HomeMy WebLinkAboutDERR-2024-007791TRACE LEVEL SELENIUM ANALYSIS
IN HIGH BRINE MATRIX
Lynn Hutchinson
Environmental Laboratory Director
Kennecott Central Laboratory
Kennecott’s Environmental Lab
n A NELAC Certified Laboratory
n A Utah State Certified Laboratory
n American Industrial Hygiene Accredited
n CLEA Licensed
n USGS SRM Audit Series
Laboratory
Instrumentation
Trace Metal Analysis of
Great Salt Lake Waters
n In the early 1970s, Kennecott recognized that
clean water analytical methods were not
appropriate for GSL brines
n Specialized procedures were required for
analysis of GSL samples—especially for
trace metals
n Results of analytical work were published in
several peerreviewed articles by
Paul Tayler, Lynn Hutchinson, & Melvin Muir
Analysis of Selenium in GSL Waters
n Kennecott and others recognized the
limitations of existing methods for analysis of
selenium in high salinity waters
n Kennecott consulted with outside experts
including:
– Dr. Gregory A. Cutter
– Dr. Eva Prusckowski
– Frontier Geoscience
– Battelle NorthW est
n A specialized Hydride Generation method
was developed
The Selenium Hydride Procedure
n Method used in oceanographic studies
n Modified EPA 7742
n Method reviewed and approved by the Utah
State Department of Health
n Method accepted by Utah Department of
Environmental Quality for Compliance with
UPDES Monitoring
Selenium Concentrations in GSL
n Selenium is less than 1 µg/L in the
Great Salt Lake water
n GSL waters were analyzed by Frontier
Geosciences
n Data levels confirmed by Battelle & Kennecott
Frontier Geosciences Lab
Hydride method
0.612 μg/L
0.607 μg/L
0.653 μg/L
0.564 μg/L
0.628 μg/L
0.638 μg/L
0.586 μg/L
0.102 μg/L
Avg = 0.549
Dissolved Selenium Concentrations in GSL
(0.5 – 20 feet sample depths)
June 2002
Concentration Factors
n Input of selenium from the Jordan River is ~4
µg/L into the GSL
n Selenium concentration in the Lake is
0.6 µg/L
n Selenium does not show concentration like
other elements i.e. chloride
n Natural processes are reducing selenium
concentration in the Lake
If USGS recognized the need to address matrix
and to use Hydride Generation for arsenic, why
did they not recognize the need to do likewise
for selenium?
from Waddell, B., et al. Preliminary investigation of selenium in
water, bottom sediment, and biota, Great Salt Lake, Utah
from Waddell, B., et al. Preliminary investigation of selenium in
water, bottom sediment, and biota, Great Salt Lake, Utah
Brine Shrimp
0.00
1.00
2.00
3.00
4.00
5.00
Se
,
(
mg/g DW)
Brine Shrimp
N=80
2.76
Kennecott USFWS
N=74
2.60
Observed Effect of Selenium on the Biota
Toxicological Perspective
n If selenium concentrations were in the range
of 2070 µg/L, selenium would be detected at
much higher levels in biota of the GSL, i.e.,
brine shrimp, brine flies, and bird eggs
n Observed selenium biota levels are
consistent with reports for other areas in the
Western US where selenium is present at
similarly low concentrations
Conclusions
n High saline GSL waters require specialized
and rigorous analytical methods
(GFAAS is not appropriate)
n Measured south arm GSL selenium
concentrations are less than 1 µg/L (ppb)
n Selenium concentrations in the GSL are
lower than source streams due to natural
reducing conditions. Selenium is not returned
to a soluble state by lake turnover and does
not become bioavailable
n Observed low selenium in GSL waters is
consistent with measured biota levels
Conclusions (cont.)
n USGS needs to update selenium analytical
procedures to reflect saline interferences as
addressed for arsenic and other transition
metals
n USFWS should revisit their conclusions in
light of appropriate analytical procedures for
selenium in high brine matrix