31. The primary risk from exposure to high levels of 131 I is the chance occurrence of radiogenic thyroid cancer in later life. 32. The primary risk from exposure to high levels of iodine-131 is the chance occurrence of radiogenic thyroid cancer in later life. 33. Radiogenic 107 Ag is a decay product of 107 Pd and was first discovered in 1978 in the Santa Clara meteorite of 1976.34. The evolution of Earth's radiogenic heat flow over time : contribution from 235 U in red and from 238 U in green 35. Other important examples of radiogenic elements are radon and helium, both of which form during the decay of heavier elements in bedrock. 36. The non-radiogenic Pb content in many laboratory tests were found to be very low, nearly always lower than 1 ppm. 37. This, thus, allows a different rate of radiogenic Sr to evolve in the separate rocks and their component minerals as time progresses. 38. The greater the initial concentration of the parent, the greater the concentration of the radiogenic daughter isotope will be at some particular time. 39. Radiogenic isotope tracers are most powerful when used together with other tracers : The more tracers used, the more control on mixing processes.40. Many radiogenic isotope measurements are made by ionization of a solid source, whereas stable isotope measurements of light elements ( e . g.
