What does the U.S. Environmental Protection Agency (EPA) say about mercury?

The following information comes from the U.S. EPA website. Italicized text has been added by the staff at BanCFLs.com for clarification purposes.

Mercury exists in three forms: elemental mercury (elemental mercury is the type used in the production of compact fluorescent lights), inorganic mercury compounds (primarily mercuric chloride), and organic mercury compounds (primarily methyl mercury). All forms of mercury are quite toxic, and each form exhibits different health effects.

What is elemental mercury used for?

Elemental mercury is used in thermometers, barometers, and pressure-sensing devices. It is also used in batteries, lamps (such as cfls), industrial processes, refining, lubrication oils, and dental amalgams (used for fillings).

What are the sources and potential exposure to elemental mercury?

A major source of exposure for elemental mercury is through inhalation in occupational settings.

What are the health hazards related to elemental mercury

• Acute Effects
  • The major systems impacted by human inhalation of elemental mercury are the kidneys and central nervous system (CNS). Acute exposure to high levels of elemental mercury in humans results in CNS effects, such as tremors, irritability, insomnia, memory loss, neuromuscular changes, headaches, slowed sensory and motor nerve function, and reduction in cognitive function.
  • Acute inhalation exposure of humans to high concentrations has resulted in kidney effects ranging from mild transient proteinuria to acute renal failure.
  • Gastrointestinal effects and respiratory effects, such as chest pains, dyspnea, cough, pulmonary function impairment, and interstitial pneumonitis have also been noted from human inhalation exposure to elemental mercury.
• Chronic Effects (Noncancer):
  • The CNS is the major target organ for elemental mercury toxicity in humans. Effects noted include erethism (increased excitability), irritability, excessive shyness, insomnia, severe salivation, gingivitis, and tremors.
  • Chronic exposure to elemental mercury also affects the kidney in humans, with the development of proteinuria.
  • Acrodynia is a rare syndrome found in children exposed to elemental mercury compounds. It is characterized by severe leg cramps, irritability, paresthesia (a sensation of prickling on the skin), and painful pink fingers and peeling hands, feet, and nose.
  • EPA has not established a Reference Dose (RfD) for elemental mercury.
  • The Reference Concentration (RfC) for elemental mercury is 0.0003 milligrams per cubic meter (mg/m3)based on CNS effects in humans. The RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious noncancer effects during a lifetime. It is not a direct estimator of risk but rather a reference point to gauge the potential effects. At exposures increasingly greater than the RfC, the potential for adverse health effects increases. Lifetime exposure above the RfC does not imply that an adverse health effect would necessarily occur.
  • EPA has medium confidence in the RfC due to: (1) medium confidence in the studies on which the RfC was based because while there were sufficient number of human subjects and appropriate control groups, exposure levels in a number of the studies had to be extrapolated from blood mercury levels; and (2) medium confidence in the database due to a lack of human or multispecies reproductive/developmental studies.
• Reproductive/Developmental Effects:
  • Studies on the reproductive and developmental effects of elemental mercury in humans have shown mixed results. One study did not see an association between mercury exposure and miscarriages, while another revealed an increase in the rate of spontaneous abortions. Another study showed a higher than expected frequency of birth defects, which was not confirmed in a fourth study.
• Cancer Risk:
  • Several studies have been carried out regarding elemental mercury and cancer in humans. These studies are inconclusive due to lack of valid exposure data and confounding factors.
  • EPA has classified elemental mercury as a Group D, not classifiable as to human carcinogenicity, based on inadequate human and animal data.