2nd Mineral Dust Workshop

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2nd Mineral Dust Workshop 10 -12 September 2003,
Paris
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(No Transcript)
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Waste Isolation Pilot Plant

• Underground repository for transuranic waste

• Located in Chihuahuan Desert near Carlsbad, NM

• Disposal rooms 2150 feet underground in ancient
  salt caverns

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WIPP-EM Aerosol Sampling Stations
On Site
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Ambient Aerosol Sampling Schedule
Week 1
Week 2
   
   
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239,240Pu in aerosol (TSP) samples shows a strong
seasonal cycle
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A seasonal cycle in 239,240Pu has been previously
observed.
But the causes for the seasonal cycles in the
current vs. historical data are different.
Perkins Thomas, 1980
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Current data suggests an association of 239,240Pu
with aluminum, an indicator of mineral dust
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239,240Pu activities are correlated with
aluminum, and the 239,240Pu/Al relationships are
similar at all sites
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Where does the 239,240Pu (and 241Am) come from?
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Carlsbad is not a Pu hotspotthe Pu is probably
associated with resuspended global fallout
Current 239,240Pu Levels in Soils (courtesy H.
Beck)
Carlsbad
Beck, H. L., and B. G. Bennett, Historical
overview of atmospheric nuclear weapons testing
and estimates of fallout in the continental
United States, Health Physics, 82, 591-608.
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but about half of the 239,240Pu activity is in
the PM10 fraction, implying contributions from
local sources
Intercept -1.2 E-10 Slope 0.58 R2 0.57
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How strong is the radionuclide/dust link globally?
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Deserts sites were used for the atmospheric
testing of nuclear weapons
Non-Polar Arid Lands
http//geography.about.com/gi/dynamic/offsite.htm?
sitehttp3A2F2Fpubs.usgs.gov2Fgip2Fdeserts2F
what2Fworld.html
Atmospheric Nuclear Test Sites (adapted from Beck
Bennett, 2002)
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A recent study indicates that Asian dust also is
contaminated with plutonium!
Recent trends of plutonium fallout observed in
Japan plutonium as a proxy for desertification
K. Hirose , Y. Igarashi , Michio Aoyama , C.
K. Kim , C. S. Kim and B. W. Chang   Abstract
Plutonium in monthly deposition samples collected
in Tsukuba (the Meteorological Research
Institute), Japan from 1990 to end of 2001 is
reported, together with monthly plutonium
deposition in Nagasaki and Yonaguni in 2000. The
annual deposition of 239,240Pu during the period
from 1990 to 2001 shows no systematic
inter-annual variation. However, monthly
239,240Pu depositions show a typical seasonal
variation with a maximum in spring season (March
to April), which corresponds to seasonal cycle of
soil dusts originating from the East Asian arid
area. Plutonium isotopic ratios in the deposition
samples suggest that significant amounts of the
recent 239,240Pu deposition observed in Japan are
attributed to the resuspension of
plutonium-bearing surface soil particles
resuspended plutonium originates from the East
Asian arid areas. The recent increased tendency
of 239,240Pu content in residues in deposition
samples may reflect desertification in the East
Asian continent.
 J. Environ. Monit., 2003, 5 (2), 302 - 307
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Chemical Composition of Atmospheric Aerosols from
Zhenbeitai, Peoples Republic of China, and
Gosan, South Korea, during ACE-Asia   R. Arimoto,
X. Zhang, B. J. Huebert, C.H. Kang, J. M.
Prospero, D. Savoie, S. Sage, C. A. Schloesslin,
and H. Khaing
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60
o
N
50
o
N
Rishiri
Dunhuang
Beijing
40
o
N
Zhenbeitai
Sado
Seoul
Tango
Qingdao
Hachijo
Gosan
Midway
Fukue
30
o
N
Linan
Chichijima
Amami
Wan-li
Hong Kong
Lan-yu
20
o
N
10
o
N
160
o
E
100
o
E
140
o
E
120
o
E
180
o
ACE-Asia Ground Station Network
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Sampling Analyses
Zhenbeitai IMPROVE-type sampler (PM2.5)
IC ICP-MS at CEMRC TSP sampler
IC at UH, PIXE at IEE/BNU
Gosan High-volume bulk sampler
IC ICP/MS at CEMRC (Same sampler used for
PEM-West)
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ACE-Asia
At Zhenbeitai
Cations are correlated with aluminum
Water Soluble (WS) Cations in Aerosol Samples
from Zhenbeitai (ZBT) Concentrations and
Relationships to Aluminum
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ACE-Asia
At Gosan Alkali/alkaline earths, major cations
and Al are generally correlated
Correlation Matrix
Numbers of sample pairs
Correlations (r-values) Bold, p lt 0.01 Plain,
p lt 0.05, Blanks , ns.
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At Zhenbeitai
? both WS and total Ca are correlated with
aluminum
? water-soluble calcium is about equal to
total calcium
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At Gosan (compared with Zhenbeitai)
? Ca Al concentrations are lower
? a smaller percentage of Ca is water soluble
? both WS and total Ca are correlated with Al,
but the ratios to Al are lower
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Zhenbeitai large particle sulfate sometimes
accompanies the dust
TSP, North Winds
TSP, South Winds
PM2.5
Al sulfate are correlated in TSP samples, but
not PM2.5
Aluminum vs Sulfate
N
r
50
0.67
TSP (North)
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0.11
PM2.5
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At Zhenbeitai during high dust events (gt 40
µg m-3 soluble Ca)
? Sulfate/WS Ca2 molar ratio averages 0.090
0.035 ? Nitrate/WS Ca2 molar ratio averages
0.015 0.005
TSP, North Winds
TSP, South Winds
PM2.5
Sulfate and nitrate in dust prior to mixing?
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ACE-Asia
At Gosan
? the sulfate/WS Ca2 molar ratio is about 5 to
10X higher than at ZBT ? the correlation between
sulfate and Al is lower than at ZBT (r 0.35),
but still significant
Daily
Multi-day
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Observations and Possible Explanations
The sources for dust at ZBT and GOS are different
Differences in Ca and WS(Ca2) concentrations at
ZBT GOS
Calcium and especially WS Ca2 are preferentially
removed relative to Al during transport
Higher percentage of WS(Ca2) at ZBT
Higher sulfate/WS(Ca2) ratio at GOS Sulfate/Al
correlation lower at GOS
Pollution sources mix non-crustal proportions of
Ca, Al and sulfate with the dust
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Summary Theres (probably) dirt on that dust!
Dust from Carlsbad, NM is contaminated with
transuranic radionuclides
Asian dust/major ion relationships
Al vs. cation relationships demonstratedAl
sulfate tend to be correlated, but theres a need
to better constrain element/ion relationships in
source materials Ca results are perplexing--need
to evaluate source differences vs. differential
removal vs. weathering reactions
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Relationship between 239,240Pu and wind speed
Wind threshold-distance (Wt,d) is the sum of
the products of the wind velocities (V) above the
threshold (t) and duration (T)
Wt,d measures wind travel and has units of meters
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Relationships between wind threshold-distance and
239,240Pu activity vary as a function of
threshold velocity