity with multiple chemical oxidants.
	● Mechanisms of losartan via chlorination, bromination, and photolysis were explored.
	● Direct and indirect photolysis contributed differently to losartan photolysis.
	● The transformation products remained certain environmental risks.

Abstract

Chlorinating wastewater before it is released into surface water can change the fate of organic pollutants. This transformation is influenced by chlorine residues, bromine-containing wastewater, and solar radiation. Losartan (LOS), one of the earliest sartan antihypertensive drugs produced, is used worldwide and has been found in the environment. However, its transformation mechanisms and environmental risks have not been systematically investigated. This research presents the degradation kinetics, transformation products, and environmental risks of LOS in different scenarios. The results revealed that k_{app, HClO (LOS)} ranged from 0.47 to 8.30 L/(mol·s) at pH 5.0–8.0. The k_{app, HBrO (LOS)} values at pH 5.0–8.0 ranged from 8.38 × 10³ to 1.55 × 10⁵ L/(mol·s), revealing a faster bromination reaction than chlorination. LOS degrades through direct photolysis, carbonate radicals (CO₃^•−), and singlet oxygen (¹O₂) under sunlight exposure. The solar/chlorination process accelerates the reaction rate through radical activity. In addition, chlorination and bromination resulted in halogen addition to the aromatic ring, whereas hydroxylation, hydrogen abstraction, demethylation, ring opening, and hydrolysis reactions were observed across all processes. Some products exhibit high biodegradation resistance and high toxicity, potentially threatening the aquatic environment. This study aims to enhance our understanding of the environmental behavior and resulting risks of LOS by exploring its environmental fate through various transformation processes.

Graphical abstract

Keywords

Chlorination / Blood pressure regulator / Kinetics / Photolysis / Reaction mechanisms

References

[1] Abdallah P, Deborde M, Dossier Berne F, Karpel Vel Leitner N. (2015). Kinetics of chlorination of benzophenone-3 in the presence of bromide and ammonia. Environmental Science & Technology, 49(24): 14359–14367

[2] Abdallah P, Dossier-Berne F, Karpel Vel Leitner N, Deborde M. (2021). Methylparaben chlorination in the presence of bromide ions and ammonia: kinetic study and modeling. Environmental Science and Pollution Research International, 28(24): 31256–31267

[3] Acero J L, Benitez F J, Real F J, Roldan G, Rodriguez E. (2013). Chlorination and bromination kinetics of emerging contaminants in aqueous systems. Chemical Engineering Journal, 219: 43–50

[4] Adams E, Neves B B, Prola L D T, De Liz M V, Martins L R R, Ramsdorf W A, De Freitas A M. (2021). Ecotoxicity and genotoxicity assessment of losartan after UV/H₂O₂ and UVC/photolysis treatments. Environmental Science and Pollution Research International, 28(19): 23812–23821

[5] Ali I, Barros de Souza A, Liu Z, Cabooter D, Katsaounis A, De Laet S, Van Eyck K, Dewil R. (2023). Improving the removal of losartan, irbesartan and their transformation products through in situ produced hydrogen peroxide in electrochemical oxidation processes. Journal of Water Process Engineering, 55: 104133

[6] Arshad R, Bokhari T H, Khosa K K, Bhatti I A, Munir M, Iqbal M, Iqbal D N, Khan M I, Nazir A. (2020). Gamma radiation induced degradation of anthraquinone Reactive Blue-19 dye using hydrogen peroxide as oxidizing agent. Radiation Physics and Chemistry, 168: 108637

[7] Baeza C, Knappe D R U. (2011). Transformation kinetics of biochemically active compounds in low-pressure UV Photolysis and UV/H₂O₂ advanced oxidation processes. Water Research, 45(15): 4531–4543

[8] Becker R W, Cardoso R M, Dallegrave A, Ruiz-Padillo A, Sirtori C. (2023). Quantification of pharmaceuticals in hospital effluent: weighted ranking of environmental risk using a fuzzy hybrid multicriteria method. Chemosphere, 338: 139368

[9] Bodrato M, Vione D. (2014). APEX (aqueous photochemistry of environmentally occurring xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters. Environmental Science. Processes & Impacts, 16(4): 732–740

[10] Calza P, Noè G, Fabbri D, Santoro V, Minero C, Vione D, Medana C. (2017). Photoinduced transformation of pyridinium-based ionic liquids, and implications for their photochemical behavior in surface waters. Water Research, 122: 194–206

[11] Carena L, Vione D, Minella M, Canonica S, Schönenberger U. (2022). Inhibition by phenolic antioxidants of the degradation of aromatic amines and sulfadiazine by the carbonate radical (CO₃^•−). Water Research, 209: 117867

[12] Carpinteiro I, Castro G, Rodríguez I, Cela R. (2019). Free chlorine reactions of angiotensin II receptor antagonists: kinetics study, transformation products elucidation and in-silico ecotoxicity assessment. Science of the Total Environment, 647: 1000–1010

[13] Chen T, Taylor-Edmonds L, Andrews S, Hofmann R. (2023). Kinetics of hydrogen peroxide quenching following UV/H₂O₂ advanced oxidation by thiosulfate, bisulfite, and chlorine in drinking water treatment. Frontiers of Environmental Science & Engineering, 17(12): 147

[14] Cruz-González G, Rivas-Ortiz I B, González-Labrada K, Rapado-Paneque M, Chávez-Ardanza A, Nuevas-Paz L, Jáuregui-Haza U J. (2016). Improving degradation of paracetamol by integrating gamma radiation and Fenton processes. Journal of Environmental Science and Health. Part A, Toxic/Hazardous Substances & Environmental Engineering, 51(12): 997–1002

[15] De Vetta M, Corral I. (2019). Insight into the optical properties of meso-pentafluorophenyl(PFP)-BODIPY: an attractive platform for functionalization of BODIPY dyes. Computational & Theoretical Chemistry, 1150: 110–120

[16] Fabbri D, Carena L, Bertone D, Brigante M, Passananti M, Vione D. (2023). Assessing the photodegradation potential of compounds derived from the photoinduced weathering of polystyrene in water. Science of the Total Environment, 876: 162729

[17] Hao Z, Ma J, Miao C, Song Y, Lian L, Yan S, Song W. (2020). Carbonate radical oxidation of ccylindrospermopsin (Cyanotoxin): kinetic studies and mechanistic consideration. Environmental Science & Technology, 54(16): 10118–10127

[18] Heeb M B, Criquet J, Zimmermann-Steffens S G, Von Gunten U. (2014). Oxidative treatment of bromide-containing waters: formation of bromine and its reactions with inorganic and organic compounds: a critical review. Water Research, 48: 15–42

[19] Hu C Y, Zhang J C, Lin Y L, Ren S C, Zhu Y Y, Xiong C, Wang Q B. (2021). Degradation kinetics of prometryn and formation of disinfection by-products during chlorination. Chemosphere, 276: 130089

[20] Hua Z, Guo K, Kong X, Lin S, Wu Z, Wang L, Huang H, Fang J. (2019). PPCP degradation and DBP formation in the solar/free chlorine system: effects of pH and dissolved oxygen. Water Research, 150: 77–85

[21] Ioannidi A, Arvaniti O S, Nika M C, Aalizadeh R, Thomaidis N S, Mantzavinos D, Frontistis Z. (2022). Removal of drug losartan in environmental aquatic matrices by heat-activated persulfate: Kinetics, transformation products and synergistic effects. Chemosphere, 287: 131952

[22] Jiang J Q, Lloyd B. (2002). Progress in the development and use of ferrate(VI) salt as an oxidant and coagulant for water and wastewater treatment. Water Research, 36(6): 1397–1408

[23] Kaminský J, Buděšínský M, Taubert S, Bouř P, Straka M. (2013). Fullerene C70 characterization by ¹³C NMR and the importance of the solvent and dynamics in spectral simulations. Physical Chemistry Chemical Physics, 15(23): 9223–9230

[24] Lai W W P, Chen K L, Lin A Y C. (2020). Solar photodegradation of the UV filter 4-methylbenzylidene camphor in the presence of free chlorine. Science of the Total Environment, 722: 137860

[25] Lastre-Acosta A M, Barberato B, Parizi M P S, Teixeira A C S C. (2019). Direct and indirect photolysis of the antibiotic enoxacin: kinetics of oxidation by reactive photo-induced species and simulations. Environmental Science and Pollution Research International, 26(5): 4337–4347

[26] Lee W, Lee Y, Allard S, Ra J, Han S, Lee Y. (2020). Mechanistic and kinetic understanding of the UV₂₅₄ photolysis of chlorine and bromine species in water and formation of oxyhalides. Environmental Science & Technology, 54(18): 11546–11555

[27] Lei H, Mariñas B J, Minear R A. (2004). Bromamine decomposition kinetics in aqueous solutions. Environmental Science & Technology, 38(7): 2111–2119

[28] Li W, Liu K, Min Z, Li J, Zhang M, Korshin G V, Han J. (2023). Transformation of macrolide antibiotics during chlorination process: kinetics, degradation products, and comprehensive toxicity evaluation. Science of the Total Environment, 858: 159800

[29] Li W, Tanumihardja J, Masuyama T, Korshin G. (2015). Examination of the kinetics of degradation of the antineoplastic drug 5-fluorouracil by chlorine and bromine. Journal of Hazardous Materials, 282: 125–132

[30] Ling L, Sun J, Fang J, Shang C. (2016). Kinetics and mechanisms of degradation of chloroacetonitriles by the UV/H₂O₂ process. Water Research, 99: 209–215

[31] Liu J, Zhang X, Li Y, Li W, Hang C, Sharma V K. (2019). Phototransformation of halophenolic disinfection byproducts in receiving seawater: kinetics, products, and toxicity. Water Research, 150: 68–76

[32] Liu Q T, Williams H E. (2007). Kinetics and degradation products for direct photolysis of β-blockers in water. Environmental Science & Technology, 41(3): 803–810

[33] Martínez-Pachón D, Serna-Galvis E A, Ibañez M, Hernández F, Ávila-Torres Y, Torres-Palma R A, Moncayo-Lasso A. (2021). Treatment of two sartan antihypertensives in water by photo-electro-Fenton using BDD anodes: degradation kinetics, theoretical analyses, primary transformations and matrix effects. Chemosphere, 270: 129491

[34] Meyer M F, Powers S M, Hampton S E. (2019). An evidence synthesis of pharmaceuticals and personal care products (PPCPs) in the environment: imbalances among compounds, sewage treatment techniques, and ecosystem types. Environmental Science & Technology, 53(22): 12961–12973

[35] Ofrydopoulou A, Evgenidou E, Nannou C, Vasquez M I, Lambropoulou D. (2021). Exploring the phototransformation and assessing the in vitro and in silico toxicity of a mixture of pharmaceuticals susceptible to photolysis. Science of the Total Environment, 756: 144079

[36] Ofrydopoulou A, Nannou C, Evgenidou E, Christodoulou A, Lambropoulou D. (2022). Assessment of a wide array of organic micropollutants of emerging concern in wastewater treatment plants in Greece: occurrence, removals, mass loading and potential risks. Science of the Total Environment, 802: 149860

[37] Oosterhuis M, Sacher F, ter Laak T L. (2013). Prediction of concentration levels of metformin and other high consumption pharmaceuticals in wastewater and regional surface water based on sales data. Science of the Total Environment, 442: 380–388

[38] Ortiz de García S A, Pinto Pinto G, García-Encina P A, Irusta-Mata R. (2014). Ecotoxicity and environmental risk assessment of pharmaceuticals and personal care products in aquatic environments and wastewater treatment plants. Ecotoxicology, 23(8): 1517–1533

[39] Ouyang W Y, Wang W L, Zhang Y L, Cai H Y, Wu Q Y. (2023). VUV/UV oxidation performance for the elimination of recalcitrant aldehydes in water and its variation along the light-path. Water Research, 228: 119390

[40] Pozdnyakov I P, Tyutereva Y E, Parkhats M V, Grivin V P, Fang Y, Liu L, Wan D, Luo F, Chen Y. (2020). Mechanistic investigation of humic substances assisted photodegradation of imipramine under simulated sunlight. Science of the Total Environment, 738: 140298

[41] Qin L, Lin Y L, Xu B, Hu C Y, Tian F X, Zhang T Y, Zhu W Q, Huang H, Gao N Y. (2014). Kinetic models and pathways of ronidazole degradation by chlorination, UV irradiation and UV/chlorine processes. Water Research, 65: 271–281

[42] Rose M R, Lau S S, Prasse C, Sivey J D. (2020). Exotic electrophiles in chlorinated and chloraminated water: when conventional kinetic models and reaction pathways fall short. Environmental Science & Technology Letters, 7(6): 360–370

[43] Rosenfeldt E J, Linden K G. (2004). Degradation of endocrine disrupting chemicals bisphenol A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes. Environmental Science & Technology, 38(20): 5476–5483

[44] Roveri V, Guimarães L L, Toma W, Correia A T. (2020). Occurrence and ecological risk assessment of pharmaceuticals and cocaine in a beach area of Guarujá, São Paulo State, Brazil, under the influence of urban surface runoff. Environmental Science and Pollution Research International, 27(36): 45063–45075

[45] Russo D, Cochran K H, Westerman D, Li Puma G, Marotta R, Andreozzi R, Richardson S D. (2020). Ultrafast photodegradation of isoxazole and isothiazolinones by UV₂₅₄ and UV₂₅₄/H₂O₂ photolysis in a microcapillary reactor. Water Research, 169: 115203

[46] Serna-Galvis E A, Isaza-Pineda L, Moncayo-Lasso A, Hernández F, Ibáñez M, Torres-Palma R A. (2019). Comparative degradation of two highly consumed antihypertensives in water by sonochemical process. Determination of the reaction zone, primary degradation products and theoretical calculations on the oxidative process. Ultrasonics Sonochemistry, 58: 104635

[47] Shang M, Kong Y, Yang Z, Cheng R, Zheng X, Liu Y, Chen T. (2023). Removal of virus aerosols by the combination of filtration and UV-C irradiation. Frontiers of Environmental Science & Engineering, 17(3): 27

[48] Shu Z, Li C, Belosevic M, Bolton J R, El-Din M G. (2014). Application of a solar UV/chlorine advanced oxidation process to oil sands process-affected water remediation. Environmental Science & Technology, 48(16): 9692–9701

[49] Shukla S, Srivastava A, Kumar P, Tandon P, Maurya R, Singh R B. (2020). Vibrational spectroscopic, NBO, AIM, and multiwfn study of tectorigenin: a DFT approach. Journal of Molecular Structure, 1217: 128443

[50] Soares D F, Faria A M, Rosa A H. (2017). Análise de risco de contaminação de águas subterrâneas por resíduos de agrotóxicos no município de Campo Novo do Parecis (MT), Brasil. Engenharia Sanitaria e Ambiental, 22: 277–284

[51] Tian Z, Zhao H, Peter K T, Gonzalez M, Wetzel J, Wu C, Hu X, Prat J, Mudrock E, Hettinger R. . (2021). A ubiquitous tire rubber-derived chemical induces acute mortality in coho salmon. Science, 371(6525): 185–189

[52] Wang W L, Jing Z B, Zhang Y L, Wu Q Y, Drewes J E, Lee M Y, Hübner U. (2024). Assessing the chemical-free oxidation of trace organic chemicals by VUV/UV as an alternative to conventional UV/H₂O₂. Environmental Science & Technology, 58(16): 7113–7123

[53] Wu Z, Fang J, Xiang Y, Shang C, Li X, Meng F, Yang X. (2016). Roles of reactive chlorine species in trimethoprim degradation in the UV/chlorine process: kinetics and transformation pathways. Water Research, 104: 272–282

[54] Xu B, Deng L, Zhang S, Luo W, Hu J, Tan C, Singh R P. (2023). Analysis of degradation kinetic modeling and mechanism of chlorinated-halonitromethanes under UV/monochloramine treatment. Environmental Pollution, 319: 120972

[55] Xu X, Xiao R, Dionysiou D D, Spinney R, Fu T, Li Q, Wang Z, Wang D, Wei Z. (2018). Kinetics and mechanisms of the formation of chlorinated and oxygenated polycyclic aromatic hydrocarbons during chlorination. Chemical Engineering Journal, 351: 248–257

[56] Young T R, Li W, Guo A, Korshin G V, Dodd M C. (2018). Characterization of disinfection byproduct formation and associated changes to dissolved organic matter during solar photolysis of free available chlorine. Water Research, 146: 318–327

[57] Zaouak A, Noomen A, Jelassi H. (2021). Degradation mechanism of losartan in aqueous solutions under the effect of gamma radiation. Radiation Physics and Chemistry, 184: 109435

[58] Zhang T, Huang C H. (2020). Modeling the kinetics of UV/peracetic acid advanced oxidation process. Environmental Science & Technology, 54(12): 7579–7590

[59] Zhou Y, Chen C, Guo K, Wu Z, Wang L, Hua Z, Fang J. (2020). Kinetics and pathways of the degradation of PPCPs by carbonate radicals in advanced oxidation processes. Water Research, 185: 116231

[60] Zhu J, Yang L, Wang M, Zhang Q, Zhang Y, Li Y. (2022). The influence of bromide and iodide ions on the sulfamethoxazole (SMX) halogenation during chlorination. Science of the Total Environment, 848: 157687

Conflict of Interests

Mingbao Feng is a youth editorial board member of Frontiers of Environmental Science & Engineering. The authors declare that they have no known competing financial interests or personal relationships that might influence the work reported.

Acknowledgements

This work was supported by the National Key R&D Program of China (No. 2023YFE0112100), the Natural Science Foundation of Xiamen (China) (No. 3502Z202373008), and the National Natural Science Foundation of China (Nos. 22476166 and 42376210).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11783-025-1968-9 and is accessible for authorized users.

RIGHTS & PERMISSIONS

2025 Higher Education Press 2025