Mercury Flux in an Urban Watershed System
description
Transcript of Mercury Flux in an Urban Watershed System
Mercury Flux in an Mercury Flux in an Urban Watershed Urban Watershed
SystemSystem
Joseph T. BusheyJoseph T. Bushey11, Peter M. Groffman, Peter M. Groffman22, , Charles T. DriscollCharles T. Driscoll11, Gary T. Fisher, Gary T. Fisher33
11Syracuse University Dept. of Civil & Syracuse University Dept. of Civil & Environmental EngineeringEnvironmental Engineering
22Institute of Ecosystem Studies, Institute of Ecosystem Studies, 33US US Geological SurveyGeological Survey
October 19, 2006October 19, 2006
OverviewOverview
BackgroundBackground ObjectivesObjectives ResultsResults
UrbanizationUrbanization Storm EventsStorm Events
ConclusionsConclusions
Why?Why? NeurotoxinNeurotoxin BioaccumulationBioaccumulation potential potential
What?What? Gaseous HgGaseous Hgoo
HgHg2+2+ (RGM, ionic, particulate) (RGM, ionic, particulate) Methyl Hg – BAD GUYMethyl Hg – BAD GUY, bioaccumulates, bioaccumulates
Where?Where? Paints, pesticides, scientific/medical, Paints, pesticides, scientific/medical,
electricalelectrical Manufacturing (e.g. chlorine)Manufacturing (e.g. chlorine) Utilities/fossil fuels → atmospheric Utilities/fossil fuels → atmospheric
depositiondeposition
(Cartoon from: www.grinningplanet.com)
Why Urban?Why Urban? Increased anthropogenic inputsIncreased anthropogenic inputs Altered ecosystem processesAltered ecosystem processes
AddedAdded
exposureexposure
ObjectivesObjectives Quantify the effect on Hg species flux Quantify the effect on Hg species flux
with respect to:with respect to: Urbanization/Land use changesUrbanization/Land use changes Elevated discharge eventsElevated discharge events
Assess the impact of ecosystem Assess the impact of ecosystem alterations on Hg transport and alterations on Hg transport and transformation processestransformation processes
11 Sites associated with Gwynns Falls 11 Sites associated with Gwynns Falls LTERLTER
Mercury: THg, MeHg, filtered vs. unfilteredMercury: THg, MeHg, filtered vs. unfiltered Ancillary chemistry: e.g. DOC, TSS, SOAncillary chemistry: e.g. DOC, TSS, SO44
2-2-, DO, DO
Main Main BranchBranch
ForestSuburban
Urban
Suburban Boundary
PB GB VN CPForest
ReferenceSuburbanHeadwater
SuburbanBoundary
UrbanOutlet
THg 1.10 0.50 0.73 0.85
MeHg 0.045 0.011 0.019 0.020
DOC 0.70 0.66 0.88 1.39
TSS 2.23 1.21 2.04 1.73
Main Stem Chemical Main Stem Chemical FluxFlux(Units: THg, MeHg – (Units: THg, MeHg – g mg m-2-2 yr yr-1-1; DOC, TSS – g m; DOC, TSS – g m-2-2 yr yr-1-1))
What are effects of What are effects of urbanization?urbanization?- Hg mobility -- Hg mobility -
THg ↑ with THg ↑ with urbanization urbanization WRTWRT
DOCDOC TSSTSS
Effect of Effect of runoff runoff
Particulate Particulate Hg Hg important important for flux for flux
What are effects of What are effects of urbanization?urbanization?
- Methylation potential -- Methylation potential - MethylationMethylation
De-coupling of De-coupling of Hg-DOC Hg-DOC
Decreased Decreased effect of biotic effect of biotic activity on Hg activity on Hg mobilitymobility
AnthropogeniAnthropogenic DOC c DOC source? Oxic source? Oxic conditions?conditions?
What are effects of elevated What are effects of elevated events?events?
Base
Forest
Suburban
Urban
ConclusionsConclusions
Urbanization alters Hg-DOC Urbanization alters Hg-DOC relationship and effects on relationship and effects on Hg mobilityHg mobility
THg and MeHg flux ↓ under THg and MeHg flux ↓ under base flow conditions for base flow conditions for developed ecosystemsdeveloped ecosystems
Importance of particulate Importance of particulate and high flow events on THg and high flow events on THg fluxflux
Future WorkFuture Work Examine link between urban Examine link between urban
DOC and Hg mobilityDOC and Hg mobility Study the effect of the short-Study the effect of the short-
circuiting of ecosystem circuiting of ecosystem processes on Hg mobilityprocesses on Hg mobility
Investigate the interaction Investigate the interaction between the urban canopy between the urban canopy cover and Hg loadingcover and Hg loading
Explore the potential for Explore the potential for diurnal variationsdiurnal variations
Funding: Funding: The Dreyfus FoundationThe Dreyfus Foundation US Environmental Protection AgencyUS Environmental Protection Agency National Science Foundation (LTER Program)National Science Foundation (LTER Program)
Support: Support: Baltimore Co. Dept. of Envir. Protection & Baltimore Co. Dept. of Envir. Protection &
Mgmt.Mgmt. USGS Cooperative Water ProgramUSGS Cooperative Water Program City of Baltimore Dept. of Public WorksCity of Baltimore Dept. of Public Works Dan Dillon, Tara Krebs (IES)Dan Dillon, Tara Krebs (IES) M. Montesdeoca, J. Flagg, J. Hanley, M. M. Montesdeoca, J. Flagg, J. Hanley, M.
Bushey (SU)Bushey (SU)
AcknowledgementsAcknowledgements
““Every Cloud Every Cloud has a has a
Quicksilver Quicksilver Lining”Lining”
PB GL MD RH
Forest Suburban Ag Urban
THg 1.10 0.46 0.33 2.02
MeHg 0.045 0.013 0.017 0.028
DOC 0.70 0.82 0.36 2.07
TSS 2.23 2.05 0.71 3.36
Land Use Chemical Land Use Chemical FluxFlux(Units: THg, MeHg – (Units: THg, MeHg – g mg m-2-2 yr yr-1-1; DOC, TSS – g m; DOC, TSS – g m-2-2 yr yr-1-1))
PB GL MD RH RH-SC
Forest Suburban Ag UrbanUrbanStorm
THg 1.10 0.46 0.33 2.02 6.72
MeHg 0.045 0.013 0.017 0.028 0.108
DOC 0.70 0.82 0.36 2.07 2.40
TSS 2.23 2.05 0.71 3.36 14.6
Effect of High Flow Effect of High Flow on Fluxon Flux(Units: THg, MeHg – (Units: THg, MeHg – g mg m-2-2 yr yr-1-1; DOC, TSS – g m; DOC, TSS – g m-2-2 yr yr-1-1))