usgs nawqa contaminant trends in lake sediment study: reconstructing historical trends in metals and...

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