Mercury does accumulate in the body but I was more pointing out that serum mercury levels can fluctuate greatly in a relatively short period. My mom eats a ton

Mercury does accumulate in the body but I was more pointing out that serum mercury levels can fluctuate greatly in a relatively short period. My mom eats a ton of that tuna from costco and had blood levels far above the reference range; which dropped into the reference range 4 months after consumption cessation. She saunas and exercises; so that may have something to do with it. I agree mercury is a bad example for the reason because the actual levels of mercury burden an individual carries can be nuanced (serum + housed into organs etc). I'm not sure I follow your final sentence.