Abstract Effective radium-226 concentration, EC Ra , is the product of radium activity concentration, C Ra , multiplied by the emanation coefficient, E , which is probability of producing a radon-222 atom in the pore spaces. It is measured by accumulation experiments in the laboratory, achieved routinely for a sample mass >50 g using scintillation flasks to measure the radon concentration. We report on 3370 EC Ra values obtained from more than 11 800 such experiments. Rocks ( n =1351) have a mean EC Ra value of 1.9±0.1 Bq kg −1 (90% of data in the range 0.11–35 Bq kg −1 ), while soils ( n =1524) have a mean EC Ra value of 7.5±0.2 Bq kg −1 (90% of data between 1.4 and 28 Bq kg −1 ). Using this large dataset, we establish that the spatial structure of EC Ra is meaningful in geology or sedimentology. For plants ( n =85), EC Ra is generally <1 Bq kg −1 , but values of larger than 10 Bq kg −1 are also observed. Dedicated experiments were performed to measure emanation, E , in plants, and we obtained values of 0.86±0.04 compared with 0.24±0.04 for sands, which leads to estimates of the radium-226 soil-to-plant transfer ratio. For most measured animal bones ( n =26), EC Ra is >1 Bq kg −1 . Therefore, EC Ra appears essential for radon modelling, health hazard assessment and also in evaluating the transfer of radium-226 to the biosphere.

For hundreds of millions of years, nature has governed the biogeochemical cycles that have shaped the diverse geology and biology of Earth, but now, within a few kilometers of the surface, where the cycles are most complex, humans are mining and redistributing material at such a rapid rate that many elements of the periodic table are already in crucially short supply, or they are under threat to become so in the next few decades. It is not just water and fossil fuels that are affected by our consumption. Top-down and bottom-up analyses make clear that many of the accessible elemental resources of our future are now largely aboveground, stored in the familiar objects of our daily lives. In order to maintain supply lines to industry and to the dinner table, and to preserve our place in the biosphere, biogeochemical cycles must produce as much useful resource as they consume. Doing so will require cross-disciplinary scientists, designers, social communities, and visionary entrepreneurs working together to completely reframe our concepts of mining, consumption, human environments, and waste.