Mercury Speciation and Fractionation

There are many potential environmental sources of mercury including mining, explosive manufacture, dye manufacture, dentistry and even herbicides. These activities can release mercury in to the environment in a variety of forms: elemental mercury, inorganic mercury (Hg(I), Hg(II)) and organo-mercury species (e.g. methyl mercury, ethyl mercury etc.).

Inorganic mercury salts are soluble in water and this allows them to be readily absorbed into the body through the gastrointestinal tract. Once absorbed they can cause severe kidney damage, however they cannot cross the blood-brain barrier easily and as a result exposure to inorganic mercury tends to cause little neurological damage unless there is prolonged or heavy exposure.

Conversely, organo (methyl) mercury is a form of toxic mercury which bioaccumulates through the food chain and the primary exposure route for humans is through the consumption of fish. Organic methyl mercury can cross the blood-brain barrier and is a neurotoxin. Mercury poisoning of this type was seen in Japan, in the Minamata bay area – and hence this kind of mercury poisoning is widely known as Minamata disease.

Elemental mercury (Hg0 liquid mercury) is a different form of mercury with a different pathway into the human body – typically through vapour inhalation into the lungs.

i2 Analytical are able to offer the following breakdown to meet the requirements of customer exposure modelling requirements:
• Total Mercury (Aqua Regia Extractable) (MCERTS)
• Inorganic mercury
• Organo mercury compounds including Methyl Mercury
• Elemental mercury

Additionally, a further detailed breakdown is available which may be of use on specific sites and contamination sources.

FractionDescriptionTypical Compounds
F1Water solubleHgCl2
F2Weak acidHgO
F3Organo- complexedHg-humic
F4Strongly complexed
(Mineral lattice)

F5Mineral boundHgS