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Title: Survey of plutonium and uranium atom ratios and activity levels in Mortandad Canyon

Technical Report ·
DOI:https://doi.org/10.2172/541834· OSTI ID:541834
; ; ;  [1];  [2]
  1. Los Alamos National Lab., NM (United States)
  2. Science Applications, Inc., White Rock, NM (United States)

For more than three decades, Mortandad Canyon has been the primary release area of treated liquid radioactive waste from the Los Alamos National Laboratory (Laboratory). In this survey, six water samples and seven stream sediment samples collected in Mortandad Canyon were analyzed by thermal ionization mass spectrometry to determine the plutonium and uranium activity levels and atom ratios. By measuring the {sup 240}Pu/{sup 239}Pu atom ratios, the Laboratory plutonium component was evaluated relative to that from global fallout. Measurements of the relative abundance of {sup 235}U and {sup 236}U were also used to identify non-natural components. The survey results indicate that the Laboratory plutonium and uranium concentrations in waters and sediments decrease relatively rapidly with distance downstream from the major industrial sources. Plutonium concentrations in shallow alluvial groundwater decrease by approximately 1,000-fold along a 3,000-ft distance. At the Laboratory downstream boundary, total plutonium and uranium concentrations were generally within regional background ranges previously reported. Laboratory-derived plutonium is readily distinguished from global fallout in on-site waters and sediments. The isotopic ratio data indicate off-site migration of trace levels of Laboratory plutonium in stream sediments to distances approximately two miles downstream of the Laboratory boundary.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
541834
Report Number(s):
LA-13379-MS; ON: DE98000767; TRN: 98:008517
Resource Relation:
Other Information: PBD: Oct 1997
Country of Publication:
United States
Language:
English