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Water-Quality Trends From Lake Cores Active

By Water Resources Mission Area February 27, 2019

Sediment cores let us look back in time at the contaminant history of a watershed. Learn about what lake and reservoir sediment cores tell us about trends in metals, organochlorine pesticides, polycyclic aromatic hydrocarbons, and other sediment-related contaminants.

Lake coring in Lake Lanier, Georgia
Sources/Usage: Public Domain.
A hydrologic technician collects a core of lake sediment from Lake Lanier, Georgia.  By examining changes in contaminant concentrations from the top of the core (most recent sediment) to the bottom (oldest sediment), contaminant histories can be reconstructed.

Water-quality trends can provide an assessment of the effectiveness of regulatory actions aimed at improving water quality, a warning of water-quality degradation, and an improved understanding of how human activities affect water quality.  

Sediment cores—long tubes of mud—are collected from a lake or reservoir and sliced into thin intervals.  Each slice represents an interval of time. By analyzing the sediments in each slice for the contaminants of interest, changes in the occurrence of contaminants and their use in the watershed can be reconstructed. The approximate date corresponding to deposition of the sediment in each slice is determined by analysis of radionuclides (cesium-137 and lead-210).

USGS studies of reconstructed trends in metals and hydrophobic organic contaminants have shed light on the effectiveness of restrictions on the use of leaded gasoline, DDT, and PCBs, and the effectiveness of the Clean Air Act in reducing concentrations of some heavy metals.  The studies also have identified some contaminants, like polycyclic aromatic hydrocarbons (PAHs), whose concentrations are increasing in urban areas, spurring efforts to identify the source or sources of these upward trends.

Find out more about coal-tar-based sealcoat, a potent source of PAHs to lake and streambed sediment, and related environmental health issues. 

Examining sediment core
Sources/Usage: Public Domain.
Preparing to cut open a sediment core to release the overlying lake water.

NATIONAL SUMMARIES

TOPICAL FINDINGS

Lake sediment core sample
Sources/Usage: Public Domain.
Lake sediment core sample.  A sediment core can represent from a few to many decades of sediment, depending on the sedimentation rate of the lake or reservoir.

LOCAL RESULTS

Processing sediment core samples
Sources/Usage: Public Domain.
Sediment cores are sliced into intervals for chemical analysis.  Each slice of sediment represents a "slice" of time.

Read about additional science related to sediment-associated contaminants and water-quality trends by following the links to web pages below.

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A mud-covered tire and algae in an urban creek

Urban Land Use and Water Quality

Wherever you live, there’s a creek or stream near you. The eighty percent of Americans who live in metropolitan areas are often unaware of the network of urban creeks—many teeming with life—that weaves through our cities and town. Nowhere are the environmental changes associated with urban development more evident than in urban streams.
By
Water Resources Mission Area, National Water Quality Program
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Urban Land Use and Water Quality

Wherever you live, there’s a creek or stream near you. The eighty percent of Americans who live in metropolitan areas are often unaware of the network of urban creeks—many teeming with life—that weaves through our cities and town. Nowhere are the environmental changes associated with urban development more evident than in urban streams.
Learn More
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Graph estimates of agricultural pesticide use in the conterminous US

Pesticides and Water Quality

Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.
By
Water Resources Mission Area, National Water Quality Program
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Pesticides and Water Quality

Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.
Learn More
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faucet

Metals and Other Trace Elements

Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.
By
Water Resources Mission Area
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Metals and Other Trace Elements

Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.
Learn More
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Image: Soil Sampling Near Uranium Mine

Radionuclides

Many people might be surprised to learn that drinking-water sources, especially groundwater, can contain radioactive elements (radionuclides). Radionuclides in water can be a concern for human health because several are toxic or carcinogenic. Other radionuclides are useful tools for determining the age of groundwater in an aquifer or of sediment deposited at the bottom of a water body.
By
Water Resources Mission Area
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Radionuclides

Many people might be surprised to learn that drinking-water sources, especially groundwater, can contain radioactive elements (radionuclides). Radionuclides in water can be a concern for human health because several are toxic or carcinogenic. Other radionuclides are useful tools for determining the age of groundwater in an aquifer or of sediment deposited at the bottom of a water body.
Learn More
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Image: Scientist Taking Water Samples

National Water-Quality Project Sampling Methods

USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.
By
Water Resources Mission Area
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National Water-Quality Project Sampling Methods

USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.
Learn More
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USGS employee collecting water quality sample at USGS gage 09359020 Animas River below Silverton, CO.

Water-Quality Trends

Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.
By
Water Resources Mission Area, National Water Quality Program
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Water-Quality Trends

Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.
Learn More
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Examining sediment core

Sediment-Associated Contaminants

Stream, river, and lake bed sediment are reservoirs for many contaminants. These contaminants include some “legacy” contaminants, like DDT, PCBs, and chlordane, and chemicals currently in use, like the insecticide bifenthrin and many flame retardants. Learn about techniques used to study sediment-associated contaminants and their importance to aquatic biota.
By
Water Resources Mission Area, National Water Quality Program
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Sediment-Associated Contaminants

Stream, river, and lake bed sediment are reservoirs for many contaminants. These contaminants include some “legacy” contaminants, like DDT, PCBs, and chlordane, and chemicals currently in use, like the insecticide bifenthrin and many flame retardants. Learn about techniques used to study sediment-associated contaminants and their importance to aquatic biota.
Learn More

Learn more about water quality trends as recorded in sediment cores at the publications below.

Trends in hydrophobic organic contaminants in urban and reference lake sediments across the United States, 1970-2001

A shift in national policy toward stronger environmental protection began in the United States in about 1970. Conversely, urban land use, population, energy consumption, and vehicle use have increased greatly since then. To assess the effects of these changes on water quality, the U.S. Geological Survey used sediment cores to reconstruct water-quality histories for38 urban and reference lakes acro
Authors
P. C. Van Metre, B.J. Mahler
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Paleoreconstruction of organic carbon inputs to an oxbow lake in the Mississippi River watershed: Effects of dam construction and land use change on regional inputs

We use a dated sediment core from Lake Whittington (USA) in the lower Mississippi River to reconstruct linkages in the carbon cycling and fluvial sediment dynamics over the past 80 years. Organic carbon (OC) sources were characterized using bulk (δ13C, ramped pyrolysis-oxidation (PyrOx) 14C, δ15N, and TN:OC ratios) and compound-specific (lignin phenols and fatty acids, including δ13C and 14C of th
Authors
Thomas S. Bianchi, Valier Galy, Brad E. Rosenheim, Michael Shields, Xingquan Cui, Peter C. Van Metre
By
Water Resources Mission Area

Declining Dioxin concentrations in the Rhone River, France, attest to the effectiveness of emissions controls

Emission-control policies have been implemented in Europe and North America since the 1990s for polychlorodibenzodioxins (PCDDs) and furans (PCDFs). To assess the effect of these policies on temporal trends and spatial patterns for these compounds in a large European river system, sediment cores were collected in seven depositional areas along the Rhone River in France, dated, and analyzed for PCD
Authors
Peter C. Van Metre, Marc Babut, Brice Mourier, Barbara Mahler, Gwenaelle Roux, Marc Desmet
By
Water Resources Mission Area

Effects of urbanization on mercury deposition and accumulation in New England

We compare total mercury (HgT) loading and methylmercury (MeHg) accumulation in streams and lakes from an urbanized area (Boston, Massachusetts) to rural regions of southern New Hampshire and Maine. The maximum HgT loading, as indicated by HgT atmospheric deposition, HgT emissions, and sediment HgT concentrations, did not coincide with maximum MeHg concentrations in fish. Urbanized ecosystems were
Authors
Ann T. Chalmers, David P. Krabbenhoft, Peter C. Van Metre, Mark A. Nilles
By
Ecosystems Mission Area, Water Resources Mission Area, Environmental Health Program, Toxic Substances Hydrology, New England Water Science Center, Upper Midwest Water Science Center, Mercury Research Laboratory

PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas

Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin’s ban by analyzing PAHs in sediment cores and bottom-sediment samples collected i
Authors
Peter C. Van Metre, Barbara Mahler
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Identification of contamination in a lake sediment core using Hg and Pb isotopic compositions, Lake Ballinger, Washington, USA

Concentrations and isotopic compositions of Hg and Pb were measured in a sediment core collected from Lake Ballinger, near Seattle, Washington, USA. Lake Ballinger has been affected by input of metal contaminants emitted from the Tacoma smelter, which operated from 1887 to 1986 and was located about 53 km south of the lake. Concentrations and loadings of Hg and Pb in Lake Ballinger increased by as
Authors
John E. Gray, Michael J. Pribil, Peter C. Van Metre, David M. Borrok, Anita Thapalia
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

An 80-year record of sediment quality in the lower Mississippi River

In 1937, the US Army Corps of Engineers cut through the "neck" of a large meander on the lower Mississippi River (below the confluence with the Ohio River) forming the Caulk Neck cutoff and creating Lake Whittington, a 26-km long oxbow lake, in northern Mississippi. Since 1938, seasonal flooding and a boat channel connecting the lake with the Mississippi River have led to sediment accumulation in
Authors
Peter C. Van Metre, Arthur J. Horowitz
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Spatial and temporal trends in PCBs in sediment along the lower Rhone River, France

Despite increasingly strict control of polychlorinated biphenyl (PCB) releases in France since the mid-1970s, PCB contamination of fish recently has emerged as a major concern in the lower Rhone River basin. We measured PCB concentrations in Rhone sediment to evaluate the effects of PCB releases from major urban and industrial areas, sediment redistribution by large floods, and regulatory controls
Authors
Marc Desmet, Brice Mourier, Barbara Mahler, Peter C. Van Metre, Gwenaelle Roux, Henri Persat, Irene Lefevre, Annie Peretti, Emmanuel Chapron, Simonneau Anaelle, Cecile Miege, Marc Babut
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Increased atmospheric deposition of mercury in reference lakes near major urban areas

Atmospheric deposition of Hg is the predominant pathway for Hg to reach sensitive ecosystems, but the importance of emissions on near-field deposition remains unclear. To better understand spatial variability in Hg deposition, mercury concentrations were analyzed in sediment cores from 12 lakes with undeveloped watersheds near to (150 km) several major urban areas in the United States. Background
Authors
P. C. Van Metre

Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes

Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) has increased in the United States during the past 40 years. We evaluated sources of PAHs in post-1990 sediments in cores from 40 lakes in urban areas across the United States using a contaminant mass-balance receptor model and including as a potential source coal-tar-based (CT) sealcoat, a recently recognized sour
Authors
Peter C. Van Metre, Barbara Mahler
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-t
Authors
P. C. Van Metre, B.J. Mahler, J.T. Wilson

Dual-core mass-balance approach for evaluating mercury and210Pb atmospheric fallout and focusing to lakes

Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations for two cores algebraically to estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied
Authors
P. C. Van Metre, C. C. Fuller
By
Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

The chemical response of particle-associated contaminants in aquatic sediments to urbanization in New England, U.S.A.

Relations between urbanization and particle-associated contaminants in New England were evaluated using a combination of samples from sediment cores, streambed sediments, and suspended stream sediments. Concentrations of PAHs, PCBs, DDT, and seven trace metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) were correlated strongly with urbanization, with the strongest relations to percentage commercial, industrial,
Authors
A.T. Chalmers, P. C. Van Metre, E. Callender