Sea salt is a popular substitute for table salt because it contains less sodium and additional minerals, such as potassium, calcium and magnesium. Mercury is a heavy metal that is toxic to humans. Mercury is contained in sea salt, but its concentration and associated health risks depend on the source of the sea salt and the amount you consume. Consult your doctor about the risks of consuming mercury in sea salt.
Sea Salt
Sea salt comes from sea water or oceans. According to the National Ocean Service, seas are found on the margins of oceans and are partially enclosed by land, whereas oceans are not enclosed by land. Salts, such as magnesium sulfate, calcium chloride and sodium chloride, originate in rocks. Salts are washed into seas and oceans by weathering, a process that breaks down minerals in rocks to salts that dissolve in water from streams and rivers, which in turn carry minerals into seas and oceans. The concentration of salts and minerals in sea water and ocean water vary. For example, Dead Sea water contains 32 percent salts, compared with ordinary sea water that contains only 3 percent salts, and water from the Dead Sea contains a much higher concentration of minerals, such as chloride, magnesium, sodium, calcium, potassium and bromide, compared with Mediterranean Sea water or ocean water.
Mercury Types
Mercury exists in three forms: elemental or metallic, inorganic, in which it combines with other elements, such as chlorine or oxygen, and organic, where it combines with carbon-containing substances, such as methane to form methylmercury. Methylmercury is the form most frequently found in oceans, seawater and sea salt. In addition to weathering, mercury enters and accumulates in the oceans and seas by falling from the air. Bacteria in the water can transform mercury into methylmercury.
Health Risks
The Environmental Protection Agency reports health risks from consuming products containing methylmercury. Methylmercury can be lethal in doses between 20 to 60 mg per kg. The most common effect from methylmercury is damage to your central nervous system, which includes your brain. Early side effects from methylmercury consumption are blurred vision, skin numbness and depression. As mercury levels build up in your body you can experience speech difficulties, impaired vision and deafness. Exposure to methylmercury can cause birth defects of the central nervous system, resulting in mental retardation, blindness, deafness and cerebral palsey. Methylmercury may also cause cancer.
Considerations
There are no published studies demonstrating harm from consuming sea salt that contains methylmercury. Nonetheless, health risk increases as the quantity of methylmercury consumed increases. Sea salt that originates from water with higher levels of mercury is more likely to contain higher levels of mercury than sea salt that originates from water with lower levels of mercury. Coastal marine systems, such as in the Arctic region, is more vulnerable to higher concentrations of mercury than inland water systems, according to research by scientists at the University of Montreal in Quebec, Canada, and published in "Environment Science and Technology" in March 2007.
References
- National Ocean Service; In Terms of Geography, a Sea Is Part of the Ocean Partially Enclosed by Land; April 19 2011
- Cornell University; Earth's Rinsing Process Creates the Salt of the Ocean; 2011
- Dead Sea Research Center; The Natural Resources; 2011
- Occupational Safety and Health Administration; Mercury; 2011
- United States Environmental Protection Agency; Consumption Advice: Joint Federal Advisory for Mercury in Fish; 2004
- Environmental Protection Agency; Mercury Compounds; November 6, 2007
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