NorthDakotaDepartmentofAgricultureticideWaterQualityProgramPes2008Surface Water Pesticide Monitoringand Assessment Project



### Jessica Orr and Jim Gra y Pesticide, Feed and Fertilizer Team ND Dept of Ag ri c u lt u r e

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 Fi sh Department, and Heather Duchscherer and Mike Hargiss from the North Dakota Department of Health.

The Department also thanks the Water Qu ality Advisory Committ ee 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

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# 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 pe sticide 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 th ree 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 a quatic life. The study supports the need for regular, comprehensive monitoring of surface wa ter 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 ag ency 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 Wate r 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 Ag riculture – Natural Resource Conservation Service, ND State University Extension Se rvice, US Geological Survey, ND Geological Survey and the ND State Water Commission.

The EPA has recently identified surface water resources as a pr iority area of focus. Therefore, the Program’s focus has expa nded to protect both groundwater and surface water from pesticide contamination. To re flect this expansion, th e Groundwater Working Committee has been renamed the Water Qua lity 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 projec t, 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 c oncentrations. A comprehensive surface water

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### monitoring program was necessary to assess th e risk of pesticides to surface water, including risk to drinking water, recreational uses and aquatic ecosystems.

The WQAC identified three pr iority watersheds for monito ring in 2008. These are the Yellowstone River in the northwest, the Sour is River (often referred to as the Mouse River) in the north-central region, and the Sheye nne River in the eastern part of the state (Figure 1). The committee chose watersheds in three regions because the state is generally divided into thr ee main geographic regions.

In the western part of the state, the Yello wstone River was selected for sampling by the USFWS because of its importance as habi tat for the endangered pallid sturgeon ( Scaphirhynchus albus)

. The Yellowstone River was also selected because it is an area with significant levels of in-furrow irrigati on, and the effects of i rrigation 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 wa s on the Montana/North Dakota to assess the quality of incoming wa ter from Montana (Figur e 2). The Souris River was chosen for the central part of th e 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 Da kota, but since it is largely downstream from the city of Minot, to assess the potential for pesticid es 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 lat itude 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



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### Figure 1. Sampling locations for the 2008 pesticide monitoring study

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### Figure 2. Sampling locations on the Yellowstone River

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### Previous surface water monitoring efforts ha ve shown pesticide detections at low concentrations. A pilot m onitoring project between the Department and the NDDoH was conducted in 2006. Eleven sites were sample d 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 concen tration of pesticides in rivers;

• determine whether any pesticides may be present at concentr ations that could adversely affect human health, aquati c life, or fish-eating wildlife; and

• determine the frequency of sampling n eeded to assess contamination, thereby helping to refine future pe sticide monitoring design .

The Department will also use the monitoring da ta as part of its cooperative agreement with the EPA. Under that agreement, the Department has committed to evaluate national and local pesticides of intere st that may pose a risk to water quality. Furthermore, the Department is required to demonstrate th at any risks are appropriately managed.

In addition, the Department administers an Endangered Species Prot ection Program that is focused on ensuring that pesticides do not negatively impact threatened and endangered species in North Dakota. Since mo st of the seven listed species in the state are found in or near surface water, the Depa rtment 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 c ooperative effort among the Department, the NDDoH, and the NDGF. Overall project coor dination was the res ponsibility of Jessica Orr, Environmental Scientist for the Depart ment. Mike Ell, Program Manager for the NDDoH’s Surface Water Quality Management Program, was responsible for sampling procedures and training. All field sampling act ivities and tasks, in cluding water quality sampling, were the responsibility of th e NDGF on the Yellowstone River and the NDDoH on the Sheyenne River and Souris River.

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# Materials and Methods

Pesticide samples and associated field measurem ents were collected at three sites in each of the three watersheds, Sheyenne River, S ouris River, and Yellowstone River, every three weeks during the 2008 growing season. Samples were collected during the weeks of April 21 st 

### , May 12 th 

### , June 2 nd 

### , June 23 rd 

### , July 14 th 

### , August 4 th 

### , August 25 th 

### , Sept 15 th 

### , Oct
6 th 

### and Oct 27 th 

### . Locations of the sampling sites can be found in Table 1 and Figures 1 and 2.

Dissolved oxygen, temperature, pH, and speci fic conductivity were measured at the time of sampling with a YSI Model 650 MDS (Multi parameter Display System) / Data Logger combined with a YSI Model 600XL 6 sensor sond e. 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 ma in current at a depth of approximately 60 percent of the total water depth below the su rface. This depth was chose for sample collection as it is assumed to be repr esentative of the en tire stream.

At the start of the season when there wa s 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 per cent 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 fo r the ND/MT border site or by boat for the other two sites.

All of the near surface sample s 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 th e 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 am ber glass jars with Teflon-coated lids. Sample bottles were provided by the la b 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 co llection (Appendix A). The samples were carefully packed with bubble wrap and rubber mesh and put into a cooler with ice and

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### more packing materials shortly after collection. There we re no problems with sample bottles breaking or leaking during shipping or handling. Coolers with the samples and ice inside were shipped to the laboratory us ing 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 c onsisted of two separate sets of samples collected one after another. Replicate samples were submitted blind to the laboratory.

Samples were analyzed for 184 different pe sticides 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 anal ytical 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 c oncentrations. There were 51 detections of ten different pesticides (Table 4). However, most concentrations were less than 1 ppb.

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### 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 ni ne sampling sites on the first two dates, April 21 st 

### and May 12 th 

### (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 dete ctions by sampling dates.

The Yellowstone River was the least contamin ated watershed, with 93% of the samples having no pesticide detections. Ninety percen t of the samples taken from the Sheyenne River had no pesticide detections. The Sour is River had the most pesticide detections with 60% of the samples having some level of pesticid es detected.

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

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### exposure. The EPA has established Maximum Contaminant Levels (MCLs) for pesticides in drinking water ba sed on risk to human health. The EPA has also established aquatic life benchmarks based on risk of pes ticides to aquatic eco systems (Appendix C). To assess risk and establish aquatic life benc hmarks, 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 aqua tic life. In most cases we were able to compare the concentration detected in surf ace 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 si tes. 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 c oncentrations ranging from 0.086 to 0.35 ppb. The chemical was found in all three waters heds 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 ot her urban uses, however this amount is not known. The relatively large number of detectio ns of 2,4-D is most likely a reflection of the fact that 2,4-D is used on such a la rge 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 harmfu l to aquatic plants. The highest 2,4-D concentration of 0.35 ppb was 854 times lower th an this benchmark, indicating that while the chemical was found in a number of locati ons, the concentrations are well below the levels of concern.

Atrazine, a broadleaf herbicid e used primarily on corn, is applied to approximately 185,500 acres in North Dakota each year (Zollinge r, 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 fo r 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, suggesti ng minimal risk of the detected atrazine levels to aquatic species.

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### Atrazine has an MCL of 3 ppb, The concentration found on the Sheyenne is 6.25 times lower than the MCL, suggesting that the dete cted 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 addi tion, it is applied in a mixture with other pesticides on 628,000 acres (Zollinger, 2004).

Bentazon was detected in one sample coll ected 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 sampli ng were over 320,000 times less than the established benchmark, suggesting very minima l risk. There are no MCLs established for bentazon.

Clopyralid was detected in five samples, with the highest con centration of 0.17 ppb found in the Souris River at Sawyer (SR-2) in late October. Clopyr alid was detected once in the Sheyenne River and four times in the Souris River. There is currently no established EPA aquatic life benchmark for clopyrali d. However, another common measure of toxicity is the LC 50 

### value, a measure of the concentra tion of a pollutant or effluent at which 50% of the test organisms die. LC 50 

### 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 LC 50 

### value over 100,000 ppb. The highest concentration found in surface water, 0.17 ppb, is 588,000 times less than the LC 50, 

### suggesting that the detected concentrations pose minimal risk to aquatic ecosystems.

Dicamba is most commonly used to manage br oadleaf 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 acr es in mixtures in the state (Zollinger 2004).

There were four detections of dicamba w ith the highest concen tration 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 be nchmark for the most sensitive species, suggesting that detected leve ls of dicamba pose minimal risk. There are no MCLs for dicamba.

Dichlorprop was found once on the Souris Ri ver at a concentration of 0.14 ppb. There are no benchmarks for dichlorprop. The LC 50 

### for the most sensitive species, blue-gill sunfish is 1.1 ppb. The concentrations found in the Souris were 7.85 times lower than the LC 50



### Imazapyr was found twice in 2008, once on the Ye llowstone 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 estab lished EPA aquatic life benchmark for

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### imazapyr. LC 50 

### 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 LC 50 

### for water fleas, suggesting minimal risk to aquatic life.

There was one detection of tric lopyr, in the Yellowstone Ri ver at a concen tration of 0.11 ppb. The lowest EPA benchmark for tricl opyr is 100 ppb established for acute nonvascular plants. The concentration of triclopyr found was 909 times less than the benchmark, suggesting a low ri sk to aquatic life.

Diuron was detected 14 times, with all detect ions 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, specifica lly 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 concentrati on 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 mitig ation 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 c onsidered by the Department and the WQAC. Mitigation measures could include increased use inspections focused on diuron, increased user education and compliance assistan ce, and voluntary or non-voluntary use restrictions. Use restricti ons could include mandatory use buffer distances from water, designating diuron products as re stricted 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 mo re 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 b ecause the study was for a longer duration, tested for more pesticides, and at lower detection limits.

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### Several years of sampling would help us to characterize pesticide concentrations in surface water during the typical pesticide use season. Right no w, 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 pestic ide 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 mon itoring 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 occu rrence in surface water would allow the Department to better protect surface water re sources from pesticides, while not imposing unnecessary burdens to our agricultural producers and othe r pesticide users

.

Zollinger, R.K., P. Glogoza, M.P. McMulle n, C.A. Bradley, A.G. Dexter, D. Knopf, E. Wilson, T. DeJong, and W. Meyer. 2004. Pesticid e use and pest management practices in North Dakota. North Dakota State University Ext. Publication W-1308. 

# References

Appendix A. Chain of Custody Form

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### 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)



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### 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)



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### 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

19Appendix 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 pl ants 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 pl ants 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