Sources and sinks of [sup 210]Pb in Concepcion Bay, Chile
The sources and sinks of [sup 210]Pb to Concepcion Bay waters were evaluated to discern the relative importance of the main removal and supply mechanisms of this radionuclide to the waters of Concepcion Bay. The main inputs of [sup 210]Pb are the atmospheric supply and the advection of offshore upwelling waters. The atmospheric input was measured in precipitation using a collector and inventories of excess [sup 210]Pb in Rocuant and Raqui marsh sediments. The average atmospheric supply of [sup 210]Pb for Concepcion area is about 0.3 dpm cm[sup [minus]2] yr[sup [minus]1]. The advective input from upwelling varies from 0.6 [+-] 1.3 to 2.1 [+-] 2.0 dpm cm[sup [minus]2] yr[sup [minus]1]. [sup 210]Pb is removed efficiently from the water column as shelf water with high [sup 210]Pb content crosses the continental shelf off Concepcion Bay, with [sup 210]Pb/[sup 226]Ra activity ratios decreasing by a factor of 3 to 4 before reaching the interior of the bay. This is coincident with an increase of suspended matter concentration towards inside the bay. The main removal of [sup 210]Pb from Concepcion Bay waters is deposition in sediments. There is an increase of the [sup 210]Pb inventories toward the bay entrance excess (by a factor of 2) and outside the bay sediments (by a factor of 7). This pattern can be explained by an increase of mixing of sediments by the benthic infauna and enhanced removal of [sup 210]Pb from the water column by particles near the bay mouth. Mass balance calculations are included. The residence time of [sup 210]Pb with respect to removal from water column is estimated to be 17 to 43 days. The results of this research indicate that [sup 210]Pb and probably other similar particle-reactive contaminants (such as heavy metals) are retained and redistributed inside the bay by circulation, resuspension and biological mixing.
- Research Organization:
- State Univ. of New York, Stony Brook, NY (United States)
- OSTI ID:
- 7285651
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Unusually large sup 210 Po deficiencies relative to sup 210 Pb in the Kuroshio Current of the East China and Philippine seas
The fate of particle-reactive radionuclides on the Amazon and Yangtze continental shelves
Related Subjects
CHILE
AIR POLLUTION
COASTAL WATERS
LEAD 210
DEPOSITION
ECOLOGICAL CONCENTRATION
BAYS
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DEVELOPING COUNTRIES
EVEN-EVEN NUCLEI
HEAVY NUCLEI
ISOTOPES
LATIN AMERICA
LEAD ISOTOPES
NUCLEI
POLLUTION
RADIOISOTOPES
SOUTH AMERICA
SURFACE WATERS
YEARS LIVING RADIOISOTOPES
540330* - Environment
Aquatic- Radioactive Materials Monitoring & Transport- (1990-)