atmospheric deposition of mercury, trace metals and major ions in the pensacola bay watershed jane...
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Atmospheric Deposition of Mercury, Trace Metals and Major
Ions in the Pensacola Bay Watershed
Jane CaffreyCenter for Environmental Diagnostics and Bioremedation
University of West Florida
and William M. LandingDepartment of Oceanography
Florida State University
Acknowledgements• EPA PERCH project• Melissa Overton, Autumn Dunn, Nathaniel Davila,
Tanner Martin, Fran Aftanas, Elizabeth Gaige , Brad Kuykendall for their dedication in the field
• Sara Cleveland, Kati Gosnell, and Nishanth Krishnamurthy at FSU
• Dr. Sikha Bagui and Jessie Brown at UWF Computer Science for database development
• Dr. Subhash Bagui and Arup Sinha at UWF Mathematics and Statistics
Escambia County 9th in total toxic emissions nationwide, 16th in air
emissions• Coal fired power plant• Papermill (coal for some
power generation) • Other industrial activities
(Solutia, Air Products, etc.)• 8 Superfund sites• Partnership for
Environmental Research and Community Health (PERCH) – EPA funded– Human health effects – Environmental effects
From Mark Cohen, NOAA ARL
Mercury emissions sources in the Gulf of Mexico region, based on the 1999 National Emissions Inventory (U.S. EPA)
Mercury deposition is an international problem
Worldwide emission estimates
US coal fired power plants represent about 1% of Hg emissions globally53% of emissions come from Asia, 18% from Africa, 11% from Europe, 9% from North America
What is the atmospheric wet deposition of mercury, trace metals and major ions
to the lower Pensacola Bay Watershed?
• Are there seasonal patterns in deposition?
• How do prior weather conditions affect deposition?
• Are there hot spots?
• How important are Local sources?
Precipitation
Nov May Nov May Nov May Nov
cm
0
4
8
12
16
EllysonMolinoPace
Sample collection began in November 2004 and will continue
through March 2010
HurricaneDennis
~ 565 samples from 225 rain events to Feb 2008
2004 2005 2006 2007 2008
Analyses
UWF -WRL• pH• Sulfate• Nitrate+nitrite• Chloride• Ammonium• Sodium• Calcium• Phosphate
FSU - Oceanography• Mercury• Trace metals
– mineral/crustal elements: Al, Si, Sc, Ti, Mn, Fe, Rb, Y, Nb, Cs, La and all rare earth elements, Th, U
– Sea Salt aerosols: Li, Na, Mg, Sr
– urban pollution, fossil fuel combustion: V, Ga, Sb, Pb, Bi, P, Cu, Zn
– As, Se, Sn
Rain is generally acidic, sometimes highly acidic
VW
M p
H
3.6
4.0
4.4
4.8
5.2
5.6
6.0
Nov May Nov May Nov May Nov
pH
3
4
5
6
7
EllysonMolinoPace
2004 2005 2006 2007 2008
Sulfate Flux
Ellyson Molino Pace11/04 5/05 11/05 5/06 11/06 5/07 11/07
SO
42- fl
ux
mg
SO
42-/m
2/e
vent
0.1
1
10
100
1000 EllysonMolinoPace
Sulfate fluxes are higher in Pensacola and AL sites
0
500
1000
1500
2000
2500
3000
LA12 LA30 AL02 AL24 M E P FL14 FL23
SO
4 fl
ux
mg
SO
4/m
2/y
2005
2006
2007
Highest fluxes at EllysonLowest at FL14 and FL23
Counties with higher sulfate emissions have higher sulfate deposition
Sulfate
AL24 AL02
FL23
FL14
SREsc
r = 0.68
500
1000
1500
2000
100 1000 10000 100000
Emissions 2002 lbs/yr
Deposi
tion m
g/m
2/y
.
Based on EPA TRI estimates for 2002
Nitrate flux
Ellyson Molino Pace11/04 5/05 11/05 5/06 11/06 5/07 11/07
NO
3- flux
mg
NO
3- /m2 /e
vent
0.1
1
10
100
1000EllysonMolino
Pace
Fluxes were similar at Pensacola Bay sitesHigher fluxes in spring and summer
Regional Nitrate Flux
0
500
1000
1500
2000
2500
LA12 LA30 AL02 AL24 M E P FL14 FL23
NO
3 fl
ux
mg
NO
3/m
2/y
2005
2006
2007
Higher nitrate fluxes at Pensacola sites than at any NADP sites
Counties with higher nitrate emissions had higher nitrate deposition
Nitrate
AL24 AL02FL23
FL14
SREsc
r = 0.80
500
1000
1500
2000
0 10000 20000 30000 40000 50000 60000
Emissions 2002 lbs/yr
Deposi
tion m
g/m
2/y
.
Based on EPA TRI estimates for 2002
Chloride Flux
Ellyson Molino Pace11/04 5/05 11/05 5/06 11/06 5/07 11/07
Cl- fl
ux
mg
Cl- /m
2 /eve
nt
0.1
1
10
100
1000
10000EllysonMolinoPace
Sodium and Chloride fluxes are high relative to other sitesP
0
500
1000
1500
2000
2500
LA12 LA30 AL02 AL24 M E P FL14 FL23
Na
flu
x m
g/m
2/y
2005
2006
2007
Higher sodium and chloride fluxes when closer to Gulf of Mexico
R2 = 0.70
0
200
400
600
800
1000
1200
1400
0 20 40 60 80 100 120 140 160
Distance from Gulf, km
Ave
rage N
a+ fl
ux
mg/m
2/y
.
Conclusions
• Low pH in some rain events (pH usually < 5, sometimes less than 4)– Ellyson and Pace sites had significantly higher H+
fluxes than NADP sites
• Sulfate and nitrate fluxes higher at Pensacola Bay sites than most NADP sites
• Sulfate and Nitrate fluxes are highest in counties that have high SO2 or NOx emissions
• Sodium and Chloride fluxes higher at Pensacola Bay sites. Sea salt aerosols are important component of rain in the region
Mercury and trace elements in rainfall from the Pensacola airshed: local,
regional, and distant sources
William M. LandingDepartment of Oceanography
Florida State University Jane Caffrey
Center for Environmental Diagnostics and Bioremedation
University of West Florida
Acknowledgements• EPA PERCH project (2005-2008)• EPRI funding for 2008-present.• FSU Graduate students: Sara Cleveland, Kati Gosnell,
Nishanth Krishnamurthy• UWF students: Nathaniel Davila, Tanner Martin, Brad
Kuykendall, Fran Aftanas, Elizabeth Gaige
Geographic Distribution of Largest Anthropogenic Mercury Emissions Sources in the U.S. (1999) and
Canada (2000); from Mark Cohen NOAA/ARLGulf coast is not loaded with Hg point sources
Generally higher mercury deposition in the Southeastern US and along the Gulf coast.
Is this due to long-range transport of GEM and GEM-> RGM conversion during summer months? (Yes)
Escambia County:• Coal fired power plant• International Paper mill (coal
for some power generation) • Other industrial activities
(Solutia, Air Products, Sacred Heart medical waste incinerator, etc.)
EPA National Emissions Inventory shows that Plant Crist is the largest air emitter of mercury in the region.
-- Need reliable mercury speciation profile for each source
(RGM, GEM, Hg-p)
1999 2002 2005Mercury Mercury Mercury
Emissions Emissions Emissions(lb/yr) (lb/yr) (lb/yr) RGM GEM Hg-p
Plant Crist 220.0000 183.0000 191.0000 68% 25% 6%International Paper Company 46.5000 1.8600Sacred Heart Hospital 2.5600 0.0103 0.0020Perdido Landfill & Mrf 0.0395 0.0395 0.0395Naval Air Station Pensacola 0.0017 0.0000Baker & Son Construction Co. C&D Lf 0.0017 0.0017 0.0017Panhandle Paving & Grading (Long Lf) 0.0010 0.0010 0.0010Beulah Landfill 0.0010 0.0010 0.0010Camp Five Landfill 0.0008 0.0008 0.0008Auto Shred Industries Dump 0.0004 0.0004 0.0004Solutia Inc 0.1820
What is the atmospheric wet deposition of What is the atmospheric wet deposition of mercury, trace metals and major ions to the lower mercury, trace metals and major ions to the lower
Pensacola Bay Watershed? Pensacola Bay Watershed? Rainfall chemistry in the Pensacola region is impacted by multiple local and regional emission sources.
Rainfall mercury deposition in the southeastern US and along the Gulf of Mexico coast is already elevated due to long-range transport and transformation of Gaseous Elemental Mercury (GEM) to Reactive Gaseous Mercury (RGM); can we reliably quantify the impacts from individual local and regional sources of RGM (and particulate Hg-p)?
What is the seasonal pattern in mercury and trace element deposition? (Completed)
What are the relationships to local and regional meteorology? (On-going)
Are there hot spots? (Not apparent)
What is the atmospheric wet deposition of What is the atmospheric wet deposition of mercury, trace metals and major ions to the lower mercury, trace metals and major ions to the lower
Pensacola Bay Watershed? Pensacola Bay Watershed?
Can we use other trace elements to “fingerprint” specific emissions sources?
Installation of Hg emission control technology on the local CFPP (Plant Crist) in late 2009 may change local rainfall chemistry and trace element deposition.
Project is monitoring rain events at multiple sites for multiple years to obtain a statistically-significant number of such events both before and after new Hg emission control technology is installed.
Rainfall impact from a point-source plume requires simultaneous presence of the plume and rainfall.
a. b.
Modified AerochemMetrics Wet/Dry samplers:
1. Plexiglas splash guard on leading edge of roof to eliminate splash contamination.
2. Foam seal inside FEP Teflon film bag.
3. Three replicate “nested” funnel/bottle sets (one for pH, N-species and major ions; two for Hg and trace elements).
Analyses: Samples collected on an “event” basis (within 24 hours).
UWF -WRL• pH• Sulfate• Nitrate+nitrite• Chloride• Ammonium• Sodium• Calcium• Phosphate
FSU - Oceanography• Mercury• Trace metals
– mineral/crustal elements: Al, Si, Sc, Ti, Mn, Fe, Rb, Y, Nb, Cs, La and all rare earth elements, Th, U
– Sea Salt aerosols: Li, Na, Mg, Sr
– urban pollution, fossil fuel combustion: V, Ga, Sb, Pb, Bi, P, Cu, Zn, As, Se, Sn
0
10
20
30
40
50
60
0 10 20 30 40 50 60
Hg-A (ng/L)
Hg
-B (
ng
/L)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Se-A (ng/L)
Se
-B (
ng
/L)
0
2000
4000
6000
8000
10000
0 2000 4000 6000 8000 10000
Ba-A (ng/L)
Ba
-B (
ng
/L)
0.0
0.1
0.2
0.3
0.4
0.0 0.1 0.2 0.3 0.4
As-A (ng/L)
As-B
(n
g/L
)
Duplicate receiving bottles allows evaluation of analytical reliability. As concentrations approach the detection limit, scatter increases (Ba).
Sample collection:November 2004 through December 2007; ~ 500 samples
from 175 rain events at three sites.
Hg concentrations consistent with regional MDN sites.Generally higher in summer; small-volume winter events
have concentrations up to 55 ng/L.
Nov Mar Jul Nov Mar Jul Nov Mar Jul
Mer
cury
ng/
L
0
10
20
30
40
50
60
EllysonMolinoPace
2005 2006 2007
Monthly Mercury Deposition
0
100
200
300
400
500
N-04 M-05 O-05 M-06 O-06 A-07 O-07
Month beginning Nov 2004
ng
/cm
2/w
ee
k
EllysonMolinoPace
Mercury deposition per month: Mercury deposition per month: summertime deposition dominates due mostly to summertime deposition dominates due mostly to
higher rainfall Hg concentrations.higher rainfall Hg concentrations.
Pensacola sites are not significantly different from each other, and not significantly higher than
regional MDN sites
-
5,000
10,000
15,000
20,000
25,000
LA28 MS22 AL24 AL02 Molino Ellyson Pace
Rai
nfal
l Hg
Flu
x (n
g/m
^2)
2005
2006
2007
Plant CristUnits and In-Service Dates: 94 MW (1959), 94 MW (1961), 370 MW (1970), 578 MW (1973)
The increase in Hg sedimentation since 1965 (-45 years) also coincides with increased industrialization and coal-fired electricity generation throughout the southeast, nationally, and globally.
Need better local coring sites to define deposition history over the past 150 years.
Should we expect to be able to measure significant differences in Hg rainfall deposition due to Plant Crist?
1. “Background” rainfall Hg deposition is already elevated along the gulf coast (15-20 ug/m2/year).
2. RGM from CFPP may convert to GEM in near-field plume.
3. Individual CFPP impact from RGM emissions typically <15% of existing rainfall Hg deposition within 50 km in the southeastern US (Mark Cohen at NOAA/ARL).
So, rainfall Hg deposition may not be significantly elevated from Plant Crist. What other tools do we have?
Can we use multi-element analysis to “fingerprint” various sources of mercury and other trace elements in
Pensacola Bay rainfall?
Simple correlation and multi-variate statistical analysis used to examine relationships among mercury and trace
metals data (Factor Analysis and Positive Matrix Factorization).
Important to convert to “deposition” (Conc. x Rain depth) since small volume events have high concentrations of
all tracers and skew regression analysis.
Pensacola Rainfall (3 sites combined)
10
100
1000
10000
100000
10 100 1000 10000
Al Deposition (ug/m2)
Si d
epos
ition
(ug
/m2)
Pensacola Rainfall (3 sites combined)
10
100
1000
10000
10 100 1000 10000
Al Deposition (ug/m2)
Fe
depo
sitio
n (u
g/m
2)
Crustal Factor: alumino-silicate aerosols (mineral dust)
Al, Si, Mn, Fe, Co, REE, Rb, Cs, Th, U
Pensacola Rainfall (3 sites combined)
1
10
100
1000
10000
1 10 100 1000
Zn Deposition (ug/m2)
P d
epos
ition
(ug
/m2)
Pensacola Rainfall (3 sites combined)
0.1
1
10
100
1000
1 100 10000 1000000
Mg Deposition (ug/m2)
Sr
depo
sitio
n (u
g/m
2)
Cd/Zn Factor: P, Cr, Zn, Cd Sea Salt Factor: Na, Mg, Sr
Pensacola Rainfall (3 sites combined)
0.1
1
10
100
0.01 0.1 1 10
Hg Deposition (ug/m2)
As
de
po
sitio
n (
ug
/m2
)
Pensacola Rainfall (3 sites combined)
0.1
1
10
0.01 0.1 1 10
Hg Deposition (ug/m2)
Sn
de
po
sitio
n (
ug
/m2
)
Pensacola Rainfall (3 sites combined)
0.01
0.1
1
10
100
0.01 0.1 1 10
Hg Deposition (ug/m2)
Se
depo
sitio
n (u
g/m
2)
“Pollution” Factor: Hg vs. As, Sn, Se, Sb (volatiles in coal)Pensacola Rainfall (3 sites combined)
0.01
0.10
1.00
10.00
0.01 0.10 1.00 10.00
Hg Deposition (ug/m2)
Sb
depo
sitio
n (u
g/m
2)R2 = 0.46
R2 = 0.54 R2 = 0.45
R2 = 0.27
Using volatile trace element concentrations to estimate Hg input from regional coal combustion (assumes volatile TE comes only from coal combustion):
1. Use Hg/TE vaporization ratios from CFPPs and “excess” rainfall TE and Hg deposition (adjust for RGM+Hg-p fraction (74%); assumes Hg/TE ratio is maintained until deposition):
%Hg from coal = Annual XS-TE deposition x (Hg/TE)coal x 100
Annual XS-Hg deposition
2. Or, use minimum observed XS-Hg/XS-TE ratios for volatile elements in rain samples to approximate Hg/TE from coal burning (average of 10-14 lowest ratios for each element).
%Hg in rainfall from regional coal combustion:
TE CFPP Hg/TE ratios Observed min. Hg/TE ratiosAs 29% 23%Se 38% 22%Sn 30% 14%Sb 40% 14%
44
Total Hg deposition (2001)= 25 ug/m2/yr
Wet Deposition (2005-2007)= 14-19 ug/m2/yr
Inferred Dry Deposition = 6-11 ug/m2/yr
78% of total Hg deposition from “background”
7.2% Plant Crist
8.2% from CFPP in Florida
Conclusions and Future research• Rainfall mercury deposition in the Pensacola Bay watershed is similar to
deposition across the northeastern Gulf of Mexico.
• Factor Analysis and other statistical tests can be used to identify source “types”, but not individual point sources. Pensacola rainfall Hg deposition appears to be impacted by coal combustion sources (14-40%). Is this true along the entire Gulf coast? Need trace element analyses at MDN sites. New Gulf Breeze site will help.
• We will conduct detailed meteorological analysis of individual storms affecting all four monitoring sites within the region (includes EPRI/OLF site).– Back trajectories– Cloud-top heights (indicator of tall convection)– Prior meteorological history– Hg isotopes in large-volume samples (Summer 2010)