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Barbara J Mahler (Former Employee)

Science and Products

Filter Total Items: 13

Bifenthrin causes trophic cascade and altered insect emergences in mesocosms: implications for small streams Bifenthrin causes trophic cascade and altered insect emergences in mesocosms: implications for small streams

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of...
By
Water Resources Mission Area, National Water Quality Program
Filter Total Items: 24
Black sealcoated pavement contrasts with unsealed pavement
Black newly applied sealcoat contrasts with unsealed asphalt
Black newly applied sealcoat contrasts with unsealed asphalt
Black sealcoated pavement contrasts with unsealed pavement

Black newly applied sealcoat contrasts with unsealed asphalt

Black newly applied sealcoat contrasts with unsealed asphalt

Newly applied coal-tar-based sealcoat is dark black, sharply contrasting with the unsealed asphalt parking lot below. Coal-tar-based sealcoat is a potent source of polycyclic aromatic hydrocarbons (PAHs). 

By
Water Resources
Black sealcoated pavement contrasts with unsealed pavement

Black newly applied sealcoat contrasts with unsealed asphalt

Black newly applied sealcoat contrasts with unsealed asphalt

Newly applied coal-tar-based sealcoat is dark black, sharply contrasting with the unsealed asphalt parking lot below. Coal-tar-based sealcoat is a potent source of polycyclic aromatic hydrocarbons (PAHs). 

By
Water Resources
Worn sealcoated pavement around storm drain
Worn sealcoat around a storm drain.
Worn sealcoat around a storm drain.
Worn sealcoated pavement around storm drain

Worn sealcoat around a storm drain.

Worn sealcoat around a storm drain.

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoated pavement around storm drain

Worn sealcoat around a storm drain.

Worn sealcoat around a storm drain.

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoat around a storm drain.
Worn sealcoat in Milwaukee, WI
Worn sealcoat in Milwaukee, WI
Worn sealcoat around a storm drain.

Worn sealcoat in Milwaukee, WI

Worn sealcoat in Milwaukee, WI

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoat around a storm drain.

Worn sealcoat in Milwaukee, WI

Worn sealcoat in Milwaukee, WI

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Filter Total Items: 106

Legacy and current‐use contaminants in sediments alter macroinvertebrate communities in southeastern US Streams Legacy and current‐use contaminants in sediments alter macroinvertebrate communities in southeastern US Streams

Sediment contamination of freshwater streams in urban areas is a recognized and growing concern. As a part of a comprehensive regional stream‐quality assessment, stream‐bed sediment was sampled from streams spanning a gradient of urban intensity in the Piedmont ecoregion of the southeastern United States. We evaluated relations between a broad suite of sediment contaminants (metals...
Authors
Patrick W. Moran, Nile E. Kemble, Ian R. Waite, Barbara Mahler, Lisa H. Nowell, Peter C. Van Metre
By
Water Resources Mission Area, Ecosystems Mission Area, California Water Science Center, Columbia Environmental Research Center, Oregon Water Science Center, Oklahoma-Texas Water Science Center, Washington Water Science Center

Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of current-use pesticides in daily composite samples to those in weekly composite and weekly discrete samples of surface water from 14 small stream sites. Samples were collected over 10–14 weeks at 7 stream sites in each...
Authors
Julia E. Norman, Barbara Mahler, Lisa H. Nowell, Peter C. Van Metre, Mark W. Sandstrom, Mark A. Corbin, Yaorong Qian, James F. Pankow, Wentai Luo, Nicholas B. Fitzgerald, William E. Asher, Kevin J. McWhirter
By
Water Resources Mission Area, California Water Science Center, National Water Quality Laboratory

Flow modification in the Nation’s streams and rivers Flow modification in the Nation’s streams and rivers

This report summarizes a national assessment of flowing waters conducted by the U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Project and addresses several pressing questions about the modification of natural flows in streams and rivers. The assessment is based on the integration, modeling, and synthesis of monitoring data collected by the USGS and the U.S
Authors
Daren Carlisle, David M. Wolock, Christopher P. Konrad, Gregory J. McCabe, Ken Eng, Theodore E. Grantham, Barbara Mahler
By
Water Resources Mission Area

Projected urban growth in the Southeastern USA puts small streams at risk Projected urban growth in the Southeastern USA puts small streams at risk

Future land-use development has the potential to profoundly affect the health of aquatic ecosystems in the coming decades. We developed regression models predicting the loss of sensitive fish (R2=0.39) and macroinvertebrate (R2=0.64) taxa as a function of urban and agricultural land uses and applied them to projected urbanization of the rapidly urbanizing Piedmont ecoregion of the...
Authors
Peter C. Van Metre, Ian R. Waite, Sharon L. Qi, Barbara Mahler, Adam Terando, Michael Wieczorek, Michael R. Meador, Paul M. Bradley, Celeste A. Journey, Travis S. Schmidt, Daren Carlisle
By
Water Resources Mission Area

Emerging contaminants in groundwater, karst, and the Edwards Aquifer Emerging contaminants in groundwater, karst, and the Edwards Aquifer

Karst aquifers have hydrogeologic characteristics that render them uniquely vulnerable to contamination from emerging contaminants (ECs). ECs comprise numerous chemical groups, including pharmaceuticals, personal-care products, flame retardants, perfluorinated and polyfluorinated compounds, nanoparticles and microplastics. Many ECs have sources, transport pathways, and chemical...
Authors
Barbara Mahler, Marylynn Musgrove
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16 Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16

As questions regarding the influence of increasing urbanization on water quality in the Edwards aquifer are raised, a better understanding of the sources, fate, and transport of compounds of concern in the aquifer—in particular, nutrients and pesticides—is needed to improve water management decision-making capabilities. The U.S. Geological Survey, in cooperation with the San Antonio...
Authors
Stephen P. Opsahl, MaryLynn Musgrove, Barbara Mahler, Rebecca B. Lambert
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

The Midwest Stream Quality Assessment—Influences of human activities on streams The Midwest Stream Quality Assessment—Influences of human activities on streams

Healthy streams and the fish and other organisms that live in them contribute to our quality of life. Extensive modification of the landscape in the Midwestern United States, however, has profoundly affected the condition of streams. Row crops and pavement have replaced grasslands and woodlands, streams have been straightened, and wetlands and fields have been drained. Runoff from...
Authors
Peter C. Van Metre, Barbara Mahler, Daren Carlisle, James F. Coles
By
Water Resources Mission Area

Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA

Simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. These three measures were evaluated at 99 wadable stream sites across 11 states in the Midwestern United States during the summer of 2013 to assess sediment...
Authors
Patrick W. Moran, Lisa H. Nowell, Nile E. Kemble, Barbara Mahler, Ian R. Waite, Peter C. Van Metre
By
Water Resources Mission Area, Columbia Environmental Research Center, Washington Water Science Center

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013...
Authors
Lisa H. Nowell, Patrick W. Moran, Travis S. Schmidt, Julia E. Norman, Naomi Nakagaki, Megan E. Shoda, Barbara Mahler, Peter C. Van Metre, Wesley W. Stone, Mark W. Sandstrom, Michelle L. Hladik
By
Water Resources Mission Area, California Water Science Center, Ohio-Kentucky-Indiana Water Science Center, National Water Quality Laboratory

Complex mixtures of Pesticides in Midwest U.S. streams indicated by POCIS time-integrating samplers Complex mixtures of Pesticides in Midwest U.S. streams indicated by POCIS time-integrating samplers

The Midwest United States is an intensely agricultural region where pesticides in streams pose risks to aquatic biota, but temporal variability in pesticide concentrations makes characterization of their exposure to organisms challenging. To compensate for the effects of temporal variability, we deployed polar organic chemical integrative samplers (POCIS) in 100 small streams across the...
Authors
Peter C. Van Metre, David Alvarez, Barbara Mahler, Lisa H. Nowell, Mark W. Sandstrom, Patrick W. Moran
By
Water Resources Mission Area, National Water Quality Laboratory

Coal-tar-based pavement sealants—a potent source of PAHs Coal-tar-based pavement sealants—a potent source of PAHs

P avement sealants are applied to the asphalt pavement of many parking lots, driveways, and even playgrounds in North America (Figure 1), where, when first applied, they render the pavement glossy black and looking like new. Sealant products used commercially in the central, eastern, and northern United States typically are coal-tarbased, whereas those used in the western United States...
Authors
Barbara Mahler, Peter C. Van Metre
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season

Glyphosate and atrazine are the most intensively used herbicides in the United States. Although there is abundant spatial and temporal information on atrazine occurrence at regional scales, there are far fewer data for glyphosate, and studies that compare the two herbicides are rare. We investigated temporal patterns in glyphosate and atrazine concentrations measured weekly during the...
Authors
Barbara Mahler, Peter C. Van Metre, Thomas E. Burley, Keith A. Loftin, Michael T. Meyer, Lisa H. Nowell
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center, California Water Science Center

Science and Products

Filter Total Items: 13

Bifenthrin causes trophic cascade and altered insect emergences in mesocosms: implications for small streams Bifenthrin causes trophic cascade and altered insect emergences in mesocosms: implications for small streams

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of...
By
Water Resources Mission Area, National Water Quality Program
Filter Total Items: 24
Black sealcoated pavement contrasts with unsealed pavement
Black newly applied sealcoat contrasts with unsealed asphalt
Black newly applied sealcoat contrasts with unsealed asphalt
Black sealcoated pavement contrasts with unsealed pavement

Black newly applied sealcoat contrasts with unsealed asphalt

Black newly applied sealcoat contrasts with unsealed asphalt

Newly applied coal-tar-based sealcoat is dark black, sharply contrasting with the unsealed asphalt parking lot below. Coal-tar-based sealcoat is a potent source of polycyclic aromatic hydrocarbons (PAHs). 

By
Water Resources
Black sealcoated pavement contrasts with unsealed pavement

Black newly applied sealcoat contrasts with unsealed asphalt

Black newly applied sealcoat contrasts with unsealed asphalt

Newly applied coal-tar-based sealcoat is dark black, sharply contrasting with the unsealed asphalt parking lot below. Coal-tar-based sealcoat is a potent source of polycyclic aromatic hydrocarbons (PAHs). 

By
Water Resources
Worn sealcoated pavement around storm drain
Worn sealcoat around a storm drain.
Worn sealcoat around a storm drain.
Worn sealcoated pavement around storm drain

Worn sealcoat around a storm drain.

Worn sealcoat around a storm drain.

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoated pavement around storm drain

Worn sealcoat around a storm drain.

Worn sealcoat around a storm drain.

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoat around a storm drain.
Worn sealcoat in Milwaukee, WI
Worn sealcoat in Milwaukee, WI
Worn sealcoat around a storm drain.

Worn sealcoat in Milwaukee, WI

Worn sealcoat in Milwaukee, WI

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Worn sealcoat around a storm drain.

Worn sealcoat in Milwaukee, WI

Worn sealcoat in Milwaukee, WI

Coal-tar-based sealcoat, a potent source of polycyclic aromatic hydrocarbons (PAHs), abrades into fine particles with time.  Here, runoff containing abraded particles goes down a storm drain and is delivered to a nearby lake. Read more about coal-tar-based sealcoat and PAHs here.

By
Water Resources
Filter Total Items: 106

Legacy and current‐use contaminants in sediments alter macroinvertebrate communities in southeastern US Streams Legacy and current‐use contaminants in sediments alter macroinvertebrate communities in southeastern US Streams

Sediment contamination of freshwater streams in urban areas is a recognized and growing concern. As a part of a comprehensive regional stream‐quality assessment, stream‐bed sediment was sampled from streams spanning a gradient of urban intensity in the Piedmont ecoregion of the southeastern United States. We evaluated relations between a broad suite of sediment contaminants (metals...
Authors
Patrick W. Moran, Nile E. Kemble, Ian R. Waite, Barbara Mahler, Lisa H. Nowell, Peter C. Van Metre
By
Water Resources Mission Area, Ecosystems Mission Area, California Water Science Center, Columbia Environmental Research Center, Oregon Water Science Center, Oklahoma-Texas Water Science Center, Washington Water Science Center

Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of current-use pesticides in daily composite samples to those in weekly composite and weekly discrete samples of surface water from 14 small stream sites. Samples were collected over 10–14 weeks at 7 stream sites in each...
Authors
Julia E. Norman, Barbara Mahler, Lisa H. Nowell, Peter C. Van Metre, Mark W. Sandstrom, Mark A. Corbin, Yaorong Qian, James F. Pankow, Wentai Luo, Nicholas B. Fitzgerald, William E. Asher, Kevin J. McWhirter
By
Water Resources Mission Area, California Water Science Center, National Water Quality Laboratory

Flow modification in the Nation’s streams and rivers Flow modification in the Nation’s streams and rivers

This report summarizes a national assessment of flowing waters conducted by the U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Project and addresses several pressing questions about the modification of natural flows in streams and rivers. The assessment is based on the integration, modeling, and synthesis of monitoring data collected by the USGS and the U.S
Authors
Daren Carlisle, David M. Wolock, Christopher P. Konrad, Gregory J. McCabe, Ken Eng, Theodore E. Grantham, Barbara Mahler
By
Water Resources Mission Area

Projected urban growth in the Southeastern USA puts small streams at risk Projected urban growth in the Southeastern USA puts small streams at risk

Future land-use development has the potential to profoundly affect the health of aquatic ecosystems in the coming decades. We developed regression models predicting the loss of sensitive fish (R2=0.39) and macroinvertebrate (R2=0.64) taxa as a function of urban and agricultural land uses and applied them to projected urbanization of the rapidly urbanizing Piedmont ecoregion of the...
Authors
Peter C. Van Metre, Ian R. Waite, Sharon L. Qi, Barbara Mahler, Adam Terando, Michael Wieczorek, Michael R. Meador, Paul M. Bradley, Celeste A. Journey, Travis S. Schmidt, Daren Carlisle
By
Water Resources Mission Area

Emerging contaminants in groundwater, karst, and the Edwards Aquifer Emerging contaminants in groundwater, karst, and the Edwards Aquifer

Karst aquifers have hydrogeologic characteristics that render them uniquely vulnerable to contamination from emerging contaminants (ECs). ECs comprise numerous chemical groups, including pharmaceuticals, personal-care products, flame retardants, perfluorinated and polyfluorinated compounds, nanoparticles and microplastics. Many ECs have sources, transport pathways, and chemical...
Authors
Barbara Mahler, Marylynn Musgrove
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16 Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16

As questions regarding the influence of increasing urbanization on water quality in the Edwards aquifer are raised, a better understanding of the sources, fate, and transport of compounds of concern in the aquifer—in particular, nutrients and pesticides—is needed to improve water management decision-making capabilities. The U.S. Geological Survey, in cooperation with the San Antonio...
Authors
Stephen P. Opsahl, MaryLynn Musgrove, Barbara Mahler, Rebecca B. Lambert
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

The Midwest Stream Quality Assessment—Influences of human activities on streams The Midwest Stream Quality Assessment—Influences of human activities on streams

Healthy streams and the fish and other organisms that live in them contribute to our quality of life. Extensive modification of the landscape in the Midwestern United States, however, has profoundly affected the condition of streams. Row crops and pavement have replaced grasslands and woodlands, streams have been straightened, and wetlands and fields have been drained. Runoff from...
Authors
Peter C. Van Metre, Barbara Mahler, Daren Carlisle, James F. Coles
By
Water Resources Mission Area

Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA

Simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. These three measures were evaluated at 99 wadable stream sites across 11 states in the Midwestern United States during the summer of 2013 to assess sediment...
Authors
Patrick W. Moran, Lisa H. Nowell, Nile E. Kemble, Barbara Mahler, Ian R. Waite, Peter C. Van Metre
By
Water Resources Mission Area, Columbia Environmental Research Center, Washington Water Science Center

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013...
Authors
Lisa H. Nowell, Patrick W. Moran, Travis S. Schmidt, Julia E. Norman, Naomi Nakagaki, Megan E. Shoda, Barbara Mahler, Peter C. Van Metre, Wesley W. Stone, Mark W. Sandstrom, Michelle L. Hladik
By
Water Resources Mission Area, California Water Science Center, Ohio-Kentucky-Indiana Water Science Center, National Water Quality Laboratory

Complex mixtures of Pesticides in Midwest U.S. streams indicated by POCIS time-integrating samplers Complex mixtures of Pesticides in Midwest U.S. streams indicated by POCIS time-integrating samplers

The Midwest United States is an intensely agricultural region where pesticides in streams pose risks to aquatic biota, but temporal variability in pesticide concentrations makes characterization of their exposure to organisms challenging. To compensate for the effects of temporal variability, we deployed polar organic chemical integrative samplers (POCIS) in 100 small streams across the...
Authors
Peter C. Van Metre, David Alvarez, Barbara Mahler, Lisa H. Nowell, Mark W. Sandstrom, Patrick W. Moran
By
Water Resources Mission Area, National Water Quality Laboratory

Coal-tar-based pavement sealants—a potent source of PAHs Coal-tar-based pavement sealants—a potent source of PAHs

P avement sealants are applied to the asphalt pavement of many parking lots, driveways, and even playgrounds in North America (Figure 1), where, when first applied, they render the pavement glossy black and looking like new. Sealant products used commercially in the central, eastern, and northern United States typically are coal-tarbased, whereas those used in the western United States...
Authors
Barbara Mahler, Peter C. Van Metre
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center

Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season

Glyphosate and atrazine are the most intensively used herbicides in the United States. Although there is abundant spatial and temporal information on atrazine occurrence at regional scales, there are far fewer data for glyphosate, and studies that compare the two herbicides are rare. We investigated temporal patterns in glyphosate and atrazine concentrations measured weekly during the...
Authors
Barbara Mahler, Peter C. Van Metre, Thomas E. Burley, Keith A. Loftin, Michael T. Meyer, Lisa H. Nowell
By
Water Resources Mission Area, Oklahoma-Texas Water Science Center, California Water Science Center
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