Low Levels Environmental

["Hooda, Benny" <HoodaB@wipp.carlsbad.nm.us>]

Hi,
I need peer opinion on very low levels of environmental activity where the
results reported are mostly negative concentrations. The DOE/EH 0173T,
"Environmental Regulatory Guide for Radiological Effluent Monitoring and
Environmental Surveillance" , section 7.3.4, states that less- than-
detectable values and negative values have to be included in the data
evaluations, and assigning zero, detection limit, or some in between value
would "severely" bias the resulting estimates and should be avoided.
Therefore, I have been including these negative values in the statistical
analyses. However, I am being asked to use the MDA instead of negative
values. What's your input?

Secondly, NCRP 50, section 4.5.4, says that plutonium presently in the
environment is mostly Pu-239, (or definitely higher than Pu-238) so if the
concentration of Pu-238 reported by the laboratory is about three times
higher than Pu-239 (with no other known source) then after investigation and
all other sample results below detection limit, it can safely be concluded
that it was an "analytical artifact". Are there any suggestion on what to
call these kind of anomalous results because " analytical artifact" does not
sound right to some people, as well as, is this "flawed logic"?
Thanks for your help. 

"Sometimes deepness is a surface. If that weren't true, we would have no
need for mirrors"( by Ray Bradbury).


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Benny Hooda
Westinghouse Electric Corporation
WIPP
P.O.Box 2078 M/S 910-20
Carlsbad, NM 88221
(505)234-8932 Voice
(505)885-0974 Fax
Hoodab@WIPP.Carlsbad.NM.US
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