Grantee Research Project Results
Distribution of Cs-137 in the Lena River Estuary-Laptev Sea System as Evidenced by Marine, Estuarine, and Lacustrine SedimentsEPA Grant Number: U915134
Title: Distribution of Cs-137 in the Lena River Estuary-Laptev Sea System as Evidenced by Marine, Estuarine, and Lacustrine Sediments
Investigators: Pyrtle, Ashanti J.
Institution: Texas A & M University
EPA Project Officer: Manty, Dale
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Fellowship - Oceanography , Academic Fellowships , Aquatic Ecosystems
The goal of this research project was to examine geochemical and physical processes that have led to the enrichment of 137Cs-137 in Lena River estuary sediments. Geochemical and physical factors examined in this investigation include mineralogy, sediment chemistry, particle transport mechanisms, and sea-ice related processes.Approach:
Surface Cs-137 activity was determined for all samples. Chemical, mineralogical, and grain-size compositions were obtained for a subset of samples, in order to determine if the distribution pattern of Cs-137 was the result of geochemical factors influencing the adsorption/desorption process of Cs-137 onto the sediment particles. Cs-137 inventory values for several cores also were also obtained. By comparing the analytical results of the marine, estuarine, and lacustrine samples, conclusions were drawn concerning the distribution pattern and the source(s) of Cs-137 in this Arctic environment. Excess Pb-210 analysis was conducted on a subset of samples, allowing conclusions to be drawn concerning particle deposition and/or removal via riverine discharge and sea-ice related processes. The Cs-137 and excess Pb-210 activities were determined using a germanium well detector and a lithium-germanium planar detector, respectively. The chemical composition of a subset of samples was obtained using x-ray fluorescence and neutron activation techniques. The mineralogical and grain-size distributions were determined using x-ray diffraction and pipetting techniques, respectively. A mathematical model was used to determine particle mixing and burial rates.Supplemental Keywords:
fellowship, Lena River Estuary, estuary sediments, marine, estuarine, lacustrine, sediment particles, particle deposition, sea-ice related processes, Arctic.