In some areas of Estonia, groundwater contains a significant number of natural radionuclides, especially radium isotopes, which may cause radiation protection concern depending on the geological structure of the aquifer. Indeed, the parametric value of 0.1 mSv y⁻¹ for the total indicative dose established by European Directive 98/83/EC, adopted as a limit value in Estonian national legislation,...

The interaction of surface water and groundwater is important in the ecology coastal basins, affecting hydrological conditions, oxygen regime, carbon, nutrient exchange. This study demonstrates a dynamic connection between salt-wedge region its underlying aquifer eutrophic estuary. In winter, this estuary covered with ice, river flow at lowest; that why specific response to discharge best marke...

Environmental radiation permeates space, air soil, and water around us. It has been naturally present since the birth of Earth about 4.65 billion years ago in a massive supernova explosion creating the heavy elements on earth and the other rocky planets Mars, Venus and Mercury. Consequently, life has evolved in the ashes and remnants of this explosion which were gravitationally grabbed in space...

Marie Curie gave outstanding contributions to science and society that were recognized still in her lifetime. In particular, the discovery of radium completely changed the therapeutic methods for treatment of cancer and other diseases, and allowed the development of radiotherapy and nuclear medicine. Radium was also used in many non-medical applications. Radium applications fostered the growth ...

Radioactive isotopes of strontium (59Sr and '*Sr) are generally regarded as the most dangerous of the products of nuclear fission. The passage of radiostrontium deposited on soil and vegetation into the human diet has therefore received considerable attention. Since strontium is similar to calcium in its metabolic behaviour it has become common practice to study the simultaneous behaviour ofthe...

The purpose of this study was to elucidate the processes controlling the distribution and behavior of the longerlived Ra isotopes in continuous Paleozoic carbonate aquifers of parts of Missouri, Kansas, and Oklahoma. Activities of (Ra) and (Ra) were analyzed in fresh and saline ground waters, brines, and rocks. The ̄uids have a wide salinity range (200±250,000 mg lÿ1 total dissolved solids). Th...

The radon isotopes (Rn-222 and Rn-220) and their progenies are responsible for more than 50% of natural radiation dose and the second leading factor in the case of the development of lung cancer after smoking [1]. Rn-222 (radon) and Rn-220 (thoron) are generated in crustal materials from their natural Ra-226 (U-238 decay series) and Ra-224 (Th-232 decay series) content, respectively. As a resul...

W ithin a decade of the discovery of radioactivity in 1896, the chemical elements uranium, radium, polonium, and thorium were recognized as radioactive; the basic theory, mechanisms, and mathematics of radioactive decay were established; decay rates of some radioactive chemical elements were determined; and the ages of two mineral specimens were calculated for the first time from their uranium ...