# Surface Water Pesticide Monitoring and Assessment Pro j ect 2009 ,

Jessica N. Johnson and James A. Gray Agriculture Chemical Division

### 1 

## Acknowledgements

The Department thanks Mike Ell from the North Da kota Department of Health for his assistance in coordinating this project. Sampling was performed by Heather Duchscherer, Mike Ell, Peter Wax, Jim Collins and Mike Hargiss from the North Dakota Departme nt of Health and Paul Scarpari from the United States Geological Survey.

The Department also thanks the Water Quality A dvisory 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

### 2 The North Dakota Department of Agriculture, working in cooperation with the North Dakota Department of Health's Division of Water Quality, coordinate d a surface water monitoring survey in 2009 to assess levels of pesticides and pesticide degradates in North Dakota rivers. Twenty-nine sites, representing all major watersheds of North Dakota, were sampled a nd tested for 180 different pesticides and pesticide degradates every six weeks from June through November. There were a total of eleven detections of four different pesticides (atrazine, bentazon, dimethen amid, and MCPA). The most commonly detected pesticides were the herbicides atrazine and bentazon, detected four and three times, respectively. MCPA and dimethenamid were each detected twice. For a ll pesticides, concentrations were significantly below levels deemed harmful by the U.S. Environmental Pr otection Agency (EPA). Results show that North Dakota streams and rivers have mini mal pesticide contamination. The study also supports the need for regular, comprehensive monitoring of surface water for pesticides to verify results, assess risks of pesticides to human health and the environment, and identify trends.

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 (hereafte r “Department”) is the lead pesticide regulatory agency in the state. Under a cooperative agreemen t with the 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.

Before 2007, the Department’s Pesticide Water Quality Program was concerned only with those pesticides that posed a risk of contaminating groun dwater. The Department has had a committee in place for over a decade to advise them on groundwater i ssues. Agencies represented on the committee include the ND Department of Health (NDDoH), US Departme nt of Agriculture – Natural Resource Conservation Service, ND State University Exte nsion Service, US Geological Survey (USGS), ND Geological Survey and the ND State Water Commission.

The EPA has recently identified surface water resour ces 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, ND Game and Fish Departme nt, and ND Parks and Recreation Department.

Identifying pesticide and surface water issues is a prio rity for the Department and the WQAC. Before the first monitoring project in 2008, no agency routinel y monitored for pesticides in North Dakota’s surface waters. A pilot monitoring project coordinated between the Department and the NDDoH was conducted 

## Summar y

Introduction

### 3 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 established by the EPA for human health or wildlife.

The Department, working in cooperation with the No rth Dakota Department of Health's Division of Water Quality, resumed a surface water monitori ng 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 184 diff erent pesticides and pesticide degradates every three weeks from April through October. A total of nine p esticides and one pesticide degradate were detected. The most commonly detected pesticides were the herb icides 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, specifically green algae.

Pesticides were not detected in any of the nine samp ling sites in April or May during the 2008 pesticide sampling season. Instead, detections began in June, peaked at the beginning of August, and were ongoing at the end of October. Because the detections bega n in June the year before, WQAC decided to start sampling in June of 2009 and allow the resources that would have been used for spring sampling to be used to increase the number of sampling sites in the state.

The pesticide water quality monitoring program receive d an increase in funding in 2009 through an EPA Clean Water Act Section 319 grant. Because of this gr ant, a later start, and a six week sampling schedule instead of a three week schedule, we were able to dramatically expand the number of sites sampled and make the program truly state-wide to represent every major North Dakota watershed.

Sampling sites were chosen from the NDDoH’s ambi ent surface water monitoring sites to make the sampling most efficient. We were able to sample at 29 of the 34 ambient monitoring sites. Five sites were dropped because of proximity to other sampling sites.

Project goals

The goals of the 2009 monitoring study were to:

• Determine the occurrence and concentrati on of pesticides in North Dakota rivers;

• Determine whether any pesticides may be present at concentrations that could adversely affect human health, aquatic life, or fish-eating wildlife; and

• Continue to determine the temporal and spatial frequency of sampling needed to assess contamination, thereby helping to further re fine 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 Enda ngered Species Protection Program that is focused on ensuring that pesticides do not negatively impact th reatened and endangered species in North Dakota.

### 4 Since most of the seven listed species in the state are found in or near surface water, the Department will use the results of the monitoring study to identify pesticides that may pose a risk to threatened and endangered species.

Pesticide samples and associated field measurements we re collected at 29 sites every six weeks from June through November 2009. Samples were collected for the Missouri River watershed during the weeks of June 1 st , July 13 th , August 24 th , October 5 th and November 16 th , 2009. Samples were collected in the eastern side of the state in the Red River, James Rive r and Souris River watersheds during the weeks of June 15 th , July 27 th , September 7 th , October 19 th and November 30 th ,2009. Locations of the sampling sites can be found in Table 1 and Figure 1.

Table 1. Sampling locations for the 2009 North Dakota surface water monitoring project with latitude and longitude information

Site ID Sampling Site Location Latitude Longitute 380007 Sheyenne River - Lisbon 1.5 Mi S, 0.5 Mi E Of Lisbon 46.40567 -97.673

380009 Sheyenne River - Cooperstown 4.5 Mi E Of Cooperstown 47.43292 -98.0278

380012 James River - LaMoure West Edge Of Lamoure On Hwy 13 46.35537 -98.3061 380013 James River - Jamestown Downstream From Jamestown 46.88339 -98.6709 380021 DeLacs River - Foxholm At Bridge In Foxholm 48.37047 -101.57

380022 Little Missouri River - Medora 1 Mi W Of Medora On Bridge 46.91661 -103.532

380031 Wild Rice River - Abercrombie 3.2 Mi NW Of Abercrobmie 46.47112 -96.782 380037 Turtle River - N Of Manvel On Hwy 81 Bridge 48.08617 -97.1843 380039 Forest River - Nr Minto 0.4 Mi E Of Hwy 81 Bridge 48.28598 -97.3698

380059 Little Missouri River - Hwy 85 On Hwy 85 Bridge 47.59233 -103.253 380067 Cannonball River 0.5 Mi S Of Breien 46.37668 -100.935

380083 Red River - at Brushville, MN 6 Mi N And 1 Mi W Of Wahpeton 46.36948 -96.6568 380087 Knife River - S Of Hazen 0. 5 Mi S Of Hazen 47.28547 -101.623

380095 Souris River - W Of Verendrye 1 Mi W Of Verendrye 48.12481 -100.749

380105 Cannonball River S Of Raleigh 16 Mi S Of Raleigh 46.12676 -101.333 380151 Heart River - W Of Mandan 3 Mi W Of Mandan 46.83378 -100.974 380156 Goose River - AT Hillsboro In Hillsboro 47.40701 -97.0574 380157 Park River - AT Grafton In Grafton At Hwy 81 Bridge 48.42479 -97.4119

380160 Heart River - S Of Richardton 8 Mi S Of Richardton 46.74585 -102.308 

## Materials and Methods

### 5 Site ID Sampling Site Location Latitude Longitute 380161 Souris River - W Of Minot 3.5 Mi W Of Minot 48.2459 -101.372 384130 James River At Gr ace City 47.55801 -98.863 384131 Knife River At Golden Valley 47.15485 -102.06 384155 Maple River at Mapleton @ Mapleton 46.9054 -97.0525 384156 Red River at Grand Forks Demers Ave Bridge 47.92686 -97.0282 384157 Red River at Pembina 48.97367 -97.2378 385001 Sheyenne River Nr Kindred On Highway 46 Nr Kindred 46.63146 -97.0003 385040 Red River Near Harwood 3 Mi E Of Harwood 46.97695 -96.8203

385345 Sheyenne River Near Warwick 3.3 Mi S of Warwick, ND 47.80526 -98.7172 385414 Red River at Fargo on Main Ave Bridge 46.87364 -96.7766

Figure 1. Sampling locations for the 2009 pesticide surface water monitoring study

Dissolved oxygen, temperature, pH, and specific conduc tivity 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.

### 6 Grab samples were collected for pesticide analysis. Samples were collected in the main current below the surface at a depth of approximately 60 percent of the total water depth. This depth was chosen 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 into the water 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. 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 and 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 bo ttle was allowed to fill facing towards the current, allowing it to fill naturally. The lid was replaced prior to removing the bottle from the 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.

The sample bottles came with appropriate labels attached. 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 w ith ice and more packing materials shortly after collection. 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.

Selected field samples were collected in replicat e to provide estimates of sample variability. The replicates consisted of two separate sets of samples co llected one after another. Replicate samples were submitted blind to the laboratory. Further inform ation on Quality Assurance/Quality Control (QA/QC) procedures can be found in the QAPP for this monitoring project (Johnson and Gray 2010).

Samples were analyzed for 180 different pesticides an d degradates (Appendix C) by Pacific Agricultural Laboratory (Portland, OR) using EPA st andard 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 (HPLC-MS) Miscellaneous pesticides Modified EPA method 8321A (HPLC-MS)



## Results and Discussion

### 7 Over 93 percent of the 174 samples analyzed in 2009 had no detectable pesticide residues. Only four pesticides were detected, all of which were herbic ides. The pesticides detected in ND surface water during the 2009 study were atrazine, bentazon, dime thenamid and MCPA (Table 3 and Appendix B). Atrazine and bentazon were detected four and three times, respectively, while dimethenamid and MCPA were both detected twice. All of the pesticides concen trations were less than 1 ppb. All of the pesticide detections were in the eastern edge of the st ate and in the Red River or its tributaries.

Table 3. Pesticides detected in the 2009 surface water monitoring project. Pesticide Trade name # of detects Maximum concentration (ppb) EPA benchmark (ppb) Atrazine Aatrex 4 0.46 17.5 Bentazon Basagran 3 0.70 4500 Dimethanamid Outlook 2 0.36 8.9 MCPA MCPA 2 1.5 177

Approximately 92 percent of the 2009 pesticide detections were in June and July, shortly after the state’s primary pesticide use season. There was one detec tion in October and no detections in August and November (Figure 2).

Figure 2. Number of pesticide detections by samplin g date during the 2009 North Dakota Surface Water Monitoring Project

All of the pesticide detections occurred in the easter n edge of the state and in the Red River or its tributaries. The detection sites of the pesticides are shown in Figure 3.

Figure 3. Locations of pesticide detections from the 2009 ND Surface Water Monitoring Project 0 1 2 3 4 5 6 7Numberosdetectionsis

### 8 The Red River valley has a higher percentage of land in high intensity agriculture. Crops that use higher amounts of pesticides such as corn, soybeans and suga rbeets are common in the Red River Valley (Figure 4).

Figure 4. Land Cover data of North Dakota provided by the National Agriculture Statistics Service

### 9 Risk of pesticides to human health or the environmen t is a function of both toxicity and exposure. The EPA has established Maximum Contaminant Levels (M CLs) for pesticides in drinking water based on risk to human health. The EPA has also established a quatic 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 av ailable in the public scientific literature. Aquatic life benchmarks, which are based on the most sensitive t oxicity 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 the department was able to compare the c oncentration detected in surface water to the aquatic life benchmark, but not an MCL, because the EPA has not established MCLs for many pesticides.

Atrazine

Atrazine, a broadleaf herbicide used primarily on corn, is applied to approximately 59,500 acres as a standalone product and to 38,600 acres in mixtures in No rth Dakota each year (Zollinger, 2008). Atrazine was detected four times in 2009 in the Red River and its tributaries. It was detected twice on the Wild

### 10 Rice River at Abercrombie, ND, once on the Red River near Brushville, MN, and once on the Red River near Grand Forks, ND. All of these areas are in or are downstream from areas with heavy atrazine use (Figure 5).

Figure 5. Locations of atrazine surface water detecti ons in 2009 and total atrazine use per county.

All atrazine detections occurred in June and July. Th is is not surprising since atrazine is a preemergence herbicide that is normally applied in late April through early May.

Atrazine was detected in the samples at a range of concentrations from 0.40 to 0.46 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 highest detected atrazine concen tration was 38 times lower than the lowest aquatic benchmark, suggesting minimal risk of the de tected atrazine levels to aquatic species.

Atrazine has an MCL of 3 ppb. The highest concentration detected is 6.52 times lower than the MCL, suggesting that the detected concentration posed minimal risk to drinking water.

Bentazon

### 11 Bentazon is a postemergence herbicide used for broa dleaf weed control in wh eat, barley, corn, flax, sugarbeet, CRP and pastures. It is used as a sta nd-alone product on 779,200 acres in North Dakota each year. In addition, it is applied in a mixture with other pesticides on 77,300 acres (Zollinger, 2008). All bentazon detection were in our downstream from counties with heavy bentazon use (Figure 6)

Figure 6. Locations of bentazon surface water detections in 2009 and total bentazon use per county.

Bentazon was detected in three samples in July in the northeast section of the state: the Red River at Pembina, ND, the Forest River near Minto, ND and th e Turtle River North of Manvel, ND. Both the Forest and Turtle Rivers are tributaries of the Red River. The detections were at concentrations ranging from 0.038-0.070 ppb. The EPA aquatic life benchmark concentration, set for acute toxicity to nonvascular plants, is 4,500 ppb. The highest con centrations found during sampling were over 64,000 times less than the established benchmark, suggesting very minimal risk. There are no MCLs established for bentazon.

Dimethenamid

### 12 Dimethenamid is a selective, pre-emergence herbic ide for control of annual grasses, annual broadleaf weeds and sedges. In North Dakota, Dimethenamid is used primarily on corn and dry beans. Demethenamid is used on 145,400 acres in No rth Dakota annually (Zollinger, 2008).

Dimethenamid was detected twice in North Dakota in the 2009 study, on the Red River near Brushville, MN in June and in October on the Goose River, a tr ibutary of the Red River, at Hillsboro. The June detection was at 0.35 ppb and the October detection was at 0.36 ppb of dimethenamid. The detection was in a county of moderate dimethenamid use and dow nstream from a county with heavy dimethenamid use (Figure 7).

Figure 7. Locations of dimethenamid surface water det ections in 2009 and total dimethenamid use per county.

The aquatic life benchmark for dimethenamid for the most sensitive species, aquatic vascular plants, is 8.9 ppb. The highest detection of dimethenamid is more than 24 times less than the aquatic life benchmark. Therefore the detections found in North Da kota represent minimal risk to aquatic life. There are no MCLs established for dimethenamid.

MCPA

### 13 MCPA is a systemic herbicide used to control annual and perennial weeds in cereal grains and grassland. MCPA use in North Dakota is primarily used on wheat, barley, oats, flax, CRP and pasture. 933,600 acres of MCPA are applied in North Dakota annuall y as a standalone product and 2,651,000 acres treated with a mixture that includes MCPA (Zollinger, 2008).

There were two detections of MCPA in 2009 study, both in the southeast corner of the state (Figure 8). MCPA was detected at 0.9 ppb near Abercormbie, ND on the Wild Rice River, and at 1.5 ppb in the Red River near Brushville, MN. Detection of MCPA were in areas of moderate use, however we do not know what was used upstream of the Red River. Other areas of the state with more intensive MCPA use did not have any MCPA detections.

Figure 8. Locations of MCPA surface water detecti ons in 2009 and total MCPA use per county.

The aquatic life benchmark for MCPA is 170 ppb for th e most sensitive species, a quatic vascular plants. The highest concentration found during sampling was over 113 times lower than the established benchmark, suggesting minimal risk. Th ere are no MCLs established for MCPA. >6,000

### 14 The results of the 2009 monitoring project are simila r to the pilot project conducted in 2006. The pilot project had monitoring at many of the same sites as the 2009 project, including the Sheyenne River in two locations, the Souris River West, James, Little Miss ouri, Cannonball, Heart, Goose and Red Rivers. The 2006 pilot study showed only one pesticide detection of picloram at 0.23 ppb. That concentration was far below levels of concern for human and environmental health. Picloram was included as an analyte in the 2008 and 2009 monitoring studies, but no picloram was detected.

Several comparisons can be made between the 2008 and 2009 monitoring results. All sampling sites from 2008 were included in the 2009 study, as were 180 of the 184 pesticides tested for in 2008. Fewer pesticides were found during the 2009 sampling than in 2008; in 2009, four pesticides were detected, while nine pesticides and one pesticid e degradate were detected in 2008. In 2009, atrazine and bentazon were the most commonly detected pesticides, while 2,4-D and diuron were the most commonly detected pesticides in 2008. In 2009, all of the pesticides were below levels that may be harmful according to EPA standards. In 2008 one pesticide, diuron was found above an aquatic life benchmark. Diuron was tested for in 2009, but it was not found.

We now have three years of ambient surface water sa mpling for pesticides in North Dakota. Results from these studies show that North Dakota rivers and streams have minimal pesticide contamination. This is a good sign for the environment and producers and others who rely on pesticides. All 2009 detections were below EPA’s aquatic life benchmarks and MCLs. Acco rding to these standards, the concentrations of pesticides found in North Dakota rivers and streams are not a risk to human health and the environment. Aquatic life benchmarks are determined by the most sensitive species tested. The concentrations of pesticide found in 2009 are not expected to harm aquatic life, including acute and chronic exposure to fish and invertebrates, acute concentration fo r vascular and non-vascular plants.

This project is the only state-wide comprehensive su rface water monitoring project for pesticides in North Dakota. For this reason, the project serves important purposes. If there are not impairments, it shows that current regulations are effective in mitigating risk of pesticide contamination to surface water. If impairments of rivers are found, these can be addressed through regulation and education. For example, in 2008 levels of diuron were found in the Souris Ri ver above aquatic life benchm arks. This is a problem that could have gone undetected for many years if not for this program. The department conducted investigations and outreach to the area following the 2 008 detections. In 2009, there were no detections of diuron in the Souris River. Despite the inherent uncertainty of the cause of th e diuron decrease, this is an excellent example of how a monitoring system can be useful in finding and mitigating a previously unnoticed problem.

Without surface water data, federal agencies such as th e EPA often use conservative models that tend to overestimate the concentrations of pesticides in surface water. Because of a lack of surface water monitoring data, these models are often used for d ecision making for policies such as set back areas from 

## Conclusion

### 15 surface water on labels, potential National Pollutant Discharge Eliminations Systems (NPDES) permits, and Endangered Species Bulletins. With more data from projects such as this one, EPA could rely on real world data instead of models for policy decisions.

A lack of surface water data can also be a probl em for state programs. At the present time, the Department has limited data on the levels of pestic ides in surface water or on the frequency of occurrence, especially data on pesticide levels in lakes and wetla nds. This lack of data has severely limited our ability to evaluate pesticide risks for many of pes ticide regulatory programs. Without reliable water quality monitoring data, the Department has been for ced 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 concentrati ons and their occurrence in surface water would allow the Department to better protect surface water res ources from pesticides, while not imposing unnecessary burdens to pesticide users

. Continuing and expanding this comp rehensive, multi-year, state-wide pesticide monitoring program is invaluable to the Depa rtment to evaluate the potential risks of pesticide use to impair the state’s surface water resources.

Gray, J.A., Orr, J.N. 2009. Surface Water Pestic ide Monitoring and Assessment Project, 2008. North Dakota Department of Agriculture, http://www.agdepartment.com/PDFFiles/ PesticideMonitoringReport2008.pdf

Gray, J.A., Orr, J.N. 2009. Quality Assurance Plan for the Pesticide Water Quality Monitoring Program. North Dakota Department of Agriculture, unpublished.

Zollinger, R.K., M.P. McMullen, J. Knodel, J.A. Gray , D. Jantzi, G. Kimmet, K. Hagameister, and C. Schmitt. 2009. Pesticide use and pest management practices in North Dakota, 2008. North Dakota State University Ext. Publication W-1446. 

## References

### 16 Appendix A. Chain of Custody Form

### 17 Appendix B. Full list of North Dakota pesticide surface water detections in 2009 Pesticide Concentration (ppb) Date Location Benchmark (ppb) Reporting limit (ppb) atrazine 0.42 6/17/2009 380031 1 0.30 atrazine 0.46 6/17/2009 380083 1 0.30 atrazine 0.40 6/23/2009 384156 1 0.30 atrazine 0.45 7/29/2009 380031 17.5 0.30 bentazon 0.38 7/13/2009 384157 4,500 0.08 bentazon 0.54 7/29/2009 384157 4,500 0.08 bentazon 0.70 7/29/2009 380039 4,500 0.08 dimethenamid 0.36 6/17/2009 380083 8.9 0.30 dimethenamid 0.35 10/7/2009 380156 8.9 0.30 MCPA 0.90 6/17/2009 380031 170 0.080 MCPA 1.5 6/17/2009 380083 170 0.080

Appendix C. List of pesticides analyzed in the 2009 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) 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)

### 18 Analyte Trade name Type Reporting Limit 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) 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)

### 19 Analyte Trade name Type Reporting Limit 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) 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) 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)

### 20 Analyte Trade name Type Reporting Limit 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) 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)

### 21 Analyte Trade name Type Reporting Limit 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) δ -BHC degradate D 0.12 ug/liter (ppb)

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