Two different forms of mercury

SourcesUsed as a preservative in vaccines and medicinesFoods, particularly fish, and dental amalgam
Mercury concentration≤ 25 μg per 0.5 mL in some influenza vaccine productsHigher in larger fish: eg, 0.003 parts per million (PPM) in scallops vs 1.23 PPM in tilefish from Gulf of Mexico
Clearance from the human bodyRapidSlow, since it is not soluble and cannot be excreted
ToxicityRedness at injection site; no increased risk of autismCentral nervous system effects: eg, tremor, weakness, and behavioral changes