Ways mercury can enter people’s bodies
Spilled elemental mercury evaporates into the air and becomes an odorless, colorless, toxic vapor. Elemental mercury that is breathed into a person’s lungs quickly moves into the bloodstream and is carried to the brain. Poor ventilation and heat can cause vapor levels to increase to dangerous levels in a very short time.
See the Mercury Vapor Experiment at Bowling Green State University video for a visual demonstration of mercury vapor.
If someone swallows elemental mercury very little is absorbed through the stomach and intestines into the bloodstream. However, methylmercury in fish is easily absorbed by the stomach and intestines into the bloodstream. It is carried by the blood to the brain and nervous system.
Very little elemental mercury is absorbed through the skin. The more serious risk is from the mercury vapor that can be breathed in. Playing with elemental mercury also increases the risk of an accidental spill which could become a long term source of mercury vapor.