Pesticides and Water Quality
Agricultural pesticide use
Access maps, graphs, and data for hundreds of pesticide compounds
Go to the websiteFeatured Study: Pesticides and degradates in our Nation's groundwater
Thousands of pesticides are used on crops and landscaping, are they in our groundwater? According to a new USGS study, the answer is a qualified yes.
Learn MoreFeatured Study: Chemical Mixtures in Small U.S. Streams
Mixtures of organic chemicals are ubiquitous in small U.S. streams, reports a new study by the U.S. Geological Survey. In many streams the mixtures could be affecting stream organisms.
Learn MoreScience Center Objects
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.
Pesticides are used in agriculture, in homes and businesses, on lawns and gardens, along roads, in recreational areas, and on pets and livestock. There are hundreds of different pesticide chemicals in use in the United States. In 2007, about 390 million kilograms (430,000 tons) of pesticides, including herbicides, insecticides, and fungicides, were used in the United States. Pesticides released into the environment for agricultural and nonagricultural purposes can contaminate surface water and groundwater, which are critical sources of drinking water.
This map shows the predicted probability that the sum of concentrations of atrazine and its degradate deethylatrazine (DEA) will exceed 3.0 micrograms per liter (µg/L) in shallow groundwater underlying agricultural lands. Although shallow groundwater is unlikely to be used as a source of drinking water, the 3.0 µg/L threshold shown on this map is EPA’s drinking water standard (Maximum Contaminant Level) for atrazine. About 95% of the nation’s agricultural areas have less than a 10% chance of exceeding this threshold. Atrazine is one of the most extensively used herbicides in the United States, with average annual use over 70 million pounds—primarily for corn and sorghum. (Credit: Paul Stackelberg, USGS)
The USGS, through its National Water Quality Program, researches numerous aspects of pesticides and water quality, and has developed maps, graphics, and tools to aid in understanding where pesticides occur, at what concentrations, and potential consequences.
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Pesticide Use: The tables, maps, and graphs provided on this web site provide estimates of agricultural pesticide use in the conterminous United States for hundreds of pesticides.
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Trends in Pesticide Occurrence in Streams: Use the online tool to view a national maps of trends in pesticide concentrations in streams.
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Concentrations of Pesticides in Water of Potential Human-Health Concern: This searchable online database provides Health-Based Screening Levels (HBSLs) for hundreds of chemicals, including pesticides and degradates.
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Pesticide Toxicity to Aquatic Organisms: The Pesticide Toxicity Index (PTI) can be used to assess the potential toxicity of pesticide mixtures in water to freshwater aquatic organisms. Benchmarks also are available for pesticides in sediment.
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Pesticides and Stream Ecology: The Regional Stream Quality Assessment (RSQA) is assessing how chemical stressors, such as pesticides and nutrients, and physical stressors, such as disturbed streambanks and sedimentation, are affecting the aquatic organisms that live in small streams across the United States.
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Pesticides and Lake Sediment: Many pesticides dissolve in water, but some pesticides, like DDT and chlordane, adhere to sediment and persist for years in the bed sediments of stream and lakes, recording the history of contaminant use in watershed.
Learn more about USGS research on pesticides and related water-quality topics at the web pages below.
Pesticides in Groundwater
Commercial pesticide applicators, farmers, and homeowners apply about 1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States. The use of pesticides has helped to make the United States the largest producer of food in the world and has provided other benefits, but has also been accompanied by concerns about their potential...
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Date published: March 3, 2019Status: Active
Drinking Water and Source Water Research
Reliable drinking water is vital for the health and safety of all Americans. The USGS works with drinking water facilities and municipal suppliers to monitor and assess the quality of the water used as a source for our nation's drinking water needs.
Contacts: Patty Toccalino, Ph.D.Attribution: Water Resources -
Date published: March 3, 2019Status: Active
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.
Contacts: Barbara MahlerAttribution: Water Resources, National Water Quality Program -
Date published: March 2, 2019Status: Active
Water Quality in the Nation’s Streams and Rivers – Current Conditions and Long-Term Trends
The Nation's rivers and streams are a priceless resource, but pollution from urban and agricultural areas pose a threat to our water quality. To understand the value of water quality, and to more effectively manage and protect the Nation's water resources, it's critical that we know the current status of water-quality conditions, and how and why those conditions have been changing over time....
Contacts: Lori SpragueAttribution: Water Resources -
Date published: March 2, 2019Status: Active
Agricultural Contaminants
About 40 percent of the land in the United States is used for agriculture, and agriculture supplies a major part of the our food, feed, and fiber needs. Agricultural chemicals move into and through every component of the hydrologic system, including air, soil, soil water, streams, wetlands, and groundwater.
Attribution: Water Resources -
Date published: March 1, 2019Status: Active
Water-Quality Benchmarks for Contaminants
How does the water quality measure up? It all depends on what the water will be used for and what contaminants are of interest. Water-quality benchmarks are designed to protect drinking water, recreation, aquatic life, and wildlife. Here you’ll find links to some of the most widely used sets of water, sediment, and fish tissue benchmarks and general guidance about their interpretation.
Contacts: Lisa NowellAttribution: Water Resources -
Date published: February 28, 2019Status: Completed
Groundwater Quality in Principal Aquifers of the Nation, 1991–2010
What’s in your groundwater? Learn about groundwater quality in the Principal Aquifers of nine regions across the United States in informative circulars filled with figures, photos, and water-quality information.
Contacts: Leslie A DeSimone, Bruce LindseyAttribution: Water Resources -
Date published: February 28, 2019Status: Active
Predicting Groundwater Quality in Unmonitored Areas
Groundwater provides nearly one-half of the Nation’s drinking water, and sustains the steady flow of streams and rivers and the ecological systems that depend on that flow. Unless we drill a well, how can we know the quality of the groundwater below? Learn about how the USGS is using sophisticated techniques to predict groundwater quality and view national maps of groundwater quality.
Contacts: Paul StackelbergAttribution: Water Resources, National Water Quality Program -
Date published: September 17, 2018Status: Active
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.
Contacts: Barbara MahlerAttribution: Water Resources, National Water Quality Program -
Date published: September 17, 2018Status: Active
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.
Contacts: Barbara MahlerAttribution: Water Resources, National Water Quality Program -
Date published: September 17, 2018Status: Active
Stream Ecology
Who lives in your stream? Rivers and streams, even small ones, are teeming with a vast number of species, including fish, aquatic invertebrates, and algae. Stream ecology is the study of those aquatic species, the way they interrelate, and their interactions with all aspects of these flowing water systems.
Contacts: Daren M Carlisle, Ph.D.Attribution: Water Resources, National Water Quality Program
Below, you’ll find the latest in peer-reviewed journal articles and USGS reports on pesticides and water quality. For more publications on this topic, search the USGS Publications Warehouse. Look here for help using the Pubs Warehouse.
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Year Published: 2006
Pesticides in the Nation's Streams and Ground Water, 1992–2001
This report is one of a series of publications, The Quality of Our Nation's Waters, that describe major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents evaluations of pesticides in streams and ground water based on findings for the first decadal cycle of NAWQA. 'Pesticides in the Nation'...
Gilliom, Robert J.; Barbash, Jack E.; Crawford, Charles G.; Hamilton, Pixie A.; Martin, Jeffrey D.; Nakagaki, Naomi; Nowell, Lisa H.; Scott, Jonathan C.; Stackelberg, Paul E.; Thelin, Gail P.; Wolock, David M.Attribution: Ohio-Kentucky-Indiana Water Science Center, Water Resources, Region 1: North Atlantic-AppalachianView CitationGilliom, R.J., Barbash, J.E., Crawford, C.G., Hamilton, P.A., Martin, J.D., Nakagaki, N, Nowell, L.H., Scott, J.C., Stackelberg, P.E., Thelin, G.P., and Wolock, D.M., 2006, Pesticides in the nation's streams and ground water, 1992–2001: U.S. Geological Survey Circular 1291, The Quality of Our Nation's Waters, 184 p., https://pubs.er.usgs.gov/publication/cir1291.
Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities
Streambed sediment is commonly analyzed to assess occurrence of hydrophobic pesticides and risks to aquatic communities. However, stream biofilms also have the potential to accumulate pesticides and may be consumed by aquatic organisms. To better characterize risks to aquatic life, the U.S. Geological Survey Regional Stream Quality Assessment...
Mahler, Barbara; Schmidt, Travis S.; Nowell, Lisa H.; Qi, Sharon L.; Van Metre, Peter C.; Hladik, Michelle; Carlisle, Daren; Munn, Mark D.; May, JasonCausal factors for pesticide trends in streams of the United States: Atrazine and deethylatrazine
Pesticides are important for agriculture in the United States, and atrazine is one of the most widely used and widely detected pesticides in surface water. A better understanding of the mechanisms by which atrazine and its degradation product, deethylatrazine, increase and decrease in surface waters can help inform future decisions for water-...
Ryberg, Karen R.; Stone, Wesley W.; Baker, Nancy T.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...
Norman, Julia E.; Mahler, Barbara; Nowell, Lisa H.; Van Metre, Peter C.; Sandstrom, Mark W.; Corbin, Mark A.; Qian, Yaorong; Pankow, James F.; Luo, Wentai; Fitzgerald, Nicholas B.; Asher, William E.; McWhirter, Kevin J.Historical changes in fish communities in urban streams of the southeastern U.S. and the relative importance of water-quality stressors
A total of 71 stream sites representing a gradient of urban land use was sampled across the Piedmont of the southeastern U.S. in 2014. Fish data collected (observed) at each site were compared to an expected community based on georeferenced historical (~1950 - ~1990) species occurrence records for stream segments (1:100,000 scale) containing the...
Meador, MichaelProjected 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...
Van Metre, Peter C.; Waite, Ian R.; Qi, Sharon L.; Mahler, Barbara; Terando, Adam; Wieczorek, Michael; Meador, Michael R.; Bradley, Paul M.; Journey, Celeste A.; Schmidt, Travis S.; Carlisle, DarenUse of Set Blanks in Reporting Pesticide Results at the U.S. Geological Survey National Water Quality Laboratory, 2001–15
Executive SummaryBackground.—Pesticide results from the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) are used for water-quality assessments by many agencies and organizations. The USGS is committed to providing data of the highest possible quality to the consumers of its data. A cooperator’s inquiries about specific...
Medalie, Laura; Sandstrom, Mark W.; Toccalino, Patricia L.; Foreman, William T.; ReVello, Rhiannon C.; Bexfield, Laura M.; Riskin, Melissa L.Effects of urban multi-stressors on three stream biotic assemblages
During 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment(NAWQA) project assessed stream quality in 75 streams across an urban disturbance gradient within the Piedmont ecoregion of southeastern United States. Our objectives were to identify primary instream stressors affecting algal, macroinvertebrate...
Waite, Ian R.; Munn, Mark D.; Moran, Patrick W.; Konrad, Christopher P.; Nowell, Lisa H.; Meador, Michael R.; Van Metre, Peter C.; Carlisle, DarenLinking the agricultural landscape of the Midwest to stream health with structural equation modeling
Multiple physical and chemical stressors can simultaneously affect the biological condition of streams. To better understand the complex interactions of land-use practices, water quality, and ecological integrity of streams, the U.S. Geological Survey National Water Quality Assessment Project is conducting regional-scale assessments of stream...
Schmidt, Travis S.; Van Metre, Peter C.; Carlisle, DarenComplex 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...
Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.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...
Van Metre, Peter C.; Alvarez, David; Mahler, Barbara; Nowell, Lisa H.; Sandstrom, Mark W.; Moran, Patrick W.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...
Mahler, Barbara; Van Metre, Peter C.; Burley, Thomas E.; Loftin, Keith A.; Meyer, Michael T.; Nowell, Lisa H.Prediction of pesticide toxicity in Midwest streams
The occurrence of pesticide mixtures is common in stream waters of the United States, and the impact of multiple compounds on aquatic organisms is not well understood. Watershed Regressions for Pesticides (WARP) models were developed to predict Pesticide Toxicity Index (PTI) values in unmonitored streams in the Midwest and are referred to as WARP-...
Shoda, Megan E.; Stone, Wesley W.; Nowell, Lisa H.Below you'll find links to data sets and tools developed for investigation of pesticides.
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Date published: July 9, 2020
Pesticide Toxicity Index (PTI) and maximum Toxic Unit (TUmax) scores and information for fish, cladocerans, and benthic invertebrates from water samples collected at National Water Quality Network sites during Water Years 2013-2017
During 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, collected water samples year-round from the National Water Quality Network – Rivers and Streams (NWQN) and reported on 221 pesticides at 72 sites across the US in agricultural, developed, and mixed land use watersheds. Pesticide Toxicity Index (PTI) scores, a screening-
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Date published: May 28, 2020
Dataset for an ecological risk assessment of Fipronil compounds in U.S. streams
The phenylpyrazole insecticide fipronil and its degradates are a potential surface-water contaminant and toxicant to nontarget species such as aquatic macroinvertebrates. To better understand how fipronil, fipronil sulfide, fipronil sulfone, desulfinyl fipronil, and fipronil amide affect aquatic communities, a 30-day mesocosm experiment was run. Rock trays were colonized with natural be
Attribution: Colorado Water Science Center -
Date published: March 26, 2020
Concentrations of pesticides in sediment in 82 streams and in biofilms in 54 streams in California in 2017
Hydrophobic (sediment-associated) pesticides were measured in sediment samples collected from 82 wadeable streams and in biofilm in 54 of those streams in the Central California Foothills and Coastal Mountains ecoregion.115 current-use and 3 legacy pesticides were measured in stream sediment; 93 of the current-use pesticides and the same 3 legacy pesticides were measured in biofilm. On aver...
Attribution: Oklahoma-Texas Water Science Center -
Date published: January 13, 2020
Pesticides in Daily and Weekly Water Samples from the NAWQA Midwest and Southeast Stream Quality Assessments (2013-2014)
These datasets are one component of the multistressor studies conducted in Midwest streams in 2013 (MSQA) and in Southeast streams in 2014 (SESQA) by the U.S. Geological Survey National Water Quality Assessment Project. High-frequency small-volume autosamplers were deployed at 7 sites each in MSQA and SESQA that collected daily and weekly composite water samples, which were analyzed for
Attribution: Oregon Water Science Center -
Date published: November 27, 2019
Estimated Annual Agricultural Pesticide Use by Major Crop or Crop Group for States of the Conterminous United States, 1992-2017
This data release provides state-level estimates of annual agricultural use of pesticide compounds by major crop or crop group for states in the conterminous United States, for the time period 1992-2017, compiled from data used to make county-level estimates by means of methods described in Thelin and Stone (2013) and Baker and Stone (2015). The source of these data is the same as the
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Date published: November 26, 2019
Estimated Annual Agricultural Pesticide Use for Counties of the Conterminous United States, 2013-17
This data release provides estimates of annual agricultural use of pesticide compounds in counties of the conterminous United States, for years 2013-17, compiled by means of methods described in Thelin and Stone (2013) and Baker and Stone (2015). For all States except California, U.S. Department of Agriculture county-level data for harvested-crop acreage were used in conjunction wit
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Date published: January 1, 2017
National Water-Quality Assessment Project replicate surface water and groundwater pesticide data analyzed by the USGS National Water Quality Laboratory schedule 2437, Water Years 2013-15.
Replicate water-quality samples are collected and prepared in the field and analyzed in the laboratory in identical ways so that they are considered to be the same in composition and analysis (Mueller and others, 2015). This data set includes one table of duplicate National Water-Quality Assessment Project (NAWQA) surface water and groundwater samples collected between October 1, 2012
Attribution: Water Resources, National Water Quality Program -
Date published: January 1, 2017
Pesticides in Weekly Water Samples from the NAWQA Midwest Stream Quality Assessment (2013)
Dissolved pesticides were measured in weekly water samples from 100 wadeable streams across eleven states in the Midwestern U.S. during May-August, 2013, as part of the Midwest Stream Quality Assessment study conducted by the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Project. Of the 100 stream sites, 12 were urban indicator sites and the remaining 8
Attribution: Water Resources, National Water Quality Program -
Date published: January 1, 2017
Watershed characteristics for study sites of the Surface Water Trends project, National Water Quality Program
This product consists of 29 datasets of tabular data and associated metadata for watershed characteristics of 1,530 study sites of the Surface Water Trends (SWT) project of the U.S. Geological Survey’s (USGS) National Water Quality Program (NWQP). The project is conducting national studies of trends in water quality of streams and rivers for periods ranging from 10 to 40 ye
Attribution: National Water Quality Program -
Date published: January 1, 2017
Pesticide concentration and streamflow datasets used to evaluate pesticide trends in the Nation’s rivers and streams, 1992-2012 (input)
In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water-Quality Program. One of the major goals of the NAWQA project is to determine how water-quality conditions change over time. To support that goal, long-term consistent and comparable monitor
Attribution: Water Resources
Pesticide science in the news! Read recent highlights.
What's In Your Stream? Get Online to Find Out!
A new update to an online interactive tool for learning about pesticides, nutrients, and overall stream health in major regions of the U.S. is available from the U.S. Geological Survey’s Regional Stream Quality Assessment.
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Date published: October 9, 2018
Midwest US: What’s in Your Stream? Get Online to Find Out!
An online interactive tool for learning about pesticides, nutrients, and the overall health of Midwest streams is now available from the U.S. Geological Survey. This information can be used by the public and resource managers to better understand the relative effects of these stressors on aquatic organisms in streams.
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Date published: May 1, 2018
Aquatic Critters Can Tell Us a Lot About How to Improve Stream Health
A trio of recently released studies shows how fish, macroinvertebrates, and algae are affected by chemical and physical stressors
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Date published: October 12, 2017
Pesticides, Pollinators, and Pestilence: Protecting Public Health and Pollinators
Tick and mosquito control provides important public health protection, but can also affect pollinator populations. The effects are often dependent on specific local conditions, such as how close the pesticide application is to places pollinators frequent, and when they frequent them.
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Date published: August 9, 2017
Pesticides Prevalent in Midwestern Streams
One hundred small streams in the Midwest were tested for pesticides during the 2013 growing season and found to contain, on average, 52 pesticides per stream
Attribution: Water Resources, National Water Quality Program -
Date published: October 12, 2016
Common Insecticide Identified in Midwestern Streams
Bifenthrin combats pests, but may harm aquatic ecosystems
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Date published: September 16, 2015
Predicting Pesticides in Streams and Rivers: Where is Water Quality at Risk?
A new interactive mapping tool provides predicted concentrations for 108 pesticides in streams and rivers across the Nation and identifies which streams are most likely to exceed water-quality guidelines for human health or aquatic life.
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Date published: August 26, 2015
Trends in River Pesticide Levels Echo Pesticide Use
Trends in pesticide concentrations in 38 major rivers in the U.S. during 1992-2010 reflect large-scale trends in pesticide use and regulatory changes, according to a new study by the U.S. Geological Survey.
Attribution: National Water Quality Program -
Date published: April 1, 2015
USGS Releases Online Tool for Estimating Atrazine Levels in Streams and Rivers
A new online, interactive tool for estimating atrazine concentrations in streams and rivers is now available.
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Date published: September 11, 2014
20-Year Study Shows Levels of Pesticides Still a Concern for Aquatic Life in U.S. Rivers and Streams
Levels of pesticides continue to be a concern for aquatic life in many of the Nation’s rivers and streams in agricultural and urban areas, according to a new USGS study spanning two decades (1992-2011). Pesticide levels seldom exceeded human health benchmarks.