The ISO 20899 standard specifies a test method for the determination of plutonium (Pu) and neodymium (Np) in water quality using Inductance Coupled Plasma Mass Spectrometry (ICP-MS). This method is suitable for the quantitative analysis of trace amounts of plutonium and neodymium isotopes in water quality monitoring and is widely used in the fields of environment monitoring, nuclear energy and radioactive waste treatment. Through ICP-MS technology, this method can accurately and sensitively detect the content of plutonium and neodymium in water samples, which helps to assess the radioactive contamination of water bodies and ensure the safety of water quality and the sustainability of the environment.