Advances in pollution source identification in the integrated drainage system

Pollution source identification (PSI) is one of the major businesses of water quality management in integrated drainage systems and has recently received increasing attention. However, a comprehensive overview of PSI methods with the latest advances is lacking from the perspective of integrated drainage systems. This chapter takes drainage systems and receiving water bodies as a whole system and summarizes the principles, advantages, limitations, and applicability of various methods under four PSI categories. It also discusses the advantages and principles of combinations of different types of PSI methods. Finally, four key future directions are identified for researchers and practitioners, outlining strategies to enhance the performance and practicality of source identification methods in the era of environmental Big Data.