Heavy Metals in the body. Transient Presence, Retention, and Durability of Retention (Deposition)
Heavy metals in the body turns out to be an entire field of science/medicine, and we are just now scratching the surface. I came to recognize this importance in treating GDD and looking at 24 hour urine reports in reports that list 20+ metals... Everyone has atleast 5 heavy metals (read 20) retained in their body, 100% have lead (Pb). These metals on their own have the prospect for Deposition Disease, and almost certainly they interact with each other in the patient's symptom complex.
The level of durability of presence of a heavy metal depends to a large extent on what it binds to in the body. In general binding to bone (as Gd and Pb do) results in durable deposition - that may mean durable for the life of the individual, and if in females deposition that can be transferred to the fetus (a sort of nasty reincarnation).
Before panicking too much, it is remarkable how the human body can manage corralling a fair amount of these potentially toxic substances and still be ok- the Storage Condition circumstance.
Being corralled into bone probably is the result of two processes (at least): 1. that the metal can substitute for Ca, passive deposition and 2. bone marrow infiltrate cells (cd 34+ circulating fibrocytes being one member, likely of 10 cell types [read 100]) corral them into bone, active deposition. My theory is that this active deposition is the last defense mechanism of the integrated host immune system: if the immune system can't kill, or eliminate (by kidneys, bile, bowel, lung, sweat, salivary secretions) the offending particles, then its last option is to corral it in a situation where it can cause the least harm - this is generally the skin and the bones.
One of the most common transient presence (I believe transient) is Bismuth, which patients acquire from products like Peptobismol that have been taken for GI upset. Again transience reflects that there is no natural effective binder in the body, and it gets (near) fully eliminated.
Other toxins may be neutralized by binding primarily in fat (this may include in neural tissue). Empirically fat-binding should be less permanent than bone, and can with some time be eliminated, over a course of 1 year or so.
Many toxins there is no molecule that can bind and remove it (yet). That is one of the (few) positives of having GDD - there is a binding agent that can remove it well (DTPA, in the future HOPO)... Almost all other drug toxicities do not have binding agents that can remove it. They get removed (hopefully) with the tincture of time, and other, not yet fully understood, strategies of the immune system (ignoring the toxin works for many- also ofcourse for Gd).