Timothy Bargar, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 15
The Interagency Coordinating Committee on the validation of alternative methods (ICCVAM) The Interagency Coordinating Committee on the validation of alternative methods (ICCVAM)
Many ICCVAM member agencies are developing new technologies and resources to replace the use of animals for chemical safety testing. These include new platforms such as microphysiological systems (MPS), data resources to support the development of predictive models and quantitative structure–activity relationships (QSARs), and web tools to facilitate data access and visualization.
Authors
Barnett A. Rattner, Timothy Bargar, Paula F.P. Henry
Low-level dietary clothianidin exposure preferentially causes prepupal mortality of monarch butterflies (Danaus plexippus) Low-level dietary clothianidin exposure preferentially causes prepupal mortality of monarch butterflies (Danaus plexippus)
Data from prior research indicate the prepupal stage of the monarch butterfly life cycle is more sensitive to clothianidin exposure than the larval stage. A set of experiments was conducted to determine if the dietary clothianidin exposures that cause prepupal mortality are environmentally relevant. Monarch larvae were raised from egg to pupae on clothianidin-contaminated swamp milkweed...
Authors
Timothy Bargar
Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays from a truck-mounted sprayer Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays from a truck-mounted sprayer
Ground applications of adulticides via a specialized truck-mounted sprayer are one of the most common practices for control of flying adult mosquitoes. Aerosols released to drift through a targeted area persist in the air column to contact and kill flying mosquitoes, but may also drift into adjacent areas not targeted by the applications where it may affect nontarget insects such as...
Authors
Timothy Bargar, Yongxing Jiang
Permethrin contamination of sawgrass marshes and potential risk for the imperiled Klot’s skipper butterfly (Euphyes pilatka klotsi) Permethrin contamination of sawgrass marshes and potential risk for the imperiled Klot’s skipper butterfly (Euphyes pilatka klotsi)
Nontarget effects from mosquito control operations are possible in habitats adjacent to areas targeted by ultra-low-volume (ULV) sprays of permethrin for adult mosquito control. We assessed the risks of permethrin exposure to butterflies, particularly the imperiled Klot's skipper, when exposed to ground-based ULV sprays. Samples of larval host plant leaves (sawgrass) were collected in...
Authors
Timothy Bargar, Michelle Hladik
Mortality and cholinesterase inhibition in butterflies following aerial naled applications for mosquito control on the National Key Deer Refuge Mortality and cholinesterase inhibition in butterflies following aerial naled applications for mosquito control on the National Key Deer Refuge
Natural resource managers are concerned about the impacts of aerial ultra-low volume spray (ULV) of insecticides for mosquito control (i.e., mosquito adulticides) and seek science-driven management recommendations that reduce risk but allow vector control for nearby human populations. Managers at the National Key Deer Refuge (Florida Keys, FL) are concerned for ULV effects upon...
Authors
Timothy Bargar, Chad Anderson, Anthony Sowers
Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need additional data to help estimate risk for wild monarch butterflies exposed...
Authors
Timothy A. Bargar, Michelle L. Hladik, Jaret C. Daniels
Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident
The Deepwater Horizon (DWH) oil spill from April to July of 2010 contaminated Gulf of Mexico waters through release of an estimated 4.1 × 106 barrels of oil. Beginning in June of 2010, semipermeable membrane devices (SPMDs) were deployed near areas with sensitive marine habitats (Alabama Alps and Western Shelf) potentially exposed to that oil. Elevated TPAH50 concentrations, flux rates...
Authors
Timothy Bargar, David Alvarez, Scott A. Stout
Assessment of bird exposure to lead at Tyndall and Beale Air Force Bases, 2016–17 Assessment of bird exposure to lead at Tyndall and Beale Air Force Bases, 2016–17
Soil contamination by lead (Pb) from past small munitions training on Beale Air Force Base, California, and Tyndall Air Force Base, Florida, may result in adverse effects for passerine birds that utilize the locations. A study was conducted during 2016-17 by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service and U.S. Air Force, at both Air Force Bases...
Authors
Timothy A. Bargar
Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators
Tick and mosquito management is important to public health protection. At the same time, growing concerns about declines of pollinator species raise the question of whether vector control practices might affect pollinator populations. We report the results of a task force of the North American Pollinator Protection Campaign (NAPPC) that examined potential effects of vector management...
Authors
Howard S. Ginsberg, Timothy A. Bargar, Michelle L. Hladik, Charles Lubelczyk
Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park
Surface water, sediment, and fish from Biscayne Bay, coastal wetlands adjacent to the Bay, and canals discharging into the Bay were sampled for determination of baseline contamination in Biscayne National Park. While the number of contaminants detected in canal waters was greater during the wet season than the dry season, no seasonal difference was evident for Biscayne Bay or coastal...
Authors
Timothy A. Bargar, Kevin R.T. Whelan, David Alvarez, Kathy R. Echols, Paul H. Peterman
Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands
Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and the sea surface microlayer (SML) were...
Authors
Timothy A. Bargar, David Alvarez, Virginia H. Garrison
Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (<i>Gambusia holbrooki</i>) Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (<i>Gambusia holbrooki</i>)
Background The eastern mosquitofish (Gambusia holbrooki) has the potential to become a bioindicator organism of endocrine disrupting chemicals (EDCs) due to its androgen-driven secondary sexual characteristics. However, the lack of molecular information on G. holbrooki hinders its use as a bioindicator coupled with biomarker data. While traditional gene-by-gene approaches provide insight...
Authors
Erica K. Brockmeier, Fahong Yu, David Moraga Amador, Timothy A. Bargar, Nancy D. Denslow
Contaminants Assessment in the Coral Reefs of the Virgin Islands National Park and Virgin Islands Coral Reef National Monument
USGS collected samples at reef locations within the Virgin Islands National Park and analyzed for the presence of contaminants, organotin compounds, or sunscreen compounds.
Environmental Management of Vector-borne Diseases
Effective management programs for vector-borne pathogens, such as West Nile Virus and the Lyme disease spirochete, are necessary to protect public health. However, some vector control methods, such as landscape manipulations and pesticide applications, can also adversely affect nontarget species and environmentally sensitive natural systems. Efficient targeting and integration of vector control...
Effect of Chronic Neonicotinoid Insecticide Exposure upon Monarch Development
The long-term viability of monarch butterfly ( Danaus plexippus) populations in North America is in doubt.
Risk of Adult Mosquito Control Pesticides to Imperiled Butterflies
Mosquito control on Department of the Interior (DOI) managed lands is a resource management challenge. The pesticides used to control mosquitoes may also affect nontarget organisms whose conservation is one of the primary responsibilities of resource managers.
Baseline Aquatic Contamination and Endocrine Status in Resident Fish Populations of Biscayne National Park and in the Adjacent Coastal Environment
As part of the Comprehensive Everglades Restoration Plan, water managers are planning to use treated wastewater from the South District Wastewater Treatment Plant (WWTP) to supplement the canal waters that will be used to rehydrate wetlands adjacent to the Biscayne National Park (Park).
Mosquito Control Pesticide Impacts to Butterflies: Implications for Imperiled Butterfly Conservation on a National Wildlife Refuge
USGS researchers evaluate the impact of a pesticide on two imperiled butterfly species in the Florida Keys.
Clothianidin concentrations in milkweed leaves that leads to prepupal mortality in monarch butterflies Clothianidin concentrations in milkweed leaves that leads to prepupal mortality in monarch butterflies
A set of experiments was conducted to determine the dietary clothianidin exposures that cause prepupal mortality in the absence of other adverse effects. Monarch larvae were raised from hatch to pupae on clothianidin contaminated swamp milkweed plants. Larval growth, larval survival, and prepupal survival were monitored throughout the experiments in which the exposures ranged from 1.4 –...
Permethrin concentrations on sawgrass collected from National Key Deer Refuge in 2015 Permethrin concentrations on sawgrass collected from National Key Deer Refuge in 2015
Sawgrass (Cladium jamaicense) samples were collected from marshes on five different keys (Big Pine, Torch, Ramrod, Cudjoe, and Sugarloaf Keys) within National Key Deer Refuge in January and June of 2015 and analyzed for contamination by the mosquito control insecticide permethrin. Permethrin was detected on 17 of 57 samples collected in January while it was detected on 40 of 56 samples...
Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays
This dataset contains data of permethrin residues on adult mosquitoes and adult butterflies following their exposure to ultra-low volume (ULV) sprays containing permethrin. The dataset also contains toxicity information for permethrin; first for adult mosquitoes and adult butterflies following their exposure to the ULV sprays, and for adult mosquitoes exposed during toxicity tests to...
Cholinesterase inhibition in butterflies on the National Key Deer Refuge following aerial application of a mosquito control pesticide Cholinesterase inhibition in butterflies on the National Key Deer Refuge following aerial application of a mosquito control pesticide
The data set contains raw data for pesticide (naled) residues on samplers collected after aerial applications over the National Key Deer Refuge in the Florida Keys, and biological response (cholinesterase activity in butterflies and mosquito mortality) for organisms co-located with the residue samplers.
Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption (ver. 2.0, January 2020) Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption (ver. 2.0, January 2020)
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need a tool to estimate risk for wild monarch butterflies exposed to clothianidin...
Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park
Surface water, sediment, and fish from Biscayne Bay, coastal wetlands adjacent to Biscayne Bay, and canals discharging into Biscayne Bay were sampled for determination of baseline contamination in Biscayne National Park. The number of contaminants detected in canal waters was greater during the wet season relative to the dry season, a relation not evident in Biscayne Bay or wetland...
Science and Products
Filter Total Items: 15
The Interagency Coordinating Committee on the validation of alternative methods (ICCVAM) The Interagency Coordinating Committee on the validation of alternative methods (ICCVAM)
Many ICCVAM member agencies are developing new technologies and resources to replace the use of animals for chemical safety testing. These include new platforms such as microphysiological systems (MPS), data resources to support the development of predictive models and quantitative structure–activity relationships (QSARs), and web tools to facilitate data access and visualization.
Authors
Barnett A. Rattner, Timothy Bargar, Paula F.P. Henry
Low-level dietary clothianidin exposure preferentially causes prepupal mortality of monarch butterflies (Danaus plexippus) Low-level dietary clothianidin exposure preferentially causes prepupal mortality of monarch butterflies (Danaus plexippus)
Data from prior research indicate the prepupal stage of the monarch butterfly life cycle is more sensitive to clothianidin exposure than the larval stage. A set of experiments was conducted to determine if the dietary clothianidin exposures that cause prepupal mortality are environmentally relevant. Monarch larvae were raised from egg to pupae on clothianidin-contaminated swamp milkweed...
Authors
Timothy Bargar
Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays from a truck-mounted sprayer Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays from a truck-mounted sprayer
Ground applications of adulticides via a specialized truck-mounted sprayer are one of the most common practices for control of flying adult mosquitoes. Aerosols released to drift through a targeted area persist in the air column to contact and kill flying mosquitoes, but may also drift into adjacent areas not targeted by the applications where it may affect nontarget insects such as...
Authors
Timothy Bargar, Yongxing Jiang
Permethrin contamination of sawgrass marshes and potential risk for the imperiled Klot’s skipper butterfly (Euphyes pilatka klotsi) Permethrin contamination of sawgrass marshes and potential risk for the imperiled Klot’s skipper butterfly (Euphyes pilatka klotsi)
Nontarget effects from mosquito control operations are possible in habitats adjacent to areas targeted by ultra-low-volume (ULV) sprays of permethrin for adult mosquito control. We assessed the risks of permethrin exposure to butterflies, particularly the imperiled Klot's skipper, when exposed to ground-based ULV sprays. Samples of larval host plant leaves (sawgrass) were collected in...
Authors
Timothy Bargar, Michelle Hladik
Mortality and cholinesterase inhibition in butterflies following aerial naled applications for mosquito control on the National Key Deer Refuge Mortality and cholinesterase inhibition in butterflies following aerial naled applications for mosquito control on the National Key Deer Refuge
Natural resource managers are concerned about the impacts of aerial ultra-low volume spray (ULV) of insecticides for mosquito control (i.e., mosquito adulticides) and seek science-driven management recommendations that reduce risk but allow vector control for nearby human populations. Managers at the National Key Deer Refuge (Florida Keys, FL) are concerned for ULV effects upon...
Authors
Timothy Bargar, Chad Anderson, Anthony Sowers
Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need additional data to help estimate risk for wild monarch butterflies exposed...
Authors
Timothy A. Bargar, Michelle L. Hladik, Jaret C. Daniels
Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident
The Deepwater Horizon (DWH) oil spill from April to July of 2010 contaminated Gulf of Mexico waters through release of an estimated 4.1 × 106 barrels of oil. Beginning in June of 2010, semipermeable membrane devices (SPMDs) were deployed near areas with sensitive marine habitats (Alabama Alps and Western Shelf) potentially exposed to that oil. Elevated TPAH50 concentrations, flux rates...
Authors
Timothy Bargar, David Alvarez, Scott A. Stout
Assessment of bird exposure to lead at Tyndall and Beale Air Force Bases, 2016–17 Assessment of bird exposure to lead at Tyndall and Beale Air Force Bases, 2016–17
Soil contamination by lead (Pb) from past small munitions training on Beale Air Force Base, California, and Tyndall Air Force Base, Florida, may result in adverse effects for passerine birds that utilize the locations. A study was conducted during 2016-17 by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service and U.S. Air Force, at both Air Force Bases...
Authors
Timothy A. Bargar
Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators
Tick and mosquito management is important to public health protection. At the same time, growing concerns about declines of pollinator species raise the question of whether vector control practices might affect pollinator populations. We report the results of a task force of the North American Pollinator Protection Campaign (NAPPC) that examined potential effects of vector management...
Authors
Howard S. Ginsberg, Timothy A. Bargar, Michelle L. Hladik, Charles Lubelczyk
Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park
Surface water, sediment, and fish from Biscayne Bay, coastal wetlands adjacent to the Bay, and canals discharging into the Bay were sampled for determination of baseline contamination in Biscayne National Park. While the number of contaminants detected in canal waters was greater during the wet season than the dry season, no seasonal difference was evident for Biscayne Bay or coastal...
Authors
Timothy A. Bargar, Kevin R.T. Whelan, David Alvarez, Kathy R. Echols, Paul H. Peterman
Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands
Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and the sea surface microlayer (SML) were...
Authors
Timothy A. Bargar, David Alvarez, Virginia H. Garrison
Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (<i>Gambusia holbrooki</i>) Custom microarray construction and analysis for determining potential biomarkers of subchronic androgen exposure in the Eastern Mosquitofish (<i>Gambusia holbrooki</i>)
Background The eastern mosquitofish (Gambusia holbrooki) has the potential to become a bioindicator organism of endocrine disrupting chemicals (EDCs) due to its androgen-driven secondary sexual characteristics. However, the lack of molecular information on G. holbrooki hinders its use as a bioindicator coupled with biomarker data. While traditional gene-by-gene approaches provide insight...
Authors
Erica K. Brockmeier, Fahong Yu, David Moraga Amador, Timothy A. Bargar, Nancy D. Denslow
Contaminants Assessment in the Coral Reefs of the Virgin Islands National Park and Virgin Islands Coral Reef National Monument
USGS collected samples at reef locations within the Virgin Islands National Park and analyzed for the presence of contaminants, organotin compounds, or sunscreen compounds.
Environmental Management of Vector-borne Diseases
Effective management programs for vector-borne pathogens, such as West Nile Virus and the Lyme disease spirochete, are necessary to protect public health. However, some vector control methods, such as landscape manipulations and pesticide applications, can also adversely affect nontarget species and environmentally sensitive natural systems. Efficient targeting and integration of vector control...
Effect of Chronic Neonicotinoid Insecticide Exposure upon Monarch Development
The long-term viability of monarch butterfly ( Danaus plexippus) populations in North America is in doubt.
Risk of Adult Mosquito Control Pesticides to Imperiled Butterflies
Mosquito control on Department of the Interior (DOI) managed lands is a resource management challenge. The pesticides used to control mosquitoes may also affect nontarget organisms whose conservation is one of the primary responsibilities of resource managers.
Baseline Aquatic Contamination and Endocrine Status in Resident Fish Populations of Biscayne National Park and in the Adjacent Coastal Environment
As part of the Comprehensive Everglades Restoration Plan, water managers are planning to use treated wastewater from the South District Wastewater Treatment Plant (WWTP) to supplement the canal waters that will be used to rehydrate wetlands adjacent to the Biscayne National Park (Park).
Mosquito Control Pesticide Impacts to Butterflies: Implications for Imperiled Butterfly Conservation on a National Wildlife Refuge
USGS researchers evaluate the impact of a pesticide on two imperiled butterfly species in the Florida Keys.
Clothianidin concentrations in milkweed leaves that leads to prepupal mortality in monarch butterflies Clothianidin concentrations in milkweed leaves that leads to prepupal mortality in monarch butterflies
A set of experiments was conducted to determine the dietary clothianidin exposures that cause prepupal mortality in the absence of other adverse effects. Monarch larvae were raised from hatch to pupae on clothianidin contaminated swamp milkweed plants. Larval growth, larval survival, and prepupal survival were monitored throughout the experiments in which the exposures ranged from 1.4 –...
Permethrin concentrations on sawgrass collected from National Key Deer Refuge in 2015 Permethrin concentrations on sawgrass collected from National Key Deer Refuge in 2015
Sawgrass (Cladium jamaicense) samples were collected from marshes on five different keys (Big Pine, Torch, Ramrod, Cudjoe, and Sugarloaf Keys) within National Key Deer Refuge in January and June of 2015 and analyzed for contamination by the mosquito control insecticide permethrin. Permethrin was detected on 17 of 57 samples collected in January while it was detected on 40 of 56 samples...
Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays Adult mosquito and butterfly exposure to permethrin and relative risk following ULV sprays
This dataset contains data of permethrin residues on adult mosquitoes and adult butterflies following their exposure to ultra-low volume (ULV) sprays containing permethrin. The dataset also contains toxicity information for permethrin; first for adult mosquitoes and adult butterflies following their exposure to the ULV sprays, and for adult mosquitoes exposed during toxicity tests to...
Cholinesterase inhibition in butterflies on the National Key Deer Refuge following aerial application of a mosquito control pesticide Cholinesterase inhibition in butterflies on the National Key Deer Refuge following aerial application of a mosquito control pesticide
The data set contains raw data for pesticide (naled) residues on samplers collected after aerial applications over the National Key Deer Refuge in the Florida Keys, and biological response (cholinesterase activity in butterflies and mosquito mortality) for organisms co-located with the residue samplers.
Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption (ver. 2.0, January 2020) Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption (ver. 2.0, January 2020)
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need a tool to estimate risk for wild monarch butterflies exposed to clothianidin...
Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park Baseline aquatic contamination and endocrine status in a resident fish of Biscayne National Park
Surface water, sediment, and fish from Biscayne Bay, coastal wetlands adjacent to Biscayne Bay, and canals discharging into Biscayne Bay were sampled for determination of baseline contamination in Biscayne National Park. The number of contaminants detected in canal waters was greater during the wet season relative to the dry season, a relation not evident in Biscayne Bay or wetland...