Mercury (Hg), atomic number 80, is unique among metals. It is the only metallic element that exists in a liquid state at standard room temperature and pressure. Known as “quicksilver” for its fluid movement, mercury historically found applications in ancient remedies and scientific instruments.
Understanding Mercury’s Phase Changes
Mercury evaporates even below its boiling point, releasing an invisible, odorless vapor at room temperature. While the rate of evaporation is slow at typical room temperatures, any increase in temperature significantly accelerates this process. The boiling point of mercury is approximately 356.7 degrees Celsius (674.1 degrees Fahrenheit). Conversely, mercury freezes into a solid at about -38.83 degrees Celsius (-37.89 degrees Fahrenheit). This wide range between its freezing and boiling points contributes to its utility in devices like thermometers and barometers.
Health Implications of Mercury Vapor
The evaporation of mercury into vapor is a significant concern due to its toxicity. When inhaled, mercury vapor is readily absorbed into the bloodstream, with absorption rates estimated between 69% and 85% in adults. Once in the body, elemental mercury can cross the blood-brain barrier, leading to its accumulation in the central nervous system.
Exposure to mercury vapor can lead to a range of health issues, affecting multiple organ systems. Short-term, high-level exposure can cause immediate symptoms such as tightness in the chest, a burning sensation in the lungs, coughing, and nausea. Prolonged or chronic exposure, even to small amounts, can result in neurological damage, manifesting as tremors, memory problems, irritability, and difficulties with coordination. Kidney damage and respiratory issues are also consequences of mercury vapor exposure.
Safe Handling and Exposure Prevention
Common household items can contain mercury, posing potential exposure risks if mishandled. These sources include older thermometers, fluorescent light bulbs, some electrical switches, and certain dental fillings. Proper handling and disposal are crucial for safety.
If an item containing mercury breaks, specific steps should be followed to prevent exposure. Ventilate the area by opening windows and doors. Avoid direct skin contact; wear gloves during cleanup.
Cleanup should involve using stiff paper or cardboard to gently push mercury beads together, then using an eyedropper or sticky tape to collect them. Never use a vacuum cleaner or broom, as this spreads mercury and increases vapor levels. All collected mercury and contaminated materials, including cleanup tools and gloves, should be placed in sealed plastic bags and disposed of according to local hazardous waste regulations.