Abstract: Environmental DNA (eDNA) is the sum of all the DNA extracted from environmental samples. eDNA technology is used for qualitative or quantitative analysis of the species, community structure, and living habits of the environment through identifying eDNA. It is a new monitoring and analysis technology advantageous in low cost, high efficiency, high sensitivity, and low interference to ecosystems. This paper reviews the related concept, technical process and analysis methods, and summarizes its advantages over traditional methods, focusing on the state of arts applications in invasive species monitoring, rare and endangered species monitoring, biomass estimation, biodiversity investigation, water quality and water pollution assessment, and river health assessment. We suggest some problems in the existing eDNA technology and potential directions for further studies.

Key words: eDNA technology, river ecosystem, biological survey, river health assessment, transport