8Th International Symposium on Natural Radiation Environment, Date: OCT 07-12, 2007, Location: Buzios, BRAZIL, Sponsors: Nat Radiat Environm Assoc, Brazilian Phys Soc, Int Atom Energy Agcy, Brazilian Petroleum Co, Vale Rio Doce Co, ELECTRONUCLEAR, Brazilian Nucl Ind, Brazilian Council Sci & Technol Dev, Inst Radioprotect & Dosimetry, Brazilian Nucl Energy Commiss, Brazilian Commiss Improvement Personnel Higher Educ, Carlos Chagas Fdn Res Support Rio De Janeiro, Univ States Rio de Janeiro