IMO, part of the problem here is the use of the word "accumulates." There are chemical and cellular cycles in the body like the Krebs cycle, and they either work normally and efficiently, or something interferes w/ them, disrupts them or slows them down. When they're disrupted and slowed down, the raw materials i.e. the "reactants" back up and wait longer than normal to be turned into "products." So they're not being stored/accumulating in the way mercury or silver would accumulate, i.e. by being deposited into fat tissue or elsewhere, but there is a glut or logjam as they wait to be processed.