Mercury (Hg) is one of earth's least abundant elements. It exists as an inorganic salt or as an organic compound (methyl mercury).

As its Latin/Greek original name implies, mercury is a silver, runny liquid. Mercury is the only element that is liquid at standard conditions for temperature and pressure.

It is the inorganic type that is detected in drinking water. Organic mercury is found in fish and comes from industrial manufacturing waste.

Inorganic mercury, if ingested, usually settles in the kidneys; organic mercury attacks the central nervous system.

• Inhalation of metallic mercury vapor, dermal application of medicinal products containing inorganic mercurous salts and ingestion of seafood contaminated with methylmercury have been known to cause neurological and behavioral disorders, such as: Hand tremors, irritability, shyness, changes in vision or hearing and memory problems.
• Short-term exposure to mercury may cause lung damage, nausea, diarrhea, increases in blood pressure or heart rate, skin rashes and eye irritation.
• Children of mothers who have been exposed to mercury have exhibited delays in motor and verbal development as well as severe brain damage.
• Mercury also has negative effects on the liver, immune system and reproductive organs.

The Factory to Fish to Fisherman Mercury Cycle

The MCL set by the EPA for mercury is 0.002 mg/L.

Treatment: Mercury is easily removed from water by activated carbon filtration. Reverse osmosis removes 95 to 97% of it.

Here are the leading treatment methods, according to Water Technology magazine:

• Both inorganic and organic mercury can be reduced in water with distillation, reverse osmosis and ion exchange.
• The activated carbon, specialty media adsorption and filtration products, such as solid block and adsorption filter, are also effective.
• EPA has approved the following methods for removing mercury from drinking water: Coagulation/filtration, granulated activated carbon, lime softening and reverse osmosis.
• Sulfide precipitation is a common method for removing inorganic mercury from wastewater.
• Starch xanthate is an alternative adsorption material to activated carbon.