Atmospheric Deposition of Mercury, Trace Metals and Major Ions in the Pensacola Bay Watershed

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Atmospheric Deposition of Mercury, Trace Metals
and Major Ions in the Pensacola Bay Watershed

• Jane Caffrey
• Center for Environmental Diagnostics and
  Bioremedation
• University of West Florida
• and William M. Landing
• Department of Oceanography
• Florida State University

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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

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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

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Mercury emissions sources in the Gulf of Mexico
region, based on the 1999 National Emissions
Inventory (U.S. EPA)
From Mark Cohen, NOAA ARL
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Generally higher mercury deposition in the SE,
most driven by higher rainfall along the Gulf
Coast
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Mercury deposition is an international
problemWorldwide emission estimates
US coal fired power plants represent about 1 of
Hg emissions globally 53 of emissions come from
Asia, 18 from Africa, 11 from Europe, 9 from
North America
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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?

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Sampling Locations
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Sample collection began in November 2004 and will
continue through March 2010
Hurricane Dennis
2004 2005
2006
2007 2008
565 samples from 225 rain events to Feb 2008
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Analyses

• UWF -WRL
• pH
• Sulfate
• Nitratenitrite
• 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

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Rain is generally acidic, sometimes highly acidic
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Sulfate Flux
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Sulfate fluxes are higher in Pensacola and AL
sites
Highest fluxes at Ellyson Lowest at FL14 and FL23
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Counties with higher sulfate emissions have
higher sulfate deposition
Based on EPA TRI estimates for 2002
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Nitrate flux
Fluxes were similar at Pensacola Bay sites Higher
fluxes in spring and summer
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Regional Nitrate Flux
Higher nitrate fluxes at Pensacola sites than at
any NADP sites
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Counties with higher nitrate emissions had higher
nitrate deposition
Based on EPA TRI estimates for 2002
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Chloride Flux
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Sodium and Chloride fluxes are high relative to
other sites
P
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Higher sodium and chloride fluxes when closer to
Gulf of Mexico
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Conclusions

• Low pH in some rain events (pH usually lt 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

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Mercury and trace elements in rainfall from the
Pensacola airshed local, regional, and distant
sources

• William M. Landing
• Department of Oceanography
• Florida State University
• Jane Caffrey
• Center for Environmental Diagnostics and
  Bioremedation
• University of West Florida

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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

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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
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Generally higher mercury deposition in the
Southeastern US and along the Gulf coast. Is
this due to long-range transport of GEM and GEM-gt
RGM conversion during summer months? (Yes)
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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.)

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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)
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What is the atmospheric wet deposition of
mercury, trace metals and major ions to the lower
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)

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What is the atmospheric wet deposition of
mercury, trace metals and major ions to the lower
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.

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Sampling Locations1. Ellyson2. Pace3. Molino
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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).
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Analyses Samples collected on an event basis
(within 24 hours).

• UWF -WRL
• pH
• Sulfate
• Nitratenitrite
• 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

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Duplicate receiving bottles allows evaluation of
analytical reliability. As concentrations
approach the detection limit, scatter increases
(Ba).
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Sample collectionNovember 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.
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Mercury deposition per month summertime
deposition dominates due mostly to higher
rainfall Hg concentrations.
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Pensacola sites are not significantly different
from each other, and not significantly higher
than regional MDN sites
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Plant Crist Units 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.
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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 lt15 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?
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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.
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Crustal Factor alumino-silicate aerosols
(mineral dust) Al, Si, Mn, Fe, Co, REE, Rb, Cs,
Th, U
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Sea Salt Factor Na, Mg, Sr
Cd/Zn Factor P, Cr, Zn, Cd
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Pollution Factor Hg vs. As, Sn, Se, Sb
(volatiles in coal)
R2 0.27
R2 0.46
R2 0.54
R2 0.45
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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 RGMHg-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 ratios As 29 23 Se 38 22 Sn 30
14 Sb 40 14
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Future Goals Use of meteorological data to
understand the chemistry of individual rain events
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Tags in Florida, updated simulation
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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
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REMSAD results courtesy of Dwight Atkinson (EPA)
and Tom Myers (ICF)
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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)