Mercury (Hg)
| Atomic number: |
80 |
| Atomic weight: |
200.59 |
| Average concentration in ocean: |
700 fmol/kg |
| Residence time: |
350 years |
Distribution in ocean
Dissolved Hg has scavenged element vertical profile.
Concentrations are high at the surface, reflecting atmospheric input and they
decrease with depth as the dissolved mercury is sorbed on to sinking particles
and transported to depth (data).
Speciation
Dissolved mercury is present in seawater in the +II oxidation state as the HgCl42-
ion and as organic mercury compounds such as methyl mercury (CH3Hg).
Residence time
The mercury esidence time was calculated from the global average river input
(Gill and Fitzgerald, 1988).
Analysis
Mercury is determined by atomic fluorescence after preconcentration by sorbing
mercury to a gold matrix and then thermally desorbing it.
References