This project is an applied basic research in the field of environmental science and technology. Drinking water safety is related to national economy and people's livelihood, and complex pollution by trace pollutants is a fundamental characteristic of the quality of drinking water sources in China. The current drinking water purification processes mainly rely on chemical agents for destruction, resulting in the generation of a large number of highly toxic by-products. The long-term effects of these complex low-concentration pollutants pose a serious threat to human health. Identifying and revealing high-risk pollutants in drinking water and their transformation mechanisms, as well as establishing principles and control systems for toxicity reduction, are important fundamental scientific issues for drinking water safety assurance and also a major strategic need in China's environmental protection. The project focuses on the key scientific issues of high-risk pollutant identification, transformation, and toxicity reduction, conducting systematic research on high-risk pollutant identification - process migration and transformation - by-product generation mechanisms - principles and methods of toxicity reduction. It aims to discover high-risk pollutants, Achievements in original research include revealing new mechanisms of transformation and generation, as well as creating new principles and methods for reducing toxicity. Significant scientific findings include: establishing a method for synchronous detection of antibiotics and trace amounts of disinfection by-products in complex environmental samples, revealing the characteristics and distribution patterns of antibiotic pollution in water environments and drinking water sources, innovatively introducing the principle of effect-oriented risk analysis, establishing quantitative evaluation and identification methods that combine biological effects with chemical analysis, discovering high-risk antibiotics and highly toxic nitrogenous disinfection by-products (N-DBPs) in drinking water, revealing the severe risk of antibiotic resistance genes in Shanghai's drinking water sources, and solving the problems that traditional analytical methods cannot determine the dose-response relationship and are difficult to quantitatively assess risk effects. The study also found that antibiotics in drinking water have a toxicity enhancement effect during transformation, elucidated the pathways of antibiotic transformation into new nitrogenous disinfection by-products, The project has pioneered the revelation of a new mechanism for the formation of highly toxic nitrogenous disinfection by-products (N-DBPs) from free and bound amino acids during chlorination, elucidated the important role of 'peptide bonds' in the process of N-DBP formation through chlorination, and deeply understood the intrinsic mechanisms of high-risk pollutants. It was also first to design an electro-adsorption magnetic material with high efficiency for heavy metal removal, innovatively proposed the principle and method of reducing pollutant toxicity through reduction transformation, reported the catalytic hydrogenation reduction of highly toxic by-product bromate for the first time, established a toxicity reduction system for drinking water that includes adsorption removal, reduction transformation detoxification, and multi-pollutant synergistic control of medium and trace pollutants, providing theoretical foundations for creating new technologies for the reduction of toxicity of drinking water trace pollutants. The project's achievements have been applied in practice. New analytical methods for antibiotics and nitrogen-containing disinfection by-products, as well as the identification of high-risk pollutants, have been operationalized by national and local drinking water quality monitoring departments. Some toxicity reduction technologies have been adopted in drinking water treatment projects. Control technologies related to heavy metals, disinfection by-products, bromates, etc., have been included in the 'Technical Guidelines for the Construction and Renovation of Urban Water Supply Facilities' issued by the Ministry of Housing and Urban-Rural Development. Eight representative papers have been widely cited in journals such as Nat. Rev. Microbiol., Chem. Soc. Rev., and Environ. Sci. Technol., with a total of 1444 citations, including 1240 SCI citations. There are four papers with more than 100 SCI citations each, and one paper has received up to 498 SCI citations. He has obtained five national authorized invention patents. The research achievements of the project have played an important role in solving major problems related to drinking water safety and have effectively promoted the development of the discipline. Since the 'Eleventh Five-Year Plan', the first project leader, Yin Daqiang, has served as a key expert for the landmark achievement of drinking water safety assurance in the Taihu Lake Basin under the National Science and Technology Water Special Project. He was selected as a Leading Talent in Shanghai (2016) and has trained one outstanding young talent in Shanghai.