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.
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.
NATIONAL SUMMARIES
- Increased mercury fallout near major U.S. cities (Environ. Pollution, 2012)
- Coal-tar sealcoat largest PAH source to U.S. lakes (Sci. Total Env., 2010)
- PAH in coal tar sealcoat a national problem (Env. Sci. & Tech., 2009)
- National-scale trends in organics (Env. Sci. & Tech., 2005)
- National-scale trends in metals (Env. Tox. & Chem., 2006) associated Data Report
- Methods and age dating of cores (USGS SIR 2004-5184)
- Urban trends in PAHs (Env. Sci. & Tech., 2000)
- Rates of decrease in DDT and PCBs (Env. Sci. & Tech., 1998)
- Trends in organochlorine compounds (Env. Sci. & Tech., 1997)
TOPICAL FINDINGS
- Evaluating mercury and 210Pb atmospheric fallout and focusing to lakes (Env. Sci. & Tech., 2009)
- Effects of Hurricanes Katrina and Rita on Lake Pontchartrain sediments (Env. Sci. & Tech., 2006)
- Parking lot sealcoat: an urban source of PAHs (Env. Sci. & Tech., 2005) associated fact sheet, data report
- Chemical response to urbanization, New England, USA (Chalmers et al. 2007)
- Contaminant trends in the Mississippi River Basin (Van Metre and Horowitz 2013)
- Reservoir cores versus stream suspended sediments (Env. Sci. & Tech., 2004)
- Monitoring suspended sediment chemistry (Arch. Env. Contam. & Tox., 2003)
- Metal diagenesis in reservoir cores (J. Paleolimnology, 2000)
LOCAL RESULTS
- PAHs decline after ban on coal-tar sealcoat, Austin, TX (Env. Sci. Technol., 2014)
- Chemical response of particle-associated contaminants in aquatic sediments to urbanization in New England (Contam. Hydro., 2007)
- Lead and zinc in greater Atlanta, Georgia (Env. Sci. & Tech., 2000)
- Trends in White Rock Lake, Texas (J. Paleolimnology, 1997)
Read about additional science related to sediment-associated contaminants and water-quality trends by following the links to web pages below.
Urban Land Use and Water Quality
Pesticides and Water Quality
Metals and Other Trace Elements
Radionuclides
National Water-Quality Project Sampling Methods
Water-Quality Trends
Sediment-Associated Contaminants
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
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
Declining Dioxin concentrations in the Rhone River, France, attest to the effectiveness of emissions controls
Effects of urbanization on mercury deposition and accumulation in New England
PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas
Identification of contamination in a lake sediment core using Hg and Pb isotopic compositions, Lake Ballinger, Washington, USA
An 80-year record of sediment quality in the lower Mississippi River
Spatial and temporal trends in PCBs in sediment along the lower Rhone River, France
Increased atmospheric deposition of mercury in reference lakes near major urban areas
Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes
Dual-core mass-balance approach for evaluating mercury and210Pb atmospheric fallout and focusing to lakes
PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States
The chemical response of particle-associated contaminants in aquatic sediments to urbanization in New England, U.S.A.
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.
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.
NATIONAL SUMMARIES
- Increased mercury fallout near major U.S. cities (Environ. Pollution, 2012)
- Coal-tar sealcoat largest PAH source to U.S. lakes (Sci. Total Env., 2010)
- PAH in coal tar sealcoat a national problem (Env. Sci. & Tech., 2009)
- National-scale trends in organics (Env. Sci. & Tech., 2005)
- National-scale trends in metals (Env. Tox. & Chem., 2006) associated Data Report
- Methods and age dating of cores (USGS SIR 2004-5184)
- Urban trends in PAHs (Env. Sci. & Tech., 2000)
- Rates of decrease in DDT and PCBs (Env. Sci. & Tech., 1998)
- Trends in organochlorine compounds (Env. Sci. & Tech., 1997)
TOPICAL FINDINGS
- Evaluating mercury and 210Pb atmospheric fallout and focusing to lakes (Env. Sci. & Tech., 2009)
- Effects of Hurricanes Katrina and Rita on Lake Pontchartrain sediments (Env. Sci. & Tech., 2006)
- Parking lot sealcoat: an urban source of PAHs (Env. Sci. & Tech., 2005) associated fact sheet, data report
- Chemical response to urbanization, New England, USA (Chalmers et al. 2007)
- Contaminant trends in the Mississippi River Basin (Van Metre and Horowitz 2013)
- Reservoir cores versus stream suspended sediments (Env. Sci. & Tech., 2004)
- Monitoring suspended sediment chemistry (Arch. Env. Contam. & Tox., 2003)
- Metal diagenesis in reservoir cores (J. Paleolimnology, 2000)
LOCAL RESULTS
- PAHs decline after ban on coal-tar sealcoat, Austin, TX (Env. Sci. Technol., 2014)
- Chemical response of particle-associated contaminants in aquatic sediments to urbanization in New England (Contam. Hydro., 2007)
- Lead and zinc in greater Atlanta, Georgia (Env. Sci. & Tech., 2000)
- Trends in White Rock Lake, Texas (J. Paleolimnology, 1997)
Read about additional science related to sediment-associated contaminants and water-quality trends by following the links to web pages below.
Urban Land Use and Water Quality
Pesticides and Water Quality
Metals and Other Trace Elements
Radionuclides
National Water-Quality Project Sampling Methods
Water-Quality Trends
Sediment-Associated Contaminants
Learn more about water quality trends as recorded in sediment cores at the publications below.