The mercury was 3 poisonings, 4 if you include the 45 x normal galvanic reaction's gas release in my mouth for 20-odd years.
The other 3 heavy metals were when I copped all 5 that were used in batteries back in the day - lead, mercury, antimony, arsenic and cadmium. That makes me realise that it was lead twice and mercury 4 times. Forgot about that one.
The first mercury was a vial I absorbed through my skin over 2-3 years. Stole it as a kid from the science lab in junior school. Played with it every day in my hands 'till it had all absorbed. Had no idea it was anything more than a bit poisonous.
Second mercury was licking batteries. Did it a lot to test charge (no money). That's when I copped the other metals as well, lead for a 2nd time.
Third mercury was my amalgam fillings. They reacted and released 45 x the normal amount of gas into my system (measured before eventual removal). Took me 20 years to convince a dentist to take the job on. Up until that time (during the '90s) they just laughed at me.
Fourth mercury was when they were finally removed. The dude didn't put a plastic barrier in, exposing just the teeth involved. 4 sessions of drill, rinse and spit. Swallowed a crapload of swarf. 3 months later the chronic fatigue and autoimmune hit me hard.