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2008

 Surface Water Pesticide Monitoring 

and Assessment Project 

Jessica Orr and Jim Gray  

Pesticide, Feed and Fertilizer Team

ND Dept of Agriculture

Bismarck, ND 58505

600 E. Boulevard Ave., Dept. 602
Acknowledgements 

The Department thanks Mike Ell from the North Dakota Department of Health for his 

assistance in coordinating the sampling events. Sampling was performed by Fred 

Ryckman from the North Dakota Game and Fish Department, and Heather Duchscherer 

and Mike Hargiss from the North Dakota Department of Health. 

The Department also thanks the Water Quality Advisory Committee for its input and 

advice. The Committee consists of the following state and federal agencies: 

 ND Department of Health 

ND Department of Parks and Recreation 

ND Game and Fish Department 

ND Geological Survey 

ND State University Extension Service 

ND State Water Commission 

US Department of Agriculture-NRCS 

US Fish and Wildlife Service 

US Geological Survey 

1 
Summary 

The North Dakota Department of Agriculture, working in cooperation with the North 

Dakota Department of Health's Division of Water Quality, coordinated a surface water 

monitoring survey in 2008 for pesticides and pesticide degradates. Nine sample sites in 

three different watersheds (Sheyenne, Souris, and Yellowstone Rivers) in North Dakota 

were sampled and tested for over 184 different pesticides every three weeks from April 

through October. A total of nine pesticides and one pesticide degradate were detected. 

The most commonly detected pesticides were the herbicides 2,4-D and diuron. For all 

but one pesticide, concentrations were below levels deemed harmful by the U.S. 

Environmental Protection Agency (EPA). Diuron was found in the Souris River at 

concentrations that could be harmful to aquatic life. The study supports the need for 

regular, comprehensive monitoring of surface water for pesticides to verify 2008 results, 

assess risks to human health and the environment, and identify trends.

Introduction

Introduction

Through the authority provided in Chapters 4-35, 4-35.1, and 19-18 of the North Dakota 

Century Code, the North Dakota Department of Agriculture (hereafter “Department”) is 

the lead pesticide regulatory agency in the state. Under a cooperative agreement with the 

U.S. Environmental Protection Agency (EPA), the Department is charged with regulating 

pesticides in the public’s interest to ensure that they do not pose a risk of unreasonable 

adverse effects to human health or the environment. 

In the past, the Department’s Pesticide Water Quality Program (hereafter “Program”) was 

concerned only with those pesticides that posed a risk of contaminating groundwater. 

The Department has had a committee in place for over a decade to advise them on 

groundwater issues. Agencies represented on the committee include the ND Department 

of Health (NDDoH), US Department of Agriculture – Natural Resource Conservation 

Service, ND State University Extension Service, US Geological Survey, ND Geological 

Survey and the ND State Water Commission. 

The EPA has recently identified surface water resources as a priority area of focus. 

Therefore, the Program’s focus has expanded to protect both groundwater and surface 

water from pesticide contamination. To reflect this expansion, the Groundwater Working 

Committee has been renamed the Water Quality Advisory Committee (WQAC) and now 

includes representatives from the US Fish and Wildlife Service (US FWS), ND Game 

and Fish Department (NDGF), and ND Parks and Recreation. 

Identifying pesticide and surface water issues is a priority for the Department and 

WQAC. Before the 2008 monitoring project, no agency routinely monitored for 

pesticides in North Dakota’s surface waters. Therefore, we do not know what pesticides 

are present in surface water or at what concentrations. A comprehensive surface water 

2 
monitoring program was necessary to assess the risk of pesticides to surface water, 

including risk to drinking water, recreational uses and aquatic ecosystems. 

The WQAC identified three priority watersheds for monitoring in 2008. These are the 

Yellowstone River in the northwest, the Souris River (often referred to as the Mouse 

River) in the north-central region, and the Sheyenne River in the eastern part of the state 

(Figure 1). The committee chose watersheds in three regions because the state is 

generally divided into three main geographic regions. 

In the western part of the state, the Yellowstone River was selected for sampling by the 

USFWS because of its importance as habitat for the endangered pallid sturgeon 

(Scaphirhynchus albus). The Yellowstone River was also selected because it is an area 

with significant levels of in-furrow irrigation, and the effects of irrigation return flows on 

the water quality were uncertain. Two of the sampling sites on the Yellowstone River 

were chosen because of their proximity to suspected pallid sturgeon spawning habitat and 

return flows from an irrigation drain. The third sampling site was on the Montana/North 

Dakota to assess the quality of incoming water from Montana (Figure 2). The Souris 

River was chosen for the central part of the state because the other major watershed, the 

James was tested during a 2005 surface water monitoring pilot project and had no 

pesticide detections. The Souris River was chosen to not only represent surface water in 

the central part of North Dakota, but since it is largely downstream from the city of 

Minot, to assess the potential for pesticides in surface water downstream from urban 

areas. The Sheyenne was chosen to represent the eastern third of the state because it is 

situated in a high intensity agricultural area and does not receive flow from Minnesota. 

Table 1. Sampling locations with latitude and longitude information 

Site ID Sampling Site Location Latitude Longitute 

SHR-1 Sheyenne River at Horace within the city of Horace 46.76059 -96.9092 

SHR-2 Sheyenne River near 

Cooperstown 4.5 Mi E Of Cooperstown 47.43292 -98.02784 

SHR-3 Sheyenne River at Lisbon 1.5 Mi S, 0.5 Mi E Of Lisbon 46.40567 -97.67297 

SR-1 Souris River E of Bantry 8 Mi E Of Bantry 48.50602 -100.4346 

SR-2 Souris River near Sawyer 1 Mi N Of Hwy 52 On Co Line 48.08934 -101.0149 

SR-3 Souris River at Verendrye 1 Mi W Of Verendrye 48.12481 -100.74933 

YR-1 Yellowstone River at 

ND/MT line 

at river mile 15 on ND/MT 

border 47.80801 -104.0431 

YR-2 Yellowstone River at river 

mile 7.3 

at river mile 7.3 return flow 

outlet 47.88258 -103.9621 

YR-3 Yellowstone River at river 

mile 5.5 at river mile 5.5 mid river 47.90332 -103.9547 

3 
Figure 1. Sampling locations for the 2008 pesticide monitoring 

study

4 
Figure 2. Sampling locations on the Yellowstone River 

5 
Previous surface water monitoring efforts have shown pesticide detections at low 

concentrations. A pilot monitoring project between the Department and the NDDoH was 

conducted in 2006. Eleven sites were sampled twice from late June through August and 

tested for 63 different pesticides. Results showed one detection of picloram at a 

concentration of 0.23 parts per billion (ppb), which is below any level of concern. 

Project goals 

The goals of the 2008 monitoring study were to: 

• determine the occurrence and concentration of pesticides in rivers; 

• determine whether any pesticides may be present at concentrations that could 

adversely affect human health, aquatic life, or fish-eating wildlife; and 

• determine the frequency of sampling needed to assess contamination, thereby 

helping to refine future pesticide monitoring design . 

The Department will also use the monitoring data as part of its cooperative agreement 

with the EPA. Under that agreement, the Department has committed to evaluate national 

and local pesticides of interest that may pose a risk to water quality. Furthermore, the 

Department is required to demonstrate that any risks are appropriately managed. 

In addition, the Department administers an Endangered Species Protection Program that 

is focused on ensuring that pesticides do not negatively impact threatened and 

endangered species in North Dakota. Since most of the seven listed species in the state 

are found in or near surface water, the Department will also use the results of the 

monitoring study to identify pesticides that may pose a risk to threatened and endangered 

species. 

Project Organization and Responsibilities 

The surface water monitoring project was a cooperative effort among the Department, the 

NDDoH, and the NDGF. Overall project coordination was the responsibility of Jessica 

Orr, Environmental Scientist for the Department. Mike Ell, Program Manager for the 

NDDoH’s Surface Water Quality Management Program, was responsible for sampling 

procedures and training. All field sampling activities and tasks, including water quality 

sampling, were the responsibility of the NDGF on the Yellowstone River and the 

NDDoH on the Sheyenne River and Souris River. 

6 
Materials and Methods

Pesticide samples and associated field measurements were collected at three sites in each 

of the three watersheds, Sheyenne River, Souris River, and Yellowstone River, every 

three weeks during the 2008 growing season. Samples were collected during the weeks of 

April 21st, May 12th , June 2nd, June 23rd, July 14th, August 4th, August 25th, Sept 15th, Oct 

6th and Oct 27th . Locations of the sampling sites can be found in Table 1 and Figures 1 

and 2. 

Dissolved oxygen, temperature, pH, and specific conductivity were measured at the time 

of sampling with a YSI Model 650 MDS (Multiparameter Display System) / Data Logger 

combined with a YSI Model 600XL 6 sensor sonde. Results were recorded in the field 

on a field log form. 

Grab samples were collected for pesticide analysis. Samples from the Souris and 

Sheyenne Rivers were collected in the main current at a depth of approximately 60 

percent of the total water depth below the surface. This depth was chose for sample 

collection as it is assumed to be representative of the entire stream. 

At the start of the season when there was greater water depth, a 1.2-L Teflon Kemmerer 

sampling device was used to collect samples. This was done by lowering the Kemmerer 

sampling device from a bridge or crossing. The device was lowered into the stream and 

the sampler tripped at 60 percent of the total stream depth. 

Later in the season when water depths were lower, grab samples were collected by 

wading into the stream. Samples from the Yellowstone River were all near surface 

samples, collected either via shore access to a rock jetty for the ND/MT border site or by 

boat for the other two sites. 

All of the near surface samples were collected by inserting a sample upside down into the 

water flow approximately a foot below the surface. The container was then placed 

upright and faced into the current, allowing it to fill naturally. Care was taken so that the 

sample was not contaminated by disturbing the stream bed upstream from the collection 

point. When the sample was collected by wading, the stream was entered slightly down 

current from the sampling site then the sampler waded to the area with the greatest 

current. The lid was placed on the sample bottle then submerged to approximately 60 

percent of the stream depth, the lid was removed and the bottle was allowed to fill facing 

towards the current. The lid was replaced prior to removing bottle from stream. 

Samples were dispensed into two 500-mL amber glass jars with Teflon-coated lids. 

Sample bottles were provided by the lab and did not need to be rinsed. 

Appropriate labels were placed on the sample bottles. Custody reports and sample logs 

were immediately completed after sample collection (Appendix A). The samples were 

carefully packed with bubble wrap and rubber mesh and put into a cooler with ice and 

7 
more packing materials shortly after collection. There were no problems with sample 

bottles breaking or leaking during shipping or handling. Coolers with the samples and 

ice inside were shipped to the laboratory using a next-day shipping service. The samples 

were usually shipped within a few hours of collection, a small number of times samples 

were kept in a fridge overnight and shipped the next day. 

Selected field samples were collected in replicate to provide estimates of sample 

variability. The replicates consisted of two separate sets of samples collected one after 

another. Replicate samples were submitted blind to the laboratory. 

Samples were analyzed for 184 different pesticides and degradates (Appendix B) by 

Pacific Agricultural Laboratory (Portland, OR) using the EPA standard methods. 

Methods employed for analysis can be found in Table 2. 

Table 2. Description of analytical methods used by Pacific Agricultural Labs. 

Pesticide Class Method Description 

Organochlorine pesticides Modified EPA method 608 (GC-ECD) 

Organophosphorous pesticides Modified EPA method 614 (GC-FPD) 

Organonitrogen pesticides Modified EPA method 625 (GC-MS) 

Chlorinated pesticides Modified EPA method 8321A (HPLCMS) 

Imidazolinone herbicides Am. Cyanamid method (HPLC-MS) 

Miscellaneous pesticides Modified EPA method 8321A (HPLCMS) 

Results and Discussion

Over 74% of the surface water samples had no detectable pesticide concentrations. There 

were 51 detections of ten different pesticides (Table 4). However, most concentrations 

were less than 1 ppb. 

8 
Table 4. Pesticides detected in the 2008 surface water monitoring project. 

Pesticide Trade name # of detects Maximum 

concentration 

EPA 

benchmark

2,4-D 2,4-D 13 0.35 299.2 

Atrazine Aatrex 1 0.48 17.5 

Bentazon Basagran 1 0.014 4500 

Clopyralid Stinger, Curtail 5 0.17 N/A 

DCPMU Diuron 

degradate 

9 0.92 N/A 

Dicamba Banvel 4 0.49 61 

Dichlorprop Weedone, 

Strike 

1 0.14 N/A 

Diuron Direx, Karmex 14 4.2 2.4 

Imazapyr Stalker 2 0.056 N/A 

Triclopyr Garlon 1 0.11 100 

No pesticides were detected in any of the nine sampling sites on the first two dates, April 

21st and May 12th (Figure 3). Detections began in June and peaked at the beginning of 

August. Pesticides were still being detected when sampling ended at the end of October. 

Figure 3. Number of pesticide detections by sampling dates. 

The Yellowstone River was the least contaminated watershed, with 93% of the samples 

having no pesticide detections. Ninety percent of the samples taken from the Sheyenne 

River had no pesticide detections. The Souris River had the most pesticide detections 

with 60% of the samples having some level of pesticides detected. 

Risk of pesticides to human health or the environment is a function of both toxicity and 

9 
exposure. The EPA has established Maximum Contaminant Levels (MCLs) for 

pesticides in drinking water based on risk to human health. The EPA has also established 

aquatic life benchmarks based on risk of pesticides to aquatic ecosystems (Appendix C). 

To assess risk and establish aquatic life benchmarks, the EPA relies on studies required 

under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as well as a wide 

range of environmental laboratory and field studies available in the public scientific 

literature. Aquatic life benchmarks, which are based on the most sensitive toxicity 

endpoint for a given taxa (e.g., freshwater fish), are estimates of the concentrations below 

which pesticides are not expected to harm aquatic life. In most cases we were able to 

compare the concentration detected in surface water to the aquatic life benchmark, but 

not an MCL, because the EPA has not established MCLs for many pesticides. 

The majority of 184 pesticides and degradates assayed in the study were not detected in 

any samples from any of the nine sampling sites. A total of nine pesticides were 

detected, all of which were herbicides. The pesticides found were: 2,4-D; atrazine; 

bentazon; clopyralid; dicamba; dichlorprop; diuron, imazapyr; and triclopyr. DCPMU, a 

degradate of diuron, was also detected. (Table 4 and Appendix B). 

2,4-D was detected in 13 samples, with concentrations ranging from 0.086 to 0.35 ppb. 

The chemical was found in all three watersheds and was most commonly found in the 

Souris River. 2,4-D is a systemic herbicide used on wheat, barley, oats, flax, alfalfa, hay, 

CRP and pastures in North Dakota. 2,4-D is used on approximately 3 million acres in 

agriculture each year, either in stand-alone products or in mixtures (Zollinger, 2004). 

Many more acres are sprayed for lawns and other urban uses, however this amount is not 

known. The relatively large number of detections of 2,4-D is most likely a reflection of 

the fact that 2,4-D is used on such a large number of acres throughout the state. 

The concentrations of 2,4-D found in North Dakota surface water are 200 times lower 

than the MCL of 70 ppb established for 2,4-D. The EPA’s lowest aquatic benchmark for 

2,4-D is 299.2 ppb, a level that may be harmful to aquatic plants. The highest 2,4-D 

concentration of 0.35 ppb was 854 times lower than this benchmark, indicating that while 

the chemical was found in a number of locations, the concentrations are well below the 

levels of concern. 

Atrazine, a broadleaf herbicide used primarily on corn, is applied to approximately 

185,500 acres in North Dakota each year (Zollinger, 2004). Atrazine was detected only 

once in 2008 on the Sheyenne River at Horace (SHR-1) in late June. The southeastern 

section of the state is the primary area for corn production, so it is not surprising that 

atrazine was only found in the Sheyenne River and not the other two watersheds. 

Atrazine was detected in the sample at a concentration of 0.48 ppb. The EPA’s lowest 

aquatic benchmark for atrazine is 17.5 ppb and is based on the risk of chronic toxicity to 

aquatic communities. The detected atrazine concentration of 0.48 ppb is 36 times lower 

than the lowest aquatic benchmark, suggesting minimal risk of the detected atrazine 

levels to aquatic species. 

10 
Atrazine has an MCL of 3 ppb, The concentration found on the Sheyenne is 6.25 times 

lower than the MCL, suggesting that the detected concentration posed minimal risk to 

drinking water. 

Bentazon is used in North Dakota for wheat, barley, corn flax, sugarbeet, CRP and 

pastures. It is used on 569,000 acres alone in North Dakota. In addition, it is applied in a 

mixture with other pesticides on 628,000 acres (Zollinger, 2004). 

Bentazon was detected in one sample collected on the Sheyenne River near Lisbon 

(SHR-3) at a concentration of 0.014 ppb. The EPA aquatic life benchmark concentration 

is 4,500 ppb for the most sensitive species, which is acute toxicity to non-vascular plants. 

The concentrations found during sampling were over 320,000 times less than the 

established benchmark, suggesting very minimal risk. There are no MCLs established for 

bentazon. 

Clopyralid was detected in five samples, with the highest concentration of 0.17 ppb found 

in the Souris River at Sawyer (SR-2) in late October. Clopyralid was detected once in the 

Sheyenne River and four times in the Souris River. There is currently no established 

EPA aquatic life benchmark for clopyralid. However, another common measure of 

toxicity is the LC50 value, a measure of the concentration of a pollutant or effluent at 

which 50% of the test organisms die. LC50 values have been established for clopyralid on 

many different organisms. Water fleas, Daphnia magna, are one of the most sensitive 

species to clopyralid with an LC50 value over 100,000 ppb. The highest concentration 

found in surface water, 0.17 ppb, is 588,000 times less than the LC50, suggesting that the 

detected concentrations pose minimal risk to aquatic ecosystems. 

Dicamba is most commonly used to manage broadleaf weeds in wheat, barley, oats, corn, 

dry beans, CRP, pasture and fallow lands in North Dakota. It is used on over 1.1 million 

acres as a stand-alone product and on 332,000 acres in mixtures in the state (Zollinger 

2004). 

There were four detections of dicamba with the highest concentration of 0.49 ppb. All 

dicamba detections were on the Souris River. The EPA aquatic life benchmark for the 

most sensitive species, acute non-vascular plants is 61 ppb. The concentration detected 

was 1,201 times less than the established benchmark for the most sensitive species, 

suggesting that detected levels of dicamba pose minimal risk. There are no MCLs for 

dicamba. 

Dichlorprop was found once on the Souris River at a concentration of 0.14 ppb. There 

are no benchmarks for dichlorprop. The LC50for the most sensitive species, blue-gill 

sunfish is 1.1 ppb. The concentrations found in the Souris were 7.85 times lower than the 

LC50 

Imazapyr was found twice in 2008, once on the Yellowstone River at river mile 7.3 (YR2) and once on the Souris River near Sawyer (SR-2). The highest concentration of 

imazapyr was 0.056 ppb. There is no established EPA aquatic life benchmark for 

11 
imazapyr. LC50 values for the most sensitive species, water flies (Daphnia magna), is 

100,000 ppb. The concentrations found were 1.7 million times lower than the LC50 for 

water fleas, suggesting minimal risk to aquatic life. 

There was one detection of triclopyr, in the Yellowstone River at a concentration of 0.11 

ppb. The lowest EPA benchmark for triclopyr is 100 ppb established for acute nonvascular plants. The concentration of triclopyr found was 909 times less than the 

benchmark, suggesting a low risk to aquatic life. 

Diuron was detected 14 times, with all detections from the Souris River. The highest 

diuron concentration found was 4.2 ppb in mid-July. DCPMU, a degradate of diuron, 

was detected in nine samples from the Souris River. The EPA aquatic life benchmark for 

diuron is 2.4 ppb for acute non-vascular plants, specifically green algae, Selenastrum 

capricornutum. The highest detected concentration of diuron was almost twice as high as 

this benchmark. Diuron concentrations did not exceed EPA benchmarks for other aquatic 

species. The second highest concentration of diuron was 1.7 ppb, which is 70% of the 

EPA benchmark. 

Diuron concentrations were high enough to be of concern for the aquatic community. 

Therefore, additional investigation and mitigation are necessary. Investigation should 

include trying to determine if the high levels of diuron found are from regular use, misuse 

or an accident such as a spill. Department compliance personnel will work to determine 

if any unusual activity has occurred that relates to diuron usage. Diuron is used on rights 

of way and as a soil sterilant, so there is a defined list of users. Department staff will also 

work to try to quantify the amount of diuron used in the Souris River watershed and the 

predominate use patterns in the area. 

If the high levels of diuron in the Souris River are a result of normal use patterns, 

possible mitigations measures need to be considered by the Department and the WQAC. 

Mitigation measures could include increased use inspections focused on diuron, increased 

user education and compliance assistance, and voluntary or non-voluntary use 

restrictions. Use restrictions could include mandatory use buffer distances from water, 

designating diuron products as restricted use pesticides to limit their use to certified 

applicators, reducing use rates or number of allowed applications, or product 

cancellations. 

The results of the 2008 monitoring study show more detections compared to one of the 

few studies in the area, a 2006 pilot study conducted by the Department and NDDoH. 

The pilot study looked at some of the same areas of the state as the 2008 study including 

the Sheyenne River in two spots, the Souris River West of Verendrye as well as areas of 

the state not monitored in 2008 including the James, Little Missouri, Cannonball, Heart, 

Goose and Red rivers. The pilot study showed only one pesticide detection of picloram 

at 0.23 ppb. This concentration was far below levels of concern. Picloram was included 

in the 2008 monitoring study, but none was found. More pesticides and degradates were 

found in the 2008 monitoring most likely because the study was for a longer duration, 

tested for more pesticides, and at lower detection limits. 

12 
Several years of sampling would help us to characterize pesticide concentrations in 

surface water during the typical pesticide use season. Right now, low or no detections of 

certain pesticides cannot be deemed as normal levels. One year of sampling would not be 

enough to show regulatory agencies that a pesticide is or is not of concern, nor do they 

indicate that we are not concerned about these chemicals. 

Because this study reflects only one year of data, the results should be viewed as 

preliminary. However, the repeated detections of several pesticides in the Souris River do 

raise concerns. 

A comprehensive, state-wide pesticide monitoring program would be invaluable to the 

Department as we evaluate the potential risks of pesticide use to impair the state’s surface 

water resources and on human health. At the present time, we have limited data on the 

levels of pesticides in surface water or on the frequency of occurrence. This lack of data 

and information has severely limited our ability to evaluate pesticide risks for many of 

our programs. Without water quality monitoring for pesticides, the Department has been 

forced to use models developed by the EPA to assess risk. These models are derived 

from data from other states, and the accuracy of the models is questionable. Quality data 

on pesticide concentrations and their occurrence in surface water would allow the 

Department to better protect surface water resources from pesticides, while not imposing 

unnecessary burdens to our agricultural producers and other pesticide users. 

Zollinger, R.K., P. Glogoza, M.P. McMullen, C.A. Bradley, A.G. Dexter, D. Knopf, E. 

Wilson, T. DeJong, and W. Meyer. 2004. Pesticide use and pest management practices in 

North Dakota. North Dakota State University Ext. Publication W-1308. 

References

Appendix A. Chain of Custody Form 

13 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

2,4,5-T N/A H 0.080 ug/liter (ppb) 

2,4,5-TP (fenoprop) Silvex H 0.080 ug/liter (ppb) 

14 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

2,4-D 2,4-D, Weed-B-Gon H 0.20 ug/liter (ppb) 

2,4-DB Butryac, Butoxone H 0.20 ug/liter (ppb) 

3-Hydroxycarbofuran degradate D 0.12 ug/liter (ppb) 

Acetochlor Surpass, Harnass H 0.30 ug/liter (ppb) 

Alachlor Intrro, Lariat, Lasso H 0.12 ug/liter (ppb) 

Aldicarb Temik I 0.12 ug/liter (ppb) 

Aldicarb sulfone degradate D 0.12 ug/liter (ppb) 

Aldicarb sulfoxide degradate D 0.12 ug/liter (ppb) 

Aldrin Aldrex I 0.12 ug/liter (ppb) 

Ametryn Evik, Gesapax H 0.30 ug/liter (ppb) 

Amitraz Avartan, Triatox, Mitac I 0.60 ug/liter (ppb) 

Aspon N/A I 0.30 ug/liter (ppb) 

Atrazine Aatrex, H 0.30 ug/liter (ppb) 

Azinphos-methyl Guthion, Bay I 0.30 ug/liter (ppb) 

Azoxystrobin Quadris F 0.30 ug/liter (ppb) 

Bendiocarb Dycarb, Niomil I 0.12 ug/liter (ppb) 

Benfluralin Balan H 0.12 ug/liter (ppb) 

Bifenthrin Talstar, Capture, 

Brigade 

I 0.12 ug/liter (ppb) 

Bolstar Sulprofos I 0.30 ug/liter (ppb) 

Bromacil Hyvar, Bromax H 0.30 ug/liter (ppb) 

Bromopropylate Acarol, Folbex I 0.60 ug/liter (ppb) 

Captafol Captafol, Sanspor F 0.12 ug/liter (ppb) 

Captan Captanex, Orthocide F 0.30 ug/liter (ppb) 

Carbaryl Sevin, Savit I 0.12 ug/liter (ppb) 

Carbophenothion Trithion, Garrathion I 0.30 ug/liter (ppb) 

Carbofuran Furadan, Carbodan I 0.12 ug/liter (ppb) 

Carfentrazone-ethyl Aim H 0.30 ug/liter (ppb) 

Chlordane Belt, Chlortox I 1.2 ug/liter (ppb) 

Chlorfenvinphos N/A I 0.30 ug/liter (ppb) 

Chlorobenzilate Akar, Acaraben I 0.30 ug/liter (ppb) 

Chloroneb Terraneb F 0.30 ug/liter (ppb) 

Chlorothalonil Bravo, Ole, Farben F 0.12 ug/liter (ppb) 

Chlorpropham Furloe, Beet-kleen H 0.30 ug/liter (ppb) 

Chlorpyrifos Lorsban, Dursban I 0.30 ug/liter (ppb) 

Chlorpyrifos-methyl Reldan, Storcide I 0.30 ug/liter (ppb) 

Clopyralid Stinger, Curtail H 0.080 ug/liter (ppb) 

Coumaphos Resistox, Asuntol I 0.30 ug/liter (ppb) 

Cyanazine Bladex H 0.60 ug/liter (ppb) 

Cyfluthrin Tempo, Baythroid I 1.2 ug/liter (ppb) 

Cyhalothrin Grenade, Karate I 1.2 ug/liter (ppb) 

Cypermethrin Ammo I 1.2 ug/liter (ppb) 

Dacthal Dacthal H 0.12 ug/liter (ppb) 

Dacthal H 0.20 ug/liter (ppb) 

DCPMU degradate D 0.12 ug/liter (ppb) 

Deltamethrin Butox, K-Othrin I 1.2 ug/liter (ppb) 

15 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

Demeton-O N/A I 0.30 ug/liter (ppb) 

Demeton-S 

(Metasystox) 

N/A I 0.30 ug/liter (ppb) 

Diazinon Knox Out, Diazol I 0.30 ug/liter (ppb) 

Dicamba Banvel H 0.080 ug/liter (ppb) 

Dichlorfenthion Mobilawn, Gro13 I 0.30 ug/liter (ppb) 

Dichlorprop Weedone, Strike, 

Envert 

H 0.20 ug/liter (ppb) 

Dichlorvos Vapona, DDVP I 0.30 ug/liter (ppb) 

Diclofop-methyl Hoelon H 0.60 ug/liter (ppb) 

Dicloran Botran F 0.12 ug/liter (ppb) 

Dicrotophos Bidrin I 0.30 ug/liter (ppb) 

Dieldrin Dieldrex I 0.12 ug/liter (ppb) 

Dimethenamid Outlook H 0.30 ug/liter (ppb) 

Dimethoate Cygon, Roxion I 0.30 ug/liter (ppb) 

Dinoseb Aretit, Dinitro H 0.20 ug/liter (ppb) 

Disulfoton Disyston, Dithiosystox I 0.30 ug/liter (ppb) 

Diuron Direx, Karmex H 0.12 ug/liter (ppb) 

Endosulfan I Thionex, Thiodan I 0.12 ug/liter (ppb) 

Endosulfan II Thionex I 0.12 ug/liter (ppb) 

Endosulfan sulfate degradate D 0.12 ug/liter (ppb) 

Endrin Endrex I 0.12 ug/liter (ppb) 

Endrin aldehyde degradate D 0.12 ug/liter (ppb) 

EPN N/A I 0.30 ug/liter (ppb) 

Esfenvalerate Asana, Pydrin I 0.12 ug/liter (ppb) 

Ethalfluralin Sonalan H 0.12 ug/liter (ppb) 

Ethion Ethiol, Cethion I 0.30 ug/liter (ppb) 

Ethofumesate Progress, Tramat H 0.30 ug/liter (ppb) 

Ethoprop Mocap I 0.30 ug/liter (ppb) 

Famphur N/A I 0.30 ug/liter (ppb) 

Fenarimol Rubigan F 0.12 ug/liter (ppb) 

Fenbuconazole Indar F 0.60 ug/liter (ppb) 

Fenhexamid Elevate F 0.12 ug/liter (ppb) 

Fenitrothion Cyfen, Folithion I 0.30 ug/liter (ppb) 

Fenobucarb Folistar, Prostar, 

Moncut 

F 0.12 ug/liter (ppb) 

Fenoxaprop-ethyl Puma, Option, Whip H 0.60 ug/liter (ppb) 

Fensulfothion Terracur, Dasanit I 0.30 ug/liter (ppb) 

Fenthion Baytex I 0.30 ug/liter (ppb) 

Fenuron Dybar, PDU H 0.30 ug/liter (ppb) 

Fenvalerate Pydrin I 0.12 ug/liter (ppb) 

Fipronil Regent I 0.60 ug/liter (ppb) 

Fluazifop-P-butyl Fusilade H 0.60 ug/liter (ppb) 

Fludioxanil Maxim, Celest F 0.30 ug/liter (ppb) 

Flumioxazin Sumisoya, Valor H 0.30 ug/liter (ppb) 

Fluometuron Cortoran, Lanex H 0.30 ug/liter (ppb) 

Fluroxypyr-meptyl Starane H 0.30 ug/liter (ppb) 

Flutolanil Moncoat F 1.2 ug/liter (ppb) 

16 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

Folpet Cosan, Fungitrol F 0.30 ug/liter (ppb) 

Heptachlor Heptamule I 0.12 ug/liter (ppb) 

Heptachlor epoxide degradate D 0.12 ug/liter (ppb) 

Hexachlorobenzene HCB F 0.12 ug/liter (ppb) 

Hexazinone Velpar H 0.30 ug/liter (ppb) 

Imazamethabenz Assert H 0.02 ug/liter (ppb) 

Imazamox Raptor H 0.02 ug/liter (ppb) 

Imazapic Plateau H 0.02 ug/liter (ppb) 

Imazapyr stalker H 0.02 ug/liter (ppb) 

Imazethapyr Pursuit H 0.02 ug/liter (ppb) 

Imidacloprid Touchstone PF I 0.30 ug/liter (ppb) 

Iprodione Rovral F 0.12 ug/liter (ppb) 

Isoxaben Cent 7, Gallery H 0.30 ug/liter (ppb) 

Kelthane Dicofol I 0.30 ug/liter (ppb) 

Linuron Linex, Lorox H 0.30 ug/liter (ppb) 

Malathion Malathion, Cythion I 0.30 ug/liter (ppb) 

MCPA MCP H 20 ug/liter (ppb) 

MCPP Encore, Trimec H 20 ug/liter (ppb) 

Mefenoxam Apron, 

Dividend,Dynasty 

F 0.30 ug/liter (ppb) 

Metalaxyl Hi-Yield, Ridomil F 0.30 ug/liter (ppb) 

Methidathion Somonic, suprathion I 0.30 ug/liter (ppb) 

Methiocarb Mesurol I 0.12 ug/liter (ppb) 

Methomyl Lannate I 0.12 ug/liter (ppb) 

Methoxychlor Methoxychlor I 0.12 ug/liter (ppb) 

Metolachlor Dual, Magnum H 0.30 ug/liter (ppb) 

Metribuzin Sencor, Lexone H 0.60 ug/liter (ppb) 

Mevinphos Phosdrin I 0.30 ug/liter (ppb) 

Mirex Ferriamicide, 

Dechlorane 

I 0.12 ug/liter (ppb) 

Monocrotophos N/A I 0.30 ug/liter (ppb) 

Monuron CMU, Telvar I 0.12 ug/liter (ppb) 

Myclobutanil Rally F 0.60 ug/liter (ppb) 

Neburon Kloben H 0.12 ug/liter (ppb) 

Norflurazon Solicam H 0.12 ug/liter (ppb) 

Oryzalin Surflan H 0.30 ug/liter (ppb) 

Ovex Ovochlor, Ovotran I 0.12 ug/liter (ppb) 

Oxamyl Vydate I 0.12 ug/liter (ppb) 

Oxyflorfen Goal H 0.12 ug/liter (ppb) 

p,p'-DDD N/A I 0.12 ug/liter (ppb) 

p,p'-DDE degradate D 0.12 ug/liter (ppb) 

p,p'-DDT N/A I 0.12 ug/liter (ppb) 

Parathion Parathion, Thiophos I 0.30 ug/liter (ppb) 

Parathion-methyl Penncap-M, Folidol-M I 0.30 ug/liter (ppb) 

PCA degradate D 0.12 ug/liter (ppb) 

PCNB (quintozene) Terraclor, Tritisan F 0.12 ug/liter (ppb) 

Pendimethalin Prowl H 0.30 ug/liter (ppb) 

17 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

Pentachlorophenol PCP H 0.080 ug/liter (ppb) 

Permethrin Ambush, Pounce I 1.2 ug/liter (ppb) 

Phorate Thimet I 0.30 ug/liter (ppb) 

Phosmet Imidan I 0.30 ug/liter (ppb) 

Phosphamidon Phosphamidon I 0.30 ug/liter (ppb) 

Picloram Tordon H 0.20 ug/liter (ppb) 

Pirimicarb Pirimor I 0.30 ug/liter (ppb) 

Pirimiphos-methyl Tomahawk,Silosan I 0.30 ug/liter (ppb) 

Prodiamine Barricade H 0.12 ug/liter (ppb) 

Prometon Pramitol H 0.60 ug/liter (ppb) 

Prometryn Caparol H 0.30 ug/liter (ppb) 

Pronamide Kerb H 0.12 ug/liter (ppb) 

Propachlor Ramrod H 0.30 ug/liter (ppb) 

Propanil Stampede, Prop-Job H 0.12 ug/liter (ppb) 

Propargite Comite, Omite I 0.60 ug/liter (ppb) 

Propazine Milogard F 0.30 ug/liter (ppb) 

Propham IPC H 0.30 ug/liter (ppb) 

Propiconazole Banner, Tilt, Radar F 0.30 ug/liter (ppb) 

Propoxur Baygon I 0.12 ug/liter (ppb) 

Pyraclostrobin Cabrio, Headline F 0.30 ug/liter (ppb) 

Pyrethrins Wilson, Mushroom 

House 

I 1.2 ug/liter (ppb) 

Pyridaben Pyromite, Dynomite I 0.60 ug/liter (ppb) 

Quinclorac Paramount H 0.20 ug/liter (ppb) 

Sethoxydim Poast H 6.0 ug/liter (ppb) 

Siduron Tupersan H 0.12 ug/liter (ppb) 

Simazine Princep H 0.60 ug/liter (ppb) 

Simetryn Gybon H 0.30 ug/liter (ppb) 

Sulfentrazone Spartan H 0.30 ug/liter (ppb) 

Tebuconazole Folicur F 0.60 ug/liter (ppb) 

Tebuthiuron Spike H 0.60 ug/liter (ppb) 

Terbacil Sinbar H 0.12 ug/liter (ppb) 

Terbufos Counter I 0.30 ug/liter (ppb) 

Tetrachlorvinphos Disvap I 0.30 ug/liter (ppb) 

Thiabendazole Arbotect F 0.30 ug/liter (ppb) 

Thiobencarb Bolero, Saturn, Abolish H 0.30 ug/liter (ppb) 

Toxaphene Phenatox,Toxakil I 6.0 ug/liter (ppb) 

Triadimefon Bayleton F 0.60 ug/liter (ppb) 

Trichlorfon Dylox, Neguvon I 0.60 ug/liter (ppb) 

Triclopyr Garlon H 0.080 ug/liter (ppb) 

Trifloxystrobin Ronilan F 0.12 ug/liter (ppb) 

Triflumazole Terraguard, Procure F 0.12 ug/liter (ppb) 

Trifluralin Treflan, Trilin H 0.12 ug/liter (ppb) 

Vinclozalin Ronilan F 0.12 ug/liter (ppb) 

α-BHC degradate D 0.12 ug/liter (ppb) 

β-BHC degradate D 0.12 ug/liter (ppb) 

γ-BHC (Lindane) Gamma BHC I 0.12 ug/liter (ppb) 

18 
Appendix B. List of pesticides analyzed in the 2008 North Dakota surface 

monitoring study 

Analyte Trade name Type Reporting Limit 

δ-BHC degradate D 0.12 ug/liter (ppb) 

* H=Herbicide, F=Fungicide, I=Insecticide, D=Degradate 

19 
Appendix C. Complete list of detections 

Chemical Concentration 

in ppb 

Lowest EPA 

Aquatic Life 

Benchmark 

Benchmark 

Organism 

Sample Location Date 

Collected 

2,4-D 0.086 299.2 acute vascular plants Souris River at Verendry 6/2/2008 

2,4-D 0.21 299.2 acute vascular plants Sheyenne near Lisbon 6/3/2008 

2,4-D 0.21 299.2 acute vascular plants Sheyenne near 

Cooperstown 

6/4/2008 

2,4-D 0.11 299.2 acute vascular plants Souris River near Sawyer 6/24/2008 

2,4-D 0.18 299.2 acute vascular plants Sheyenne at Horace 6/23/2008 

2,4-D 0.15 299.2 acute vascular plants Souris River near Bantry 7/15/2008 

2,4-D 0.24 299.2 acute vascular plants Souris River near Sawyer 7/15/2008 

2,4-D 0.24 299.2 acute vascular plants Souris River near Bantry 8/4/2008 

2,4-D 0.35 299.2 acute vascular plants Souris River at Verendry 8/4/2008 

2,4-D 0.12 299.2 acute vascular plants Souris River near Sawyer 8/4/2008 

2,4-D 0.14 299.2 acute vascular plants Souris River at Verendry 9/15/2008 

2,4-D 0.25 299.2 acute vascular plants Sheyenne at Horace 10/7/2008 

2,4-D 0.088 299.2 acute vascular plants Yellowstone at rm 5.5 11/3/2008 

Atrazine 0.48 17.5 chronic aquatic 

community 

Sheyenne at Horace 6/23/2008 

Bentazon 0.014 4,500 acute non-vascular 

plants 

Sheyenne near Lisbon 9/15/2008 

Clopyralid 0.089 none N/A Sheyenne at Horace 6/23/2008 

Clopyralid 0.14 none N/A Souris River near Sawyer 7/15/2008 

Clopyralid 0.097 none N/A Souris River at Verendry 8/4/2008 

Clopyralid 0.13 none N/A Souris River at Verendry 10/29/2008

Clopyralid 0.17 none N/A Souris River near Sawyer 10/29/2008

DCPMU 0.92 none N/A Souris River near Sawyer 7/15/2008 

DCPMU 0.35 none N/A Souris River at Verendry 8/4/2008 

DCPMU 0.58 none N/A Souris River near Sawyer 8/4/2008 

DCPMU 0.26 none N/A Souris River at Verendry 8/26/2008 

DCPMU 0.52 none N/A Souris River near Sawyer 8/26/2008 

DCPMU 0.48 none N/A Souris River at Verendry 9/15/2008 

DCPMU 0.31 none N/A Souris River near Sawyer 9/15/2008 

DCPMU 0.35 none N/A Souris River at Verendry 10/7/2008 

DCPMU 0.45 none N/A Souris River near Sawyer 10/7/2008 

Dicamba 0.49 61 acute non-vascular 

plants 

Souris River near Sawyer 6/24/2008 

Dicamba 0.35 61 acute non-vascular 

plants 

Souris River at Verendry 7/15/2008 

Dicamba 0.081 61 acute non-vascular 

plants 

Souris River at Verendry 8/4/2008 

Dicamba 0.12 61 acute non-vascular 

plants 

Souris River near Sawyer 8/4/2008 

Dichlorprop 0.14 none Souris River near Sawyer 7/15/2008 

Diuron 0.2 2.4 acute non-vascular 

plants 

Souris River near Sawyer 6/24/2008 

Diuron 0.14 2.4 acute non-vascular 

plants 

Souris River at Verendry 7/15/2008 

Diuron 4.2 2.4 acute non-vascular Souris River near Sawyer 7/15/2008 

20 
21 

Appendix C. Complete list of detections 

Chemical Concentration 

in ppb 

Lowest EPA 

Aquatic Life 

Benchmark 

Benchmark 

Organism 

Sample Location Date 

Collected 

plants 

Diuron 1 2.4 acute non-vascular 

plants 

Souris River at Verendry 8/4/2008 

Diuron 1.7 2.4 acute non-vascular 

plants 

Souris River near Sawyer 8/4/2008 

Diuron 0.62 2.4 acute non-vascular 

plants 

Souris River at Verendry 8/26/2008 

Diuron 1.2 2.4 acute non-vascular 

plants 

Souris River near Sawyer 8/26/2008 

Diuron 1.5 2.4 acute non-vascular 

plants 

Souris River at Verendry 9/15/2008 

Diuron 0.62 2.4 acute non-vascular 

plants 

Souris River near Sawyer 9/15/2008 

Diuron 0.8 2.4 acute non-vascular 

plants 

Souris River at Verendry 10/7/2008 

Diuron 1.3 2.4 acute non-vascular 

plants 

Souris River near Sawyer 10/7/2008 

Diuron 0.17 2.4 acute non-vascular 

plants 

Souris River near Bantry 10/29/2008

Diuron 0.27 2.4 acute non-vascular 

plants 

Souris River at Verendry 10/29/2008

Diuron 0.17 2.4 acute non-vascular 

plants 

Souris River near Sawyer 10/29/2008

Imazapyr 0.026 none N/A Souris River near Sawyer 6/24/2008 

Imazapyr 0.056 none N/A Yellowstone at rm 7.3 8/4/2008 

Triclopyr 0.11 100 acute non-vascular 

plants 

Yellowstone at rm 5.5 11/3/2008