Research on the application of soluble, metal chelates for
water tracing using thermal neutron activation analysis for tracer
determination has led to the development of several tracers with
promising solution stabilities (conservative behavior) and determination sensitivities. The solution stabilities of the ethylenediamine
tetraacetic acid (EDTA) and the diethylenetriamine pentaacetic acid
(DTPA) chelates of the activable elements Cr, Co, Eu, In, Sb, Sc
and Tb were evaluated in a series of laboratory, radiotracer experiments
conducted under simulated field conditions. They showed that
1) chelation of metals produces highly conservative solution behavior,
2) DTPA is generally better than EDTA for improving tracer behavior,
3) non-chelated metals are rapidly sorbed onto sediments and
4) chelation reduces sorption of metals onto sediments.
Field tests of EuDTPA, TbDTPA, InDTPA and Rhodamine B
fluorescent dye in a small eastern Washington stream demonstrated
that the metal chelates have significantly improved solution stabilities
in natural water compared to widely used Rhodamine B. Minimum
detection levels in natural waters for the activable tracers were determined
to be 0.075 ppb for Eu, 0.10 ppb for Tb and 0.55 ppb for In
in comparison to 0.49 ppb for Rhodamine B. Associated determination
uncertainties (one standard deviation) amount to ±12% for Eu at
12 ppb, ±12% for Tb at 13 ppb, and ±13% for In at 10 ppb compared
to ±7.3% for Rhodamine B at 1-10 ppb. Activation procedures are
feasible which decrease the minimum detection levels to 0.0015 ppb
for Eu, 0.0019 ppb for Tb and 0.0057 ppb for In in comparison to
0.075 ppb for Rhodamine B.
Anion-exchange proved uniquely suited for recovery and concentration
of metal-chelate tracers from natural water and as a low
background irradiation and counting matrix. A method evaluation
and economic analysis clarify the potential application of activable
metal chelates for water tracing. / Graduation date: 1970
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29002 |
| Date | 20 October 1969 |
| Creators | Hanson, Peter James |
| Contributors | Osterberg, Charles L. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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