Natural and technologically enhanced radioactivity (NORM/TENORM) in soils, mining residues and waters of mining areas worldwide: a systematic review and multivariate synthesis of the 1976–2026 literature

Mining and mineral processing redistribute naturally occurring radionuclides and can generate technologically enhanced naturally occurring radioactive material (TENORM). A PRISMA 2020-guided systematic review of the 1976–2026 literature was combined with a quantitative, multivariate synthesis of activity concentrations reported in abstracts. Of 60,242 records from seven bibliographic sources, including the IAEA INIS database, and citation searching, 16,689 were eligible and 1308 studies from 103 countries provided 4532 values (4276 study-level records). In mining-impacted soils, geometric means of 226 Ra( 238 U), 232 Th and 40 K were 56.7, 38.1 and 306 Bq kg −1 ; medians exceeded the UNSCEAR world medians by 11% and 26% for 226 Ra( 238 U) and 232 Th, whereas 40 K was 18% lower. Uranium mining showed the highest soil 226 Ra( 238 U) (geometric mean 324 Bq kg −1 ) and tin/rare-earth/mineral-sand operations the highest 232 Th (78.9 Bq kg −1 ). The 232 Th/ 226 Ra( 238 U) ratio was lowest in phosphate and uranium operations (medians 0.30 and 0.56) and 0.7–1.4 in the other industries. After adjustment for industry, region and publication year, tailings and residues contained 6.6 times more 226 Ra( 238 U) than soils, and 31% of tailings records exceeded 1 Bq g −1 . Uranium exceeded the WHO drinking-water guideline (30 μg L −1 ; a yardstick for mine waters) in 45% of groundwater and 83% of mine-water records, and 53% of mine-water records exceeded 1 Bq L −1 of 226 Ra. The median outdoor effective dose from soils was 0.072 mSv y −1 . In this abstract-level dataset, the largest enhancements and guideline exceedances occurred in residues and mine waters and differed among industries; harmonised reporting would enable full-text meta-analysis.