NORM survey within the second census on pollution sources in China.

The Second Census of Pollution Source in China was conducted from 2017 to 2020, and the radioactive target in this census was Naturally Occurring Radioactive Material (NORM).The census plan for the radioactive component was prepared by the Nuclear and Radiation Safety Centre of the Ministry of Ecology and Environment in accord with the work requirement of the overall census. The work steps involved in performing the census included establishing the organization structure, document formulation, conducting a pilot survey, relevant training, screening of preliminary survey data, quality assurance, detailed data collection and analysis, data verification and reporting, and final summarizing. The survey mainly involved 15 kinds of NORM industries, which include the rare earth, niobium/tantalum, zircon, zirconia and tin industries, etc. Almost 30,000 enterprises were investigated in the screening phase, and nearly 2000 enterprises were determined to satisfy the screening criteriafor the presence of NORM. A total of 3500 samples including discharge water, raw ore, milling ore and solid waste were obtained and measured resulting in about20,000 individual datum. The Nuclear and Radiation Safety Centre of the Ministry of Ecology and Environment had responsibility for the NORM census and has completed a comprehensive statistical analysis of the data including analysis of the characteristics from different perspectives.