Polonium (Po)
| Atomic number: |
84 |
| Atomic weight: |
[210] |
| Average concentration in ocean: |
30 zmol/L |
| Residence time: |
100 years |
Distribution in ocean
Polonium is a radioactive element. The major isotope is 210Po
(half-life 138 days), produced by the decay of 210Pb, a daughter
product of primordial 238U. The polonium vertical
concentration profile
generally mimics that of 210Pb. The isotopes are close to
secular equilibrium, except in surface waters
where scavenging removal of Po removes it faster than Pb (data).
Note: 1 zeptomol (zmol) = 10-21
mol
Speciation
Polonium is present in the +IV
oxidation state as Po(OH)40.
Residence time
The residence time was estimated by analogy to Pb and Te.
Analysis
210Po is determined by a-counting after
preconcentrating the isotope from large volumes by precipitation.
References & Notes