Biogeochemistry of (210)Pb and (210)Po in fresh waters and sediments. Doctoral thesis

Technical Report · Wed Jun 01 00:00:00 EDT 1988

OSTI ID:5608186

Benoit, G

The geochemical cycling of (210)Pb in a Massachusetts lake was studied. A mass balance for the epilimnion showed that (210)Pb inputs by precipitation were matched by outputs on settling particles, so direct uptake by bottom sediments was inconsequential. Below the epilimnion, vertical mixing was very low because of a steep temperature/density gradient, and this limited vertical transport. Anoxic conditions caused remobilization of iron and (210)Pb, which reprecipitated at the oxycline and returned to the bottom via settling. Below the zone of precipitation, (210)Pb and iron distributions resulted from constant release from anoxic sediments and dilution in the water column. Sediment (210)Pb distributions were caused by sedimentation and Fickian transport. The Fickian component was equal to the pore water diffusive flux. In pore waters, (210)Pb and (210)Po were 100 times greater that in overlying water and had steep concentration gradients, unlike Fe, Mn, S(-II), and alkalinity. (210)Pb partition coefficients decreased from 15000 to 1500 with depth controlled by sorption on iron oxides. Remobilization to the water column comes from a thin layer of iron-rich floc near the sediment/water interface. Deeper in the cores, diffusive transport can cause redistribution of (210)Pb to an extent that can affect (210)Pb dating.

• Research Organization: Woods Hole Oceanographic Institution, MA (USA)
• OSTI ID: 5608186
• Report Number(s): PB-89-198097/XAB; WHOI-88-26; TRN: 91-010987
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
FRESH WATER
RADIONUCLIDE MIGRATION
LEAD 210
BIOGEOCHEMISTRY
POLONIUM 210
SEDIMENTS
AGE ESTIMATION
GEOCHEMICAL SURVEYS
PARTITION FUNCTIONS
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ENVIRONMENTAL TRANSPORT
EVEN-EVEN NUCLEI
FUNCTIONS
GEOCHEMISTRY
HEAVY NUCLEI
HYDROGEN COMPOUNDS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEAD ISOTOPES
MASS TRANSFER
NANOSEC LIVING RADIOISOTOPES
NUCLEI
OXYGEN COMPOUNDS
POLONIUM ISOTOPES
RADIOISOTOPES
SURVEYS
WATER
YEARS LIVING RADIOISOTOPES
520300* - Environment
Aquatic- Radioactive Materials Monitoring & Transport- (1989)