usgs nawqa contaminant trends in lake sediment study: reconstructing historical trends in metals and...
TRANSCRIPT
USGS NAWQA Contaminant Trends in Lake Sediment study: reconstructing historical trends in metals and hydrophobic organic contaminants using sediment cores
NAWQA Trends: Objectives NAWQA Trends: Objectives
CTLS: http://tx.usgs.gov/coring/index.html
1) Identify trends in metals and organic compounds in U.S. surface waters,
2) Characterize relations between the trends and changes in land use and environmental regulations,
3) Improve our understanding of transport processes and fate of contaminants in aquatic sediment,
4) Identify and quantify major urban sources of contaminants transported to lakes.
Paleolimnology Paleolimnology
core
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 AnalysesStandard Analyses
137Cs 210Pb 226Ra
Emerging ContaminantsEmerging 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
Lakes Sampled from 1996-Lakes Sampled from 1996-20072007
Decrease in releases Decrease in releases decreasing trendsdecreasing trends
Trends since the 1970sTrends since the 1970s
Mixed SignalsMixed Signals
And a signal of concernAnd a signal of concern
The “urban airshed” and atmospheric The “urban airshed” and atmospheric deposition of contaminantsdeposition of contaminants
SRV:CRK8:1
Atmospheric deposition of Hg and PAHs is Atmospheric deposition of Hg and PAHs is 8 times greater in Boston (SRV) than 200 8 times greater in Boston (SRV) than 200 km north (CRK)km north (CRK)
SRVMYS
Atmospheric versus local urban sourcesAtmospheric versus local urban sources
SRVMYS
Fluvial inputs swamp out atmospheric Fluvial inputs swamp out atmospheric deposition, even when atmospheric deposition, even when atmospheric deposition is large deposition is large
MYS:SRV30:1
Determining Determining atmospheric atmospheric fallout rates: fallout rates: Dual-core Dual-core mass-balance mass-balance modelmodel
Relations between concentration and mass flux in cores can tell us where contaminants came from
Van Metre and Fuller, Van Metre and Fuller, in reviewin review, ES&T, ES&T
2008-2010 coring sites2008-2010 coring sites
Current funded 2009 workplan for CaliforniaCurrent funded 2009 workplan for California
• Two reference lakes– Sierras– Bay Area
• E vs W
• Potential Bay Area add-ons:– 1 urban lake– 1 add’l
reference lake
What are we looking for in a What are we looking for in a lake?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
Sierras reference Sierras reference lakes?lakes?
Bay Area reference lake(s)Bay Area reference lake(s)
Urban lakes?Urban lakes? Lake MercedLake Merced
• 100-yr history• Large urban
watershed• Hasn’t been
dredged• No water
diverted in• BUT most
storm runoff diverted to CSOsocean