The goal of environmental management in China is transitioning from pollution control to the improvement of ecological quality. The establishment of regional differential water quality standards can better adapt to the ecological characteristics and development needs of different regions. Given the shortcomings of current water quality standards and the needs of technological development, this study analyzed the causes and influencing factors of regional differences in water quality standards and summarized China's regional variations in areas such as the characteristics of receiving water bodies, social attributes, climate conditions, physicochemical properties of water, and aquatic biotic populations. It also examined the impact of regional characteristics on the assessment of biological toxicity. Based on these analyses, the study identified key scientific questions that may arise in the development of regional differential water quality standards in China and outlined future critical research directions in this field. These directions include developing theories and methods for determining the effluent dilution coefficient, establishing methods for identifying regional key water quality indicators and assessing their impact on water quality standards, determining regional characteristic species and their influence on water quality standards, and formulating theories and methods for categorizing different regions across the country. The aim of the study was to provide a reference for the scientific establishment of water quality standards in China.
Keywords: biotoxicity; dilution coefficients; environmental elements; regional differences; water quality standard.