Q:In junior high school, our science teacher demonstrated the difference between the surface tension of water and that of mercury by letting us dip our finger in a small container of mercury. I am not sure what compound of mercury was used. I probably did this 3 or 4 times (for about a second each time) over a couple of years (he performed the same demonstration each year, I recall). I don't remember whether we washed our hands afterward or not. This was 32 years ago. Should I be concerned at this point for any harmful long-term sequelae from this "experiment"? Also, aside from insanity, what other neurological effects have been linked to mercury exposure? One of my classmates died from multiple sclerosis four years ago, after an illness of only three years. Could this have been linked to mercury exposure (assuming she also dipped her finger in this)?

R:

You have nothing to worry about. Your teacher did not use a compound of mercury. It was probably pure mercury metal. Exposure of a second or two is totally insignificant. People who get sick from mercury poisoning are exposed for hours and hours over many days and even years. Metallic mercury which you touched is not such a big deal. The bigger problem is with organomercury compounds. That is: mercury that has combined with carbon and other elements to form larger molecules that are biologically active. Mercury has to be vaporized and inhaled to become a problem to humans. You were not exposed in this way.

The relationship between mercury and multiple sclerosis has not been demonstrated scientifically. In fact it is a false idea that is used by quacks to sell unnecessary medical and dental treatments that are not needed. Read this report on QuackWatch.