GB/T 7468-1987 provides for cold Atomic absirption spectroscopy-tometry, AAS, for the determination of total mercury in water quality. It is based on the absorption characteristics of mercury atoms to specific wavelengths of light. The standard specifies the key parameters of the required instruments, such as cold atomic absorption spectrophotometer. Detailed description of the collection, storage and pretreatment steps of water samples to prevent mercury loss or pollution. Standardized test procedures, including instrument commissioning, standard Linear dispersion drawing and water sample determination. With this standard, the total mercury content in water quality can be accurately detected, providing important data support for water environment monitoring, water pollution prevention and control, and ensuring water quality safety.