Retention 5 : The amount of substance that is left of the deposited amount after a certain time. If the retention follows a course in relation to time that is a first-order process, it may be described in terms of biological half-life
International Programme on Chemical Safety IPCS (A joint venture of the United Nations Environment Programme UNEP, the International Labour Organisation, ILO and the World Health Organization WHO), Glossary of Terms on Chemical Safety for Use in IPCS Publications, World Health Organization, Division of Environmental Health, World Health Organization, Geneva, Switzerland, ILO 1996-2010. http://www.ilo.org/legacy/english/protection/safew ork/cis/products/safetytm/glossary.ht, (IPCS Chem Sfty - Brit) {103}