Uranium and radium are present in soil, rocks, water and building materials, therefore the presence of 222Rn in the air is natural, and its concentration is determined mainly by physical factors such as soil cover, altitude, porosity and soil particle size, and meteorological conditions. In rooms with poor ventilation,222Rn can accumulate to high concentrations, which increases the risk of developing lung cancer due to continuous exposure to this gas. In this work,222Rn was monitored, with the aid of a real-time radon monitor, RAD7, in offices and rooms at Hospital Universitário Antônio Pedro in order to evaluate the levels of 222Rn to which people are exposed. In general, the values measured in this work are similar to values observed in other studies around the world. The obtained 222Rn level of 40 Bq m-3 is close to the world average of 37 Bq m-3 defined by the United States Environmental Protection Agency (US EPA).

The aim of this review is to take a look at Cold War era nuclear tests signatures found in Brazilian coastal sediments. Both137Cs and 240+239Pu signatures have been documented in mangrove, coastal mudflats and continental shelf sediments, associated with above ground nuclear tests beginning in the 1950's. The dates associated to the anthropogenic radionuclide signatures 137Cs and 240+239Pu along sediment columns are confirmed by 210Pb geochronology in many of the studies highlighted in this review. The results outlined in this review characterize the extent to which nuclear fallout products reach the Brazilian coast in quantities sufficient for detection, allowing the use of these radioisotopes as geochronometers.