The invention discloses a method for determining an N-DAMO (
nitrite-dependent anaerobic
methane oxidation) rate, belongs to the field of environmental research, and discloses a method for determining an N-DAMO rate of soil, sediments or
activated sludge by using an
isotope tracer technique. The method disclosed by the invention comprises a sample mixing and subpackaging device, an anaerobic environment creation device and an anaerobic environment creation method, a method for pretreating samples before being determined, and a sample determining and calculating method. Under the conditions of high-purity
helium protection, samples are uniformly mixed and subpackaged, and then an anaerobic environment is created by using a high-purity
helium to blow the sample mixture. After residual NO2<->, NO3<-> and O2 in a
reaction system are consumed by pre-culturing, an
electron acceptor and a labeled substrate <13>C-CH4 are added into a reactant, and by measuring the contents of <45>CO2 generated by reacting at different time nodes, an N-DAMO rate is calculated. According to the method, equipment is simple and the operation is easy, and a strict anaerobic environment can be created without being operated in an anaerobic tank. An N-DAMO rate is calculated by labeling a reaction substrate by using an
isotope and determining a labeled product, and the calculation of the N-DAMO rate is not affected by other physical and chemical changes.