2003-10-10 The Dirt on Dust
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Transcript of 2003-10-10 The Dirt on Dust
The Dirt on Dust
Rich Arimoto
Carlsbad Environmental Monitoring & Research Center New Mexico State University
2nd Mineral Dust Workshop10 -12 September 2003, Paris
Part I
Carlsbad (New Mexico) Studies
• Underground repository for transuranic waste
• Located in Chihuahuan Desert near Carlsbad, NM
• Disposal rooms 2150 feet underground in ancient salt caverns
WasteIsolationPilotPlant
WIPP-EM Aerosol Sampling Stations
On Site
Ambient Aerosol Sampling Schedule
Day
MondayTuesdayWednesdayThursdayFridaySaturdaySundayMondayTuesdayWednesdayThursdayFridaySaturdaySunday
Type of Sample
Ions
Radionuclides (4- 6 weeks)
Trace Elements
Ions
Trace Elements
Ions
Trace Elements
Week 1
Week 2
239,240Pu in aerosol (TSP) samples shows a strong seasonal cycle
Start Date of Sample Collection
Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan
Act
ivity
Con
cent
ratio
n, B
q m
-3
0
20x10-9
40x10-9
60x10-9
80x10-9
1998 1999 2000 2001 2002 | | | | | |
Cactus Flats Near Field Hobbs On Site
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
Alu
min
um,
g m
-3
0
1
2
3
4
5
6
Cactus FlatsNear FieldOn Site
Date of Sample Collection (Midpoint)
01/98 07/98 01/99 07/99 01/00 07/00 01/01 07/01 01/02 07/02
Alu
min
um,
g m
-3
0.0
0.5
1.0
1.5
Dichot--Coarse Fraction
Dichot--Fine Fraction
Current data suggests an association of 239,240Pu with aluminum, an indicator of mineral dust
239,240Pu activities are correlated with aluminum, and the 239,240Pu/Al relationships are similar at all sites
239,240Pu Activity Concentration, Bq m-3
0 20x10-9 40x10-9 60x10-9 80x10-9
Alu
min
um,
g m
-3
0
1
2
3
4
5
6
7
Cactus Flats Near Field On Site
Where does the 239,240Pu (and 241Am) come from?
Current 239,240Pu Levels in Soils (courtesy H. Beck)
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.
Carlsbad is not a Pu hotspot—the Pu is probably associated with resuspended global fallout
Carlsbad
…but about half of the 239,240Pu activity is in the PM10 fraction, implying contributions from local sources
TSP 239,240Pu Activity Concentration (Bq m-3)
0 20x10-9 40x10-9 60x10-9 80x10-9
PM10
239,
240 P
u Act
ivity
Con
cent
ratio
n (Bq
m-3
)
0
20x10-9
40x10-9
60x10-9
80x10-9
Cactus FlatsNear Field
Intercept = -1.2 E-10Slope = 0.58R2 = 0.57
How strong is the radionuclide/dust link globally?
http://geography.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fpubs.usgs.gov%2Fgip%2Fdeserts%2Fwhat%2Fworld.html
Atmospheric Nuclear Test Sites
(adapted from Beck & Bennett, 2002)
Non-Polar Arid Lands
Deserts sites were used for the atmospheric testing of nuclear weapons
Alamagordo
NTS(USA)
Johnston Is. Christmas Is.Malden Is.
Mururoa Fangataufa
(USA)
Reggane (FR)
• Kapustin Yar • Totsk
•
Semipalatinsk• Lop Nor
Monte Bello Is.
Maralinga• Emu
• Bikini
Enewetak
Novaya Zemlya
• • •
•
• •
•
•
(USA)• •
• •
•
•
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
A recent study indicates that Asian dust also is contaminated with plutonium!
Part I I
ACE- Asia Studies
Chemical Composition of Atmospheric Aerosols from Zhenbeitai, People’s 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
Rishiri
Sado
Hachijo
Chichijima
Seoul
GosanGosan
Amami
30oN
40oN
20oN
10oN
50oN
60oN
160oE100oE 140oE120oE 180o
Midway
ACE-Asia Ground Station Network
Fukue
Tango
Lan-yuHong Kong
Beijing
Qingdao
Linan
ZhenbeitaZhenbeitaiiDunhuang
Wan-li
Sampling & Analyses
Zhenbeitai IMPROVE-type sampler (PM2.5) IC & ICP-MS at CEMRC TSP sampler IC at UH, PIXE at IEE/BNUGosan High-volume bulk sampler IC & ICP/MS at CEMRC (Same sampler used for PEM-West)
Concentration (g m-3) Ion
Type of
Sample
Number of
Samples Mean Standard Deviation
Correlation with Al (r)
PM2.5 9 6.0 4.2 0.87 WS Ca2+
TSP 56 14.0 16.8 0.85
PM2.5 8 0.51 0.29 0.57 WS K+
TSP 56 0.32 0.33 0.68
PM2.5 9 0.38 0.1.2 0.81 WS Mg2+
TSP 56 0.48 0.43 0.85
PM2.5 9 0.99 1.1 0.89 WS Na+
TSP 56 1.07 1.02 0.74
Water Soluble (WS) Cations in Aerosol Samples from Zhenbeitai (ZBT): Concentrations and Relationships to Aluminum
Cations are correlated with aluminumAt Zhenbeitai
ACE-Asia
Al Ca WS Ca2+ K WS K+ Mg WS Mg2+ Na WS Na+
Al 58 54 64 53 63 54 63 53
Ca 0.93 50 58 50 58 50 59 46
WS Ca2+ 0.64 0.72 54 53 54 55 55 51
K 0.87 0.94 0.54 53 63 54 63 52
WS K+ 0.71 0.72 0.76 0.64 52 53 53 50
Mg 0.82 0.83 0.38 0.89 0.58 54 63 51
WS Mg+ 0.58 0.61 0.68 0.57 0.82 0.65 55 51
Na 0.31 0.37 0.59 0.43 51
WS Na+ 0.64 0.67 0.47 0.63 0.77 0.72 0.82 0.55
Correlations (r-values) Bold, p < 0.01Plain, p < 0.05, Blanks , ns.
At Gosan Alkali/alkaline earths, major cations and Al are generally correlated
Correlation Matrix
Numbers of sample pairs
ACE-Asia
Aluminum, g m-3
10-1 100 101 102 103
Calci
um or
WS
Calci
um,
g m-3
10-1
100
101
102
103
0.331
Calcium, PM2.5
Calcium, TSP (North)
WS Calcium, PM2.5
WS Calcium, TSP (North)
water-soluble calcium is about equal to total calcium
At Zhenbeitai both WS and total Ca are correlated with aluminum
Aluminum, g m-3
10-2 10-1 100 101 102 103
Calci
um or
WS
Calci
um,
g m-3
10-1
100
101
102
103
0.10.331WS Calcium, TSPCalcium, TSP
Ca & Al concentrations are lower
At Gosan (compared with Zhenbeitai)
a smaller percentage of Ca is water soluble both WS and total Ca are correlated with Al, but the ratios to Al are lower
TSP, North Winds TSP, South Winds PM2.5
Zhenbeitai: large particle sulfate sometimes accompanies the dust
Aluminum vs Sulfate
50 0.67
8 0.11
N r
TSP (North)PM2.5
Feb Mar Apr May Jun
Sul
fate
, g
m-3
0
10
20
30
40
50
Date of Sample Collection (2001)
Feb Mar Apr May Jun
Sol
uble
Cal
cium
, g
m-3
0
20
40
60
80
100
120
140
160
Al & sulfate are correlated in TSP samples, but not PM2.5
Soluble Calcium, g m-3
0 20 40 60 80 100 120 140
Sul
fate
to S
olub
le C
alci
um(M
olar
Rat
io)
0.001
0.01
0.1
1
10
100
Soluble Calcium, g m-3
0 20 40 60 80 100 120 140
Nitr
ate
to S
olub
le C
alci
um
(Mol
ar R
atio
)
0.001
0.01
0.1
1
10
100
Sulfate/WS Ca2+ molar ratio averages 0.090 ± 0.035 Nitrate/WS Ca2+ molar ratio averages 0.015 ± 0.005
At Zhenbeitai during high dust events (> 40 µg m‑3 soluble Ca)
Sulfate and nitrate in dust prior to mixing?
TSP, North Winds
TSP, South Winds
PM2.5
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
At Gosan
Soluble Calcium, g m-3
0 2 4 6 8
Sul
fate
to S
olub
le C
alci
um(M
olar
Rat
io)
0.01
0.1
1
10
100
ACE-Asia
Observations and Possible Explanations
The sources for dust at ZBT and GOS are different
Calcium and especially WS Ca2+ are preferentially removed relative to Al during transport
Pollution sources mix non-crustal proportions of Ca, Al and sulfate with the dust
Differences in Ca and WS(Ca2+) concentrations at ZBT & GOS
Higher percentage of WS(Ca2+) at ZBT
Higher sulfate/WS(Ca2+) ratio at GOSSulfate/Al correlation lower at GOS
Summary: There’s (probably) dirt on that dust!
Dust from Carlsbad, NM is contaminated with transuranic radionuclidesAsian dust/major ion relationships
Al vs. cation relationships demonstrated
Al & sulfate tend to be correlated, but there’s 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
,1
;n
t dW VT V t
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
Relationship between 239,240Pu and wind speed
Relationships between wind threshold-distance and 239,240Pu activity vary as a function of threshold velocity
Threshold Velocity (m sec-1)0 2 4 6 8 10 12 14 16
Corr
elatio
n Coe
fficie
nt (r
)
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6