Metformin chlorination byproducts in drinking water exhibit marked toxicities of a potential health concern. (January 2021)

• Record Type: Journal Article
• Authors: Zhang, Runshuai; He, Yuanzhen; Yao, Luxia; Chen, Jie; Zhu, Shihao; Rao, Xinxin; Tang, Peiyuan; You, Jia; Hua, Guoqiang; Zhang, Lu; Ju, Feng; Wu, Lianfeng
• Is Part Of: Environment international. Volume 146(2021)
• Publication Date: 2021-01
• Subjects: Metformin -- Metformin chlorination byproduct -- Drinking water -- Toxicity -- Public health; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2020.106244
• Languages: English
• ISSNs: 0160-4120

Abstract

Graphical abstract: Highlights: Metformin (MET) chlorination byproducts Y and C are first purified for research. The worldwide occurrences of MET and C in drinking water are demonstrated. Byproducts Y and C exhibit no evident genotoxicity to nematode worms. Both byproducts are markedly toxic to worms, human cells, and mice. Y and C can be removed via boiling and powered activated carbon adsorption. Abstract: Metformin (MET), a worldwide used drug for type 2 diabetes, has been found with the largest amount by weight among all drugs in aquatic environment, including the drinking water systems where this emerging micropollutant is inevitably transformed during chlorination process. Whether MET chlorination byproducts Y (C4 H6 ClN5 ) and C (C4 H6 ClN3 ) exist in drinking water remains unknown. Although MET has health-promoting properties, whether or how its chlorination byproducts affect health is still uncharacterized. Here we reveal that MET and byproduct C are present in worldwide drinking water with the highest doses detected for MET and C as 1203.5 ng/L and 9.7 ng/L respectively. Under simulated chlorination conditions, we also demonstrate that both byproducts can be increasingly produced with increment of MET concentration, suggesting a hidden threat on the safety and sustainability of global water supply. Through systematic evaluations, we demonstrate that MET chlorination byproducts Y and C exhibit toxicities instead of genotoxicity to live worms and human HepG2 cells at millimolar doses. Moreover, both byproducts are harmful to mice and particularly Y at 250 ng/L destroys the mouse small intestine integrity. Unprecedentedly, we unveil boiling and activated carbon adsorption as effective alternative solutions that may be in urgent demand globally for removing these byproducts from drinking water.