Two different forms of mercury
| Ethylmercury | Methylmercury | |
|---|---|---|
| Sources | Used as a preservative in vaccines and medicines | Foods, particularly fish, and dental amalgam |
| Mercury concentration | ≤ 25 μg per 0.5 mL in some influenza vaccine products | Higher 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 body | Rapid | Slow, since it is not soluble and cannot be excreted |
| Toxicity | Redness at injection site; no increased risk of autism | Central nervous system effects: eg, tremor, weakness, and behavioral changes |