# National Water-Quality Assessment Program 

# An Overview Comparing Results from Two Decades of **Monitoring for Pesticides in the Nation’s Streams and Rivers, 1992–2001 and 2002–2011** 

Scientific Investigations Report 2014–5154

**U.S. Department of the Interior U.S. Geological Survey** 

# An Overview Comparing Results from Two **Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers, 1992–2001**  **and 2002–2011**

By Wesley W. Stone, Robert J. Gilliom, and Jeffrey D. Martin

National Water-Quality Assessment Program



# Scientific Investigations Report 2014–5154

**U.S. Department of the Interior U.S. Geological Survey** 

# U.S. Department of the Interior SALLY JEWELL, Secretary **U.S. Geological Survey** Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2014

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Suggested citation: Stone, W.W., Gilliom, R.J., and Martin, J.D., 2014, An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and Rrvers, 1992–2001 and 2002–2011: U.S. Geological Survey Scientific Investigations Report 2014–5154, 23 p.
, http://dx.doi.org/10.3133/sir20145154

.

ISSN 2328-0328 (online) http://dx.doi.org/10.3133/sir20145154

### iii



# Contents

Abstract

.......................................................................................................................................................... 1 Introduction

..................................................................................................................................................... 1 Purpose and Scope

.............................................................................................................................. 2 Pesticide Monitoring Design

.............................................................................................................. 2 Methods

........................................................................................................................................................... 2 Pesticides

............................................................................................................................................... 3 Stream-Site Selection

.......................................................................................................................... 4 Detection Frequency and Concentration Statistics

........................................................................ 4 Land-Use Classifications

..................................................................................................................... 6 Pesticide Occurrence

................................................................................................................................... 7 Concentrations And Benchmark Comparisons

........................................................................................ 8 Summary

........................................................................................................................................................ 10 References Cited

.......................................................................................................................................... 11 Appendix 1

..................................................................................................................................................... 1 3 

# Figures

1. Estimated agricultural use of synthetic organic herbicides, insecticides, and fungicides in the conterminous U.S. during first (1992–2001) and second (2002–11) decades of stream monitoring

.................................................................................................... 3 2. Map showing the national monitoring network for pesticides in streams and rivers included 182 sites during 1992–2001 and 125 sites during 2002–11, with 96 of the sites common to both decades.

................................................................................................................... 5 

### 3. Percentage of time during a year that the most frequently detected pesticides were detected in streams and rivers in relation to land-use classification

....................... 7 4. Pesticides that exceeded chronic Aquatic Life Benchmarks at more than 5 percent of stream sites and percent of streams by land-use classification

..................................... 9


# Tables

1. Minimum samples, per water year, by watershed size

.......................................................... 4 2. Land-use classifications and watershed land-use criteria

........................................................... 6 

### 3. Number of stream sites by land-use classification

................................................................ 6 4. Percent of time one or more pesticides or pesticide degradates were detected in streams, by land-use classification

........................................................................................... 7 5. Percent of streams with one or more pesticide concentration statistics that exceeded a chronic Aquatic Life Benchmark (ALB), by land-use classification

............ 10

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# Conversion Factors and Abbreviations

SI to Inch/Pound **Multiply By**  **To obtain** Area square kilometer (km 2 ) 247.1 acre square kilometer (km 2 ) 0.3861 square mile (mi 2 ) 

### Water year is the 12-month period of October 1, for any given year through September 30, of the following year. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months.



# Abbreviations used in this report

ALB Aquatic Life Benchmark GCMS gas chromatography/mass spectrometry HHB Human Health Benchmark NASQAN National Stream Quality Accounting Network NAWQA National Water-Quality Assessment NLCD National Land Cover Data NLCD06 National Land Cover Data 2006 NLCDe National Land Cover Data enhanced NWQL National Water Quality Laboratory USGS U.S. Geological Survey

# An Overview Comparing Results from Two Decades of **Monitoring for Pesticides in the Nation’s Streams and Rivers, 1992–2001 and 2002–2011** 

By Wesley W. Stone, Robert J. Gilliom, and Jeffrey D. Martin



# Abstract
This report provides an overview of the U.S. Geologi

cal Survey National Water-Quality Assessment program and National Stream Quality Accounting Network findings for pes

ticide occurrence in U.S. streams and rivers during 2002–11 and compares them to findings for the previous decade (1992–2001). In addition, pesticide stream concentrations were compared to Human Health Benchmarks (HHBs) and chronic Aquatic Life Benchmarks (ALBs). The comparisons between the decades were intended to be simple and descrip

tive. Trends over time are being evaluated separately in a series of studies involving rigorous trend analysis. During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time. In con

trast, alachlor, chlorpyrifos, cyanazine, diazinon, EPTC, Dac

thal, and tebuthiuron were detected less frequently in streams during the second decade than during the first decade. Dur

ing 2002–11, only one stream had an annual mean pesticide concentration that exceeded an HHB. In contrast, 17 percent of agriculture land-use streams and one mixed land-use stream had annual mean pesticide concentrations that exceeded HHBs during 1992–2001. The difference between the first and sec

ond decades in terms of percent of streams exceeding HHBs was attributed to regulatory changes. During 2002–11, nearlytwo-thirds of agriculture land-use streams and nearly onehalf of mixed land-use streams exceeded chronic ALBs. For urban land use, 90 percent of the streams exceeded a chronic ALB. Fipronil, metolachlor, malathion, cis-permethrin, and dichlorvos exceeded chronic ALBs for more than 10 percent of the streams. For agriculture and mixed land-use streams, the overall percent of streams that exceeded a chronic ALB was very similar between the decades. For urban land-use streams, the percent of streams exceeding a chronic ALB during 2002–11 nearly doubled that seen during 1992–2001. The reason for this difference was the inclusion of fipronil moni

toring during the second decade. Across all land-use streams, the percent of streams exceeding a chronic ALB for fipronil during 2002–11 was greater than all other insecticides dur

ing both decades. The percent of streams exceeding a chronic ALB for metolachlor, chlorpyrifos, diazinon, malathion, and carbaryl decreased from the first decade to the second decade. The results of the 2002–11 summary and comparison to 1992–2001 are consistent with the results from more rigorous trend analysis of pesticide stream concentrations for individual streams in various regions of the U.S.


# Introduction
The U.S. Geological Survey (USGS) National WaterQuality Assessment (NAWQA) and National Stream Quality Accounting Network (NASQAN) are monitoring programs that collect and report data for national assessments of pesti

cide concentrations in the Nation’s streams and rivers. Gilliom and others (2006) reported findings for the first decade (1992– 2001) of the NAWQA program and found that pesticides or their degradates were present in one or more water samples from every stream included in the assessment; one or more pesticides were detected more than 90 percent of the time in agricultural, urban, and mixed land-use streams; and the most frequently detected pesticides also had the greatest use. This report builds upon the 1992–2001 assessment of pesticides in the Nation’s streams (Gilliom and others, 2006) by summarizing pesticide occurrence in streams during the second decade (2002–11) of NAWQA stream monitor

ing, including pesticide stream concentration data from the NASQAN program, and providing descriptive comparisons between the two decades of pesticide monitoring. Gilliom and others (2006) assessed the occurrence of 83 pesticides and degradates from 186 stream sites that represented agriculture, urban, mixed, and undeveloped land uses during 1992–2001.

### 2 **An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers** Changes in the NAWQA program between the first and second decades reduced the number of monitored stream sites. The sampling design (number of samples to be collected and when they were to be collected) also changed between the decades. Specifically, the 1992–2001 sampling design was a mix of fixed-frequency sampling and high-flow sampling (to char

acterize times of expected higher stream pesticide concentra

tions); however, the 2002–11 sampling design was fixed-fre

quency with minimal high-flow sampling efforts. In addition, the number of pesticides and degradates that were monitored in streams sufficient for a national assessment nearly doubled during the second decade. The changes in the NAWQA pesticide stream monitor

ing program from the first to second decade made it difficult to do simple, stream site to stream site comparisons between the decades and compare directly to the assessment by Gilliom and others (2006). In addition, this assessment differs from the previous assessment by Gilliom and others (2006) because (1) Human Health Benchmarks (HHBs) and chronic Aquatic Life Benchmarks (ALBs) have been updated; (2) some pesticides assessed during 1992–2001 were not sampled at enough sites to attain a reasonable national distribution during 2002–11; (3) land use ancillary data used to group sites have changed over time; (4) the stream-site selection process was revised; and (5) this assessment includes multiple years of data for sites, when available. The inclusion of multiple years of concentra

tion data rather than a single year in the assessment, as was done by Gilliom and others (2006), was evaluated in terms of occurrence and percent of stream sites exceeding an HHB or chronic ALB for 1992–2001. The occurrence of pesticides in streams and the percent of stream sites that exceeded an HHB or chronic ALB for a single year compared to multiple years were all within 10 percent of each other for 1992–2001. Overall, the 1992–2001 results in this report are not markedly different than those reported by Gilliom and others (2006) except in cases where an ALB has been more recently estab

lished. For example, an ALB for metolachlor or S -metolachlor did not exist when Gilliom and others (2006) completed the initial assessment for 1992–2001; however, ALBs for S -meto

lachlor have been established and are used in this assessment. This report uses the most current HHBs and chronic ALBs for assessment of annual pesticide stream concentrations. Acute ALBs were not used in the comparisons between decades because the differences in sampling designs between them would likely bias the comparisons. 

## Purpose and Scope The purpose of this report is to summarize pesticide occurrence in U.S. streams and rivers during 2002–11 in comparison to the previous decade, 1992–2001. This overview focuses on pesticide occurrence (percent of time detected) and pesticide concentrations in relation to HHBs and chronic ALBs. Although pesticide occurrence is compared between the decades for perspective, the comparisons are simple and descriptive, and are not meant as a rigorous trend analysis. Trends are being evaluated separately in a series of studies involving quantitative site-based trend models, including Corn-Belt streams (Sullivan and others, 2009) and urban streams (Ryberg and others, 2010). 

## Pesticide Monitoring Design The national design for monitoring pesticides in streams and rivers has evolved from the combination of two USGS programs, NAWQA and NASQAN. NAWQA stream monitor

ing during 1992–2001 focused on assessing water-quality con

ditions in 51 of the Nation’s river basins, referred to as “Study Units,” on a rotational schedule—20 Study Units during 1992– 95, 16 during 1996–98, and 15 during 1998–2001 (Gilliom and others, 2006). Pesticide samples generally were collected at each stream site by using a combination of fixed-frequencyand high-flow sampling (Gilliom and others, 1995). Fixedfrequency sampling means that a given number of waterquality samples were allocated to each month (more samples for months with expected higher potential for pesticide runoff and fewer samples during months of lower expected potential for pesticide runoff), and the water samples were collected at regularly spaced intervals within each month. High-flow sampling was used to allocate additional water samples to characterize high-flow events during seasonal periods of high pesticide use and potential runoff. Changes to the design of the NAWQA program during 2002–2011 included reduction in the number of long-term stream-monitoring sites, an increasedemphasis on regional assessments, and supplemental highflow sampling was limited to special regional studies. The NASQAN program was redesigned in 1995 to esti

mate the mass flux of pesticides and other constituents at 41 monitoring sites in four large river systems: the Mississippi, the Rio Grande, the Columbia, and the Colorado. Similar to the NAWQA program, water samples generally were collected at each stream site by using a combination of fixed-frequency and high-flow sampling (Hooper and others, 2001). Alsosimilar to the NAWQA program, the frequency of waterquality sampling typically changed seasonally, with more frequent samples during the peak pesticide-runoff months. The NASQAN sampling strategy was revised in 2000 (U.S. Geological Survey, 2010), with reduced monitoring in the Columbia and Colorado River Basins.


# Methods
This report summarizes pesticide stream concentration data from samples collected during 2002–11 and compares the results to findings from 1992–2001. Site selection was based on the number of years with data, watershed size, and frequency of sampling within each year. For a sampling site, all years of sampling that met the minimum sampling criteria were included in the summaries. The summaries for

### Methods **3**

both decades are based on the estimated amount of time a pesticide was detectable at a stream site and the number of times HHBs and chronic ALBs were exceeded. For summary purposes, sampling sites were grouped by dominant land-use classification. 

## Pesticides During any given year more than 400 different pesticides are used in agricultural settings (Stone, 2013). The large num

ber of pesticides in use and the phasing out and introduction of new pesticides make it not possible to monitor all pesti

cides because of budget and method constraints. This report includes a selected subset of pesticides in use over the last two decades that were sampled at enough sites to attain a reason

able national distribution during 2002–11. Pesticides included in this report are listed in appendix 1 (table 1–1). Martin (2009) determined that only pesticide data from a single laboratory and analytical method were sufficiently extensive in time and space for a national assess

ment across decades. Hence, only pesticides and pesticide data that were analyzed at the National Water-Quality Labora

tory (NWQL) by a gas chromatography/mass spectrometry (GCMS) method were included in this report. The NAWQA and NASQAN programs periodically evaluate the full range of pesticides in use to prioritize monitoring to include the most important ones in relation to ecosystem and human health (Norman and others, 2012). This prioritization process also evaluates the likelihood that a pesticide will be found in sur

face water or sediment, based on chemical properties. During 2002–11, there were 123 pesticides and pesticide degradates with sufficient stream concentration data to include in this assessment. Gilliom and others (2006) included 83 pesticides in their assessment of 1992–2001; however, only 47 of these pesticides were sampled at enough sites during 2002–11 for a national-level comparison between the decades. The difference between the 47 pesticides assessed during the first decade and the 123 pesticides assessed during the second decade included 39 (or 51 percent) pesticide degradates; 21 (or 28 percent) insecticides; 8 (or 11 percent) fungicides; and the remaining were herbicides, nematicides, plant growth regulators, and defoliants. Figure 1 shows an overview by one measure—amount used—of how pesticides included in this report relate to total national use and to selected pesticides or groups not included. A large portion of the difference between national total her

bicide use and the proportion included in this report was the result of increased use of glyphosate that came with the rapid adoption of genetically modified crops resistant to glypho

sate, beginning in the mid-1990s. Glyphosate is difficult and costly to measure, and efforts to assess glyphosate have been limited primarily to local or short-term studies. Other types of pesticides not comprehensively included in this report, such as fungicides and neonicotinoid insecticides, are not individu

ally as prominent as glyphosate in terms of amounts applied, but may be environmentally important because of their greater toxicity. Finally, some hydrophobic pesticides, such as legacy organochlorines and pyrethroid insecticides, are important as contaminants of sediment and (or) tissues, but are not often found in filtered-water samples.

0 100 200 300 400 500 600

2010200820062004200220001998199619941992 YearEstimated use, in million pounds

0 20 40 60 80 100 120

200820062004200220001998199619941992 2010 Year Herbicides Insecticides

**Included in assessment Total use** * **EXPLANATION**

**Glyphosate Fungicides**  **Neonicotinoids** *Does not include fumigants or inorganic compounds



## Figure 1. Estimated agricultural use of synthetic organic herbicides, insecticides, and fungicides in the conterminous U.S. during first (1992-2001) and second (2002-11) decades of stream monitoring. (GfK Kynetec, Inc., proprietary data, written commun., December 2011 and July 2013). **Figure 1.** Estimated agricultural use of synthetic organic herbicides, insecticides, and fungicides in the conterminous U.S. during first (1992–2001) and second (2002–11) decades of stream monitoring. (GfK Kynetec, Inc., proprietary data, written commun., December 2011 and July 2013).

### 4 **An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers** 

## Stream-Site Selection
Stream-site selection was based on total number of samples each year, watershed size, and the number of samples during potentially high pesticide runoff months. A year was defined as the water year, beginning October 1 and ending September 30. Stream-site selection was based on modifi

cation of the criteria used in Stone and others (2013). The stream-site selection process began with an evaluation of the number of samples collected for the water year compared to minimums based on watershed size (table 1). Stream sites retained from the previous step were then evaluated to make sure there was at least one sample during the months of May, June, and July. These three months are typically the months of expected higher transport of pesticides to streams for the most heavily used pesticides (Stone and others, 2013). Stream sites retained to this point were then evaluated to ensure that samples were present during times when pesticides are less likely transported to streams in order to better represent their occurrence during the entire water year. Specifically, each stream site could not have a consecutive 3-month period with

out a sample. The stream-site selection process was done by individual pesticide because changing analysis schedules over time caused variations in sample numbers between pesticides for some years. The stream-site selection process also did not limit the selection to a single year; all years of sampling at a stream site that met the selection criteria were included in this summary. Stream sites selected for the summary are shown in figure 2 and listed in appendix 1 (table 1–2).

**Table 1.** Minimum samples, per water year, by watershed size. [km 2 , square kilometer; water year, the 12-month period of October 1, for any given year through September 30, of the following year. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months] **Watershed size (km 2**  **) Minimum number of samples**  Less than 500 16 500 to 4,999 12 5,000 to 50,000 10 Greater than 50,000 8 

## Detection Frequency and Concentration **Statistics** Time-weighted detection frequencies account for the more frequent sample collection during some months than in other months and provide an estimate of the percentage of time (throughout the water year) that a pesticide was detected. The weights were calculated as the amount of time extending from one-half the time interval between an observation and the preceding observation and one-half the time interval extending from the observation to the subsequent observation, divided by the total time in one year. Sample weights for a pesticide at a stream site sum to one for each year; therefore, the sum of the weights for samples with detections represent the percent

age of time that pesticide was detected for that stream site and year. When there were multiple water years for a stream site and pesticide, the median percentage of time detected across the years was used for that stream site and pesticide. Both the mean and median were evaluated for sites and pesticides with multiple water years of data, and there was not a large difference between the two statistics for the sites and pesti

cides used in this summary. Annual concentration statistics were calculated for each stream site and pesticide for comparison to HHBs (Toccalino and others, 2014) and chronic ALBs (U.S. Environmental Protection Agency Office of Pesticide Program, http://www. epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm , accessed July 2013). Specifically, the annual mean concentra

tion for comparison to HHBs, the annual maximum 21-day moving-average concentration for comparison to the chronicinvertebrate ALBs, and the annual maximum 60-day movingaverage concentration for comparison to chronic fish and chronic aquatic community (atrazine) ALBs were calculated for this comparison. Annual mean pesticide concentrations were calculated following the methods described in Larson and others (2004). Specifically, each observed concentration was weighted according to the amount of time it was used to represent the pesticide concentration in the stream. The weights were calcu

lated as the amount of time extending from one-half the time interval between an observation and the preceding observation and one-half the time interval extending from the observa

tion to the subsequent observation, divided by the total time in 1 year. Censored observations complicate the calculation of annual mean concentrations. As described in Larson and others (2004), if less than 10 percent of the weighted data for a site, pesticide, and year combination were censored, censored observations were replaced by one-half the censoring thresh

old reported by the laboratory. If more than 10 percent of the weighted data were censored, and there were at least 20 annual observations with at least 10 uncensored observations and at least 33 percent of the sample weights were represented by uncensored observations, then the log-regression method (Gil

liom and Helsel, 1986; Helsel and Gilliom, 1986) was used to approximate the annual mean concentration. Otherwise, the annual mean concentration was considered to be censored at the censoring threshold reported by the laboratory. For stream sites and pesticides with multiple years of data, if an HHB was exceeded for a pesticide in any year during the first or second decade then the HHB was considered exceeded for that stream site and pesticide in the respective decade. Annual maximum moving-average pesticide concentra

tions were calculated following the methods described in Stone and others (2008). Hourly pesticide concentrations were estimated for each stream site through linear interpolation of actual observations. Censored observations were assigned a value of zero for the process of linear interpolation. The hourly concentration estimates were averaged to obtain an

### Methods **5 EXPLANATION** **Sites by land-use classification**MixedUrbanAgriculture**Decade**2002–111992–2001BothFigure 2.The national monitoring network for pesticides in streams and rivers included 182 sites during 1992-2001 and 125 sites during2002-11, with 96 of the sites common to both decades.**Figure 2.**The national monitoring network for pesticides in streams and rivers included 182 sites during 1992–2001 and 125 sites during 2002–11, with 96 of the sites common toboth decades.

### 6 **An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers** estimated daily concentration. The hourly estimates facili

tated computations for days with multiple samples but were not used for other purposes. Moving-average concentrations for the selected durations (21 and 60 days) were computed for each day. The annual maximum moving-average pesti

cide concentrations for each duration were then determined for each stream site/year combination meeting the selection criteria. In most cases, insufficient observations were available for stream sites to calculate moving-average concentrations (21- or 60-day durations) for the beginning of the selected year used in the summary. For example, if the selected year for a stream site was 1993, and there were no observations availableprior to that year. To address this issue and estimate movingaverage concentrations for the beginning of the selected year, the actual observations for the selected year for that stream site and pesticide were used as surrogate observations for the prior year. For stream sites and pesticides with multiple years of data, if a chronic ALB was exceeded for a pesticide in any year during the first or second decade then the chronic ALB was considered exceeded for that stream site and pesticide in the respective decade. For discussion and illustration purposes, the percentage of time pesticides were detected in streams and percent of streams exceeding an HHB or chronic ALB were grouped by land-use classification, which is discussed in the subsequent section. The percentage of time a pesticide was detected in a stream for a land-use classification was normalized by the number of stream sites within that land-use classification to avoid one stream site having more influence than another in the summary. 

## Land-Use Classifications The summaries and comparisons in this report group streams into three land-use classifications: agriculture, urban,and mixed. The land-use classifications and watershed landuse criteria are similar to those used in Gilliom and others (2006), with two modifications. First, the 2006 National Land Cover Data (NLCD06) was used to classify streams based on land use instead of the 1992 enhanced NLCD (NLCDe). Second, the amount of urban land use allowable in a water

shed for the agriculture stream classification was increased from 5 to 10 percent because of the differences in methodol

ogy between NLCDe and NLCD06. In addition, Gilliom and others (2006) included streams with a land-use classification of undeveloped; however, this summary does not include streams with this land-use classification. The land-use classi

fications and watershed land-use criteria are shown in table 2. For some streams (fewer than 5 percent), the area within the watershed that contributed the majority of water to the stream was not reflective of the land use for the total watershed area. Differences between the total watershed area and the area con

tributing the majority of water to a stream can be caused by natural landscape variations and water-management practices. In these cases, the land-use classification for the stream was changed to reflect the land use for the area contributing the majority of water to the stream. The land-use classifications for each stream are shown in figure 2 and listed in appendix 1 (table 1–2). The number of stream sites by land-use classifica

tion is shown in table 3.

**Table 2.** Land-use classifications and watershed land-use criteria.
**Land-use classification Watershed land-use criteria**  Agriculture Greater than 50 percent agricultural land and less than or equal to 10 percent urban land Urban Greater than 25 percent urban land and less than or equal to 25 percent agricultural land Undeveloped Less than or equal to 5 percent urban land and less than or equal to 25 percent agriculture land Mixed All other combinations of agriculture, urban, and undeveloped land use



### Table 3. Number of stream sites by land-use classification.

**Land-use classification Number**  **of stream sites**

**1992–2001 Number**  **of stream sites 2002–11**  **Number of common stream sites**  Agriculture 59 36 28 Mixed 83 59 45 Urban 40 30 23 Total 182 125 96

### Pesticide Occurrence **7** 

# Pesticide Occurrence
One or more pesticides or pesticide degradates were detectable more than 90 percent of the time in streams across all land uses during 2001–11 (table 4). As mentioned previ

ously, the data from this second decade included analysis of nearly twice as many pesticides and pesticide degradates than the first decade; however, the overall percent of time they were detected in streams was nearly the same for both decades (table 4). Variations in percent of time pesticides and pesticide degradates were detected in streams was more evident for individual compounds. Figure 3 shows the percent of time individual compounds were detected in streams. For illustration purposes, only the top 20 most frequently detected pesticides and degradates by land-use classification and decade are shown. The top 20 most frequently detected are a composite of the top 10 most frequently detected from each land use/decade combination. Across all land-use classifications, the herbicides atrazine, deethylatrazine (atrazine degradate), metolachlor, and sima

zine were detected more than 50 percent of the time in streams during 2002–11 (fig. 3). The herbicide prometon was detected more than 50 percent of the time in mixed and urban land-use classification streams during 2002–11. The insecticides fipro

nil, fipronil sulfide (degradate), and carbaryl, were detected more than 50 percent of the time in urban land-use classifica

tion streams during 2002–11. **Table 4.** Percent of time one or more pesticides or pesticide degradates were detected in streams, by land-use classification.

**Land-use classification Percent of time**  **detected for 1992–2001**  **Percent of time detected for** 

**2002–11** Agriculture 98 95 Mixed 96 96 Urban 98 99

ND ND ND

ND

1992

– 200 1 2002 –11

100 0 7550 100 0 52 7550 100 0 52 755025

100 0 7550 100 0 52 7550 100 0 52 755025 **Mixed**

Percentage of time detected **Urban** At ra zine Deethyla tr azine

Met o la chlor

Sima zi ne Prom et on Tebu thi uron

Cyanazine Acet oc hlor

Alac hlo r Metri bu zin EPTC Dacthal

Diazi no n Carb ar yl Ch lo rpyrifos **Agriculture In** **sect ic** **id es** **Her bi** **c id** **es**

3, 4- Di ch l or o an i lin e Fipronil Desu lfi n yl fi pr onil

Fi pr on il s ul f id e Metalaxyl **Mixed**

Percentage of time detected **Urban Agriculture**  **Pesticides measured only during 2002–11**

**Fig. 3** 

## Percentage of time during a year that the most frequently detected pesticides were found in streams and rivers in relation to land-use classification. **Figure 3.** Percentage of time during a year that the most frequently detected pesticides were detected in streams and rivers in relation to land-use classification.

### 8 **An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’ s Streams and Rivers**  The herbicides alachlor, cyanazine, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams (more than 10 percent change) during the second decade than during the first decade. Sullivan and others (2009) found generally decreasing stream concentration trends for alachlor, cyanazine, and EPTC at individual stream sites within the Corn Belt. The decrease in the amount of time these pesticides were detected in streams between decades may reflect use changes from pesticide-registration cancellations and increased use of other herbicides. For example, cyanazine registration was volun

tarily cancelled in the mid-1990s, which was followed by a rapid decline in cyanazine use. Alachlor use steadily declined after the introduction of acetochlor in the mid-1990s, which was an expected result following the registration of acetochlor (de Guzman and others, 2005). In addition, the introduction of genetically modified crops that are resistant to the herbicide, glyphosate, has seen rapid adoption over the course of the last two decades with a corresponding decrease in other herbicides over the same time period (fig. 1). The or ganophosphate insecticides chlorpyrifos and diazinon were detected less frequently in streams (more than 10 percent change) during the second decade than during the first decade (fig. 3). Sullivan and others (2009) and Ryberg and others (2010) found generally decreasing stream concentra

tion trends for these two pesticides at individual stream sites in agricultural and urban land-use areas, respectively. The change in detection frequency between the two decades for these pesticides reflects registration changes and changes in pesti

cide-use patterns. Various uses of chlorpyrifos and diazinon, primarily residential, began being voluntarily cancelled during the late-1990s, and these regulatory changes continued into the early-2000s. In addition, fipronil was first registered for use in the United States in 1996 (Jackson and others, 2009) and was suggested as an alternative to organophosphate insecticides forresidential and commercial turf applications during the early2000s (U.S. Environmental Protection Agency, 2001). Fipronil was detected in streams across all land-use clas

sifications from 17 to 63 percent of the time during 2002–11 (fig. 3); however, fipronil was not included in the NAWQA and NASQAN efforts during 1992–2001 because it was not registered for use until 1996. Ryberg and others (2010) found a preponderance of increasing fipronil stream concentration trends for urban land-use streams from 2000 to 2008. An important consideration when comparing detec

tion frequencies over time is the possible impacts of analysis instrument changes. The assumption is that improvements in laboratory instrumentation could result in increased detection sensitivity over time. Alternatively, changes in instrumenta

tion over time could possibly result in decreased sensitivity over time. Ryberg and others (2010) evaluated detections of trace concentrations in duplicate quality-control water samples collected from 1994 to 2005. They found that for most of the pesticides evaluated, improvements to instrumentation did not result in changes to detection sensitivities through time. However, instrumentation improvements did increase the detection sensitivity for tebuthiuron and carbaryl (Ryberg and others, 2010). As discussed previously, the amount of time tebuthiuron was detected in streams decreased from the first to the second decade (fig. 3); therefore, improvements to instrumentation was not a factor for this pesticide. For carba

ryl, the differences in detection frequency between the first and second decades were less than 10 percent in all land-use classifications.


# Concentrations And Benchmark **Comparisons** Annual mean pesticide concentrations in streams were compared to HHBs to provide perspective; however, these comparisons are not appropriate for assessing compliance with drinking-water regulations, which are applied to treated water. The pesticide stream concentrations used in this report represent untreated water from sites that are not located at drinking-water intakes. During 2002–11, one agriculture land-use stream had an annual mean pesticide concentration that exceeded an HHB (atrazine), and no urban or mixed land-use streams had annual mean pesticide concentrations that exceeded HHBs. In contrast, 17 percent of the agriculture land-use streams and 5 percent of mixed land-use streams exceeded HHBs during 1992–2001. During the previous decade, alpha-HCH (lin

dane), atrazine, cyanazine, molinate, dieldrin, and propargite annual mean concentrations exceeded HHBs in 10 agriculture and 4 mixed land-use streams. The differences in the percent of streams exceeding an HHB between the first and second decade are related to regulatory and use changes. Throughout the last three decades, various lindane uses were voluntarily cancelled by registrants; the last remaining uses were can

celled in 2006. Sullivan and others (2009) found downward trends in atrazine concentrations measured in agriculture streams of the Corn Belt. As mentioned previously, cyanazine registration was voluntarily cancelled in the mid-1990s, and cyanazine use sharply declined from the first to the second decade. During the early-2000s, molinate registration was vol

untarily cancelled, and use sharply declined during 2002–11. Dieldrin registration was voluntarily cancelled during the late-1980s, and certain uses of propargite were voluntarily cancelled during the mid-1990s. Pesticide concentrations in streams were compared to chronic ALBs. Acute ALBs were not used because thesampling frequencies do not adequately represent the highest concentrations that may be present in a stream during the year (Crawford, 2004). In addition, differences in sampling designs between the two decades limit comparisons between the decades based on the highest concentrations measured in streams. Specifically, sampling during the first decade included samples targeting high-flow events during the season when pesticides were expected to be transported to streams,

### Concentrations And Benchmark Comparisons **9** while sampling during the second decade maintained a fixed-frequency sampling design. Therefore, comparison of the highest pesticide stream concentrations between the two decades would be biased. During 2002–11, nearly two-thirds of agriculture land-use classification streams and nearly one-half of mixed land-use classification streams exceeded a chronic ALB (table 5). For urban land-use classification streams, 90 percent exceeded a chronic ALB. The insecticide fipronil exceeded chronic ALBs for more than 20 percent of the streams across all land-use classifications (fig. 4). The herbicide metolachlor (chronic ALB for S -metolachlor) exceeded chronic ALBs for more than 10 percent of agriculture and mixed land-use streams. Similarly, the insecticide malathion exceeded chronic ALBs for more than 10 percent of agriculture and urban land-use streams. The insecticides cis-permethrin (chronic ALB for per

methrin) and dichlorvos exceeded chronic ALBs for more than 10 percent of mixed and urban land-use streams, respectively. Overall, the percent of streams with pesticides that exceeded a chronic ALB was very similar between the two decades for the agriculture and mixed land-use groups (table 5). In terms of pesticides that were evaluated dur

ing both decades, the percent of urban land-use streams that exceeded a chronic ALB during the second decade was about the same as that for the first decade. However the inclusion of fipronil and dichlorvos during the second decade nearly doubled the percent of urban land-use streams that exceeded a chronic ALB during the second decade in comparison to the first decade (table 5; fig. 4). During 2002–11, there were 21 pesticides that exceeded chronic ALBs compared to 16 that exceeded chronic ALBs during 1992–2001. Figure 4 shows a subset of the pesticides that had annual concentration statistics that exceeded a chronic ALB (pesticides and degradates that exceeded a chronic ALB for more than 5 percent of the stream sites, by pesticide and land-use classification). The second decade had a lower percent of streams exceeding a chronic ALB for the herbicide metolachlor than the first decade for all land-use classifica

tions. For the agriculture land-use streams, this difference was greater than 10 percent. During the last part of the first decade

**Figure 4.** Pesticides that exceeded chronic Aquatic Life Benchmarks at more than 5 percent of stream sites and percent of streams by land-use classification. **Urban** Metolachlor
Atrazine

Diazinon
Malathion Chlorpyrifos Carbaryl Azinphos methyl

cis-Permethrin
Disulfoton
Parathion **Agriculture**

1992–2001 2002–11 **Mixed**

**Urban** Fipronil Fipronil sulfone Dichlorvos **Agriculture Mixed**  0 50403020 70 10 50 0 60 403020 70 10 60 0 50403020 70 10 60

0 50403020 70 10 60 0 50403020 70 10 50 0 60 403020 70 10 60 Percent of stream sites exceeding chronic Aquatic Life Benchmarks

Percent of stream sites exceeding chronic Aquatic Life Benchmarks **Pesticides measured only during 2002–11 He** **rbicides Insecticides** 

Figure 4. Pesticides that exceeded chronic Aquatic Life Benchmarks at more than 5 percent of stream sites and percent of streams by land-use classification.

### 10 **An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers**

**Table 5.** Percent of streams with one or more pesticide concentration statistics that exceeded a chronic Aquatic Life Benchmark (ALB), by land-use classification.

**Land-use classification**  **Percent of streams exceeding**  **ALB 1992–2001 Percent of streams**  **exceeding ALB 2002–11**  Agriculture 69 61 Mixed 45 46 Urban 53 90 

### replaced by the resolved isomer S -metolachlor, which reduces the amount of pesticide required for the same agronomic effect (Hartzler, 2000). Although metolachlor was detected in streams for nearly the same amount of time for both decades (fig. 3), the decreased use (in terms of mass applied) because of the introduction of S -metolachlor likely contributed to the decrease in the percent of streams that exceeded a chronic ALB during 2002–11 when compared to 1992–2001. For streams in the urban land-use classification group, the organophosphate insecticides chlorpyrifos, diazinon, and malathion, and the carbamate insecticide carbaryl all had decreases (greater than 10 percent) in the percent of streams exceeding a chronic ALB from the first decade to the second decade (fig. 4). This is consistent with the decreasing stream concentration trends found by Ryberg and others (2010) for chlorpyrifos and diazinon in individual urban land-use streams. These pesticides also were detected less frequently in streams during 1992–2001 compared to 2002–11 (fig. 3). In contrast, the percent of streams, across all land-use classifica

tions, exceeding a chronic ALB for fipronil during the second decade was greater than all other insecticides during both decades. As discussed previously, fipronil registration and use began toward the end of the first decade and was a suggested alternative for organophosphate insecticides during the second decade. 

# Summary
This report provides an overview of U.S. Geological Survey National Water-Quality Assessment (NAWQA) and National Stream Quality Accounting Network (NASQAN) findings for pesticide occurrence (percent of time pesticides were detected) in U.S. streams during 2002–11 and compares them to findings during 1992–2001. In addition, pesticide stream concentrations are compared to Human Health Bench

mark (HHBs) and chronic Aquatic Life Benchmark (ALBs) and differences between the decades discussed. Direct and simple, one to one comparisons of pesticides in stream water between the two decades are not possible because of changes in stream sampling sites, sampling designs, and pesticides monitored within the programs over the last two decades. The comparisons in this report are from a site selection and land-use classification based on 2002–11 information that is applied to evaluate results for the 1992– 2001 sites. In addition, the most current chronic ALBs are used in comparison to annual concentration statistics. During 2002–11, atrazine, deethylatrazine (atrazine degradate), carbaryl, fipronil, fipronil sulfide (fipronil deg

radate), metolachlor, prometon, and simazine were detected more than 50 percent of the time in streams. One or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all land uses during both decades. The overall amount of time pesticides were detected in streams was nearly the same between the first and second decades. However, there were differences between the two decades when comparing individual pesticides. The herbi

cides alachlor, cyanazine, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams during 2002–11 than during 1992–2001. Regulatory changes and the increased use of acetochlor and glyphosate between the first decade and the second decade may be contributing to the decrease in the amount of time these pesticides were detected in streams. The organophosphate insecticides diazinon and chlorpyrifos were detected less frequently during 2002–11 than during 1992– 2001. Product registration changes as well as the registration of the insecticide fipronil during the last part of the first decade may be contributing to the decrease in the amount of time these pesticides were detected in streams. When stream concentration statistics were compared to HHBs, only one agriculture land-use stream had an annual mean pesticide concentration that exceeded an HHB (atrazine) during 2002–11. In contrast, during 1992–2001, about 17 per

cent of the agriculture land-use streams and one mixed landuse stream exceeded HHBs. The HHB exceedance difference between the first and second decades was the result of regula

tory changes; specifically, cancellation of pesticide registration and subsequent decreased use. During 2002–11, most agriculture and urban land-use classification streams and nearly one-half of mixed land-use classification streams had pesticide concentration statistics that exceeded a chronic ALB. The overall percent of streams that exceeded a chronic ALB was very similar between the two decades for agricultural and mixed land-use classification streams. However, for urban land-use classification streams the percent of streams exceeding a chronic ALB during 2002– 11 nearly doubled that seen during 1992–2001. The inclusion of fipronil and dichlorvos monitoring during 2002–11 was the reason for this difference. The summaries and comparisons between the two decades in this report were intended to be simple and descrip

tive overviews and not substitutes for more quantitative trend analysis that account for streamflow and other factors. Pesticide stream concentration trends at individual stream sites have been evaluated with more rigorous analysis methods for regions of the U.S. and selected time periods during these decades (Sullivan and others, 2009; Ryberg and others, 2010). Pesticide stream concentration trends using NAWQA and NASQAN results will continue to be evaluated in a series of studies involving quantitative site-based trend models.

### References Cited **11** 

# References Cited
Crawford, C.G., 2004, Sampling strategies for estimating acute and chronic exposures of pesticides in streams: Jour

nal of the American Water Resources Association, v. 40, no. 2, p. 485–502, DOI:10.1111/j.1752-1688.2004.tb01045.x. de Guzman, N.P., Hendley, P., Gustafson, D.I., van Wesen

beeck, I., Klein, A.J., Fuhrman, J.D., Travis, K., Simmons, N.D., Teskey, W.E., and Durham, R.B, 2005, The Aceto

chlor Registration Partnership state ground water moni

toring program: Journal of Environmental Quality, v. 34, p. 793–803, doi:10.2134/jeq2003.0412. Gilliom, R.J., Alley, W.M., and Gurtz, M.E., 1995, Design

of the National Water-Quality Assessment Program— Occurrence and distribution of water-quality conditions: U.S. Geological Survey Circular 1112, 33 p. Gilliom, R.J., Barbash, J.E., Crawford, C.G., Hamilton, P.A.,

Martin, J.D., Nakagaki, Naomi, Nowell, L.H., Scott, J.C., Stackelberg, P.E., Thelin, G.P., and Wolock, D.M., 2006, The quality of our Nation’s waters—Pesticides in the Nation’s streams and ground water, 1992–2001: U.S. Geological Survey Circular 1291, 172 p. Gilliom, R.J., and Helsel, D.R., 1986, Estimation of distribu

tional parameters for censored trace level water quality data 1—Estimation techniques: Water Resources Research, v. 22, no. 2, p. 135–146, DOI:10.1029/WR022i002p00135. Hartzler, Bob, 2000, Resolved isomers explained: Ames, Iowa, Iowa State University, Weed Science, accessed February 14, 2014, at http://www.weeds.iastate.edu/mgmt/qtr00-1/ isomers.htm

. Helsel, D.R., and Gilliom, R.J., 1986, Estimation of distri

butional parameters for censored trace level water quality data, 2—Verification and applications: Water Resources Research, v. 22, no. 2, p. 147–155, DOI:10.1029/ WR022i002p00147. Hooper, R.P., Aulenbach, B.T., and Kelly, V.J., 2001, The

National Stream Quality Accounting Network—A fluxbased approach to monitoring the water quality of large rivers: Hydrological Processes, v. 15, p. 1089–1106. Jackson, D., Cornell, C.B., Luukinen, B., Buhl, K., and Stone,

D., 2009, Fipronil Technical Fact Sheet: National Pesticide Information Center, Oregon State University Extension Services, accessed July 21, 2014, at http://npic.orst.edu/ factsheets/fiptech.pdf

. Larson, S.J., Crawford, C.G., and Gilliom, R.J., 2004,

Development and application of Watershed Regressions for Pesticides (WARP) for estimating atrazine concentrationdistributions in streams: U.S. Geological Survey WaterResources Investigations Report 03–4047, 68 p. Martin, J.D., 2009, Sources and preparation of data for assess

ing trends in concentrations of pesticides in streams of the United States, 1992–2006: U.S. Geological Survey Scien

tific Investigations Report 2009–5062, 41 p. Norman, J.E., Kuivila, K.M., and Nowell, L.H., 2012, Priori

tizing pesticide compounds for analytical methods devel

opment: U.S. Geological Survey Scientific Investigations Report 2012–5045, 206 p. Ryberg, K.R., Vecchia, A.V., Martin, J.D., and Gilliom, R.J., 2010, Trends in pesticide concentrations in urban streams in the United States, 1992–2008: U.S. Geological Survey Scientific Investigations Report 2010–5139, 101 p. Stone, W.W., 2013, Estimated annual agricultural pesticide use

for counties of the conterminous United States, 1992–2009: U.S. Geological Survey Data Series 752, 1–p. pamphlet, 14 tables. Stone, W.W., Crawford, C.G., and Gilliom, R.J, 2013, Water

shed Regressions for Pesticides (WARP) models for predict

ing stream concentrations of multiple pesticides: Journal of Environmental Quality, v. 42, no. 6, p. 1838–1851, doi:10.2134/jeq2013.05.0179. Stone, W.W., Gilliom, R.J., and Crawford, C.G., 2008, Water

shed Regressions for Pesticides (WARP) for predicting annual maximum and maximum moving-average concentra

tions of atrazine in streams: U.S. Geological Survey OpenFile Report 2008–1186, 19 p. Sullivan, D.J., Vecchia, A.V., Lorenz, D.L., Gilliom, R.J.,

and Martin, J.D., 2009, Trends in pesticide concentrations in corn-belt streams, 1996–2006: U.S. Geological Survey Scientific Investigations Report 2009–5132, 75 p. Toccalino, P.L., Norman, J.E., and Schoephoester, K.M., 2014,

Health-based screening levels for evaluating water-quality data: U.S. Geological Survey National Water-Quality Assessment Program, updated June 2014, accessed July 22, 2014, at http://water.usgs.gov/nawqa/HBSL

. U.S. Environmental Protection Agency, 2001, FY2001 con

ventional pesticides registration decisions, accessed Febru

ary 14, 2014, at http://www.epa.gov/opprd001/workplan/ regdec2001.pdf

. U.S. Geological Survey, 2010, NASQAN National Stream Quality Accounting Network, 2001–2007 NASQAN design information, accessed September 15, 2011, at http://water. usgs.gov/nasqan/2001_2007_design_info.html

.

### Appendix 13


# Appendix 1.

Table 1–1. Pesticide compounds used in the 1992–2001 and 2002–11 summaries.

....................... 14
Table 1–2. Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries

...................................................................................................................... 18

### 14 **An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers**

**Table 1–1.** Pesticide compounds used in the 1992–2001 and 2002–11 summaries.—Continued [CASRN, Chemical Abstracts Service Registry Number®;—, not applicable] **Pesticide compound (synonym)**  **Type of pesticide compound (parent pesticide, if degradate)**  **CASRN 1**  **Parameter code**  **1992– 2001**  **2002–11**
Acetochlor Herbicide 34256-82-1 49260 Yes Yes Alachlor Herbicide 15972-60-8 46342 Yes Yes 2,6-Diethylaniline Degradate (Alachlor) 579-66-8 82660 Yes Yes 2-Chloro-2,6-diethylacetanilide Degradate (Alachlor) 6967-29-9 61618 Yes alpha-Endosulfan Insecticide 959-98-8 34362 Yes Endosulfan ether Degradate (alpha-Endosulfan) 3369-52-6 61642 Yes Endosulfan sulfate Degradate (alpha-Endosulfan, beta-Endosulfan) 1031-07-8 61590 Yes

Atrazine Herbicide 1912-24-9 39632 Yes Yes Deethylatrazine Degradate (Atrazine) 6190-65-4 04040 Yes Yes Azinphos-methyl (Guthion) Insecticide 86-50-0 82686 Yes Yes Azinphos-methyl-oxon Degradate (Azinphos-methyl) 961-22-8 61635 Yes Benfluralin Herbicide 1861-40-1 82673 Yes Yes 2-Amino-N-isopropylbenzamide Degradate (Bentazon) 30391-89-0 61617 Yes beta-Endosulfan Insecticide 33213-65-9 34357 Yes Bifenthrin Insecticide 82657-04-3 61580 Yes Butylate Herbicide 2008-41-5 04028 Yes Yes Carbaryl Insecticide 63-25-2 82680 Yes Yes 1-Naphthol Degradate (Carbaryl, Napromide) 90-15-3 49295 Yes Carbofuran Insecticide 1563-66-2 82674 Yes Yes 2,5-Dichloroaniline Degradate (Chloramben) 95-82-9 61614 Yes Chlorpyrifos Insecticide 2921-88-2 38933 Yes Yes Chlorpyrifos_oxon Degradate (Chlorpyrifos) 5598-15-2 61636 Yes cis-Permethrin Insecticide 61949-76-6 82687 Yes Yes cis-Propiconazole Fungicide 112721-87-6 79846 Yes Cyanazine Herbicide 21725-46-2 04041 Yes Yes Cycloate Herbicide 1134-23-2 04031 Yes Cyfluthrin Insecticide 68359-37-5 61585 Yes cis-Methyl-3-(2,2-dichlorovinyl)-

2,2-dimethyl-(1-cyclopropane)- carboxylate Degradate (Cyfluthrin) 59897-93-7 79842 Yes

trans-Methyl-3-(2,2-dichlorovinyl)-

2,2-dimethyl-(1-cyclopropane)- carboxylate Degradate (Cyfluthrin) 59897-94-8 79843 Yes

Cypermethrin Insecticide 52315-07-8 61586 Yes Dacthal (DCPA) Herbicide 1861-32-1 82682 Yes Yes Diazinon Insecticide 333-41-5 39572 Yes Yes Diazoxon Degradate (Diazinon) 962-58-3 61638 Yes Dichlorvos Insecticide/Fumigant/Degradate (Naled) 62-73-7 38775 Yes Dicrotophos Insecticide 141-66-2 38454 Yes

### Appendix **15**

**Table 1–1.** Pesticide compounds used in the 1992–2001 and 2002–11 summaries.—Continued [CASRN, Chemical Abstracts Service Registry Number®;—, not applicable] **Pesticide compound (synonym)**  **Type of pesticide compound (parent pesticide, if degradate)**  **CASRN 1**  **Parameter code**  **1992– 2001**  **2002–11**
Dieldrin Dimethoate Disulfoton Disulfoton_sulfone Disulfoton_sulfoxide E-Dimethomorph 3,4-Dichloroaniline EPTC Ethalfluralin Ethion Ethion_monoxon Ethoprophos (Ethoprop)O-Ethyl-O-methyl-S-propylphosphorothioate Fenamiphos Fenamiphos_sulfone Fenamiphos_sulfoxide Fenthion Fenthion_sulfoxide Fipronil Desulfinylfipronil Desulfinylfipronil_amide Fipronil_sulfide Fipronil_sulfone Flumetralin 3-(Trifluoromethyl)aniline Fonofos gamma-HCH (Lindane) alpha-HCH Hexazinone Iprodione 3,5-Dichloroaniline Isofenphos lambda-Cyhalothrin Linuron Malathion Malaoxon Metalaxyl 4-Chloro-2-methylphenol Methidathion Insecticide Insecticide Insecticide Degradate (Disulfoton) Degradate (Disulfoton) Fungicide Degradate (Diuron) Herbicide Herbicide Insecticide Degradate (Ethion) Insecticide Degradate (Ethoprophos)

Nematocide Degradate (Fenamiphos) Degradate (Fenamiphos) Insecticide Degradate (Fenthion) Insecticide Degradate (Fipronil) Degradate (Fipronil) Degradate (Fipronil) Degradate (Fipronil) Plant_Growth_Regulator Degradate (Fluometuron) Insecticide Insecticide Degradate (gamma-HCH) Herbicide Fungicide Degradate (Iprodione) Insecticide Insecticide Herbicide Insecticide Degradate (Malathion) Fungicide Degradate (MCPA) Insecticide 60-57-1 60-51-5 298-04-4 2497-06-5 2497-07-6

— 95-76-1 759-94-4 55283-68-6 563-12-2 17356-42-2 13194-48-4 76960-87-7

22224-92-6 31972-44-8 31972-43-7 55-38-9 3761-41-9 120068-37-3

—

— 120067-83-6 120068-36-2 62924-70-3 98-16-8 944-22-9 58-89-9 319-84-6 51235-04-2 36734-19-7 626-43-7 25311-71-1 91465-08-6 330-55-2 121-75-5 1634-78-2 57837-19-1 1570-64-5 950-37-8 39381 82662 82677 61640 61641 79844 61625 82668 82663 82346 61644 82672 61660

61591 61645 61646 38801 61647 62166 62170 62169 62167 62168 61592 61630 04095 39341 34253 04025 61593 61627 61594 61595 82666 39532 61652 61596 61633 61598 Yes

Yes

Yes Yes

Yes

Yes Yes Yes

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

### 16 **An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers**

**Table 1–1.** Pesticide compounds used in the 1992–2001 and 2002–11 summaries.—Continued [CASRN, Chemical Abstracts Service Registry Number®;—, not applicable] **Pesticide compound (synonym)**  **Type of pesticide compound (parent pesticide, if degradate)**  **CASRN 1**  **Parameter code**  **1992– 2001**  **2002–11**
Metolachlor 2-Ethyl-6-methylaniline Metribuzin Molinate Myclobutanil Napropamide 1,4-Napthaquinone Oxyfluorfen p,p’-DDE 4,4’-Dichlorobenzophenone Paraoxon-ethyl Parathion (Ethyl parathion) Parathion-methyl (Methyl parathion) Paraoxon-methyl Pebulate Pendimethalin Phorate Phorate_oxon Phosmet Phosmet_oxon Profenofos Prometon Prometryn Propachlor Propanil Propargite 2-(4-tert-butylphenoxy)-cyclohexanol Propetamphos Propyzamide (Pronamide) Simazine Sulfotepp Sulprofos Tebuconazole Tebupirimfos Tebupirimfos_oxon Tebuthiuron Tefluthrin Temephos Terbacil Herbicide Degradate (Metolaclor) Herbicide Herbicide Fungicide Herbicide Degradate (Napromide) Herbicide Degradate (DDT) Degradate (DDT, Dicofol) Insecticide/Degradate (Parathion) Insecticide Insecticide Degradate (Methyl parathion) Herbicide Herbicide Insecticide Degradate (Phorate) Insecticide Degradate (Phosmet) Insecticide Herbicide Herbicide Herbicide Herbicide Acaricide Degradate (Propargite) Insecticide Herbicide Herbicide Insecticide Insecticide Fungicide Insecticide Degradate (Tebupirimfos) Herbicide Insecticide Insecticide Herbicide 51218-45-2 24549-06-2 21087-64-9 2212-67-1 88671-89-0 15299-99-7 130-15-4 42874-03-3 72-55-9 90-98-2 311-45-5 56-38-2 298-00-0 950-35-6 1114-71-2 40487-42-1 298-02-2 2600-69-3 732-11-6 3735-33-9 41198-08-7 1610-18-0 7287-19-6 1918-16-7 709-98-8 2312-35-8 1942-71-8 31218-83-4 23950-58-5 122-34-9 3689-24-5 35400-43-2 107534-96-3 96182-53-5

— 34014-18-1 79538-32-2 3383-96-8 5902-51-2 39415 61620 82630 82671 61599 82684 61611 61600 34653 61631 61663 39542 82667 61664 82669 82683 82664 61666 61601 61668 61603 04037 04036 04024 82679 82685 61637 61604 82676 04035 61605 38716 62852 61602 61669 82670 61606 61607 82665 Yes

Yes Yes

Yes

Yes

Yes Yes

Yes Yes Yes

Yes

Yes Yes Yes

Yes Yes

Yes

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

### Appendix **17**

**Table 1–1.** Pesticide compounds used in the 1992–2001 and 2002–11 summaries.—Continued [CASRN, Chemical Abstracts Service Registry Number®;—, not applicable] **Pesticide compound (synonym)**  **Type of pesticide compound (parent pesticide, if degradate)**  **CASRN 1**  **Parameter code**  **1992– 2001**  **2002–11**
Terbufos Insecticide 13071-79-9 82675 Yes Yes Terbufos_sulfone_oxygen_analog Degradate (Terbufos) 56070-15-6 61674 Yes Terbuthylazine Herbicide 5915-41-3 04022 Yes Thiobencarb Herbicide 28249-77-6 82681 Yes Yes 4-Chlorobenzylmethyl_sulfone Degradate (Thiobencarb) 98-57-7 61634 Yes trans-Propiconazole Fungicide 120523-07-1 79847 Yes Triallate Herbicide 2303-17-5 82678 Yes Yes Tribuphos Defoliant 78-48-8 61610 Yes Trifluralin Herbicide 1582-09-8 82661 Yes Yes Z-Dimethomorph Fungicide

— 79845 Yes

1 This report contains CAS Registry Numbers ® , which is a Registered Trademark of the American Chemical Society. CAS recommends the verification of the CASRNs through CAS Client Services SM

.

### 18 **An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon]

**Site number Site name**  **Watershed area (km**  **2 )**  **Land use Number of years**  **1992– 2001**  **2002–11**
01102500 Aberjona River at Winchester, MA 60 Urban 2 01104615 Charles River near Watertown, MA 695 Urban 2 01184000 Connecticut River at Thompsonville, CT 25,000 Mixed 4 3 01209710 Norwalk River at Winnipauk, CT 85 Urban 5 3 01349150 Canajoharie Creek near Canajoharie, NY 155 Agriculture 5 3 01356190 Lisha Kill northwest of Niskayuna, NY 40 Urban 1 3 01357500 Mohawk River at Cohoes, NY 9,110 Mixed 8 2 01403300 Raritan River at Bound Brook, NJ 2,070 Urban 3 6 01403900 Bound Brook at Middlesex, NJ 126 Urban 2 2 01410784 Great Egg Harbor River near Sicklerville, NJ 39 Urban 2 01454700 Lehigh River at Easton, PA 3,520 Mixed 1 01463500 Delaware River at Trenton, NJ 17,600 Mixed 2 2 01464907 Little Neshaminy Creek near Warminster, PA 72 Urban 2 1 01470779 Tulpehocken Creek near Bernville, PA 179 Mixed 2 01472157 French Creek near Phoenixville, PA 152 Mixed 1 01474500 Schuylkill River at Philadelphia, PA 4,900 Mixed 2 01485000 Pocomoke River at Willards, MD 138 Mixed 1 01493112 Chesterville Branch near Crumpton, MD 17 Agriculture 1 01493500 Morgan Creek near Kennedyville, MD 33 Agriculture 3 01555400 East Mahantango Creek at Klingerstown, PA 116 Agriculture 2 01571490 Cedar Run at Eberlys Mill, PA 33 Urban 3 01573095 Bachman Run at Annville, PA 20 Mixed 1 01576540 Mill Creek near Lyndon, PA 141 Mixed 2 01578310 Susquehanna River at Conowingo, MD 70,100 Mixed 2 6 01621050 Muddy Creek at Mount Clinton, VA 37 Agriculture 2 3 01636500 Shenandoah River at Millville, WV 7,880 Mixed 1 01639000 Monocacy River at Bridgeport, MD 449 Mixed 1 01646580 Potomac River at Washington, DC 30,000 Mixed 4 7 01654000 Accotink Creek near Annandale, VA 61 Urban 2 4 02082731 Devils Cradle Creek near Alert, NC 35 Mixed 1 02083500 Tar River at Tarboro, NC 5,750 Mixed 1 02083833 Pete Mitchell Swamp near Penny Hill, NC 45 Agriculture 1 02084160 Chicod Cr near Simpson, NC 109 Mixed 1 1 02084558 Albemarle Canal near Swindell, NC 191 Agriculture 1 02087580 Swift Creek near Apex, NC 54 Urban 5 02089500 Neuse River at Kinston, NC 7,020 Mixed 4 7

### Appendix **19**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon]

**Site number Site name**  **Watershed area (km**  **2 )**  **Land use Number of years**  **1992– 2002–11**  **2001** 02091500 02169570 02174250 02175000 02215100 02226160 02281200 02289034 02306774 02317797 02318500 02326838 02335870 02336300 02338000 02350080 02356980 02359170 02424000 02429500 02444490 02469762 02470500 03049625 03049646 03167000 03176500 03201300 03267900 03274000 03303280 03353637 03357330 03360895 03374100 03378500 Contentnea Creek at Hookerton, NC Gills Creek at Columbia, SC Cow Castle Creek near Bowman, SC Edisto River near Givhans, SC Tucsawhatchee Creek near Hawkinsville, GA Altamaha River near Everett City, GA Hillsboro Canal near Shawano, FL U.S. Sugar Outflow Canal near Clewiston, FL Rocky Creek near Citrus Park, FL Little River near Tifton, GA Withlacoochee River near Quitman, GA Lafayette Creek near Tallahassee, FL Sope Creek near Marietta, GA Peachtree Creek at Atlanta, GA Chattahoochee River near Whitesburg, GA Lime Creek near Cobb, GA Aycocks Creek near Boykin, GA Apalachicola River near Sumatra, FL Cahaba River at Centreville, AL Alabama River at Claiborne, AL Bogue Chitto near Memphis, AL Tombigbee River near Coffeeville, AL Mobile River at Mt. Vernon, AL Allegheny River at New Kensington, PA Deer Creek near Dorseyville, PA Reed Creek at Grahams Forge, VA New River at Glen Lyn, VA Kanawha River at Winfield, WV Mad River near Eagle City, OH Great Miami River at Hamilton, OH Ohio River at Cannelton Dam at Cannelton, IN Little Buck Creek near Indianapolis, IN Big Walnut Creek near Roachdale, IN Kessinger Ditch near Monroe City, IN White River at Hazleton, IN Wabash River at New Harmony, IN 1,910 154 62 7,080

420 36,100 806

73 46 335 3,860 25 80 222 6,250

162 271 49,800

2660 56,900 136 47,800 111,400 29,700 70 669 9,780 30,600 802 9,400 251,200 45 339 146 29,300 75,700 Agriculture Urban Mixed Mixed Mixed Mixed Agriculture Agriculture Urban Mixed Mixed Urban Urban Urban Urban Mixed Mixed Mixed Mixed Mixed Agriculture Mixed Mixed Mixed Urban Mixed Mixed Mixed Agriculture Mixed Mixed Urban Agriculture Agriculture Mixed Agriculture 3 1 2 4 1

3 1

1 3 2 2 1 3 2 1

2 1 1

1 1 1 1 1 3 2 6 3

1 10 5 3 2 2 3

4 1

2 1 3

4

7 4

1 1 3

1 4

3

10 2 2

7 10

### 20 **An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon] **Number of years Watershed area**  **Site number Site name**  **Land use (km**  **2 )**  **1992– 2002–11**  **2001** 03455000 French Broad River near Newport, TN 4,800 Mixed 1 03466208 Big Limestone Creek near Limestone, TN 205 Agriculture 2 1 03467609 Nolichucky River near Lowland, TN 4,370 Mixed 2 1 03526000 Copper Creek near Gate City, VA 277 Mixed 1 03528000 Clinch River above Tazewell, TN 3,820 Mixed 1 03575100 Flint River near Brownsboro, AL 969 Agriculture 3 2 03609750 Tennessee River at Highway 60 near Paducah, 104,500 Mixed 5 4 KY 03612500 Ohio River at Dam 53 near Grand Chain, IL 526,000 Mixed 6 10 04072050 Duck Creek near Howard, WI 247 Agriculture 3 3 04087000 Milwaukee River at Milwaukee, WI 1,810 Mixed 3 2 04159492 Black River near Jeddo, MI 1,200 Agriculture 1 04161820 Clinton River at Sterling Heights, MI 803 Urban 1 2 04175600 River Raisin near Manchester, MI 331 Mixed 1 04178000 St. Joseph River near Newville, IN 1,600 Agriculture 2 04183000 Maumee River at New Haven, IN 5,040 Mixed 1 04186500 Auglaize River near Fort Jennings, OH 858 Agriculture 1 2 04193500 Maumee River at Waterville, OH 16,400 Mixed 5 3 04208504 Cuyahoga River at Cleveland, OH 2,040 Urban 1 04211820 Grand Ri at Harpersfield, OH 1,430 Mixed 1 04213500 Cattaraugus Creek at Gowanda, NY 1,130 Mixed 1 05062500 Wild Rice River at Twin Valley, MN 2,410 Mixed 1 05082625 Turtle River near Arvilla, ND 658 Agriculture 1 05085900 Snake River above Alvarado, MN 566 Agriculture 1 05102490 Red River of the North at Pembina, ND 92,100 Agriculture 5 05288705 Shingle Creek at Minneapolis, MN 73 Urban 1 3 05320270 Little Cobb River near Beauford, MN 336 Agriculture 1 2 05330000 Minnesota River near Jordan, MN 42,000 Agriculture 2 05330902 Nine Mile Creek at Bloomington, MN 116 Urban 1 05331580 Mississippi River at Hastings, MN 96,000 Agriculture 5 3 05420500 Mississippi River at Clinton, IA 221,700 Mixed 6 10 05420680 Wapsipinicon River near Tripoli, IA 897 Agriculture 1 05449500 Iowa River near Rowan, IA 1,080 Agriculture 2 05451210 South Fork Iowa River near New Providence, IA 581 Agriculture 2 5 05455570 English River at Riverside, IA 1,620 Agriculture 1 05464220 Wolf Creek near Dysart, IA 775 Agriculture 2 05465500 Iowa River at Wapello, IA 32,400 Agriculture 5 3

### Appendix **21**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon]

**Site number Site name**  **Watershed area (km**  **2 )**  **Land use Number of years**  **1992– 2002–11**  **2001** 05490500 05525500 05531500 05532500 05553500 05572000 05584500 05586100 05587455 06208500 06279500 06295000 06329500 06713500 06714000 06753990 06754000 06795500 06800000 06800500 06805500 06923150 06934500 07022000 07031692 07043500 07053250 07263620

07288650 07288955 07369500 07373420 07374000 07374525 07375050 07379960 Des Moines River at Keosauqua, IA Sugar Creek at Milford, IL Salt Creek at Western Springs, IL Des Plaines River at Riverside, IL Illinois River at Ottawa, IL Sangamon River at Monticello, IL La Moine River at Colmar, IL Illinois River at Valley City, IL Mississippi River Below Grafton, IL Clarks Fork Yellowstone River near Edgar, MT Bighorn River at Kane, WY Yellowstone River at Forsyth, MT Yellowstone River near Sidney, MT Cherry Creek at Denver, CO South Platte River at Denver, CO Lonetree Creek near Greeley, CO South Platte River near Kersey, CO Shell Creek near Columbus, NE Maple Creek near Nickerson, NE Elkhorn River at Waterloo, NE Platte River at Louisville, NE Dousinbury Creek near Wall Street, MO Missouri River at Hermann, MO Mississippi River at Thebes, IL Fletcher Creek at Memphis, TN Little River Ditch No 1 near Morehouse, MO Yocum Creek near Oak Grove, AR Arkansas River at David D Terry Lock and Dam

below Little Rock, AR Bogue Phalia near Leland, MS Yazoo River near Long Lake, MS Tensas River at Tendal, LA Mississippi River near St. Francisville, LA Mississippi River at Baton Rouge, LA Mississippi River at Belle Chasse, LA Tchefuncte River near Covington, LA Dawson Creek at Baton Rouge, LA 36,400 1,160

291 1,630 28,300

1,430 1,700 69,200 443,700

5,240 40,800 102,000 177,000

1,060 10,000

1,480 25,000 762 955 18,000 221,000 106 1,353,000 1,847,000 79 1,140

134 401,000

1,300 34,800 721 2,915,000 2,926,000 2,727,000 366

39 Agriculture Agriculture Urban Urban Mixed Agriculture Agriculture Mixed Agriculture Mixed Mixed Mixed Mixed Urban Urban Agriculture Mixed Agriculture Agriculture Agriculture Mixed Mixed Mixed Mixed Urban Agriculture Agriculture Mixed Agriculture Mixed Agriculture Mixed Mixed Mixed Mixed Urban 2 1 1 3 2 2 5 5 1 1 3 5 2 4 2 5

5

7 1 6 6 1 2 1 6

3 6 4 6

2 2

2 1

2

6 7

3 4 5

1 3 1 5 4 8

8 8

1 9

3 10

10 7 5 1 1

### 22 **An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon]

**Site number Site name**  **Watershed area (km**  **2 )**  **Land use Number of years**  **1992– 2002–11**  **2001** 07381440 07381495 07381590 07381600 08010000 08012150 08012470 08049240 08051500 08057200 08057410 08064100 08116650 08178800 08180640 08181800 08364000 09153290 09481740 09514000 09517000 10102200 10168000 10171000 10350500 11060400 11074000 11075610 11261100 11262900 11273500 11274538 11274560 11274570 11303500 11390890 Bayou Grosse Tete at Rosedale, LA Atchafalaya River at Melville, LA Wax Lake Outlet at Calumet, LA Lower Atchafalaya River at Morgan City, LA Bayou Des Cannes near Eunice, LA Mermentau River at Mermentau, LA Bayou Lacassine near Hayes, LA Rush Creek at Arlington, TX Clear Creek near Sanger, TX White Rock Creek at Dallas, TX Trinity River below Dallas, TX Chambers Creek near Rice, TX Brazos River near Rosharon, TX Salado Creek at San Antonio, TX Medina River at La Coste, TX San Antonio River near Elmendorf, TX Rio Grande at El Paso, TX Reed Wash near Mack, CO Santa Cruz River at Tubac, AZ Buckeye Canal near Avondale, AZ Hassayampa River near Arlington, AZ Cub River near Richmond, UT Little Cottonwood Creek at Salt Lake City, UT Jordan River at Salt Lake City, UT Truckee River at Clark, NV Warm Creek near San Bernardino, CA Santa Ana River below Prado Dam, CA Santa Ana River near Anaheim, CA Salt Slough near Stevinson, CA Mud Slough near Gustine, CA Merced River near Newman, CA Orestimba Creek near Crows Landing, CA Turlock Irr Dist Lateral No. 5 near Patterson, CA San Joaquin River near Patterson, CA San Joaquin River near Vernalis, CA Colusa Basin Drain near Knights Landing, CA 305 241,700

5,600 245,100 369 3,580

767

74 763 173 16,200 2,140 117,400 506 2,100 4,530 77,600 36 3,120 117,000

3,970

577 117 9,100 4,310 31 3,730 3,870 1,270 1,270 3,620 28 218 9,800 19,200 4,260 Agriculture Mixed Mixed Mixed Mixed Agriculture Agriculture Urban Mixed Urban Mixed Mixed Mixed Urban Mixed Urban Mixed Mixed Urban Mixed Mixed Agriculture Urban Mixed Mixed Urban Urban Urban Agriculture Agriculture Agriculture Agriculture Mixed Mixed Mixed Agriculture 1 6

1 2 3 1

2 5 1

1 1 2 5 1

2 1 2 2 3 4 2

2 2 1 6 5 1 1 8 1 10 5 5

2

1 5 7 2 2 2

9

1

1

1 2

5

3 3

7

### Appendix **23**

**Table 1–2.** Stream sites used in the first decade (1992–2001) and second decade (2002–11) summaries.—Continued [km 2 , square kilometer; Cr, Creek; Ri, River; Irr Dist; Irrigation District; No., number; MA, Massachusetts; CT, Connecticut; NY, New York; NJ, New Jersey; PA, Pennsylvania; MD, Maryland; VA, Virginia; WV, West Virginia; DC, District of Columbia; NC, North Carolina; SC, South Carolina; GA, Georgia; FL, Florida; AL, Alabama; OH, Ohio; IN, Indiana; TN, Tennessee; KY, Kentucky; IL, Illinois; WI, Wisconsin; MI, Michigan; MN, Minnesota; ND, North Dakota; IA, Iowa; MT, Montana; WY, Wyoming; CO, Colorado; NE, Nebraska; MO, Missouri; AR, Arkansas; MS, Mississippi; LA, Louisiana; TX, Texas; AZ, Arizona; VT, Vermont; NV, Nevada; CA, California; WA, Washington; ID, Idaho; OR, Oregon]

**Site number Site name**  **Watershed area (km**  **2 )**  **Land use Number of years**  **1992– 2002–11**  **2001** 11447360 11447650 12113390 12128000 12212100 12424500 12464770 12471400 12472380 12473740 12500420 12505450 12510500 13055000 13092747 13154500 13351000 14201300 14202000 14206950 14211720 040863075

040869415 073814675 094196783 0242354750 0357479650 252414080333200 322023090544500 393944084120700 394340085524601 Arcade Creek near Del Paso Heights, CA Sacramento River at Freeport, CA Duwamish River at Tukwila, WA Thornton Creek near Seattle, WA Fishtrap Creek at Lynden, WA Spokane River near Spokane, WA Crab Creek near Ritzville, WA Lind Coulee Wasteway near Warden, WA Crab Creek Lateral near Othello, WA El 68 D Wasteway near Othello, WA Moxee Drain near Union Gap, WA Granger Drain at Granger, WA Yakima River at Kiona, WA Teton River near St Anthony, ID Rock Creek at Twin Falls, ID Snake River at King Hill, ID Palouse River at Hooper, WA Zollner Creek near Mt. Angel, OR Pudding River at Aurora, OR Fanno Creek at Durham, OR Willamette River at Portland, OR North Branch Milwaukee River near Random

Lake, WI Lincoln Creek at Milwaukee, WI Bayou Boeuf at Amelia, LA Las Vegas Wash near Las Vegas, NV Cahaba Valley Creek at Pelham, AL Hester Creek near Plevna, AL C-111 Canal near Homestead, FL Mississippi River above Vicksburg, MS Holes Creek at Kettering, OH Sugar Creek at New Palestine, IN 82 61,700

1,190 29 99 13,000

1,190 1,820

146 377 353 160 14,500 2,290

623 92,900

6,380 39 1,260 81 28,900 130

26 3,170 2,650 66 76 132 2,929,500 52 246 Urban Mixed Urban Urban Mixed Urban Agriculture Agriculture Agriculture Agriculture Mixed Agriculture Mixed Mixed Agriculture Mixed Agriculture Agriculture Agriculture Urban Mixed Agriculture

Urban Mixed Urban Urban Agriculture Mixed Mixed Urban Agriculture 1 5 5 2 1 1

3 1 1 1 1 1 1 5 5 8

1

6 1

1 5 2 2 1

2 7 2 10

3

1

4 3 1 2 6 2 3

5 9

5

5 3 1

1 2 5Stone and others**—An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers—**Scientific Investigations Report 2014–5154

ISSN 2328-0328 (online) http://dx.doi.org/10.3133/sir20145154