The sum of exposures of an organism to a pollutant over a period of time. [USEPA, 1997a: EPA Terms of Environment] "Glossary of Exposure Assessment Related Terms: A Compilation". Prepared by the Exposure Terminology Subcommittee of the IPCS Exposure Assessment Planning Workgroup for the International Programme on Chemical Safety Harmonization of Approaches to the Assessment of Risk from Exposure to Chemicals, November 1, 2001