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Mercury cycling and bioaccumulation in a Central Adirondack stream ecosystem Karen Murray and Doug Burns October 14, 2009 U.S. Department of the Interior EMEP, Albany NY 1 U.S. Geological Survey Presentation outline Background - Mercury

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Karen Murray and Doug Burns

U.S. Department of the Interior U.S. Geological Survey

October 14, 2009 EMEP, Albany NY

Mercury cycling and bioaccumulation in a Central Adirondack stream ecosystem

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Presentation outline

  • Background - Mercury cycle in

aquatic ecosystems

  • Mercury in streams across the US

(NAWQA mercury studies)

  • Intensive research on a Central

Adirondack stream

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Acknowledgments

Mark Brigham , USGS, MN Water Science Center Lia Chasar, USGS, FL Water Science Center Barb Scudder, USGS, WI Water Science Center Adirondack Ecological Center (Huntington Wildlife Forest) Nature Conservancy, Finch-Paper Co, RMK Timberland

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Aquatic mercury cycle

MeHg

MeHg

MeHg

Biomagnification Atmospheric sources Point sources

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Methylation

Hg++ MeHg

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Key questions

  • How does mercury move from source to

fish & other organisms?

  • How does mercury vary geographically

among stream fish?

  • What controls mercury concentrations in

stream biota?

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National stream study Scudder et al. 2009

  • Game fish, water, sediment
  • 291 streams across the US
  • Variety of landscapes
  • 1998-2005
  • Methylmercury & Total mercury in

water & bed sediment

  • Total mercury in game fish

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Mercury in Game Fish

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Scudder and

  • thers, 2009
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How does mercury move from source to fish?

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8 streams Different settings Single reach Intensively sampled Water, sediment Complete food web ES&T:

Brigham et al. 2008 Chasar et al. 2008 Marvin-DiPasquale et al. 2008

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Key findings

  • Runoff of methylmercury produced in

watershed (wetlands)

– Water quality (DOC, pH)

  • Source versus methylation

– Modest source with high methylation – Large source with low methylation

  • Biomagnification

– Similar among ecosystems – Methylmercury in the water determines methylmercury in fish

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ES&T: Brigham et al. 2008, Chasar et al. 2008, Marvin-DiPasquale et al. 2008

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Intensive watershed studies 2007-2009

  • Where is meHg produced in the

watershed?

  • How / when is it transported to the

stream?

  • What controls its bioaccumulation?

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Intensive watershed studies 2007-2009

  • Forested catchments; atmospheric

deposition primary source

  • Multiple sites sampled throughout

small catchments

  • Fishing Brook (Hudson R basin, NY)
  • McTier Creek (Edisto R basin, SC)

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Fishing Brook study area

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  • Central Adirondacks
  • Upper Hudson R. basin
  • Near MDN site at HWF
  • 26mi2 area
  • 89% forest
  • 8% wetland
  • <3% open water
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Fishing Brook sites

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12 sites overall Range of characteristics Bio collected @ 9 sites Gage at outlet

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Approach

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  • Sample seasonally 2007-09
  • Sample biota from 9 sites
  • Collect invertebrates & fish representing

multiple feeding groups

  • Analyze for MeHg, THg, d13C, d15N
  • Analyze water for MeHg, THg, DOC, sulfate,

pH, & more

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Hg in top predator fish

Hg in top predators all HDSN & SANT sites Study Unit HDSN SANT 0.0 0.2 0.4 0.6 0.8 n = 26 n = 23

Hg (ppm wet weight) 0.30 guideline

Includes Hudson R & Edisto R samples

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Methylmercury in invertebrates – all sites

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Mercury Concentrations in Invertebrates All HDSN Samples

Mercury Concentration (ng/g dw)

1 10 100 1000 Shredder Scraper Omnivore Predator N = 36 N = 12 N = 16 N = 61

Shredder Scraper Omnivore Predator MeHg ug/g dry weight

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MeHg Spatial patterns

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Creek chub Darner dragonflies

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Spatial patterns in fish

Creek chub

blacknose dace

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Factors influencing Hg in stream biota

% wetland Feeding level R2 0.60 p<0.0001 R2 0.60 p < 0.0001

logHg ng/g dw

shredders

Hg ng/g dw

inverts sh sc om pr cs cc fish

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Mercury in Fishing Brook biota as a function of feeding level & % wetland

Adj R2 0.85 p <0.0001 Observed log MeHg ng/g dw Predicted Log Hg ng/g dw

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Summary & Conclusions

  • Streams vary widely in mercury in biota across

a relatively small (<30 mi2) area

  • Mercury in biota of Central Adirondack streams

are strongly linked to riparian wetlands

  • Recovery is expected to be highly variable
  • There is a need for monitoring of multiple

media & multiple organisms in variety of settings

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Further information

Karen R Murray

krmurray@usgs.gov 518-285-5617

Douglas A Burns

daburns@usgs.gov 518-285-5662

http://water.usgs.gov/nawqa/mercury

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