why should we care about mercury deposition? david gay illinois state water survey university of...
TRANSCRIPT
Why Should We Care About
Mercury Deposition?David Gay
Illinois State Water SurveyUniversity of Illinois
Champaign, IL [email protected] (217) 244.0462
http://nadp.sws.uiuc.edu
Goal of this Presentation….
Describe the issues surrounding the mercury problem, and
Introduce you to how we operate and measure wet deposition (& dry deposition).
Why Monitor for Mercury in
Precipitation?
Issues Surrounding Mercury
NWQMN’s “Relevant Questions”
2. Which water quality-related coastal resource management issues would be addressed by the Network?
Examples• Excessive algal growth, loss of aquatic vegetation
• Toxic chemicals in food chains, and fish consumption advisories
• Protracted, recurring or episodic hypoxic (or anoxic) conditions• Habitat loss or impairment affecting propagation of fish and wildlife
resources• Harmful algal blooms that pose human health risks • Beach and shellfish bed closures• Impacts of extreme natural events and climate change
• Quantity and trends in freshwater delivery, groundwater contamination, and atmospheric deposition of contaminants.
Problems NWQMN is Designed to Address
• …. improving the water quality of our streams, estuaries and coastal waters…
• …. 22,000 waterbodies are not attaining their designated uses …
• Transport of contaminants from non-point sources: o Atmospheric Deposition – rapid and long-range
transport of certain pollutantso Groundwater flow – wide range of residence timeo Seepage from on-site waste treatment -- septic systemso Agricultural drainage -- fertilizer and manure
applications o Runoff from coastal watersheds o Riverine transport from upland watersheds –gathering
pollutants from multiple sources• others….
The mercury problem?Bioaccumulation
Bacterial action(water and sediment)
Zooplankton Small fish predatory fish
Water Body
Me-Mercury
Concentration
Dry Deposition
Wet Deposition Geologic Sources(soil, rock, base flow etc.)
Methylation
Hg Hg Hg
Through Fall(wet+dry)
Litter Fall
Why monitor for Mercury in Precipitation?
Atmospheric transport and deposition is the dominant pathway to most aquatic ecosystems.
Between 40 and 75% of the mercury input to lakes and streams is by wet deposition
most falls into water; <20% of catchment deposition reaches lake
probably less in the West.(Sorensen et al., 1997; Scherbatskoy et al., 1997; Lamborg et al., 2005; Mason et al., 1997)
“New” mercury is more likely converted to organic form than “old” mercury (preliminary, METAALICUS)
How Mercury is Wet Deposited
Hgo
RGMHgp
Hgp
RGM
HgoHgp
RGM
rainout
washout
How Mercury is Wet Deposited
Hgo
RGM
RGM
Oxidation
Oxidation
Atmospheric Mercury Species Abundance
Hg0 – Elemental Mercury(lifetime up to 1 year)
RGM – Reactive Gaseous Mercury(lifetime hours to days)
Hgp – Particulate Bound Mercury(lifetime hours to days)
Typical Atm. Mercury Species Abundance
1.4-1.81.4-1.8ng/mng/m33
Many Mercury Sources
Coal combustion (Power 50t/yr)
Incineration Industrial emissions
chlor-alkali cement production (lime) Hg use in mining and
mining of Hg Automobile Recycling
Mercury in Landfills fluorescent lamps dental amalgams (also in
sewers) thermometers, batteries electrical switches
Taconite mining
Volcanoes (St. Helens) Enriched ores/soils
Tectonic (plate) boundaries
Cinnabar (HgS), taconite, others
Soil surfaces (0.5 ppm in crust)
Fresh water and oceans Forests (surfaces and
stomates) Forest fires
(wood fire places?) Tree bark, volatilization
from rocks?
Map of Fish Consumption Warnings (EPA)
Conclusion
It is important to measure the major source of mercury input to your water bodies
Fits the purpose of your network Important contribution to your water bodies Definitely a water concern
fish wildlife humans
How Should You Monitor?
here is how we operate and measure mercury…..
The Mercury Deposition Network?
A 93 site sub-network of the NADP
Measuring wet deposition of mercury
Our Charge: to determine if trends exist in wet
deposition of mercury over time
How Do We Measure Wet?
ETI or Ott_Pluvio
Where We Measure Mercury(Active Sites, May 2006)
Analysis Methods
Cold Vapor Atomic Florescence Spectroscopy (CVAFS) Contract Lab is Frontier Geosciences, Inc. EPA Method 1631 reporting Limit – 0.2 ng/L detection appr. 0.05 ng/L report concentration (ng/L)
Two precipitation depth measurements rain gage bottle catch report deposition (ng/m2 week)
Problems, Things to Remember
Very low concentrations (ng/L), so contamination is always a concern,
Mercury is volatile, so loss is possible,
Cleaning Glassware No Teflon Keeping lab clean Gloves on site Strict protocols
Problems, Things to Remember
Sampling difficulties Hard to measure low concentrations Rain bounce Cold always a problem
Light rain events very difficult but have the high concentrations
Good Operators are essential,
Need lots of sites Concentration change over space Precipitation is highly variable
MDN is being integrated into NWQMN
M. Brigham/USGS Locating MDN sites on the side of water
bodies of concern Michigan (MI31), north east of Detroit South Carolina (SC05), coastal New Jersey (NJ30), Rutgers area
Provides him with input values, wet deposition
MDN integration………
M. Risch/USGS Has five MDN sites in Indiana
Along Ohio River (IN21) Side of Lake Michigan (IN34)
Also measuring atmospheric concentrations and calculating dry deposition
Reporting total mercury deposition
Other Things We Measure
Methyl mercury in rainfall methyl comes down in rain also
Trace metals in rainfall
QA Summary, Docs and the like
Quality Management Plan
Quality Assurance Plan Program and lab
Blanks, Lab Blanks
Blind Tests run by USGS
Mercury Concentrations in Precipitation2004
Mercury Wet Deposition2004
Total Deposition
(we need to estimate dry deposition)
Measurements of Dry Deposition
?•Very few measurements•Very few calculations of dry deposition
•BUT YOU WANT TOTAL DEPOSTION
(wet + dry)
DRY DEPOSITION
Seigneur and others, ES&T, 2004, V38, 555-569
Modeling Dry Deposition
Sampling box for
manual system
Monitoring station for manually-operated sampling system
Plans for Dry Deposition Manually Operated Mercury Species
Sampling
EPA Method IO-5Gold-Trap Method for Hg0 i
Automated Hg Speciation
Methods are:-Lab Tested-Widely used-QA
challenged-EPA Accepted
PHg
RGM
Hg0
Future Directions for MDN
Monitoring Network Design Document Where future sites should be located Environmental Response Committee
Dry Deposition Initiative
Why Should We Care About
Mercury Deposition?David Gay
Illinois State Water SurveyUniversity of Illinois
Champaign, IL [email protected] (217) 244.0462
http://nadp.sws.uiuc.edu