U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3124

November 2012

A Collaboration Between the U.S. Geological Survey and the U.S. Environmental Protection Agency

The Midwest Stream Quality Assessment

Printed on recycled paper

In 2013, the U.S. Geological Survey (USGS) National 

Water-Quality Assessment Program (NAWQA) and USGS Columbia 

Environmental Research Center (CERC) will be collaborating with 

the U.S. Environmental Protection Agency (EPA) National Rivers 

and Streams Assessment (NRSA) to assess stream quality across the 

Midwestern United States. The sites selected for this study are a subset of the larger NRSA, implemented by the EPA, States and Tribes 

to sample flowing waters across the United States (http://water.epa.

gov/type/rsl/monitoring /riverssurvey/index.cfm). The goals are to 

characterize water-quality stressors—contaminants, nutrients, and 

sediment—and ecological conditions in streams throughout the 

Midwest (fig. 1) and to determine the relative effects of these stressors on aquatic organisms in the streams. Findings will contribute 

useful information for communities and policymakers by identifying 

which human and environmental factors are the most critical in controlling stream quality. This collaborative study enhances information provided to the public and policymakers and minimizes costs by 

leveraging and sharing data gathered under existing programs.

In the spring and early summer, NAWQA will sample streams 

weekly for contaminants, nutrients, and sediment. During the same 

time period, CERC will test sediment and water samples for toxicity, 

deploy time-integrating samplers, and measure reproductive effects 

and biomarkers of contaminant exposure in fish or amphibians. 

NRSA will sample sites once during the summer to assess ecological 

and habitat conditions in the streams by collecting data on algal, 

macroinvertebrate, and fish communities and collecting detailed 

physical-habitat measurements. Study-team members from all three 

programs will work in collaboration with USGS Water Science Centers 

and State agencies on study design, execution of sampling and 

analysis, and reporting. 

Objectives

In perennial (year-round) streams in the Midwest,

1. Assess the status of ecological conditions; the 

geographic distribution of spring-summer seasonal 

concentrations of contaminants, nutrients, and sediment; 

and the toxicity of water and sediment. 

2. Assess relations among concentrations of contaminants, 

nutrients, and sediment; toxicity of water and sediment; 

and ecological conditions in the sampled streams. 

3. Identify and evaluate statistically the natural and 

anthropogenic factors in the watersheds affecting 

concentrations of contaminants, nutrients, and sediment, 

and ecological conditions in sampled streams. 

4. Develop models to predict concentrations of 

contaminants, nutrients, and sediment, and, if possible, 

ecological conditions in the region on the basis of 

findings from objectives 2 and 3. 

Approach

As many as 100 sites will be sampled jointly by study partners 

across the region (fig. 1). The jointly sampled sites in the Midwest 

Stream Quality Assessment are expected to include about 50 sites 

selected by the EPA using a probabilistic design, which are a subset of 

the approximately 150 NRSA sites in the midwestern study area, and 

about 50 sites selected by the USGS using a targeted design to ensure 

coverage of a wide range of land-use conditions. In combination, the 

sites sampled will provide the data necessary to assess the water 

quality and ecological condition of streams and to support empirical 

modeling of factors affecting those conditions for extrapolation to 

unsampled streams in the region.

The 50 USGS targeted sites will be added primarily to achieve 

full coverage of stressor levels found in the region, mainly by adding 

reference sites, low-intensity agricultural sites, and urban sites. The 

targeted sites also will include a few sites with long-term data or 

those identified as high priority by the States or USGS Water Science 

Centers in the region, to put study findings in a temporal context and to 

augment local studies. 

IOWA

KANSAS

OHIO

ILLINOIS

NEBRASKA

MISSOURI

MINNESOTA

SOUTH 

DAKOTA

WISCONSIN

INDIANA

MICHIGAN

KENTUCKY

LAKE 

MICHIGAN

95° 90° -85°

45°

40°

0 60 120 240 Miles

0 150 300 75 Kilometers

Base from U.S. Geological Survey digital data

Land cover from Multi-Resolution Land Characteristics Consortium

North American Datum of 1983 (NAD 83)

EXPLANATION

Urban

Forest

Open water

Barren land

Grassland

Pasture/hay

Cultivated crops

Woody wetlands

Figure 1. Midwest Stream Quality Assessment study area. Study-area 

boundary is based on aggregated Level 3 Ecoregions (ecological regions) 

of the United States (http:/www.epa.gov/wed/pages/ecoregions.htm

accessed on October 19, 2012). 
Study Components

Ecological Condition—Algae, benthic macroinvertebrates, and fish 

communities will be sampled and physical habitat assessed once 

during summer 2013. Samples will be collected along multiple 

transects within the stream reach in accordance with USEPA protocols 

(U.S. Environmental Protection Agency, 2009). Additionally, basic 

water chemistry, including nutrient data, will be collected at the same 

time as the biological data.

Water Sampling—By use of depth- and widthintegrating methods, water samples will be collected 

weekly at each site for about 3 months preceding 

the ecological sampling, to capture the heavy agrochemical use and runoff season. Water samples will be 

analyzed for nutrients, suspended sediment, sulfate, 

chloride, and about 250 dissolved pesticides and 

pesticide degradates. 

Integrated Samplers—Passive samplers deployed in streams for 

extended periods will be used to collect dissolved chemicals from 

stream water and mimic the respiratory exposure of aquatic organisms. 

Two types of samplers will be deployed, one type to concentrate hydrophobic contaminants such as polycyclic aromatic hydrocarbons (PAH) 

and the other to concentrate polar chemicals such as water-soluble 

pesticides and degradates. The concurrent deployment of the passive 

samplers with weekly water sampling will also allow 

comparison of contaminant exposure measured by the 

two approaches. 

Sediment Sampling—Streambed sediment will be 

sampled coincident with the ecological sampling. 

Surficial bed sediment will be collected from depositional areas, composited, and sieved. Sediment samples 

will be analyzed for about 25 trace elements and 

120 currently used pesticides at all sites. At sites with 

urban land use in the basin, analyses also will include about 

40 PAHs and about 60 halogenated organic compounds. 

Toxicity Testing—Ambient water samples will be used to conduct 

7-day toxicity tests to measure survival and reproduction of cladocerans 

(Ceriodaphnia) and survival and growth of fish (fathead minnow, 

Pimephales promelas). Bed-sediment samples will be tested by means 

of a 28-day whole-sediment toxicity test with amphipods (Hyalella azteca) or freshwater mussels to 

measure effects on survival and growth. Amphipods 

and mussels are sensitive to many contaminants, 

notably some current-use insecticides, and a number 

of species of freshwater mussels and fish, such as 

the Topeka shiner (Notropis topeka; see photo) are 

endangered in Midwestern streams.

Fish and Amphibian Field Studies—Caged organisms (fathead 

minnows or leopard frogs, Lithobates species) will be deployed at a 

small subset of sites to test whether exposure to atrazine and other 

stressors in the field might cause effects on reproduction and organism 

health, similar to effects observed previously in laboratory exposures 

(Tillitt and others, 2010). Measured endpoints will likely include egg 

production, growth metrics, histopathology, levels of steroid hormones 

and vitellogenin (an egg-related protein), and other biomarkers.

Additional Opportunities

Opportunities are available to gain additional 

valuable information in the region and to optimize 

resources through partnerships with other 

monitoring or research studies. Possible examples 

include additional monitoring at some or all sites 

to evaluate mercury fate and fish contamination; 

analysis for endocrine-disrupting compounds 

in stream water; and analysis for the herbicide 

glyphosate, the most widely used pesticide in the 

region (but one that requires specialized analysis 

and is typically not included in assessments of 

pesticides in streams). To facilitate these and 

additional collaborative studies, the USGS and 

EPA are seeking input from States and other 

interested parties on site selection, local issues and 

priorities, and complementary research topics. 

References

Tillitt, D.E., Papoulias, D.M., Whyte, J.J., 

and Richter, C.A., 2010, Atrazine reduces 

reproduction in fathead minnow (Pimephales 

promelas): Aquatic Toxicology, v. 99, no. 2, 

p. 149–159.

U.S. Environmental Protection Agency, 2009, 

National Rivers and Streams Assessment 

Field Operations Manual: Washington, D.C., 

EPA–841–B–07–009 [variously paged]. 

For Additional Information

Visit the NAWQA Web site to access reports, 

water-quality data, and maps:

http://water.usgs.gov/nawqa.

Visit the EPA Web site to access information on 

the National Rivers and Streams Assessment: 

http://water.epa.gov/type/rsl/monitoring/

riverssurvey/index.cfm.

Or contact:

Peter C. Van Metre 

(512) 927-3506 pcvanmet@usgs.gov

Jeffrey W. Frey

(317) 600-2751 jwfrey@usgs.gov

Ellen Tarquinio

(202) 566-2267 tarquinio.ellen@epa.gov

Shi-Kwun Wang

Konrad Schmidt, MN DNR

All images by Carl Wycoff unless otherwise noted. cc