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Published byBrian Hernandez Modified over 11 years ago
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USGS NAWQA Contaminant Trends in Lake Sediment study: reconstructing historical trends in metals and hydrophobic organic contaminants using sediment cores
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NAWQA Trends: Objectives CTLS: http://tx.usgs.gov/coring/index.htmlhttp://tx.usgs.gov/coring/index.html 1) 1)Identify trends in metals and organic compounds in U.S. surface waters, 2) 2)Characterize relations between the trends and changes in land use and environmental regulations, 3) 3)Improve our understanding of transport processes and fate of contaminants in aquatic sediment, 4) 4)Identify and quantify major urban sources of contaminants transported to lakes.
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Paleolimnology core
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Arsenic* Cadmium* Chromium Copper Mercury* Nickel Lead* Zinc DDT* DDE* DDD* Total PCBs* Dieldrin* Chlordane* Metals OCs PAHs Rads Naphthalene Fluorene Phananthrene Anthracene Fluoranthene Pyrene Benz[a]anthracene Chrysene Benzo[a]pyrene* Total PAH* *EPA/ATSDR top 20 priority pollutant Standard Analyses 137 Cs 210 Pb 226 Ra
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Emerging Contaminants Anthraquinone (pulp and paper, dye) Indole (fragrance, inert ingredient) Cholesterol Phenol, p-cresol (inert ingredients, industrial apps.) Triclosan (anti- bacterial) PBDEs (flame retardants) Nonylphenols (surfactants, emulsifiers) Tri (…) phosphates (flame retardants) AHTN, HHCB (fragrances (musk)) PFOS (stain guard, teflon) PCNs (plastics, industrial apps.) Pharmaceuticals
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Lakes Sampled from 1996-2007
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Decrease in releases decreasing trends Trends since the 1970s
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Mixed Signals And a signal of concern
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The urban airshed and atmospheric deposition of contaminants
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SRV:CRK 8:1 Atmospheric deposition of Hg and PAHs is 8 times greater in Boston (SRV) than 200 km north (CRK) Atmospheric deposition of Hg and PAHs is 8 times greater in Boston (SRV) than 200 km north (CRK)
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SRV MYS Atmospheric versus local urban sources SRV MYS
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Fluvial inputs swamp out atmospheric deposition, even when atmospheric deposition is large Fluvial inputs swamp out atmospheric deposition, even when atmospheric deposition is large MYS:SRV 30:1
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Determining atmospheric fallout rates: Dual-core mass-balance model Relations between concentration and mass flux in cores can tell us where contaminants came from Van Metre and Fuller, in review, ES&T
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2008-2010 coring sites
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Current funded 2009 workplan for California Two reference lakes –Sierras –Bay Area E vs W Potential Bay Area add-ons: –1 urban lake –1 addl reference lake
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What are we looking for in a lake? Requirements –Freshwater –Lake or reservoir (reservoir 40+ yrs old) –Access –Undisturbed sediment record –No water diverted in or away Reference lake –Pristine watershed –Small DA:SA Urban lake –Large watershed with mixed residential and commercial land use
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Sierras reference lakes?
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Bay Area reference lake(s)
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Urban lakes? Lake Merced 100-yr history Large urban watershed Hasnt been dredged No water diverted in BUT most storm runoff diverted to CSOs ocean
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