Body burden

The total amount of a specific substance (for example, lead) in an organism, including the amount stored, the amount that is mobile, and the amount absorbed. The amount of a chemical stored in the body at a given time, especially a potential toxin in the body as the result of exposure. The concentration or total amount of a substance in a living organism; implies accumulation of a substance above background levels in exposed organisms.

http://www.epa.gov/oswer/riskassessment/glossary.htm#b http://sra.org/resources_glossary_a-c.php