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Water-Quality Trends From Lake Cores

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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. View Media Details
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. View Media Details
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. View Media Details
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. View Media Details
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.

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
Filter Total Items: 42

Major and trace elements in 35 lake and reservoir sediment cores from across the United States, 1994-2001

This report presents data on major and trace element concentrations in sediment cores collected from 35 lakes and reservoirs during 1994-2001. The lakes and reservoirs are located in or near 18 major urban areas across the United States and provide a geographically diverse coverage of urban land use for the country as well as some reference settings. Vertical intervals of the cores were analyzed f
Authors
Peter C. Van Metre, Barbara Mahler, Jennifer T. Wilson, Edward Callender
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Trends in metals in urban and reference lake sediments across the United States, 1970 to 2001

Trends in metals concentrations in sediment cores from 35 reservoirs and lakes in urban and reference settings were analyzed to determine the effects of three decades of legislation, regulation, and changing demographics and industrial practices in the United States on concentrations of metals in the environment. Decreasing trends outnumber increasing trends for all seven metals analyzed (Cd, Cr,
Authors
B.J. Mahler, P. C. Van Metre, E. Callender

Effects of hurricanes Katrina and Rita on the chemistry of bottom sediments in Lake Pontchartrain, Louisiana, USA

The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the sediment chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom sediments exce
Authors
P. C. Van Metre, A. J. Horowitz, B.J. Mahler, W.T. Foreman, C. C. Fuller, M.R. Burkhardt, K. A. Elrick, E. T. Furlong, S. C. Skrobialowski, J.J. Smith, J.T. Wilson, S.D. Zaugg
By
Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

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

Parking lot sealcoat: a major source of polycyclic aromatic hydrocarbons (PAHs) in urban and suburban environments

Collaborative studies by the City of Austin and the U. S. Geological Survey (USGS) have identified coal-tar based sealcoat—the black, shiny emulsion painted or sprayed on asphalt pavement such as parking lots—as a major and previously unrecognized source of polycyclic aromatic hydrocarbon (PAH) contamination. Several PAHs are suspected human carcinogens and are toxic to aquatic life. Studies in Au
Authors
Peter C. Van Metre, Barbara Mahler, Mateo Scoggins, Pixie A. Hamilton
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Parking lot sealcoat: An unrecognized source of urban polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are a ubiquitous contaminant in urban environments. Although numerous sources of PAHs to urban runoff have been identified, their relative importance remains uncertain. We show that a previously unidentified source of urban PAHs, parking lot sealcoat, may dominate loading of PAHs to urban water bodies in the United States. Particles in runoff from parking lo
Authors
B.J. Mahler, P. C. Van Metre, T. J. Bashara, J.T. Wilson, D. A. Johns

Tire-wear particles as a source of zinc to the environment

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936−1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle dis
Authors
T.B. Councell, K.U. Duckenfield, E. R. Landa, E. Callender
By
Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and major and trace elements in simulated rainfall runoff from parking lots, Austin, Texas, 2003

Samples of creek bed sediment collected near seal-coated parking lots in Austin, Texas, by the City of Austin during 2001–02 had unusually elevated concentrations of polycyclic aromatic hydrocarbons (PAHs). To investigate the possibility that PAHs from seal-coated parking lots might be transported to urban creeks, the U.S. Geological Survey, in cooperation with the City of Austin, sampled runoff a
Authors
Barbara Mahler, Peter C. Van Metre, Jennifer T. Wilson
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Contaminant trends in reservoir sediment cores as records of influent stream quality

When reconstructing water-quality histories from lake and reservoir cores, it is sometimes assumed that the chemical signatures in the cores reflect historical water quality in the influent streams. To investigate this assumption, concentrations of metals, PAHs, and organochlorine compounds in sediment cores were compared to those associated with an influent-stream suspended sediment for three res
Authors
P. C. Van Metre, B.J. Mahler

Collection, analysis, and age-dating of sediment cores from 56 U.S. lakes and reservoirs sampled by the U.S. Geological Survey, 1992-2001

The U.S. Geological Survey Reconstructed Trends National Synthesis study collected sediment cores from 56 lakes and reservoirs between 1992 and 2001 across the United States. Most of the sampling was conducted as part of the National Water-Quality Assessment (NAWQA) Program. The primary objective of the study was to determine trends in particle-associated contaminants in response to urbanization;
Authors
Peter Van Metre, Jennifer T. Wilson, Christopher C. Fuller, Edward Callender, Barbara Mahler
By
Water Resources Mission Area, Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program, Oklahoma-Texas Water Science Center

Trends in chemical concentration in sediment cores from three lakes in New Jersey and one lake on Long Island, New York

Sediment cores were extracted from three lakes in northeastern New Jersey and one lake on western Long Island, New York, as part of the U.S. Geological Survey National Water-Quality Assessment Program. Sediment layers were dated by use of cesium-137 (137Cs), copper, lead, or dichlorodiphenyl-trichloroethane (DDT) profiles. Sediment layers were analyzed for seven selected trace elements, including
Authors
Gary R. Long, Edward C. Callender, Mark A. Ayers, Peter C. Van Metre
By
Water Resources Mission Area, National Water Quality Program, Oklahoma-Texas Water Science Center, Ohio-Kentucky-Indiana Water Science Center

A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We de
Authors
B.J. Mahler, P. C. Van Metre

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. View Media Details
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. View Media Details
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. View Media Details
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. View Media Details
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.

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
Filter Total Items: 42

Major and trace elements in 35 lake and reservoir sediment cores from across the United States, 1994-2001

This report presents data on major and trace element concentrations in sediment cores collected from 35 lakes and reservoirs during 1994-2001. The lakes and reservoirs are located in or near 18 major urban areas across the United States and provide a geographically diverse coverage of urban land use for the country as well as some reference settings. Vertical intervals of the cores were analyzed f
Authors
Peter C. Van Metre, Barbara Mahler, Jennifer T. Wilson, Edward Callender
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Trends in metals in urban and reference lake sediments across the United States, 1970 to 2001

Trends in metals concentrations in sediment cores from 35 reservoirs and lakes in urban and reference settings were analyzed to determine the effects of three decades of legislation, regulation, and changing demographics and industrial practices in the United States on concentrations of metals in the environment. Decreasing trends outnumber increasing trends for all seven metals analyzed (Cd, Cr,
Authors
B.J. Mahler, P. C. Van Metre, E. Callender

Effects of hurricanes Katrina and Rita on the chemistry of bottom sediments in Lake Pontchartrain, Louisiana, USA

The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the sediment chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom sediments exce
Authors
P. C. Van Metre, A. J. Horowitz, B.J. Mahler, W.T. Foreman, C. C. Fuller, M.R. Burkhardt, K. A. Elrick, E. T. Furlong, S. C. Skrobialowski, J.J. Smith, J.T. Wilson, S.D. Zaugg
By
Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

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

Parking lot sealcoat: a major source of polycyclic aromatic hydrocarbons (PAHs) in urban and suburban environments

Collaborative studies by the City of Austin and the U. S. Geological Survey (USGS) have identified coal-tar based sealcoat—the black, shiny emulsion painted or sprayed on asphalt pavement such as parking lots—as a major and previously unrecognized source of polycyclic aromatic hydrocarbon (PAH) contamination. Several PAHs are suspected human carcinogens and are toxic to aquatic life. Studies in Au
Authors
Peter C. Van Metre, Barbara Mahler, Mateo Scoggins, Pixie A. Hamilton
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Parking lot sealcoat: An unrecognized source of urban polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are a ubiquitous contaminant in urban environments. Although numerous sources of PAHs to urban runoff have been identified, their relative importance remains uncertain. We show that a previously unidentified source of urban PAHs, parking lot sealcoat, may dominate loading of PAHs to urban water bodies in the United States. Particles in runoff from parking lo
Authors
B.J. Mahler, P. C. Van Metre, T. J. Bashara, J.T. Wilson, D. A. Johns

Tire-wear particles as a source of zinc to the environment

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936−1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle dis
Authors
T.B. Councell, K.U. Duckenfield, E. R. Landa, E. Callender
By
Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and major and trace elements in simulated rainfall runoff from parking lots, Austin, Texas, 2003

Samples of creek bed sediment collected near seal-coated parking lots in Austin, Texas, by the City of Austin during 2001–02 had unusually elevated concentrations of polycyclic aromatic hydrocarbons (PAHs). To investigate the possibility that PAHs from seal-coated parking lots might be transported to urban creeks, the U.S. Geological Survey, in cooperation with the City of Austin, sampled runoff a
Authors
Barbara Mahler, Peter C. Van Metre, Jennifer T. Wilson
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Contaminant trends in reservoir sediment cores as records of influent stream quality

When reconstructing water-quality histories from lake and reservoir cores, it is sometimes assumed that the chemical signatures in the cores reflect historical water quality in the influent streams. To investigate this assumption, concentrations of metals, PAHs, and organochlorine compounds in sediment cores were compared to those associated with an influent-stream suspended sediment for three res
Authors
P. C. Van Metre, B.J. Mahler

Collection, analysis, and age-dating of sediment cores from 56 U.S. lakes and reservoirs sampled by the U.S. Geological Survey, 1992-2001

The U.S. Geological Survey Reconstructed Trends National Synthesis study collected sediment cores from 56 lakes and reservoirs between 1992 and 2001 across the United States. Most of the sampling was conducted as part of the National Water-Quality Assessment (NAWQA) Program. The primary objective of the study was to determine trends in particle-associated contaminants in response to urbanization;
Authors
Peter Van Metre, Jennifer T. Wilson, Christopher C. Fuller, Edward Callender, Barbara Mahler
By
Water Resources Mission Area, Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program, Oklahoma-Texas Water Science Center

Trends in chemical concentration in sediment cores from three lakes in New Jersey and one lake on Long Island, New York

Sediment cores were extracted from three lakes in northeastern New Jersey and one lake on western Long Island, New York, as part of the U.S. Geological Survey National Water-Quality Assessment Program. Sediment layers were dated by use of cesium-137 (137Cs), copper, lead, or dichlorodiphenyl-trichloroethane (DDT) profiles. Sediment layers were analyzed for seven selected trace elements, including
Authors
Gary R. Long, Edward C. Callender, Mark A. Ayers, Peter C. Van Metre
By
Water Resources Mission Area, National Water Quality Program, Oklahoma-Texas Water Science Center, Ohio-Kentucky-Indiana Water Science Center

A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We de
Authors
B.J. Mahler, P. C. Van Metre