Half-Life, Effective 2 : The time required for a radionuclide contained in a biological system, such as a human or an animal, to reduce its activity by half as a combined result of radioactive decay and biological elimination.
US Army Center for Health Promotion and Preventive Medicine CHPPM, TG 204 Glossary of Terms For Nuclear, Biological, and Chemical Agents And Defense Equipment (Section 3 - Nuclear Terms), MD, USA 2001. http://www.au.af.mil/au/awc/awcgate/army/tg204.pdf , (Def Equip/ Nucl Terms - Amer) {488}
Madison County North Carolina Government, Madison County Emergency Operations Plan Glossary (Section 3: Nuclear Terms), NC, USA 2009. http://www.madisoncountync.org/eop/Madison_EOP_PDF /Glossary.pdf, (CBRNEmr - Amer) {875}