Becquerel Becquerel The becquerel (; symbol: Bq) is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The becquerel is therefore equivalent to an inverse second, s. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity. As with every International System of Units (SI) unit named for a person, the first letter of its symbol is uppercase (Bq). However, when an SI unit is spelled out
Environmental radioactivity Environmental radioactivity Environmental radioactivity is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 (Sr) and technetium-99 (Tc), are only found on Earth as a result of human activity, and some, like potassium-40 (K), are only present due to natural processes, a few isotopes, "e.g." tritium (H), result from both natural processes and human activities. The concentration and location of some natural isotopes, particularly uranium-238 (U), can be affected by human activity. Radioactivity is present everywhere, and has been since the formation of the earth. According to the IAEA, soil typically contains the following four