2013 Water Quality Monitoring Report - the Minnesota Department of ...

2013 Water Quality Monitoring Report January – December 2013

Published May 2014

MINNESOTA DEPARTMENT OF AGRICULTURE

MAU-14-101 In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

Minnesota Department of Agriculture 625 Robert Street North Saint Paul, MN 55155-4194

www.mda.state.mn.us 651-201-6000 or 800-967-2474 TTY: 1-800-627-3529 651-201Authors and Contributors Monitoring and Assessment Unit Supervisor - Bill VanRyswyk; Lead Hydrologist - John Hines Hydrologists - Marie Juenemann, Scott Matteson, Matt Ribikawskis, Katie Rassmussen, Brennon Schaefer, and David Tollefson Editor – PFMD Staff, Heather Johnson

Minnesota Department of Agriculture Pesticide and Fertilizer Management Division Monitoring and Assessment Unit

ACKNOWLEDGEMENTS

The following cooperating organizations were critical to the collection of much of the data presented in this report:

MDA Laboratory Water Analysis Unit MDA Staff Russ Derickson and Luke Stuewe, former MDA staff Constance Holth Chippewa River Watershed Project, Fillmore County SWCD, Goodhue County SWCD, Hawk Creek Watershed Project, International Water Institute, Metropolitan Council Environmental Services, Minnesota State University, Mankato – Water Resources Center, Minnesota Department of Natural Resources, Minnesota Pollution Control Agency, Mower County SWCD, Redwood Cottonwood River Control Area, and U.S. Geological Survey.

Report Review: Monitoring and Assessment Unit Staff, PFMD staff: Annie Felix-Gerth, Jeff Berg, and Assistant Division Director for PFMD Dan Stoddard.

In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

TABLE OF CONTENTS TABLE OF CONTENTS ................................................................................................................i LIST OF FIGURES ........................................................................................................................iii LIST OF TABLES ..........................................................................................................................vi LIST OF APPENDICES .................................................................................................................viii ABBREVIATIONS ........................................................................................................................ix DEFINITIONS ................................................................................................................................xi SECTION 1: INTRODUCTION .................................................................................................1 1.1. Program history...................................................................................................................1 1.2. Program elements................................................................................................................1 1.3. Pesticide Monitoring Regions (PMRs) ...............................................................................2 1.4. New program activities for 2014 ........................................................................................4 1.5. Recent precipitation patterns...............................................................................................3 1.6. Chemical analytes and 2013 detection summary ................................................................4 SECTION 2: GROUNDWATER MONITORING RESULTS ...............................................10 2.1. 2013 Groundwater pesticide sampling summary..............................................................11 2.2. Analysis of the most frequently detected pesticides .........................................................17 2.2.1. Acetochlor results ...................................................................................................21 2.2.2. Alachlor results.......................................................................................................30 2.2.3. Atrazine results .......................................................................................................39 2.2.4. Dimethenamid results .............................................................................................51 2.2.5. Metolachlor results .................................................................................................61 2.2.6. Metribuzin results ...................................................................................................71 2.3. Monitoring of deep wells in PMR 4 .................................................................................77 2.4. Urban groundwater sampling ............................................................................................81 2.5. Statewide groundwater nitrate ..........................................................................................85


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SECTION 3: SURFACE WATER MONITORING RESULTS .............................................88 3.1. 2013 Pesticide monitoring season summary .....................................................................88 3.1.1 2013 Pesticide monitoring sample number summary .............................................88 3.2. Surface water Tier 1 and 2 pesticide sampling .................................................................95 3.2.1. Statewide Tier1 and Tier 2 pesticide sampling summary ......................................97 3.2.2. Urban Tier 1 surface water pesticide sampling summary ....................................100 3.3. Surface water Tier 3 pesticide sampling .........................................................................104 3.3.1. 2013 surface water Tier 3 pesticide monitoring results .......................................104 3.4. Long-term analysis of pesticides in surface water ..........................................................109 3.4.1. Long-term pesticide results for Tier 1 and Tier 2 from 2007 -2013 ....................111 3.4.2. Long term chlorpyrifos detections at Tier 1, Tier 2 and Tier 3 locations .............114 3.4.3. Detailed analysis of May and June herbicide detections at Tier 1 and Tier 2 from 2007 – 2013 ......................................................................................116 3.4.4. Number of sample pesticide concentrations above 10 percent or 50 percent of surface water numeric standards at Tier 3 locations from 2008 – 2013 ..........124 3.4.5. Period of record data at current Tier 3 pesticide sampling locations ...................129 3.5. Precipitation sampling ....................................................................................................134 3.6. Glyphosate monitoring....................................................................................................136 3.7. 2013 Nutrient and Total Suspended Solids monitoring ..................................................137 3.7.1. Surface Water Tier 1 and Tier 2 monitoring ........................................................137 3.7.2. Surface Water Tier 3 monitoring..........................................................................140 SECTION 4: SPECIAL MONITORING STUDIES IN 2013 ...............................................143 4.1. Plot and field scale evaluations .......................................................................................143 4.2. Root River Pesticide Pilot Study.....................................................................................149 4.2.1. Root River Pesticide Pilot Study results ...............................................................150 SECTION 5: REFERENCES ..................................................................................................152


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FIGURES Figure 1.

MDA’s Pesticide Monitoring Regions (PMRs) ........................................................2

Figure 2.

Statewide annual precipitation total and departure from normal for 201 ..................3

Figure 3.

Location of groundwater monitoring sites sampled in 2013 ...................................12

Figure 4.

Number of common detection pesticides detected in groundwater samples per sampling site in 2013 ...............................................................................................18

Figure 5.

Pesticide Monitoring Regions and groundwater monitoring sites with acetochlor and/or acetochlor degradate detections in 2013 ......................................................22

Figure 6.

Acetochlor degradate analysis results over time for MDA PMR 4 and PMR 9 groundwater samples ...............................................................................................24

Figure 7.

Acetochlor and acetochlor degradate detection frequencies over time for MDA groundwater monitoring in PMRs 4 and 9 ..............................................................26

Figure 8.

Acetochlor ESA analysis results over time for MDA PMRs 1, 5, 6, 7 and 8 groundwater samples ...............................................................................................27

Figure 9.

Acetochlor OXA analysis results over time for MDA PMRs 5, 6, 7 and 8 groundwater samples ...............................................................................................28

Figure 10. Acetochlor and acetochlor degradate detection frequencies over time for MDA groundwater monitoring in PMRs 5, 6, 7, and 8 .....................................................29 Figure 11. Pesticide Monitoring Regions and groundwater monitoring sites with alachlor and/or alachlor degradate detections in 2013 ..........................................................31 Figure 12. Alachlor and alachlor degradates concentration results over time for MDA groundwater monitoring in PMRs 4 and 9 ..............................................................34 Figure 13. Alachlor and alachlor degradate detection frequencies over time for MDA groundwater monitoring in PMRs 4 and 9 ..............................................................35 Figure 14. Alachlor ESA concentration results over time for MDA PMRs 5, 6, 7 and 8 groundwater samples ...............................................................................................36 Figure 15. Alachlor OXA concentration results over time for MDA PMRs 5 and 8 groundwater samples ...............................................................................................37 Figure 16. Alachlor and alachlor degradate detection frequencies over time for MDA groundwater monitoring in PMRs 5, 6, 7, and 8 .....................................................38 Figure 17. Pesticide Monitoring Regions and groundwater monitoring sites with atrazine and/or atrazine degradate detections in 2013 ..........................................................40 Figure 18. Atrazine concentration over time for MDA PMRs 4 and 9 groundwater samples .44 Figure 19. Desethylatrazine concentration over time for MDA PMRs 4 and 9 groundwater samples ....................................................................................................................45 In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

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Figure 20. Deisopropylatrazine concentration over time for MDA PMRs 4 groundwater samples ....................................................................................................................46 Figure 21. Atrazine and atrazine degradate detection frequencies over time for MDA groundwater monitoring in PMRs 4 and 9 ..............................................................47 Figure 22. Atrazine concentration over time for MDA PMRs 1, 5, and 7 groundwater samples ...................................................................................................................48 Figure 23. Desethylatrazine concentration over time for MDA PMRs 1, 5, 6, and 8 groundwater samples ...............................................................................................49 Figure 24. Atrazine and atrazine degradate detection frequencies over time for MDA groundwater monitoring in PMRs 1, 5, 6, 7, and 8 .................................................50 Figure 25. Pesticide Monitoring Regions and groundwater monitoring sites with dimethenamid and/or dimethenamid degradate detections in 2013 ........................52 Figure 26. Dimethenamid groundwater sample analysis results over time for MDA PMRs 4 and 9 .....................................................................................................................55 Figure 27. Dimethenamid OXA groundwater sample analysis results over time for MDA PMR 4......................................................................................................................56 Figure 28. Dimethenamid and dimethenamid degradate detection frequencies over time for MDA groundwater monitoring in PMRs 4 and 9 ....................................................57 Figure 29. Dimethenamid ESA concentration results over time for MDA PMRs 5, 6, 7 and 8 groundwater samples .....................................................................................58 Figure 30. Dimethenamid OXA concentration results over time for MDA PMR 6 groundwater samples ...............................................................................................59 Figure 31. Dimethenamid and dimethenamid degradates detection frequency over time for MDA groundwater monitoring in PMRs 5 and 6 ..............................................60 Figure 32. Pesticide Monitoring Regions and groundwater monitoring sites with metolachlor and/or metolachlor degradate detections in 2013. ...............................62 Figure 33. Metolachlor groundwater sample analysis results over time for MDA PMRs 4 and 9 ........................................................................................................................65 Figure 34. Metolachlor ESA groundwater sample analysis results over time for MDA PMRs 4 and 9 ..........................................................................................................65 Figure 35. Metolachlor OXA groundwater sample analysis results over time for MDA PMRs 4 and 9. .........................................................................................................66 Figure 36. Metolachlor and metolachlor degradate detection frequencies over time for MDA groundwater monitoring in PMRs 4 and 9 ....................................................67 Figure 37. Metolachlor ESA groundwater sample analysis results over time for MDA PMRs 5, 6, 7 and 8 ..................................................................................................68 In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

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Figure 38. Metolachlor OXA groundwater sample analysis results over time for MDA PMRs 5, 6, 7 and 8 ....................................................................................... 69 Figure 39. Metolachlor and metolachlor degradates detection frequency over time for MDA groundwater monitoring in PMRs 1, 5, 6, 7 and 8. .......................................70 Figure 40. Pesticide Monitoring Regions and groundwater sites with metribuzin and/or metribuzin degradate detections in 2013 .................................................................72 Figure 41. Metribuzin and metribuzin degradates analysis results over time for MDA PMR 4 groundwater samples ..................................................................................75 Figure 42. Metribuzin and metribuzin degradates detection frequency over time for MDA groundwater monitoring in PMR 4 .........................................................................76 Figure 43. Location of deep wells within MDA’s groundwater monitoring network ..............78 Figure 44. 2013 MDA urban groundwater monitoring wells by Pesticide Monitoring Region .....................................................................................................................82 Figure 45. Nitrate-nitrogen analysis results over time for MDA PMR 4 groundwater samples ....................................................................................................................86 Figure 46. Nitrate-nitrogen analysis results over time for MDA PMRs 1, 5, 6, 7, 8, and 9 groundwater samples ...............................................................................................87 Figure 47. 2013 Tier 1 and 2 and Urban Tier 1 and Tier 2 pesticide monitoring sites .............96 Figure 48. Tier 3 monitoring sites sampled in 2013 ...............................................................105 Figure 49. Current and historic surface water sampling locations .........................................110 Figure 50. 2007-2013 acetochlor detection frequency by PMR and statewide ......................118 Figure 51. 2007-2013 acetochlor concentration percentiles by PMR and statewide ..............119 Figure 52. 2007-2013 atrazine detection frequency by PMR and statewide ..........................120 Figure 53. 2007-2013 atrazine concentration percentiles by PMR and statewide ..................121 Figure 54. 2007-2013 metolachlor detection frequency by PMR and statewide ....................122 Figure 55. 2007-2013 metolachlor concentration percentiles by PMR and statewide ...........123 Figure 56. Concentration pesticide results from rainfall precipitation collected at the Little Cobb River precipitation monitoring station, 2013 .....................................134 Figure 57. Concentration pesticide results from rainfall precipitation collected at the Rochester precipitation monitoring station, 2013 .................................................134 Figure 58. 2013 glyphosate monitoring locations ..................................................................137 Figure 59. MDA field scale monitoring sites .........................................................................144 Figure 60. Sub-watershed locations being monitored as part of the Root River Field to Stream Partnership ................................................................................................149 In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

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TABLES Table 1.

2013 list for target pesticide and pesticide degradates analyzed in both surface water and groundwater with associate.......................................................................6

Table 2.

Other pesticide analyte methods..............................................................................10

Table 3.

Nutrient and sediment target analyte list .................................................................10

Table 4.

2013 summary of groundwater samples analyzed and reference values .................13

Table 5.

2013 MDA analytical results for acetochlor and acetochlor degradates in groundwater .............................................................................................................23

Table 6.

Total number of detections and detection frequencies in groundwater samples for acetochlor and acetochlor degradates in 2013 by PMR.....................................24

Table 7.

2013 MDA analytical results for alachlor and alachlor degradates in groundwater .............................................................................................................32

Table 8.

Total number of detections and detection frequencies in groundwater samples for alachlor and alachlor degradates in 2013 by PMR ...........................................33

Table 9.

2013 MDA analytical results for atrazine and atrazine degradates in groundwater .............................................................................................................41

Table 10.

Total number of detections and detection frequencies in groundwater samples for atrazine and atrazine degradates in 2013 by PMR.............................................42

Table 11.

2013 MDA analytical results for dimethenamid and dimethenamid degradates in groundwater .........................................................................................................53

Table 12.

Total number of detections and detection frequencies in groundwater samples for dimethenamid and dimethenamid degradates in 2013 by PMR ........................54

Table 13.

2013 MDA analytical results for metolachlor and metolachlor degradates in groundwater .............................................................................................................63

Table 14.

Total number of detections and detection frequencies in groundwater samples for metolachlor and metolachlor degradates in 2013 by PMR ................................64

Table 15.

2013 MDA analytical results for metribuzin and metribuzin degradates in groundwater .............................................................................................................73

Table 16.

Total number of detections and detection frequencies in groundwater samples for metribuzin and metribuzin degradates in 2013 by PMR ...................................74

Table 17.

MDA PMR 4 2013 pesticide samples results for chemicals with detections in more than two of the shallow and deep well nests ..............................................79

Table 18.

Summary of pesticides detected in 2013 urban groundwater samples ....................83

Table 19.

Summary of nitrate-nitrogen results in groundwater samples for 2013 ..................84


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Table 20.

Summary of nitrate-nitrogen results in groundwater samples for 2013 compared against MDH health risk limits ...............................................................85

Table 21.

Summary of nitrate-nitrogen results in paired shallow and deep wells in PMR 4......................................................................................................................85

Table 22.

Summary of surface water maximum detections and reference values ..................90

Table 23.

2013 Tier 1 and Tier 2 GC-MS/MS surface water results ......................................98

Table 24.

2013 Tier 1 and Tier 2 LC-MS/MS surface water results .......................................99

Table 25.

2013 Urban Tier 1 GC-MS/MS surface water results ...........................................101

Table 26.

2013 Urban Tier 2 GC-MS/MS surface water results ...........................................101

Table 27.

2013 Urban Tier 1 LC-MS/MS surface water results ...........................................102

Table 28.

2013 Urban Tier 2 LC-MS/MS surface water results ...........................................103

Table 29.

2013 Tier 3 GC-MS/MS surface water results ......................................................107

Table 30.

2013 Tier 3 LC-MS/MS surface water results ......................................................108

Table 31.

Total number of acetochlor, atrazine, chlorpyrifos, and metolachlor detections in surface water at Tier 1 and Tier 2 locations, 2008 through 2013 ......................111

Table 32.

Tier 1 and Tier 2 acetochlor, atrazine, chlorpyrifos, and metolachlor surface water concentration results from 2009 through 2013 ............................................112

Table 33.

Detections of chlorpyrifos in Minnesota surface waters since 2005 .....................115

Table 34.

Number of sample concentrations above 10% or 50% of the acetochlor, atrazine and metolachlor standards from 2008 - 2013 for Tier 3 sites based on the aquatic life standard ....................................................................................126

Table 35.

Number of sample concentrations above 10% or 50% of the 3,400 ng/L atrazine standard from 2008 - 2013 for current Tier 3 sites located on Class 2A waters ...............................................................................................................128

Table 36.

Period of record surface water concentration results at current Tier 3 locations for acetochlor, atrazine, chlorpyrifos and metolachlor..........................................130

Table 37.

Inorganic data summary from rainfall precipitation sampling in 2013 .................132

Table 38.

GC-MS/MS pesticide data summary from rainfall precipitation sampling in 2013. ..................................................................................................................133

Table 39.

LC-MS/MS pesticide data summary from rainfall precipitation sampling in 2013 .......................................................................................................................133

Table 40.

2010-2013 GC-MS/MS pesticide data summary from rainfall precipitation sampling ................................................................................................................135

Table 41.

2013 river and stream glyphosate and AMPA results ...........................................136


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Table 42.

Tier 1 and Tier 2inorganic results for surface water samples by PMR, 2013 .......139

Table 43.

Inorganic analyte detections in storm event and base flow samples for MDA Tier 3 surface water monitoring sites, 2013 ................................................141

Table 44.

2013 plot and field scale monitoring projects .......................................................145

Table 45.

MDA field scale monitoring sites .........................................................................147

APPENDICES Appendix 1. 2013 MDA Pesticide list by method and analyte: analyte name; Chemical Abstracts Service (CAS) registry number; and Method Reporting Limit (MRL). Appendix 2. Pesticide compounds detected in Minnesota water resources by Minnesota Department of Agriculture. Appendix 3. Groundwater monitoring network sample results, 2013. Appendix 4. Site code, site description, and sampling history for current and historic MDA river/stream and lake monitoring locations. Appendix 5. Surface water quality sample results, 2013. Appendix 6. MDA Tier 1 through 3 surface water monitoring site names and characteristics of locations sampled in 2013.

In accordance with the Americans with Disabilities Act, this information is available in alternative forms of communication upon request by viii calling 651/201-6000. TTY users can call the Minnesota Relay Service at 711 or 1-800-627-3529. The MDA is an equal opportunity employer and provider.

ABBREVIATIONS µg/L AMPA CAS CIG DFM DNR DOP EFI ELISA ETI ERL FAV GC-MS GC-MS/MS HA HBV HHBP HRL LCCMR LC-MS/MS LOWESS MAU MAWRC MCL MDA MDH MPCA MRL na nd ng/L NLAP NRCS NO3-N OPP OW P ppb ppm ppt PMR PMU

Micrograms per liter (equivalent to one part per billion of water sample or ppb) aminomethylphosphonic acid Chemical Abstract Service Conservation Innovation Grant Discovery Farms Minnesota Minnesota Department of Natural Resources Dissolved orthophosphorus Equal-Flow Increment Enzyme-linked Immunosorbent Assay Equal-Time Increment Estimated Reporting Limit Final Acute Value Gas Chromatography with Mass Spectrometry Gas Chromatography with tandem Mass Spectrometry Health Advisory Health Based Value Human Health Benchmark for Pesticides Health Risk Limit Legislative-Citizen Commission on Minnesota Resources Liquid Chromatography with tandem Mass Spectrometry Locally Weighted Scatter Plot Smoothing Monitoring and Assessment Unit Minnesota Agricultural Water Resources Center Maximum Contaminant Level Minnesota Department of Agriculture Minnesota Department of Health Minnesota Pollution Control Agency Method Reporting Limit Not applicable Not detected Nanograms per liter (equivalent to one parts per trillion or ppt) National Lakes Assessment Project Natural Resources Conservation Service Nitrate-Nitrogen Office of Pesticide Programs (USEPA) Office of Waters (USEPA) Present parts per billion (equivalent to micrograms of chemical per liter of water sample or g/L) parts per million (equivalent to milligrams of chemical per liter of water sample or mg/L) parts per trillion (equivalent to nanograms of chemical per liter of water sample or ng/L) Pesticide Monitoring Region Pesticide Management Unit


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RAA STID TP TSS ug/L USGS USEPA

Risk Assessment Advice Biological Stressor Identification Total phosphorus Total suspended solids microgram per Liter (the same as µg/L and equivalent to parts per billion or ppb) United States Geological Survey United States Environmental Protection Agency


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DEFINITIONS Chronic Standard, Criterion or Advisory Value The highest water concentration of a chemical to which organisms can be exposed without causing chronic toxicity to organisms in question. Established for individual chemicals based on toxicity to aquatic life (the “toxicity-based”) and based on toxicity to human life (the “human health-based”), when sufficient information exists to establish one or both of these numbers. The more stringent of the two numbers is used as the chronic standard, criterion or advisory value for purposes of implementation of Minnesota Rules Chapter 7050. The underlying exposure assumptions (e.g., timeframes for exposure comparisons) and applicability of any numbers are established by the MPCA and may vary depending on the state classification of the water body, the nature of the data comparisons being made, and the regulatory status of the number being used for comparison. Enzyme-linked immunosorbent assays (ELISA) ELISA is an alternative laboratory analysis method. The MAU have used this methodology to screen water quality samples for both surface and groundwater for atrazine, acetochlor and/or glyphosate. Estimated reporting Limit (ERL) An estimate of the lowest concentration that a given method may be capable of reporting when final validation of the method is complete. Used for reporting mass estimates for analytes of interest before the analytical method is fully developed and validated. Analytes with an ERL may be reported as “present” when there is enough mass of the chemical to be measured although total mass is below the ERL. Final Acute Value (FAV) and Maximum Standard (MS) An estimate of the concentration of a pollutant corresponding to the cumulative probability of 0.05 in the distribution of all the acute toxicity values for the genera or species from the acceptable acute toxicity tests conducted on a chemical. The FAV is the value found to be toxic in 5% of all studies conducted. Ninety five percent of all tests conducted found toxicity values to be higher than the FAV chosen. One-half the value of the FAV is the Maximum Standard (MS), and is the highest concentration of a toxicant in water to which aquatic organisms can be exposed for a brief time with zero to slight mortality. The MS is often used as a remedial action cleanup goal to protect surface waters in some groundwater contamination situations. Health Based Value (HBV) Identical to an HRL except that the value is issued on an interim basis for specific situations and until such time that the basis of its derivation and calculation are reviewed and subject to rulemaking.


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Health Risk Limit (HRL) The concentration of a substance or chemical (i.e., one that has been determined to be a potential private well drinking water contaminant) in drinking water that can produce a potential toxicological result due to systemic or carcinogenic effect in humans upon consumption. The underlying exposure assumptions (e.g., volume of water consumed and timeframes for exposure comparisons) and the general applicability of any HRL are established for Minnesota by the MDH and adopted by rule of the MDH Commissioner. Maximum Contaminant Level (MCL) A value set by the USEPA as the maximum amount of a chemical allowed in a federally regulated public water supply, considering health, economic or other factors including technological factors such as treatment cost and feasibility. Method Reporting Limit (MRL) Represents the minimum concentration of an analyte that can be reliably quantified and reported by the laboratory. Analytes may be positively identified via qualitative procedures and reported as “Present” below the MRL.


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Section 1: INTRODUCTION This annual report presents groundwater and surface water pesticide data collected by the Monitoring and Assessment Unit (MAU) of the Minnesota Department of Agriculture (MDA). Water quality results for 2013, as well as summaries of historical pesticide data, are shown. The report also presents monitoring results for select nutrients and sediment from samples collected at the same time as the pesticide samples. 1.1 Program history In 1985, MDA and Minnesota Department of Health (MDH) undertook a cooperative survey of groundwater for pesticides and nitrate-nitrogen in areas of agricultural land use considered susceptible to contamination (outwash sands and karst bedrock areas). This survey found that pesticides commonly applied to fields in agricultural production (normal use) were present in groundwater at detectable concentrations. The most frequently detected pesticides were atrazine and alachlor (both herbicides) (Klaseus, Buzicky, and Schneider, 1988). A second survey by MDH in 1986 that targeted primarily private (farm) drinking water wells showed similar results (Klaseus and Hines, 1989). In 1987, the Minnesota Legislature amended the Minnesota Pesticide Control Law (Chapter 18B of Minnesota State Statutes). Minnesota Statute 18B.04 requires: “The commissioner shall: (1) determine the impact of pesticides on the environment, including the impacts on surface water and groundwater in this state; (2) develop best management practices involving pesticide distribution, storage, handling, use, and disposal; and (3) cooperate with and assist other state agencies and local governments to protect public health and the environment from harmful exposure to pesticides.” In response to this charge, the MDA initiated a groundwater monitoring program in 1987 and began monitoring surface water in 1991. In 1989, the Minnesota Comprehensive Groundwater Protection Act (Chapter 103H of Minnesota State Statutes) expanded groundwater protection responsibilities of the MDA, including specific direction regarding monitoring for agricultural chemicals and the management of those chemicals when found to impact groundwater. The Groundwater Protection Act mandated development of a State Pesticide Management Plan with monitoring data to act as the primary information to guide management decisions within that plan. 1.2 Program elements In general, MDA monitors river and stream quality using a combination of sampling techniques (grab sampling characterizes water quality at a single point in time during base and storm flow, and composite sampling characterizes water quality during periods of dynamic storm flow at Tier 3 locations). Groundwater is monitored by collecting samples from networks of wells Minnesota Department of Agriculture 2013 Annual Monitoring Report

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established by MDA to characterize long-term trends in specific aquifers. Both surface and groundwater samples are analyzed by the MDA Laboratory Services (MDA Laboratory) using well-established laboratory methods. Occasionally there are departures from these monitoring and analytical approaches as MDA explores new ways to implement its mandates and enhance its capabilities. 1.3 Pesticide Monitoring Regions (PMRs) MDA has developed regional water quality monitoring networks, called Pesticide Monitoring Regions (PMRs), for the purposes of collecting, assessing, and reporting monitoring data (Figure 1). Minnesota was divided into ten PMRs on the basis of agricultural practices and hydrologic/geologic characteristics. The PMR boundaries follow county boundaries, but are intended to generally follow different hydrologic regions in Minnesota.

Figure 1. MDA’s Pesticide Monitoring Regions (PMRs).

Minnesota Department of Agriculture 2013 Annual Monitoring Report

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1.4 New program activities for 2014 Several new program activities planned for 2014 are discussed below: 

Surface Water -The expansion of the liquid chromatography with tandem mass spectrometry (LC-MS/MS) sampling began in 2013 and will continue at selected Tier 1 and Tier 2 sites across MN, as well as at all Tier 3 locations. -There will be pesticide sampling of wetland water samples, in collaboration with MPCA, and possibly wetland sediment samples for selected pesticides if a feasible laboratory method is developed. -The addition of two new stream sites to aid the Minnesota Pollution Control Agency’s (MPCA) intensive watershed approach. This program provides an increasing amount, and more accurate representation, of pesticide information earlier in the stressor identification process. -An additional wet precipitation collector (installation set for spring 2014) at the Buffalo River near Georgetown Tier 3 site in the Red River Valley to provide an assessment of atmospheric pesticide transport, including chlorpyrifos.



Groundwater -The Private Well Pesticide Project will begin in 2014, and the primary goal is to provide information to homeowners and the general public on the presence of pesticides in private drinking water wells in geologically sensitive areas of Minnesota. This will be achieved by hiring a contract laboratory to analyze water samples at environmentally relevant concentrations for common detection pesticides and their primary metabolites. It is planned that 300 to 500 private wells will be sampled in 2014 as a part of this project. -It is anticipated that expanded coordination on projects with the Minnesota Department of Natural Resources (MDNR) will occur in 2014. These projects relate to making recommendations to the MDNR for monitoring and assessment of nitrate nitrogen concentrations in groundwater at different scales. The first is a small-scale effort related to sites requiring an irrigation permit. The second is a large-scale effort with other agencies related to regional monitoring of aquifers on a groundwater province basis. - Coordination will occur with the United States Geological Survey (USGS) in 2014 related to studying denitrification processes in Minnesota’s groundwater resources. The USGS will begin by compiling information and data from Minnesota to evaluate data gaps, and then proceed to evaluate geologic setting and geochemical regime effects on well geochemistry as related to denitrification.


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1.5 Recent precipitation patterns There is often a strong relationship between pesticide concentrations measured in groundwater and surface water samples and precipitation patterns during a given year. Pesticide movement from the point of application to the broader environment is often related to the timing and magnitude of precipitation events with respect to pesticide application periods. Total annual precipitation and annual precipitation departure for 2013, as reported by the State Climatology Office, are shown in Figure 2.

Figure 2. Statewide annual precipitation total and departure from normal for 2013. 1.6 Chemical analytes and 2013 detection summary Water samples were analyzed in the MDA Laboratory for pesticides and inorganic compounds and are referred to as “analytes” throughout this report. A new analytical method was used to analyze water quality monitoring samples in 2013. The gas chromatography with tandem mass spectrometry (GC-MS/MS) method replaced the gas chromatography with mass spectrometry (GC-MS) procedure. The incorporation of the GC-MS/MS method, along with the LC-MS/MS method, means that all pesticide analyses are quantified at levels of parts per trillion (ppt), or nanograms per liter (ng/L). Analysis with GC-MS (previous years) were quantified in parts per billion (ppb), or micrograms per liter (µg/L). With the new GC-MS/MS method there are some lower Method Reporting Limits (MRLs), the “target analyte list” expanded to include several new analytes, and detections are no longer noted as “present below MRL” by the MDA Laboratory.


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Due to limited resources, the MDA carefully selects which agricultural chemicals are included in its monitoring program. A pesticide may be included in MDA’s “target analyte list” based on several factors. To be included, a pesticide must:    

Have been used or planned to be used in Minnesota or neighboring states; Have environmental fate characteristics or use patterns that could potentially result in adverse water resource impacts; Have a laboratory analytical method that can achieve reasonable results given prevailing resource limitations; and Generally have available risk guidance for human health and aquatic life toxicity.

The “target analyte list” typically includes many of the most commonly used pesticide products or degradates; however, historically there were also additional pesticides detected and quantified (if possible) that were “non-target” analytes if they fell into the same chemical class as the target analytes. With the development of the LC-MS/MS and GC-MS/MS methods discussed above, “non-target analytes” are no longer quantified or reported. The MAU uses water quality reference values and standards to compare against the monitoring results. These reference values come from state and federal agency sources, and the Pesticide Management Unit (PMU) provided values for each of the individual analytes. For 2013, these reference values were included with the results summaries for groundwater and surface water. Refer to Sections 2 and 3 to view these values for groundwater and surface water, respectively. All pesticides analyzed by the MDA Laboratory in 2013, along with their detection status in surface water or groundwater, are listed in Table 1. Laboratory MRLs for each analyte are included in Table 1, and analytes associated with expanded laboratory methods for 2013 are indicated as well. Additional information pertaining to chemical abstracts service (CAS) registry numbers can be found in Appendix 1. Glyphosate and its primary degradate, AMPA, analysis was performed by the MDA Laboratory with a newly developed LC-MS/MS method, on a limited number of surface water samples in 2013 (Table 2). A list of inorganic analytes is provided in Table 3. For a historic listing of all pesticide analytes detected in either surface or groundwater, see Appendix 2.


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Table 1. 2013 list of target and non-target pesticide and pesticide degradates detection status in surface and/or groundwater with associated method reporting limits (MRLs). 2013 Analyte Detected in Surface Water

2013 Analyte Detected in Groundwater

GC-MS/MS

LC-MS/MS

MRL (ng/L)

MRL (ng/L)

Common Name

Type

2,4,5-T

Herbicide

50

2,4,5-TP

Herbicide

50

2,4-D

Herbicide

2,4-DB

Herbicide

20

Acetamiprid

Insecticide

25

Acetochlor

Herbicide

x

x

x

x

8.3

30

Acetochlor ESA

Herbicide Degradate

x

x

30

Acetochlor OXA

Herbicide Degradate

x

x

33.3

Alachlor

Herbicide

x

30

Alachlor ESA

Herbicide Degradate

x

x

41.6

Alachlor OXA

Herbicide Degradate

x

x

33.3

Aldicarb Sulfone

Insecticide Degradate

15

Aldicarb Sulfoxide


50

Atrazine

Herbicide

x

x

30

DEDI Atrazine

Herbicide Degradate

x

x

Deisopropylatrazine

Herbicide Degradate

x

x

150

Desethylatrazine

Herbicide Degradate

x

x

50

Hydroxyatrazine

Herbicide Degradate

x

x

Azoxystrobin

Fungicide

Benfluralin

Herbicide

Bensulfuron-methyl

Herbicide

Bentazon

Herbicide

Bifenthrin

Insecticide

Boscalid

Fungicide

x

Bromacil

Herbicide

x

Carbaryl

Insecticide

Carbendazim

Fungicide Degradate

50

6.7

x

10 25 16.7

x

x

5 20 50

x

30 25

x

10

Carbofuran

Insecticide

13.3

Chlorantraniliprole

Insecticide

50

Chlorimuron-ethyl

Herbicide

20

Chlorothalonil

Fungicide

Chlorpyrifos

Insecticide

Chlorpyrifos Oxon



50 x

40 40

Page 6

Table 1 continued. 2013 Analyte Detected in Surface Water


GC-MS/MS MRL (ng/L)

LC-MS/MS MRL (ng/L)

Common Name

Type

Clomazone

Herbicide

Clopyralid

Herbicide

x

x

41.6

Clothianidin

Insecticide

x

x

25

Cyanazine

Herbicide

Cyfluthrin

Insecticide

100

Diazinon

Insecticide

30

Diazinon Oxon

15

25


75

Dicamba

Herbicide

x

50

Dichlobenil

Herbicide

x

Dichlorprop

Herbicide

Dichlorvos

Insecticide

Dicrotophos

Insecticide

25

Difenoconazole

Fungicide

25

Dimethenamid

Herbicide

5 50

x

15

x

x

15

Dimethenamid ESA

Herbicide Degradate

x

x

6.7

Dimethenamid OXA

Herbicide Degradate

x

x

10

Dimethoate

Insecticide

Dinotefuran

Insecticide

Disulfoton

Insecticide

Disulfoton Sulfone

Insecticide

Diuron

Herbicide

EPTC

Herbicide

10

Esfenvalerate

Insecticide

150

Ethalfluralin

Herbicide

50

Ethofumesate

Herbicide

Flufenacet OXA

100 x

25 60 20

x

x

x

13.3

50

Herbicide Degradate

8.3

Flumetsulam

Herbicide

Flutriafol

Fungicide

Fonofos

Insecticide

Halosulfuron-methyl

Herbicide

30

Hexazinone

Herbicide

10

Imazamethabenz-methyl

Herbicide

5

Imazamethabenz Acid

x

x

10 15

Herbicide Degradate

Imazamox

Herbicide

Imazapic

Herbicide


50

10 x x

13.3 10

Page 7

Table 1 continued. 2013 Analyte Detected in Surface Water


x

x

GC-MS/MS MRL (ng/L)

LC-MS/MS MRL (ng/L)

Common Name

Type

Imazapyr

Herbicide

Imazaquin

Herbicide

Imazethapyr

Herbicide

x

x

6.7

Imidacloprid

Insecticide

x

x

20

Isoxaflutole

Herbicide

Isoxaflutole DKN

8.3 16.7

40

Herbicide Degradate

50

lambda-Cyhalothrin

Insecticide

75

Linuron

Herbicide

Malathion

Insecticide

MCPA

Herbicide

MCPB

Herbicide

MCPP

Herbicide

x

x

50

Mesotrione

Herbicide

x

x

50

Metalaxyl

Fungicide

x

x

8.3

Methoxychlor

Insecticide

Metolachlor

Herbicide

20 50 x

5 20

50 x

x

25

Metolachlor ESA

Herbicide Degradate

x

x

10

Metolachlor OXA

Herbicide Degradate

x

x

10

x

x

Metribuzin

Herbicide

Metribuzin DA

Herbicide Degradate

Metribuzin DADK

Herbicide Degradate

Metribuzin DK

Herbicide Degradate

75 1000 (estimated)

x

1200 (estimated) 1200 (estimated)

Metsulfuron-methyl

Herbicide

Myclobutanil

Fungicide

10

Neburon

Herbicide

10

Nicosulfuron

Herbicide

Norflurazon

Herbicide

Norflurazon-desmethyl

23.3

x

26.6 20

Herbicide Degradate

Oxadiazon

Herbicide

Oxydemeton-methyl

Insecticide

Parathion-methyl

Insecticide

Parathion-methyl Oxon

x

50 75 20 100


25

Pendimethalin

Herbicide

Phorate

Insecticide

Picloram

Herbicide

x

Prometon

Herbicide

x


75 25 41.6 100

Page 8

Table 1 continued.

Common Name

Type

Prometryn

Herbicide

Propachlor

Herbicide

2013 Analyte Detected in Surface Water


GC-MS/MS MRL (ng/L)

LC-MS/MS MRL (ng/L) 3.3

30

Propachlor ESA

Herbicide Degradate

30

Propachlor OXA

Herbicide Degradate

10

Propazine

Herbicide

x

Propiconazole

Fungicide

x

10

Pyraclostrobin

Fungicide

x

25

Pyroxasulfone

Herbicide

x

50

Saflufenacil

Herbicide

x

Siduron

Herbicide

x

Simazine

Herbicide

x

Sulfometuron-methyl

Herbicide

x

8.3

Tebuconazole

Fungicide

x

10

Tebupirimphos

Fungicide

Tembotrione

Herbicide

Terbufos

Insecticide

x

Tetraconazole

Fungicide

x

Thiamethoxam

Insecticide

x

Thifensulfuron-methyl

Herbicide

16.7

Thiobencarb

Herbicide

8.3

Triallate

Herbicide

Triasulfuron

Herbicide

Triclopyr

Herbicide

Trifluralin

Herbicide

50

zeta-Cypermethrin

Insecticide

500


25

x

15 6.7 75

30 50 30 10 x

25

50 23.3 x

50

Page 9

Table 2. Other pesticide analyte methods.

Common Name Glyphosate AMPA

Method Glyphosate Analysis in Water by LC-MS/MS Glyphosate Analysis in Water by LC-MS/MS

Type

2013 Detected in Surface Water

2013 Detected in Groundwater

Herbicide

x

na

3.04

na

5.06

Herbicide

MRL (ng/L)

Table 3. Nutrient and sediment target analyte list. Compound Nitrate/Nitrite-Nitrogen Dissolved Orthophosphorus Total Phosphorus Total Suspended Solids

Method MDA Method #WC-105 MDA Method # WC-255 MDA Method # WC-250 MDA Method # WC-164

MRL (mg/L) 0.40 0.005 0.01 0.10

Section 2: GROUNDWATER MONITORING RESULTS The MDA began monitoring groundwater in November 1985 and redesigned the program in 1998. New wells were installed in 1999, and the MDA began sampling the re-designed monitoring network in January 2000. The current program is established around the goal of providing the information necessary to manage pesticide use for water quality protection on a regional basis. All monitoring sites are established to evaluate pesticide impacts to the most vulnerable groundwater conditions in their associated PMR and are considered sensitive to contamination from activities at the land surface. The first network was established in PMR 4 (central sands), which contains the majority of sites in the program. The network was designed for the purpose of tracking trends over time. Sampling in PMRs 1, 5, 6, 7 and 8 started in 2004. PMR 9 groundwater is sampled via naturally occurring springs and domestic drinking water wells. Readers of this report are cautioned that domestic drinking water wells are used simply as access points to the groundwater and do not represent a statistically valid sample of domestic drinking water wells in PMR 9. Accordingly, no general conclusions regarding regional drinking water quality may be drawn, or extrapolations made, based on the results for samples collected from this small number of drinking water wells. Thus, data for both naturally occurring springs and drinking water wells (groundwater access points) are combined in data tables for PMR 9. As with the entire MDA monitoring program, all data from PMR 9 is used


Page 10

collectively to draw broad, general inferences concerning pesticide impacts to groundwater on a regional basis. Urban sampling is performed by MPCA for MDA through interagency collaboration, and urban samples are collected primarily from PMR 10 with some urban samples historically sometimes coming from PMR’s 2, 4, and 9. PMRs 2 and 3 are not currently monitored for groundwater due to very limited agricultural production in these heavily forested regions. Appendix 3 contains the 2013 groundwater quality results, which are available online only (www.mda.state.mn.us/monitoring). 2.1 2013 Groundwater pesticide sampling summary Groundwater pesticide samples were collected from 165 sites across the state (Figure 3).  140 monitoring sites came from monitoring wells.  13 monitoring sites came from naturally occurring springs.  12 monitoring sites came from private drinking water wells. In total, 271 samples were collected from the groundwater monitoring sites (Table 4).  Thirty-five different pesticides or degradates were detected in groundwater monitoring samples during 2013.  The most frequently detected analyte was metolachlor ESA (221 detections; 82 percent of samples; 78 percent of sites).  No groundwater pesticide detection exceeded any human health-based drinking water standards or reference values in 2013.


Page 11

Figure 3. Location of groundwater monitoring sites sampled in 2013.


Page 12

Table 4. 2013 summary of groundwater samples analyzed and reference values. Pesticide Analyte 2,4,5-T 2,4,5-TP 2,4-D 2,4-DB Acetamiprid Acetochlor Acetochlor ESA Acetochlor OXA Alachlor Alachlor ESA Alachlor OXA Aldicarb Sulfone Aldicarb Sulfoxide Atrazine DEDI Atrazine Deisopropylatrazine Desethylatrazine Hydroxyatrazine Azoxystrobin Benfluralin Bensulfuron-methyl Bentazon Bifenthrin Boscalid Bromacil Carbaryl Carbendazim Carbofuran Chlorantraniliprole Chlorimuron-ethyl Chlorothalonil Chlorpyrifos Chlorpyrifos Oxon Clomazone Clopyralid Clothianidin Cyanazine Cyfluthrin Diazinon Diazinon Oxon Dicamba Dichlobenil Dichlorprop Dichlorvos Dicrotophos Difenoconazole Dimethenamid Dimethenamid ESA

Samples Analyzed

Number of Detections

Percent Detected (%)

Maximum Detection (ng/L)

Guidance Value (ng/L)

Value Type

271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271 271

0 0 1 0 0 1 110 24 0 134 9 0 0 58 81 3 74 50 0 0 0 30 0 0 2 0 0 0 0 0 0 0 0 0 2 32 0 0 0 0 0 0 0 0 0 0 2 35

0 0 10,000,000 (n)

Azoxystrobin

486

─

─

─

─

130,000 (i)

44,000 (i)

Benfluralin

nd

─

─

─

─

34,850 (f)

1,900 (f)

Bensulfuron-methyl

nd

─

─

─

─

─

─

Bentazon

190

─

─

─

─

> 50,000,000 (f)(i)

4,500,000 (n)

Bifenthrin

75 (f)

1.3 (i)

nd

─

─

─

─

Boscalid

841

─

─

─

─

>533,000 (i)

116,000 (f)

Bromacil

82.1

─

─

─

─

18,000,000 (f)

6,800 (n)

Carbaryl

nd

─

─

─

─

850 (i)

500 (i)

352

─

─

─

─

3,300 (i)

3,100 (i)

Carbofuran

nd

40,000 H

40,000 H

─

─

1,120 (i)

750 (i)

Chlorantraniliprole

nd

─

─

─

─

4,900 (i)

4,500 (i)

Chlorimuron-ethyl

nd

─

─

─

─

─

─

Carbendazim

Chlorothalonil Chlorpyrifos Chlorpyrifos Oxon

nd

─

─

─

─

1,800 (i)

600 (i)

53.4

41 T

41 T

41 T

83 T

na

na

nd

─

─

─

─

─

─


Page 90

Table 22 continued. 2013 summary of surface water maximum detections and available reference values and standards for pesticide analytes as of February 2014. Surface Water Reference Values as of February 20141 (ng/L) ─ ─ MPCA USEPA/OPP Benchmark2 ─ ─ ─ Chronic 3 Chronic Standards Acute Value Value

MDA 2013 Maximum Detections


Class 2A5

Class 2Bd6

Class 2B,C,D7

Clomazone

nd

─

─

─

─

167,000 (n)

Clopyralid

256

─

─

─

─

56,000,000 (i)

─

Clothianidin

150

─

─

─

─

>46,800,000 (f)

120,000 (i)

Cyanazine

nd

─

─

─

─

─

─

Cyfluthrin

nd

─

─

─

─

12.5 (i)

7 (i)

Diazinon

nd

─

─

─

─

110 (i)

170 (i)

nd

─

─

─

─

─

─

Dicamba

114

─

─

─

─

14,000,000 (f)

61,000 (n)

Dichlobenil

97.1

─

─

─

─

1,850,000 (i)

30,000 (v)

Dichlorprop

nd

─

─

─

─

─

─

Dichlorvos

66

─

─

─

─

35 (i)

5.8 (i)

Dicrotophos

nd

─

─

─

─

6,350 (i)

990 (i)

Difenoconazole

nd

─

─

─

─

385,000 (i)

5,000 (i)

Dimethenamid

1,300

─

─

─

─

3,150,000 (f)

5,100 (v)8

Dimethenamid ESA

278

─

─

─

─

─

─

Dimethenamid OXA

Pesticide Analyte

Diazinon Oxon

Maximum Standard4

163

─

─

─

─

─

─

Dimethoate

nd

─

─

─

─

21,500 (i)

500 (i)

Dinotefuran

> 49,650,000 (f)

>6,360,000 (f)

11,700

─

─

─

─

Disulfoton

nd

─

─

─

─

1,950 (i)

10 (i)

Disulfoton Sulfone

nd

─

─

─

─

17,500 (i)

140 (i)

Diuron

474

─

─

─

─

80,000 (i)

2,400 (n)

EPTC

nd

─

─

─

─

3,245,000 (i)

810,000 (i)

Esfenvalerate

25 (i)

17 (i)

nd

─

─

─

─

Ethalfluralin

nd

─

─

─

─

16,000 (f)

400 (f)

Ethofumesate

287

─

─

─

─

250,000 (f)

250,000 (i)

Flufenacet OXA

nd

─

─

─

─

─

─

Flumetsulam

296

─

─

─

─

125,000,000 (i)

3,100 (v)

Flutriafol

nd

─

─

─

─

33,000,000 (f)

780,000 (v)

Fonofos

nd

─

─

─

─

─

─

Halosulfuron-methyl

nd

─

─

─

─

─

─

Hexazinone

nd

─

─

─

─

75,800,000 (i)

7,000 (n)

Imazamethabenz-methyl

nd

─

─

─

─

─

─

Imazamethabenz Acid

nd

─

─

─

─

─

─

nd

─

─

─

─

> 59,500,000 (f)

11,000 (v)

Imazamox


Page 91




Class 2A5

Class 2Bd6

Class 2B,C,D7

Maximum Standard4

Imazapic

14.1

─

─

─

─

Imazapyr

26.5

─

─

─

─

Imazaquin

nd

─

─

─

Imazethapyr

355

─

─

Imidacloprid

708

─

─

Isoxaflutole

Pesticide Analyte

24,000 (v)

─

> 49,350,000 (f) (f) 50,000,000 (i) ─

4,230 (v)

─

─

> 55,000,000 (f)(i)

8,100 (v)

─

─

35,000 (i)

1,050 (i)

─

nd

─

─

─

─

> 750,000 (i)

4,900 (v)

Isoxaflutole DKN

nd

─

─

─

─

> 15,300,000 (f)

75,000 (v)

Lambda-Cyhalothrin

nd

─

─

─

─

3.5 (i)

2 (i)

Linuron

nd

─

─

─

─

60,000 (i)

90 (i)

Malathion

nd

─

─

─

─

300 (i)

35 (i)

MCPA

88.7

─

─

─

─

90,000 (i)

20,000 (v)

MCPB

nd

─

─

─

─

1,950,000 (f)

210,000 (v)

MCPP

14,000 (n)

200

─

─

─

─

45,500,000 (i)

Mesotrione

220

─

─

─

─

> 60,000,000 (f)

9,800 (v)

Metalaxyl

31.3

─

─

─

─

14,000,000 (i)

100,000 (i)

Methoxychlor

nd

─

─

─

─

700 (i)

─

5,720

23,000 T

23,000 T

23,000 T

271,000 T

na

na

Metolachlor ESA

2,550

─

─

─

─

24,000,000 (f)

> 95,100,000 (v)

Metolachlor OXA

1,070

─

─

─

─

7,700,000 (i)

57,100,000 (n)

97

─

─

─

─

2,100,000 (i)

8,700 (n)

Metribuzin DA

nd

─

─

─

─

─

─

Metribuzin DADK

nd

─

─

─

─

─

─ ─

Metolachlor

Metribuzin

Metribuzin DK

nd

─

─

─

─

─

Metsulfuron-methyl

38

─

─

─

─

> 75,000,000 (f)(i)

360 (v)

Myclobutanil

nd

─

─

─

─

1,200,000 (f)

830,000 (n)

Neburon

nd

─

─

─

─

─

─

Nicosulfuron

nd

─

─

─

─

─

─

Norflurazon

nd

─

─

─

─

4,050,000 (f)

9,700 (n)

Norflurazon-desmethyl

nd

─

─

─

─

─

─

Oxadiazon

nd

─

─

─

─

440,000 (f)

880 (f)

Oxydemeton-methyl

nd

─

─

─

─

95,000 (i)

5,000 (f)

Parathion-methyl

nd

─

─

─

─

490 (i)

250 (i)

nd

─

─

─

─

─

─

nd

─

─

─

─

69,000 (f)

5,200 (n)

Parathion-methyl Oxon Pendimethalin


Page 92



Pesticide Analyte


Class 2A5

Class 2Bd6

Class 2B,C,D7

Maximum Standard4

Phorate

nd

─

─

─

─

300 (i)

210 (i)

Picloram

122

500,000 H

500,000 H

─

─

6,500,000 (f)

550,000 (f)

Prometon

167

─

─

─

─

6,000,000 (f)

98,000 (n)

Prometryn

nd

─

─

─

─

1,450,000 (f)

1,000 (n)

Propachlor

nd

─

─

─

─

85,000 (f)

13,500 (n)

Propachlor ESA

nd

─

─

─

─

─

─

Propachlor OXA

nd

─

─

─

─

─

─

Propazine

30.6

─

─

─

─

>2,660,000 (i)

24,800 (n)

Propiconazole

110

─

─

─

─

425,000 (f)

21,000 (n)

Pyraclostrobin

32.7

─

─

─

─

3,100 (f)

1,500 (n)

Pyroxasulfone

198

─

─

─

─

1,100,000 (f)

6,000 (v)

Saflufenacil

373

─

─

─

─

> 49,000 ,000 (f)(i)

42,000 (n)

Siduron

14.4

─

─

─

─

4,050,000 (f)

6,000 (i)

Simazine

80.9

4,000 H

4,000 H

─

─

500,000 (i)

36,000 (n)

Sulfometuron-methyl

119

─

─

─

─

> 74,000,000 (f)

480 (v)

Tebuconazole

61.5

─

─

─

─

1,135,000 (f)

12,000 (f)

Tebupirimiphos

nd

─

─

─

─

39 (i)

11 (i)

Tembotrione

915,000 (f)

310,000 (n)

nd

─

─

─

─

Terbufos

39.3

─

─

─

─

100 (i)

30 (i)

Tetraconazole

22.3

─

─

─

─

1,315,000 (i)

190,000 (i)

Thiamethoxam

84

─

─

─

─

17,500 (i)

20,000,000 (f)

Thifensulfuron-methyl

nd

─

─

─

─

─

─

Thiobencarb

nd

─

─

─

─

50,000 (i)

1,000 (i)

Triallate

nd

─

─

─

─

45,500 (i)

13,000 (i)

Triasulfuron

nd

─

─

─

─

> 50,000,000 (f)(i)

68,600,000 (f)

Triclopyr

451

─

─

─

─

180,000 (f)

100,000 (n)

Trifluralin

nd

─

─

─

─

20,500 (f)

1,140 (f)

zeta-Cypermethrin

nd

─

─

─

─

1.8 (i)

.59 (i)

11,900

─

─

─

─

21,500,000 (f)

1,800,000 (f)

nd

─

─

─

─

─

─

MDA Glyphosate Method Glyphosate AMPA


Page 93

Table 22 continued. 2013 summary of surface water maximum detections and reference values. Key to value types and symbols in surface water reference values ─ – For some analytes, reference values have not been identified or evaluated na – not applicable (f) – USEPA/OPP benchmark value for fish. (i) – USEPA/OPP benchmark value for invertebrates. (n) – USEPA/OPP benchmark value for nonvascular plants. (v) – USEPA/OPP benchmark value for vascular plants. H – “H” Chronic Standard values are human health-based and protective for an exposure duration of 30 days. T – “T” Chronic Standard values are toxicity-based for aquatic organisms and protective for an exposure duration of 4 days. 1

Reference Values are given for all detected target and non-target analytes. They are also given for non-detected target analytes when a reference value is available. Other non-detected analytes do not have an available reference value from the sources listed below. For a complete list of all target analytes and detected non-target analytes, refer to Table 2. 2

Aquatic Life Benchmarks based on toxicity values derived from data available to the USEPA OPP supporting registration of the pesticide are provided only when an MPCA value is not available. Current values posted by the USEPA’s OPP may differ from those of previous MDA reports. See USEPA’s web site for more detailed information and definitions. 3

Chronic Standard as defined in Minn. Rule Chap. 7050. “H” value is human health-based and is protective for an exposure duration of 30 days. Human health-based values are shown only when they are less than toxicity-based values. “T” value is toxicity-based for aquatic organisms and is protective for an exposure duration of 4 days. 4

Maximum Standard Value for Aquatic Life & Recreation as defined on MPCA’s web site and Minn. Rule Chap. 7050. Values are the same for all classes of surface waters. 5

State Water Classification for aquatic life (cold water streams) & all recreation. Protected as drinking water sources. 6

State Water Classification for aquatic life (cold and warm water streams) & all recreation. Protected as drinking water sources. 7

State Water Classification for aquatic life (2B – sport and commercial; 2C – noncommercial; 2D – wetlands) & recreation (2B – all types; 2C,D – limited types). Not protected as drinking water sources. 8

For the Dimethenamid Chronic Value, the MPCA has calculated a non-promulgated criterion for aquatic plants using two point estimates of toxicity to the vascular plant duckweed.


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3.2 Surface water Tier 1 and 2 pesticide sampling Samples were collected at the Tier 1 and Tier 2 level from the 52 locations shown in Figure 47. During the 2013 season, 222 samples were collected from the Tier 1 sites (Tier 1 = 159 and Urban Tier 1 = 63) and 385 samples were collected from the Tier 2 sites (Tier 2 = 335 and Urban Tier 2 = 50). The primary objective was to collect grab samples from each stream during major storm events once in each of the eight two-week periods beginning on May 1st and ending on August 31st. If no storm events were anticipated during a given period, a base flow grab sample was collected near the end of the two-week period. Analysis was generally limited to the GC-MS/MS pesticide list in non-urban areas; however, one Tier 1 or Tier 2 site was selected in each PMR (except PMR 2 and 3) to receive up to eight LC-MS/MS samples to provide additional monitoring of pesticides associated with this laboratory method. All analyses were conducted by the MDA Laboratory. Additionally, inorganic samples were collected for analysis at most sampling locations. Inorganic analytes included the nutrients nitrate-nitrogen, dissolved orthophosphorus and total phosphorus. Results for all inorganic analyses will be discussed in Section 3.8 Urban tiered sampling has a slightly modified sampling season starting in mid-April and ending in mid-August. Urban sampling sites are displayed in Figure 47. The objective is the same as the other Tier 1 and Tier 2 monitoring sites: to collect grab samples from each stream during major storm events once in each of the eight two-week periods beginning on April 15th and ending on August 15th. If no storm events were anticipated during a given period, a base flow grab sample was collected near the end of the two-week period. Along with GC-MS/MS analysis, LC-MS/MS analysis was completed at all urban tiered locations. All analyses were completed by the MDA Laboratory. Data collected from the Urban Tier 1 and Urban Tier 2 surface water sampling locations can be found in Section 3.2.2.


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Figure 47. 2013 Tier 1 and 2 and Urban Tier 1 and Tier 2 pesticide monitoring sites. Minnesota Department of Agriculture 2013 Annual Monitoring Report

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3.2.1 Statewide Tier 1 and Tier 2 pesticide sampling summary Tables 23 and 24 present the Tier 1 and Tier 2 GC-MS/MS and LC-MS/MS detection results for 2013. Only compounds that were detected are displayed in these tables. These tables also present results comparing flow conditions during sample collection (base flow vs. storm flow periods). Highlights of the 2013 monitoring season are as follows: 



GC-MS/MS o Atrazine was the most frequently detected pesticide at the Tier 1 and Tier 2 sites (60 percent detection frequency). o Metolachlor was detected in 58 percent and acetochlor was detected in 45 percent of the samples collected at Tier 1 and Tier 2 sites. o Storm flow generally exhibited higher frequency of detection and concentration than base flow. o One sample, collected from the South Fork of the Root River in PMR 9 on May 30th, 2013, had a concentration greater than the acetochlor chronic aquatic life standard (3,600 ng/L). o In addition to the one sample discussed above, there were eight additional acetochlor detections at the Tier 1 or Tier 2 level greater than 50 percent of the acetochlor chronic aquatic life standard (3,600 ng/L). These samples were collected at sites in PMR’s 1, 5, 6, 8, 9 and 10 in May and June (two in base flow and seven in storm flow). o One sample, collected during base flow from Three Mile Creek in PMR 7 on August 15th, 2013, had a concentration greater than the chlorpyrifos chronic aquatic life standard (41 ng/L). o One sample, collected during storm flow from the South Fork of the Root River in PMR 9 on May 30th, 2013, had a concentration greater than the applicable terbufos reference value (30 ng/L). o Seven compounds were detected in four or fewer samples (431 total samples). o GC-MS/MS has 44 target analytes: 14 target analytes were detected and 30 target analytes were not detected at Tier 1 and Tier 2 sites in 2013. LC-MS/MS o 2,4-D was the most frequently detected pesticide parent compound at the Tier 1 and Tier 2 sites (66 percent detection frequency). o The degradate (breakdown) products of acetochlor, alachlor, atrazine, dimethenamid, and metolachlor were frequently found in both base and storm flow. o No pesticide compounds were measured greater than 50 percent of an applicable reference value. o LC-MS/MS has 85 target analytes: 31 target analytes were detected and 54 target analytes were not detected at Tier 1 and Tier 2 sites in 2013.


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Table 23. 2013 Tier 1 and Tier 2 GC-MS/MS surface water results. Base flow (n = 254) Tier 1 and Tier 2 2013 GC-MS/MS Detected Analytes

Acetochlor Alachlor Atrazine Chlorpyrifos Deisopropylatrazine Desethylatrazine Dimethenamid Ethofumesate Metolachlor Metribuzin Prometon Propazine Simazine Terbufos

Total Total Total Total Detects Percent Max Median (n= 431) Detects (ng/L) (ng/L)

196 2 257 1 27 123 122 13 251 3 4 3 1 1

45% 0% 60% 0% 6% 29% 28% 3% 58% 1% 1% 1% 0% 0%


4,710 594 3,080 53.4 291 317 1,300 287 5,720 97 167 30.6 80.9 39.3

nd nd 41.4 nd nd nd nd nd 43.2 nd nd nd nd nd

Base Base Flow Flow Percent Detects Detects 61 0 123 1 6 39 32 7 115 0 3 0 1 0

24% 0% 48% 0% 2% 15% 13% 3% 45% 0% 1% 0% 0% 0%

Storm flow (n = 177)

Base Flow Max (ng/L)

Base Flow Median (ng/L)

Samples Exceeding 50% of Reference Value

Storm Flow Detects

Storm Flow Percent Detects

Storm Flow Max (ng/L)

Storm Flow Median (ng/L)


2,960 nd 1,920 53.4 184 172 917 287 704 nd 151 nd 80.9 nd

nd nd nd nd nd nd nd nd nd nd nd nd nd nd

2 0 0 1 0 0 0 0 0 0 0 0 0 0

135 2 134 0 21 84 90 6 136 3 1 3 0 1

76% 1% 76% 0% 12% 47% 51% 3% 77% 2% 1% 2% 0% 1%

4,710 594 3,080 nd 291 317 1,300 174 5,720 97 167 30.6 nd 39.3

115 nd 71 nd nd nd 15.2 nd 137 nd nd nd nd nd

7 0 0 0 0 0 0 0 0 0 0 0 0 1

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Table 24. 2013 Tier 1 and Tier 2 LC-MS/MS surface water results. Tier 1 and Tier 2 2013 LC-MS/MS Detected Analytes

Base flow (n = 42 or *n=43) Total Samples Detects Total Total Total Base Base Base Exceeding (n= 62 Percent Max Median Base Flow Flow Flow 50% of or Detects (ng/L) (ng/L) Flow Percent Max Median Detects Reference *n= 63) Detects (ng/L) (ng/L) Value

2,4-D 41 66% 398 Acetochlor ESA 49 79% 1,500 Acetochlor OXA 49 79% 1,320 Alachlor ESA 36 58% 678 Alachlor OXA 4 6% 60.8 Azoxystrobin* 7 11% 261 Bentazon 14 23% 190 Bromacil* 2 3% 47.7 Clopyralid 6 10% 256 Clothianidin* 5 8% 150 DEDI Atrazine* 5 8% 82.4 Dicamba 2 3% 114 Dimethenamid ESA 27 44% 62.7 Dimethenamid OXA 15 24% 38.2 Dinotefuran* 1 2% 30.9 Diuron* 2 3% 15.7 Flumetsulam* 7 11% 296 Hydroxyatrazine* 52 83% 157 Imazapyr* 1 2% 24.3 Imazethapyr* 17 27% 37.7 Imidacloprid* 2 3% 26.8 MCPA 5 8% 15.9 Mesotrione 2 3% 220 Metalaxyl* 7 11% 31.3 Metolachlor ESA 54 87% 2,550 Metolachlor OXA 48 77% 1,020 Saflufenacil* 10 16% 148 Sulfometuron-methyl* 1 2% 8.37 Tebuconazole* 4 6% 45.8 Thiamethoxam* 4 6% 84 Triclopyr 1 2% 57.2 *Refer to note in table heading related to sample count


17.4 268 103 58.4 nd nd nd nd nd nd nd nd nd nd nd nd nd 29.1 nd nd nd nd nd nd 295 59.2 nd nd nd nd nd

25 30 30 23 2 6 8 1 1 0 1 0 13 6 0 1 2 32 1 10 0 3 0 4 35 29 0 0 4 0 1

60% 71% 71% 55% 5% 14% 19% 2% 2% 0% 2% 0% 31% 14% 0% 2% 5% 74% 2% 23% 0% 7% 0% 9% 83% 69% 0% 0% 9% 0% 2%

271 719 375 678 60.8 261 15.4 47.7 42.5 nd 76.6 nd 38.9 26.1 nd 14.8 98.6 120 24.3 17.8 nd 15.4 nd 31.3 2550 904 nd nd 45.8 nd 57.2

9.45 197 86.8 57.0 nd nd nd nd nd nd nd nd nd nd nd nd nd 23.2 nd nd nd nd nd nd 256 28.7 nd nd nd nd nd

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Storm flow (n = 20) Storm Flow Detects





16 19 19 13 2 1 6 1 5 5 4 2 14 9 1 1 5 20 0 7 2 2 2 3 19 19 10 1 0 4 0

80% 95% 95% 65% 10% 5% 30% 5% 25% 25% 20% 10% 70% 45% 5% 5% 25% 100% 0% 35% 10% 10% 10% 15% 95% 95% 50% 5% 0% 20% 0%

398 1,500 1,320 224 45.1 14 190 30.1 256 150 82.4 114 62.7 38.2 30.9 15.7 296 157 nd 37.7 26.8 15.9 220 12.8 2,170 1,020 148 8.37 nd 84 nd

26 407 266 59.8 nd nd nd nd nd nd nd nd 21.7 nd nd nd nd 36.0 nd nd nd nd nd nd 309 89.9 7.7 nd nd nd nd

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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3.2.2 Urban Tier 1 surface water pesticide sampling summary Urban watershed sampling is conducted to evaluate the concentrations of commonly used pesticides in runoff from urban watersheds. All urban surface water monitoring sites were located in the Twin Cities Metropolitan area (PMR 10). These sites are sampled essentially in the same manner as the other Tier 1 and Tier 2 sites, except that the monitoring season occurs from mid-April through mid-August. This time frame was selected to capture the main application period for pesticides used in turf, landscape, structural and other management applications within urban areas. In 2013, four sites were sampled using the Urban Tier 1 protocol and two sites were sampled using the Urban Tier 2 protocol. Samples were collected for both GC-MS/MS and LC-MS/MS pesticide analyses at these six monitoring sites. Tables 25 through 28 summarize the pesticide results for the six urban tiered sites sampled in 2013.  113 pesticide samples were collected from the six urban streams.  42 different pesticide compounds and degradates were detected in the urban streams.  2,4-D was detected in all Urban Tier 1 and Urban Tier 2 samples collected in 2013.  Atrazine, acetochlor, desethylatrazine, and/or metolachlor (agricultural herbicides) were detected in at least 36 percent of all samples collected in urban areas.  Seventeen pesticide compounds were detected in urban streams at the highest maximum detection of all surface water streams sampled statewide in 2013.  One storm flow sample indicated pesticide concentrations exceeded 50 percent of the applicable reference value. o Imidacloprid was detected at 708 ng/L in Fish Creek during a storm flow event on June 21st, 2013, which exceeded 50 percent of the USEPA/OPP Benchmark of 1,050 ng/L. MDA is investigating the source of this detection along with other detections in this watershed.


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Table 25. 2013 Urban Tier 1 GC-MS/MS surface water results. Base flow (n = 13) Urban Tier 1 GC-MS/MS Detected Analyte

Total Detects

Acetochlor Atrazine Deisopropylatrazine Desethylatrazine Dichlobenil Dimethenamid Metolachlor

(n = 32)

Total Percent Detects

Total Max (ng/L)

Total Median (ng/L)

14 19 1 15 8 5 18

44% 59% 3% 47% 25% 16% 56%

320 462 181 201 97.1 169 1,010

nd 35.1 nd nd nd nd 32.7

Base Flow Detects

Base Flow Percent Detects



2 5 0 3 5 2 5

15% 38% 0% 23% 38% 15% 38%

320 462 nd 136 33.7 169 794

nd nd nd nd nd nd nd

Storm flow (n = 19) Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0

Storm Flow Detects




12 14 1 12 3 3 13

63% 74% 5% 63% 16% 16% 68%

264 425 181 201 97.1 58.0 1,010

44.0 58.9 nd 57.5 nd nd 36.0

Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0

Table 26. 2013 Urban Tier 2 GC-MS/MS surface water results. Base flow (n = 7) Urban Tier 2 GC-MS/MS Detected Analyte

Acetochlor Atrazine Desethylatrazine Dimethenamid Metolachlor

(n = 25)


Total Max (ng/L)

Total Median (ng/L)

9 20 15 5 10

36% 80% 60% 20% 40%

120 238 134 598 237

nd 51.7 53.9 nd nd

Total Detects


Base Flow Detects




0 4 2 1 0

0% 57% 29% 14% 0%

nd 51.7 51.2 27.0 nd

nd 38.0 nd nd nd

Storm flow (n = 18) Samples Exceeding 50% of Reference Value 0 0 0 0 0

Storm Flow Detects




9 16 13 4 10

50% 89% 72% 22% 56%

120 238 134 598 237

15.8 69.6 78.1 nd 27.0

Samples Exceeding 50% of Reference Value 0 0 0 0 0

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Table 27. 2013 Urban Tier 1 LC-MS/MS surface water results. Base flow (n = 13) Urban Tier 1 LC-MS/MS Detected Analytes

2,4-D Acetochlor ESA Acetochlor OXA Alachlor ESA Azoxystrobin Bentazon Carbendazim DEDI Atrazine Dimethenamid ESA Dimethenamid OXA Diuron Flumetsulam Hydroxyatrazine Imazapic Imazapyr Imazethapyr Imidacloprid MCPA MCPP Metolachlor ESA Metolachlor OXA Propiconazole Saflufenacil Siduron Tebuconazole Triclopyr

Total Detects (n = 31)


Total Max (ng/L)

Total Median (ng/L)

31 8 8 5 1 1 2 4 8 3 3 1 28 2 4 4 2 17 7 15 11 5 4 1 6 6

100% 26% 26% 16% 3% 3% 6% 13% 26% 10% 10% 3% 90% 6% 13% 13% 6% 55% 23% 48% 35% 16% 13% 3% 19% 19%

913 637 387 67.1 10.2 5.43 30.3 150 51.5 35.4 474 77.4 56.4 13.6 13.9 28.4 32.2 88.7 200 314 162 43.2 44.1 9.32 49.5 277

102 nd nd nd nd nd nd nd nd nd nd nd 14.0 nd nd nd nd 7.39 nd nd nd nd nd nd nd nd


Base Flow Detects


13 3 3 2 0 1 0 0 3 2 0 1 11 1 3 2 0 7 1 8 5 1 1 0 2 3

100% 23% 23% 15% 0% 8% 0% 0% 23% 15% 0% 8% 85% 8% 23% 15% 0% 54% 8% 62% 38% 8% 8% 0% 15% 23%

Base Base Flow Flow Median Max (ng/L) (ng/L) 672 637 387 50.8 nd 5.43 nd nd 51.5 35.4 nd 77.4 56.4 12.9 13.9 28.4 nd 32.8 200 310 148 43.2 44.1 nd 49.5 277

67.9 nd nd nd nd nd nd nd nd nd nd nd 12.2 nd nd nd nd 5.19 nd 12.6 nd nd nd nd nd nd

Storm flow (n = 18) Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Storm Flow Detects




18 5 5 3 1 0 2 4 5 1 3 0 17 1 1 2 2 10 6 7 6 4 3 1 4 3

100% 28% 28% 17% 6% 0% 11% 22% 28% 6% 17% 0% 94% 6% 6% 11% 17% 56% 33% 37% 33% 22% 17% 6% 22% 17%

913 493 281 67.1 10.2 nd 30.3 150 33.1 15.9 474 nd 45.6 13.6 13.0 19.2 32.2 88.7 140 314 162 27.0 25.4 9.32 28.9 180

270 nd nd nd nd nd nd nd nd nd nd nd 14.1 nd nd nd nd 7.80 nd nd nd nd nd nd nd nd

Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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Table 28. 2013 Urban Tier 2 LC-MS/MS surface water results. Base flow (n = 7) Urban Tier 2 LC-MS/MS Detected Analytes

2,4-D Acetochlor ESA Acetochlor OXA Azoxystrobin Boscalid Bromacil Carbendazim Clothianidin DEDI Atrazine Dicamba Dimethenamid ESA Dimethenamid OXA Dinotefuran Diuron Hydroxyatrazine Imazapic Imazapyr Imidacloprid MCPA MCPP Metolachlor ESA Metolachlor OXA Metsulfuron-methyl Picloram Propiconazole Pyraclostrobin Siduron Sulfometuron-methyl Tebuconazole Triclopyr

Total Detects (n = 25)


Total Max (ng/L)

Total Median (ng/L)

25 1 2 4 5 2 9 1 3 1 3 3 12 5 24 3 13 10 21 16 12 7 1 2 1 1 2 8 11 7

100% 4% 8% 16% 20% 8% 36% 4% 12% 4% 12% 12% 48% 20% 96% 12% 52% 40% 84% 64% 48% 28% 4% 8% 4% 4% 8% 32% 44% 28%

561 50.8 44.3 27.9 841 82.1 352 67.3 105 53.7 17.0 37.1 11,700 76.1 19.2 14.1 26.5 708 65.8 189 32.8 17.6 38.0 105 28.7 32.7 14.4 119 61.5 451

288 nd nd nd nd nd nd nd nd nd nd nd nd nd 11.2 nd 8.94 nd 10.3 85.8 nd nd nd nd nd nd nd nd nd nd


Base Flow Detects


7 0 0 0 1 1 3 0 0 0 0 0 4 0 7 1 5 2 5 1 4 4 0 1 0 0 0 2 4 1

100% 0% 0% 0% 14% 14% 43% 0% 0% 0% 0% 0% 57% 0% 100% 14% 71% 29% 71% 14% 57% 57% 0% 14% 0% 0% 0% 29% 57% 14%

Base Base Flow Flow Median Max (ng/L) (ng/L) 410 nd nd nd 200 51.8 14.1 nd nd nd nd nd 1,310 nd 18.0 14.1 26.5 192 65.8 84.0 32.8 17.6 nd 86.2 nd nd nd 19.4 33.3 68.6

93.4 nd nd nd nd nd nd nd nd nd nd nd 79.4 nd 11.2 nd 12.8 nd 5.97 nd 17.6 13.1 nd nd nd nd nd nd 11.9 nd

Storm flow (n = 18) Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Storm Flow Detects




18 1 2 4 4 1 6 1 3 1 3 3 8 5 17 2 8 8 16 15 8 3 1 1 1 1 2 6 7 6

100% 6% 11% 27% 22% 6% 33% 6% 17% 6% 17% 17% 44% 28% 94% 11% 44% 44% 89% 83% 44% 17% 6% 6% 6% 6% 11% 33% 39% 33%

561 50.8 44.3 27.9 841 82.1 352 67.3 105 53.7 17.0 37.1 11,700 76.1 19.2 13.2 24.0 708 43.8 189 28.1 17.0 38.0 105 28.7 32.7 14.4 119 61.5 451

331 nd nd nd nd nd nd nd nd nd nd nd nd nd 11.1 nd nd nd 15.9 100 nd nd nd nd nd nd nd nd nd nd

Samples Exceeding 50% of Reference Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

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3.3 Surface water Tier 3 pesticide sampling In 2013, there were seven MDA Tier 3 monitoring sites in operation. Tier 3 sites are the most intensively monitored sites out of the tiered monitoring structure, and are monitored year-round. Most Tier 3 sites include both equal-flow increment (EFI) and equal-time increment (ETI) composite sample collection during storm flow periods use stage activated automated samplers. Since 2006, the MDA has made an effort to collect storm flow samples on an ETI basis at Tier 3 sites to generate pesticide data that is more readily comparable to duration based standards or reference values. Base flow periods are characterized by grab samples collected between storm events. 3.3.1 2013 surface water Tier 3 pesticide monitoring results The 2013 Tier 3 sites included the Beauford Ditch, Le Sueur River and Seven Mile Creek in the Minnesota River Basin (south central); the Middle Branch of the Whitewater River, the North Branch of the Root River and South Branch of the Root River in southeastern Minnesota; and the Buffalo River near Georgetown in northwestern Minnesota (Figure 48). The 2013 growing season displayed a variety of climate conditions. Late spring snowstorms followed by heavy rains and cool temperatures through late June slowed agriculture crop planting progress and delayed associated pesticide applications. In south-central and southeastern Minnesota, many fields were not planted in 2013 due to wet field conditions. Conditions were more favorable for planting in southwest and northwest Minnesota. The associated 2013 monitoring season was slightly later than recent years; however, heavy spring rains were followed by a dry July through September period. Most elevated herbicide detections in the rivers and streams of Minnesota were measured in May and June, aligning with previous years. Fall precipitation led to decreased drought severity and elevated stream flows across Minnesota in October.


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Figure 48. Tier 3 monitoring sites sampled in 2013. Tier 3 results for the 2013 monitoring season are presented in Tables 29 and 30. A total of 137 GC-MS/MS and 91 LC-MS/MS samples were collected in 2013. Only compounds that were detected are displayed in these tables. These tables also present results comparing flow conditions during sample collection (base flow vs. storm flow periods). Highlights of the 2013 monitoring season are as follows:  GC-MS/MS o Metolachlor was the most frequently detected compound (67 percent detection frequency), followed by atrazine (56 percent detection frequency). o Storm flow generally exhibited higher frequency of pesticide detection and concentration. o Acetochlor exceeded 50 percent of the aquatic life standard in one sample collected as a storm flow equal-time composite at the South Branch of the Root River (SR4) in PMR 9.


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

o Atrazine exceeded 50 percent of the 30-day chronic human health standard that applies to Class 2A waters in one sample collected as a storm flow equal-time composite at the South Branch of the Root River (SR4) in PMR 9. o Dichlorvos exceeded its applicable reference value in four storm flow equal-time composites at the Beauford Ditch (BD1) in PMR 8. o GC-MS/MS has 44 target analytes: eight target analytes were detected and 36 target analytes were not detected at Tier 3 sites in 2013. LC-MS/MS o Metolachlor ESA and metolachlor OXA had detection frequencies of 99 percent and 98 percent, respectively. o The degradate products of acetochlor, alachlor, atrazine, dimethenamid, and metolachlor were frequently found in both base and storm flow. o Storm flow generally exhibited higher frequency of detection and concentration. o No LC-MS/MS compounds exceeded 50 percent of an applicable reference value at Tier 3 sites in 2013. o LC-MS/MS has 85 target analytes: 32 target analytes were detected and 53 target analytes were not detected at Tier 3 sites in 2013.


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Table 29. 2013 Tier 3 GC-MS/MS surface water results. Base flow (n = 69) Tier 3 2013 GC-MS/MS Detected Analytes

Acetochlor Atrazine Deisopropylatrazine Desethylatrazine Dichlorvos Dimethenamid Metolachlor Propazine

Total Detects (n= 137)


Total Max (ng/L)

Total Median (ng/L)

49 77 4 56 4 44 92 1

36% 56% 3% 41% 3% 32% 67% 1%

2,920 3,120 210 204 66 476 5,350 28.7

nd 32.4 nd nd nd nd 47.2 nd


Storm flow (n = 68)

Base Flow Detects





Storm Flow Detects





7 34 0 29 0 3 27 0

10% 49% 0% 42% 0% 4% 39% 0%

601 422 nd 108 nd 37.8 1,100 nd

nd nd nd nd nd nd nd nd

0 0 0 0 0 0 0 0

42 43 4 27 4 41 65 1

62% 63% 6% 40% 6% 60% 96% 1%

2,920 3,120 210 204 66 476 5,350 28.7

72.6 36.7 nd nd nd 23.8 144 nd

1 1 0 0 4 0 0 0

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Table 30. 2013 Tier 3 LC-MS/MS surface water results. Base flow (n = 42) Tier 3 2013 LC-MS/MS Detected Analytes

2,4-D Acetochlor ESA Acetochlor OXA Alachlor ESA Alachlor OXA Azoxystrobin Bentazon Clopyralid Clothianidin DEDI Atrazine Dicamba Dimethenamid ESA Dimethenamid OXA Flumetsulam Hydroxyatrazine Imazapyr Imazethapyr Imidacloprid MCPA Mesotrione Metalaxyl Metolachlor ESA Metolachlor OXA Picloram Propiconazole Pyroxasulfone Saflufenacil Sulfometuron-methyl Tebuconazole Tetraconazole Thiamethoxam Triclopyr

Total Detects (n= 91)


Total Max (ng/L)

Total Median (ng/L)

65 80 62 63 5 11 1 5 17 29 1 52 36 6 88 1 44 1 8 4 1 90 89 5 7 1 34 5 1 5 12 1

71% 88% 68% 69% 5% 12% 1% 5% 19% 32% 1% 57% 40% 7% 97% 1% 48% 1% 9% 4% 1% 99% 98% 5% 8% 1% 37% 5% 1% 5% 13% 1%

1,870 2,610 862 586 48.4 486 30.7 147 61.4 151 54.2 278 163 102 144 9.33 355 30.4 80.8 111 11 2,090 1,070 122 110 198 373 11.4 19.4 22.3 67.2 57.9

23.5 170 67.2 99.5 nd nd nd nd nd nd nd 13.7 nd nd 32.5 nd nd nd nd nd nd 590 110 nd nd nd nd nd nd nd nd nd


Storm flow (n = 49)

Base Flow Detects





Storm Flow Detects





21 35 20 31 0 4 1 0 0 13 0 17 7 0 39 0 14 0 3 0 0 41 41 1 1 0 9 3 0 0 0 0

50% 83% 48% 74% 0% 10% 2% 0% 0% 31% 0% 40% 17% 0% 93% 0% 33% 0% 7% 0% 0% 98% 98% 2% 2% 0% 21% 7% 0% 0% 0% 0%

1,030 1,090 278 586 nd 20.2 30.7 nd nd 151 nd 128 42.2 nd 93 nd 55 nd 8.7 nd nd 1,490 484 51.4 13.5 nd 85.3 11.4 nd nd nd nd

4.715 77.35 nd 125 nd nd nd nd nd nd nd nd nd nd 26 nd nd nd nd nd nd 568 43.05 nd nd nd nd nd nd nd nd nd

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

44 45 42 32 5 7 0 5 17 16 1 35 29 6 49 1 30 1 5 4 1 49 48 4 6 1 25 2 1 5 12 1

90% 92% 86% 65% 10% 14% 0% 10% 35% 33% 2% 71% 59% 12% 100% 2% 61% 2% 10% 8% 2% 100% 98% 8% 12% 2% 51% 4% 2% 10% 24% 2%

1,870 2,610 862 217 48.4 486 nd 147 61.4 141 54.2 278 163 102 144 9.33 355 30.4 80.8 111 11 2,090 1,070 122 110 198 373 10.1 19.4 22.3 67.2 57.9

37.5 315 171 97.6 nd nd nd nd nd nd nd 27.7 15.3 nd 40.2 nd 9.79 nd nd nd nd 621 249 nd nd nd 17 nd nd nd nd nd

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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3.4 Long-term analysis of pesticides in surface water This section presents a review of MDA’s long-term pesticide data from surface water monitoring sites located throughout the state. Figure 49 displays the sites monitored in 2013, as well as sites that were historically monitored (prior to 2013). In most years, acetochlor, atrazine and metolachlor are among the most frequently detected pesticides in Minnesota’s rivers and streams; however, almost all detections are well below applicable water quality reference values. Acetochlor, atrazine and chlorpyrifos have been designated as “surface water pesticides of concern” by the Commissioner of Agriculture. The Tier 1 season was lengthened to include July and August in 2013, and the Tier 2 season was extended into July and August in 2012, to provide more comprehensive pesticide monitoring. Historically, sampling focused on herbicides and monitoring was conducted in May and June. Furthermore, many Tier 1 sites became Tier 2 sites in 2013. These two changes resulted in more samples that were collected later in the growing season in 2013, and may result in overall lower detection frequencies and percentile concentrations for herbicides presented in this section. Ongoing monitoring in the future will continue to include July and August. New GC-MS/MS analytical methods, which began in 2013, resulted in lower MRL’s for most compounds. In addition to the changes to the MRL, the MDA Laboratory stopped reporting detections as “present.” These “present” detections in the past were below the MRL. Due to the changes to the monitoring season and MDA Laboratory reporting limits in 2013, additional data analysis was prepared for this report. Please refer to the introduction of each section for additional information.


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Figure 49. Current and historic surface water sampling locations.


Page 110

3.4.1 Long-term pesticide results for Tier 1 and Tier 2 from 2008-2013 Tier 1 and 2 acetochlor, atrazine, chlorpyrifos and metolachlor results from 2008-2013 are presented by PMR in Tables 31 and 32. The summary numbers presented are a total of all collected samples in each PMR annually. The summary from each year is calculated using that year’s MRL, and includes all “present” detections from 2008-2012 as detections. The data are presented in this section as reported from the MDA Laboratory in each year. These data have not been censored to account for changing MRLs and laboratory methods. Please refer to Section 3.4 for a discussion of monitoring season and MDA Laboratory changes that have occurred since 2008. Table 31. Total number of acetochlor, atrazine, chlorpyrifos, and metolachlor detections in surface water at Tier 1 and Tier 2 locations, 2008 through 2013. Acetochlor Detections Detections/Total number of Samples

PMR

Atrazine Detections Detections/Total number of Samples

2008

2009

2010

2011

2012

2013

2008

2009

2010

2011

2012

2013

1

16/26

6/23

12/24

14/54

9/29

13/62

20/26

15/23

18/24

20/54

18/29

17/62

2 3 4

--9/18

0/4 0/4 3/13

0/4 0/4 4/19

0/4 0/4 7/16

0/4 0/3 8/16

-0/7 5/32

--18/18

2/4 0/4 7/13

0/4 0/4 9/19

1/4 0/4 8/16

1/4 2/3 14/16

-0/7 6/32

5

6/16

4/26

1/12

8/16

7/16

9/34

13/16

21/26

6/12

13/16

14/16

13/34

6

13/16

10/16

10/16

13/16

19/22

20/34

16/16

13/16

10/16

15/16

18/22

15/34

7

13/17

11/16

17/21

22/25

16/23

29/42

16/17

16/16

18/21

24/25

23/23

33/42

8

48/51

50/57

46/54

51/58

48/64

68/109

49/51

56/57

46/54

55/58

61/64

93/109

9

28/31

23/31

27/42

27/43

25/46

27/64

31/31

31/31

42/42

42/43

46/46

47/64

10

17/22 150/ 197

15/25 21/27 27/27 28/38 25/47 122/ 138/ 169/ 160/ 196/ 215 223 263 261 431 Chlorpyrifos Detections Detections/Total number of Samples 2008 2009 2010 2011 2012 2013

21/22 184/ 197

1

0/26

0/23

4/24

6/54

1/29

0/62

12/26

3/23

13/24

23/54

9/29

2

--

0/4

0/4

0/4

0/4

--

--

0/4

0/4

0/4

0/4

--

3

--

0/4

0/4

0/4

0/3

0/7

--

0/4

0/4

0/4

0/3

0/7

4

0/18

0/13

0/19

0/16

0/16

0/32

12/18

4/13

7/19

5/16

6/16

2/32

5

0/16

0/26

0/12

0/16

0/16

0/34

9/16

2/26

3/12

10/16

11/16

11/34

6

0/16

0/16

0/16

0/16

0/22

0/34

13/16

4/16

9/16

13/16

17/22

14/34

7

0/17

0/16

0/21

0/25

1/23

1/42

14/17

9/16

18/21

24/25

16/23

31/42

8

0/51

0/57

0/54

1/58

4/64

0/109

46/51

48/57

54/54

57/58

58/64

92/109

9

0/31

0/31

0/42

0/43

0/46

0/64

31/31

27/31

37/42

40/43

39/46

47/64

10

0/22

0/25

0/27

0/24

0/38

0/47

Statewide

0/197

0/215

4/223

7/263

6/261

1/ 431

21/22 158/ 197

21/25 121/ 215

20/27 161/ 223

27/27 199/ 263

37/38 193/ 261

38/47 251/ 431

Statewide PMR


25/25 17/27 24/27 36/38 33/47 186/ 166/ 202/ 233/ 257/ 215 223 263 261 431 Metolachlor Detections Detections/Total number of Samples 2008 2009 2010 2011 2012 2013 16/62

Page 111

Table 32. Tier 1 and Tier 2 acetochlor, atrazine, chlorpyrifos, and metolachlor surface water concentration results from 2009 through 2013. Acetochlor (chronic 4-day standard of 3,600 ng/L)

Maximum (ng/L)

Atrazine (chronic 4-day standard of 10,000 ng/L)

Chlorpyrifos (chronic 4-day standard of 41 ng/L acute 1 day standard of 83 ng/L)

Metolachlor (chronic 4-day standard of 23,000 ng/L)

PMR

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

1

60

810

690

1,670

2,960

60

2,180

220

420

1,920

nd

60

160

110

nd

P

800

530

120

891

2

nd

nd

nd

nd

--

P

Nd

P

P

--

nd

nd

nd

nd

--

nd

nd

nd

nd

--

3

nd

nd

nd

nd

nd

nd

nd

nd

P

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

4

70

70

700

200

503

P

80

140

140

160

nd

nd

nd

nd

nd

P

P

110

P

177

5

P

P

60

6,300

2,020

P

P

120

3,550

2,990

nd

nd

nd

nd

nd

P

P

P

90

1,350

6

60

990

1,920

5,150

2,240

90

380

110

240

908

nd

nd

nd

nd

nd

P

740

780

430

868

7

570

860

1,650

6,050

1,400

260

360

4,010

4,000

2,660

nd

nd

nd

P

53

780

420

4,580

430

2,160

8

600

340

1,940

6,015

1,800

90

280

680

1,440

3,080

nd

nd

50

80

nd

1,430

660

2,360

4,150

5,720

9

12,300

990

20,200

1,100

4,710

9,400

720

5,120

2,230

2,100

nd

nd

nd

nd

nd

4,450

3,960

4,240

6,000

5,540

10

80

840

1,950

5,950

2,210

500

410

460

1,580

985

nd

nd

nd

nd

nd

720

1,360

750

2,920

5,090

90th Percentile (ng/L)

(chronic 4-day standard of 3,600 ng/L)


(chronic 4-day standard of 41 ng/L acute 1 day standard of 83 ng/L)


PMR

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

1

P

90

160

200

263

P

110

90

140

271

nd

P

P

nd

nd

nd

P

80

P

164

2

nd

nd

nd

nd

--

P

nd

nd

nd

--

nd

nd

nd

nd

--

nd

nd

nd

nd

--

3

nd

nd

nd

nd

nd

nd

nd

nd

P

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

4

P

P

190

70

70

P

60

P

60

33

nd

nd

nd

nd

nd

P

P

P

P

nd

5

P

nd

P

P

68

P

P

90

250

144

nd

nd

nd

nd

nd

nd

P

P

P

137

6

P

370

670

840

698

P

P

80

170

330

nd

nd

nd

nd

nd

P

P

220

180

414

7

200

550

1,110

3,760

460

200

130

750

980

846

nd

nd

nd

nd

nd

100

120

90

230

711

8

120

220

530

1,080

630

80

140

280

580

781

nd

nd

nd

nd

nd

120

500

670

860

1,188

9

690

500

490

460

553

580

380

420

900

600

nd

nd

nd

nd

nd

1,010

480

750

1,610

1,716

10

P

200

570

640

1,064

90

90

200

380

346

nd

nd

nd

nd

nd

170

280

50

140

2,014


Page 112

Table 32 (continued). Tier 1 and Tier 2 acetochlor, atrazine, chlorpyrifos, and metolachlor surface water concentration results 2009 through 2013. Acetochlor 75th Percentile


(ng/L)

Atrazine

Chlorpyrifos

Metolachlor




PMR

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

2009

2010

2011

2012

2013

1

nd

50

nd

P

nd

nd

60

P

50

34

nd

nd

nd

nd

nd

nd

P

P

P

23

2

nd

nd

nd

nd

--

P

nd

nd

nd

--

nd

nd

nd

nd

--

nd

nd

nd

nd

--

3

nd

nd

nd

nd

nd

nd

nd

nd

P

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

4

nd

nd

P

50

nd

P

P

P

P

nd

nd

nd

nd

nd

nd

P

P

P

P

nd

5

nd

nd

P

P

24

P

P

P

100

73

nd

nd

nd

nd

nd

nd

nd

P

P

45

6

P

P

330

400

263

P

P

50

80

126

nd

nd

nd

nd

nd

nd

P

P

50

91

7

P

200

570

1,000

195

100

90

300

240

208

nd

nd

nd

nd

nd

P

90

100

P

165

8

50

170

320

780

299

P

100

150

180

184

nd

nd

nd

nd

nd

70

190

300

330

254

9

130

80

140

130

49

190

120

70

180

125

nd

nd

nd

nd

nd

220

230

210

330

230

10

P

100

420

230

353

70

P

60

210

108

nd

nd

nd

nd

nd

80

P

240

680

436

Median


(ng/L)


PMR

2009

2010

2011

2012

2013

2009

2010

2011

1

nd

nd

nd

nd

nd

2

nd

nd

nd

nd

--

nd

P

nd

nd

3

nd

nd

nd

nd

nd

nd

4

nd

nd

nd

P

nd

5

nd

nd

nd

nd

6

P

P

P

7

P

P

8

P

9 10



2012

2013

2009

2010

2011

2012

2013

2009

nd

P

nd

nd

nd

nd

nd

nd

nd

nd

--

nd

nd

nd

nd

--

nd

nd

P

nd

nd

nd

nd

nd

P

nd

nd

P

nd

nd

nd

nd

nd

P

nd

P

80

nd

nd

nd

120

44

P

P

P

P

nd

nd

170

110

82

P

60

50

100

73

70

90

90

76

P

P

60

90

P

P

P

P

nd

70

70

50

P

P

140

80

41

50

P

P


2010

2011

2012

2013

nd

P

nd

nd

nd

nd

nd

nd

nd

--

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

nd

P

P

nd

nd

nd

nd

nd

nd

P

P

P

nd

nd

nd

nd

nd

nd

P

P

P

P

71

71

nd

nd

nd

nd

nd

P

P

80

120

95

80

51

nd

nd

nd

nd

nd

70

100

P

P

63

100

59

nd

nd

nd

nd

nd

P

P

100

320

105

Page 113

3.4.2 Long term chlorpyrifos detections at Tier 1, Tier 2 and Tier 3 locations Due to infrequent and limited detections, all chlorpyrifos detections in surface water since its first detection in 2005 are shown in Table 33. Prior to 2010, chlorpyrifos had never been detected at concentrations above the MRL. However, there had been several detections qualified by the MDA Laboratory as “present”, as indicated in Table 33. All chlorpyrifos detections in surface water prior to 2010 were at the “present” level as reported by the MDA Laboratory. This indicates that in 2008 and 2009 maximum concentrations were generally below the chlorpyrifos MRL of 40 ng/L and therefore, below the chronic standard. Prior to 2008, the MRL for chlorpyrifos was 100 ng/L. Starting in 2013, the MDA Laboratory discontinued reporting “present” detections below the MRL for any analytes. From 2005 through 2009, chlorpyrifos was detected once or twice annually. Starting in 2010, and through 2012, there were eight chlorpyrifos detections annually across Minnesota. In 2013, there was one chlorpyrifos detection in Minnesota. Tier 1 and Tier 2 monitoring was extended through August 30th (previously this ended on June 30th) in 2013 to better assess insecticide and fungicide applications in Minnesota. Chlorpyrifos o Chlorpyrifos was only detected once in 2013 (PMR 7). o Chlorpyrifos has been detected in PMRs 1, 4, 7, and 8 since 2010. o Chlorpyrifos was not detected in PMR 1 in 2013, after being detected 21 times from 2005 through 2012. o Chlorpyrifos has not been detected in PMRs 2, 3, 5, 6, 9 and 10.


Page 114

Table 33. Detections of chlorpyrifos in Minnesota surface waters since 2005. PMR

Date

Chlorpyrifos (ng/L)

MRL through 2007 (ng/L)

Beauford Ditch

8

5/13/2005

P

100

Snake River

1

7/5/2005

P

100

Buffalo River- Georgetown

1

7/17/2006

P

100

Snake River

1

7/18/2006

P

100


1

5/23/2007

P

100

Le Sueur River- Hwy 66

8

8/2/2007

P

100


1

6/9/2008

P

40


1

9/3/2009

P

40

Snake River

1

6/28/2010

40

40

Snake River

1

6/30/2010

P

40

Grand Marais Creek

1

5/25/2010

50

40

Tamarac River Unnamed Ditch-Tamarac River (EMAP) Black River near Thief River Falls (EMAP) Unnamed Ditch-South Fork Crow River (EMAP) Seven Mile Creek

1

6/23/2010

60

40

1

6/30/2010

P

40

1

6/30/2010

110

40

4

8/5/2010

50

40

8

9/2/2010

240

40

Tamarac River-Stephen

1

6/23/2011

100

40


1

7/12/2011

110

40

Buffalo River-Georgetown

1

7/21/2011

P

40

Grand Marais Creek

1

7/25/2011

80

40

Grand Marais Creek

1

7/27/2011

80

40

Grand Marais Creek

1

8/11/2011

160

40

Snake River

1

8/11/2011

50

40

Jack Creek

8

8/15/2011

50

40

Le Sueur River- Hwy 66

8

8/3/2012

P

40


1

8/3/2012

P

40

South Fork Crow River - Cosmos

8

8/13/2012

50

40


1

8/14/2012

110

40

South Fork Crow River - Cosmos

8

8/15/2012

50

40

Sleepy Eye Creek

8

8/21/2012

80

40

Pipestone Creek

7

8/28/2012

P

40

Sleepy Eye Creek

8

8/29/2012

P

40

Three Mile Creek - Green Valley

7

8/15/2013

53.4

40

Site


Current MRL (ng/L)

Page 115

3.4.3 Detailed analysis of May and June herbicide detections at Tier 1 and Tier 2 from 2007-2013 MDA began using a tiered network approach in 2006, and the network was fully implemented in 2007. Since that time, MDA has monitored a large number of locations across Minnesota (Figure 49) and has built a substantial database of pesticide results. This section was created to provide a more detailed analysis of the selected herbicides by PMR. Please refer to Section 3.4 for a discussion of monitoring season and MDA Laboratory changes that have occurred since 2008. Basic summary statistics were calculated on a PMR level. Annually, MDA collected between four and eight samples from at least four different stream and/or river locations within each agricultural PMR. There are small annual variations in sample numbers per PMR based on site selection, monitoring intensity, and environmental conditions (rainfall); however, on a statewide level, total May and June sample counts have ranged from 175 samples in 2007 to 237 samples in 2013. Sampling is targeted towards storm events, however, samples were collected from both base and storm flow conditions. This analysis does not differentiate samples collected between base flow and storm flow conditions. Annually, there is variability in pesticide detections related to the timing of pesticide applications, large rainfall events, and run-off events within each PMR. Long-term trends may be difficult to detect based on the natural variability of environmental conditions; however, this section presents a snapshot of pesticide occurrence by PMR across the state. The MDA will pursue robust trend analysis as additional years of data become available. Within this section, the y-axis values will vary between the graphics presenting different PMR’s. The differences in the data presented in Section 3.4.1 and 3.4.2 are related to the following: 





Only data collected in May and June was included. o This time period aligns with most herbicide detections in Minnesota rivers/streams, and eliminates late season (July and August) samples collected only in 2012 and 2013. Data was censored to the highest MRL for each herbicide. o To account for changing MRL’s over consecutive years, all data was censored to the highest MRL. For example, acetochlor had an MRL of 50 ng/L from 2008 through 2012, while the MRL lowered to 30 ng/L in 2013. All acetochlor data was censored to 50 ng/L for all years. All detections below the highest MRL (including “present” detections) were censored to non-detections. Annual statistics were calculated using Kaplan-Meier statistical methods.

The following describes the detailed analysis of May and June herbicide detections at Tier 1 and Tier 2 locations from 2007 through 2013. 

Acetochlor o Detection frequency graphics are presented in Figure 50; concentration graphics are presented in Figure 51.


Page 116





o Acetochlor detection frequencies appear to be increasing since 2010 in PMR’s 5, 6, 7, 8, 9, 10 and on a statewide basis. o Statewide acetochlor detection frequency has ranged from 20 to 62 percent from 2007 through 2013. o Statewide acetochlor percentile concentrations appear to be increasing since 2009. Atrazine o Detection frequency graphics are presented in Figure 52; concentration graphics are presented in Figure 53. o Atrazine detection frequency and percentile concentrations vary each year in each PMR. o Statewide atrazine detection frequency has ranged from 31 to 87 percent from 2007 through 2013. Metolachlor o Detection frequency graphics are presented in Figure 54; concentration graphics are presented in Figure 55. o Statewide metolachlor detection frequencies have increased since 2009; ranging from 29 to 50 percent.


Page 117

Figure 50. 2007-2013 acetochlor detection frequency by PMR and statewide.


Page 118

Figure 51. 2007-2013 acetochlor concentration percentiles by PMR and statewide. The acetochlor chronic 4-day standard is 3,600 ng/L.


Page 119

Figure 52. 2007-2013 atrazine detection frequency by PMR and statewide.


Page 120

Figure 53. 2007-2013 atrazine concentration percentiles by PMR and statewide. The atrazine chronic 4-day standard is 10,000 ng/L.


Page 121

Figure 54. 2007-2013 metolachlor detection frequency by PMR and statewide.


Page 122

Figure 55. 2007-2013 metolachlor concentration percentiles by PMR and statewide. The metolachlor chronic 4-day standard of 23,000 ng/L applies.


Page 123

3.4.4 Number of sample pesticide concentrations above 10 percent or 50 percent of surface water numeric standards at Tier 3 locations from 2008 - 2013 Sample concentrations occurring at either greater than 10 percent or 50 percent of the surface water chronic aquatic life standard for atrazine, acetochlor and metolachlor are shown in Table 34. All seven current Tier 3 locations are included in this analysis. Additionally, a human health based chronic standard for atrazine also applies to Class 2A streams. The monitoring locations where the human health standard for atrazine is applicable are displayed in Table 35. All results are compared against the current standards, which may or may not have been the standard in place at the time of sampling. All results are displayed from 2008-2013 and were collected as grab samplers or using equal-time increment composite samples. Data from previous monitoring efforts (1994-2007) can be found in previous MAU monitoring reports (www.mda.state.mn.us/monitoring). MDA uses the thresholds of 10 percent and 50 percent of applicable chronic water quality standards for analyzing water quality data in accordance with the Minnesota Pesticide Management Plan (PMP). These thresholds provide context to historical data and in some instances, trigger specific actions by MDA, such as initiating the development of pesticide specific Best Management Practices, or increased monitoring. A summary of the results are as follows: 





Acetochlor o Acetochlor was detected in 49 of the 135 samples in 2013 (36 percent). o From 2008-2013, the Le Sueur River has had the most samples (17) over 10 percent of the aquatic life standard whereas Seven Mile Creek has had the most samples (3) over 50 percent. o The Buffalo River near Georgetown had six samples over 10 percent of the aquatic life standard in 2013 (the most since monitoring began). o Of the 135 acetochlor samples collected in 2013, no samples were above 50 percent of the aquatic life standard. Atrazine – Chronic aquatic life standard (10,000 ng/L, 4-day duration aquatic toxicity based) o Atrazine was detected in 77 of the 135 samples in 2013 (57 percent). o Atrazine has not been detected above 10 or 50 percent of the standard at the Le Sueur River (2008-2013). o The Buffalo River near Georgetown had two samples over 10 percent of the aquatic life standard in 2013 (tied for the most since monitoring began). o Of the 135 atrazine samples collected in 2013, no samples were above 50 percent of the aquatic life standard. Atrazine – Human health based standard (3,400 ng/L, 30-day human health based) o Three of the seven Tier 3 sites are classified as class 2A waters.


Page 124





o Atrazine was detected in 34 of 57 samples (60 percent) at Class 2A Tier 3 monitored streams in 2013. o In 2013, the South Branch of the Root River had two samples above 10 percent of the standard and one sample above 50 percent of the human health based standard. Metolachlor o Metolachlor was detected in 92 of the 135 samples in 2013 (68 percent). o Six samples, collected at five different locations, were above 10 percent of the chronic aquatic life standard in 2013. o The Buffalo River near Georgetown had one sample over 10 percent of the aquatic life standard in 2013 (first since monitoring began). o Of the 135 metolachlor samples collected in 2013, no samples were above 50 percent of the aquatic life standard. Chlorpyrifos o Chlorpyrifos data is not contained within this section due to limited detections at Tier 3 locations. In addition, the MRL from the MDA Laboratory is 40 ng/L while the chronic aquatic life standard is 41 ng/L and therefore, 10 and 50 percent of the standard cannot be calculated.


Page 125

Table 34. Number of sample concentrations above 10% or 50% of the acetochlor, atrazine, and metolachlor standards from 2008 - 2013 for Tier 3 sites based on the aquatic life standard. Acetochlor Standard of 3,600 ng/L

Tier 3 Location

Beauford Ditch

Total Detections # > 10% Standard # > 50% Standard

Buffalo River Georgetown

Total Detections # > 10% Standard # > 50% Standard Total Detections

Le Sueur River

Seven Mile Creek

# > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard

North Branch of the Root River

Total Detections # > 10% Standard

South Branch of the Root River

Total Detections

Middle Branch of the Whitewater

# > 50% Standard # > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard


Atrazine Standard of 10,000 ng/L

2008

2009

2010

2011

2012

2013

2008

2009

2010

2011

2012

2013

13/20 3

10/13 1

17/29 3

12/23 5

12/14 3

4/18 0

13/20 0

9/13 0

12/29 0

9/23 0

14/14 0

8/18 1

0

0

0

1

0

0

0

0

0

0

0

0

3/5

12/26

6/21

9/21

6/16

10/22

4/5

20/26

9/21

16/21

10/16

14/22

2 0

1 0

0 0

5 1

1 0

6 0

0 0

0 0

0 0

2 0

0 0

2 0

15/23

16/20

16/20

17/21

9/15

13/17

20/23

16/20

15/20

16/21

14/15

12/17

3 1

5 0

1 0

3 0

3 0

2 0

0 0

0 0

0 0

0 0

0 0

0 0

9/15 0

4/13 0

14/23 2

12/26 2

8/16 4

3/14 0

14/15 0

10/13 0

16/23 1

20/26 0

15/16 0

3/14 0

0

0

1

1

1

0

0

0

0

0

0

0

8/20 2

10/23 3

5/23 0

12/21 0

5/15 1

6/21 2

20/20 1

23/23 5

19/23 0

20/21 0

14/15 0

9/21 1

0

0

0

0

0

0

0

0

0

0

0

0

4/14

13/23

10/26

9/20

5/15

8/20

13/14

23/23

26/26

19/20

12/15

14/20

0 0

6 0

0 0

4 0

0 0

2 0

0 0

8 0

0 0

0 0

0 0

1 0

8/22

3/13

4/26

6/23

9/20

5/23

22/22

13/13

23/26

21/23

19/20

17/23

2 0

3 1

0 0

0 0

3 1

1 0

3 0

0 0

0 0

1 0

1 0

1 0

Page 126

Table 34 continued. Number of sample concentrations above 10% or 50% of the acetochlor, atrazine, and metolachlor standards from 2008 - 2013 for Tier 3 sites based on the aquatic life standard. Metolachlor Tier 3 Location

Standard of 23,000 ng/L Total Detections

Beauford Ditch

Buffalo River Georgetown

Le Sueur River

# > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard

Seven Mile Creek


North Branch of the Root River South Branch of the Root River Middle Branch of the Whitewater

Total Detections # > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard Total Detections # > 10% Standard # > 50% Standard


2008

2009

2010

2011

2012

2013

18/20

13/13

29/29

23/23

14/14

18/18

0 0

1 1

2 0

0 0

0 0

2 0

3/5

15/26

15/21

15/21

8/16

16/22

0 0

0 0

0 0

0 0

0 0

1 0

21/23 0

20/20 1

20/20 0

21/21 0

14/15 0

16/17 0

0

0

0

0

0

0

12/15 0

8/13 0

22/23 1

22/26 0

10/16 0

6/14 0

0

0

0

0

0

0

15/20

20/23

17/23

17/21

9/15

11/21

0 0

2 0

0 0

0 0

0 0

1 0

11/14

20/23

23/26

18/20

11/15

13/20

0 0

4 0

0 0

0 0

0 0

1 0

12/22 2

2/13 0

15/26 0

16/23 0

15/20 1

12/23 1

0

0

0

0

0

0

Page 127

Table 35. Number of sample concentrations above 10% or 50% of the 3,400 ng/L atrazine standard from 2008 - 2013 for current Tier 3 sites located on class 2A waters. Tier 3 Location

Seven Mile Creek


South Branch of the Root River Middle Branch of the Whitewater

2008

Atrazine Standard of 3,400 ng/L 2009 2010 2011 2012

14/15

10/13

16/23

20/26

15/16

3/14

0

0

1

2

0

1

2013

0

0

0

0

0

0

13/14

23/23

26/26

19/20

12/15

14/20

# > 10% Standard

2

11

1

1

0

2

# > 50% Standard

0

6

0

0

0

1

Total Detections

22/22

13/13

23/26

21/23

19/20

17/23

# > 10% Standard

Total Detections

4

2

0

1

2

1

# > 50% Standard

2

0

0

0

1

0


Page 128

3.4.5 Period of record data at current Tier 3 pesticide sampling locations Since 2006, the MDA has collected storm flow samples on an ETI basis at Tier 3 sites to generate data that is readily comparable to duration based standards or reference values. Since 2006, surface water monitoring at Tier 3 sites utilize an ETI composite sample collection during storm flow periods using stage activated automated samplers. Grab samples are also collected during and between storm events. In the following table, composite sample concentrations collected before 2006 (generally EFI) and starting in 2006 (generally ETI) are presented together with grab sample concentration data. Table 36 summarizes results for the period of record at each of the current Tier 3 locations. The Tier 3 period of record ranges from 21 years at the Middle Branch of the Whitewater River to five years at the Buffalo River near Georgetown. The number of samples collected per year varies, though on average it is between 20 to 30 samples per Tier 3 site. The following is a summary of the acetochlor, atrazine, chlorpyrifos and metolachlor concentration results at the current Tier 3 locations: 







Acetochlor o Acetochlor results are available from 1995 to 2012. o Maximum measured acetochlor concentration occurred at Beauford Ditch in 2005 (12,100 ng/L). o Maximum acetochlor concentrations were higher in 2013 than 2012 maximums for three of seven sites. o Median values ranged from non-detect to 71 ng/L in 2013. o Median values at the Buffalo River near Georgetown, North Branch of the Root River, South Branch of the Root River and the Middle Branch of the Whitewater River have been at non-detect or “present” since monitoring began at these locations. Atrazine o Maximum measured atrazine concentration occurred at Middle Branch of the Whitewater River occurred in 2004 (32,000 ng/L). o Maximum concentrations ranged from 516 ng/L (Seven Mile Creek) to 3,120 ng/L (South Branch of the Root River) in 2013 o In 2013, three of the seven Tier 3 sites had median concentrations of non-detect. Chlorpyrifos o At the seven Tier 3 locations, only one detection of chlorpyrifos has had a concentration that was quantifiable (Seven Mile Creek in 2010). All other maximum concentrations have been either non-detect or “present.” Metolachlor o Highest metolachlor concentration recorded was 76,000 ng/L at Beauford Ditch in 2009, and was collected during a snowmelt runoff event. o In 2013, the highest maximum concentration recorded was 5,350 ng/L at the Beauford Ditch.


Page 129

o Median metolachlor concentrations ranged from non-detect to 143 ng/L in 2013. Table 36. Period of record surface water concentration results at current Tier 3 locations for acetochlor, atrazine, chlorpyrifos and metolachlor. Acetochlor (ng/L)

Atrazine (ng/L)

Chlorpyrifos (ng/L)

Metolachlor (ng/L)

Beauford Ditch

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

2005 2006 2007 2008 2009 2010 2011 2012 2013 Buffalo River - Georgetown

P 60 40 P P P P 70 nd

12,100 1,580 190 1,460 430 510 4,130 1,740 265

P nd 40 P P nd nd P nd

2,850 P 220 P 80 50 890 130 1,170

nd nd nd nd nd nd nd nd nd

P nd nd nd nd nd nd nd nd

P P P P 120 110 140 P 97

3,700 170 420 1,990 76,000 3,040 1,640 1,750 5,350

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

2009

nd

440

60

880

nd

P

P

1,470

2010 2011

nd

150

nd

220

nd

nd

P

370

nd

3,310

P

1,560

nd

P

P

1,900

2012

nd

490

P

760

nd

P

nd

690

2013

nd

1,400

40

1,660

nd

nd

37

4,070

Le Sueur River

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Seven Mile Creek 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

90 110 130 80 90 60 P 130 P P 60 100 60 P 71

3,630 3,550 9,000 7,100 2,380 1,520 5,300 1,240 1,500 2,050 470 400 980 1,630 515

40 480 100 240 70 220 70 50 80 P P P P 60 37

2,040 2,800 3,800 2,970 430 1,950 720 290 470 660 290 330 460 390 628

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

nd nd nd nd nd nd nd nd P nd nd nd nd P nd

130 210 220 100 80 110 70 P P 100 80 120 150 70 143

700 1,410 1,440 650 680 1,300 980 240 570 1,540 9,440 1,560 1,120 1,520 977

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

70 90 nd 60 nd P nd 50 nd nd nd

2,190 2,450 1,180 480 210 120 70 2,800 1,900 1,920 327

90 160 50 60 40 P P P P P nd

2,590 1,350 10,000 1,060 220 90 110 1,530 370 230 516

nd nd nd nd nd nd nd nd nd nd nd

nd nd nd nd nd nd nd 240 nd nd nd

110 320 50 P P P P 120 90 P nd

1,650 3,200 900 400 P 300 100 3,560 1,050 1,320 1,170


Page 130

Table 36 continued. Period of record surface water concentration results at current Tier 3 locations for acetochlor, atrazine, chlorpyrifos, and metolachlor. Acetochlor (ng/L) North Branch Root River 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 South Branch Root River 2008 2009 2010 2011 2012 2013 Middle Branch Whitewater River 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Atrazine (ng/L)

Chlorpyrifos (ng/L)

Metolachlor (ng/L)

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

nd nd nd nd nd nd nd P nd nd

1,830 60 1,710 2,160 690 920 P 320 460 1,020

240 70 150 80 P 70 110 P P nd

7,400 1,270 720 1,060 1,020 3,250 110 850 160 1,230

nd nd nd nd nd nd nd nd nd nd


120 P 50 P P P 350 70 P 47

5,800 1,590 1,550 2,010 1,570 3,150 170 1,210 270 2,410

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

nd P nd nd nd nd

600 1,230 220 940 130 2,920

P 80 50 P P 32

960 4,700 510 460 70 3,120

nd nd nd nd nd nd

nd nd nd nd nd nd

P P P P P 55

1,080 5,000 1,590 300 P 3,010

Median

Maximum

Median

Maximum

Median

Maximum

Median

Maximum

--nd nd nd nd nd P nd nd nd P nd nd nd nd nd nd nd nd nd

--2,530 1,500 220 2,550 6,350 4,890 7,800 9,600 1,190 2,170 2,200 P P 530 1,880 60 240 5,750 866

230 250 180 200 140 120 120 340 130 170 160 180 90 80 70 70 80 60 P 50 39

5,140 5,010 5,580 3,420 640 3,750 1,550 16,500 17,400 29,400 7,150 32,000 2,000 160 350 3,640 690 250 1,550 1,980 1,350

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

nd nd nd nd nd P P 190 P P nd 130 P P P P nd P P P 29

6,150 1,410 980 1,850 37 1,270 1,580 7,790 690 4,300 3,900 1,620 3,700 P 390 3,320 450 310 800 6,550 4,690


Page 131

3.5 Precipitation sampling Precipitation monitoring for pesticides and nutrients began in south-central Minnesota in 2008 at the Little Cobb River (LTP) near Beauford and in southeastern Minnesota in 2009 at the MDA Rochester office (ZRP). The Little Cobb precipitation monitoring site is located in an agricultural area, while the Rochester precipitation site is located within the City of Rochester. Differences in detection frequency and concentrations between the sites may be related to their relative location and associated pesticide applications within close proximity of the collection equipment. Samples were collected via wet precipitation collectors for rainfall events from April through late September. These collectors automatically open a collection vessel at the onset of a rainfall event. The sampler collects composite rainfall samples over the rainfall event, or over a series of rainfall events. Samples were transferred to an on-site refrigerator at the time of collection for temporary storage until sufficient volume was available for pesticide analysis. Nutrient samples were collected when sufficient volume was available after the volume for pesticide analysis was attained (Table 37). Within this section, the sample date refers to the end date for the composite sample.   

One nitrate-nitrogen detection occurred at both the Little Cobb and Rochester precipitation samplers; concentrations were 0.54 and 0.60 mg/L, respectively. Total phosphorus was detected once at the Rochester location with a concentration of 0.01 mg/L. Dissolved ortho-phosphorus was not detected in precipitation in 2013.

Table 37. Inorganic data summary from rainfall precipitation sampling in 2013. Analyte Nitrate/Nitrogen Total Phosphorus Dissolved Ortho-phosphorus

Location Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester


P M R 8 9 8 9 8 9

Detections/ Total Samples

Detection Frequency

Median (g/L)

Maximum (g/L)

Date of Maximum

1/4 1/3 0/4 1/3 0/4 0/3

25% 33% 0% 33% 0% 0%

nd nd nd nd nd nd

0.54 0.60 nd 0.01 nd nd

July 15 July 29 -June 3 ---

Page 132

GC-MS/MS pesticide results from rainfall precipitation samples are presented in Table 38.  Acetochlor, atrazine, and metolachlor were the most commonly found pesticides at both sites in 2013.  All maximum parent pesticide concentrations in rainfall occurred in June.  Generally, detection frequencies and maximums were similar between the Little Cobb and Rochester locations.  Generally, detections occurred during the presumed application period for each individual pesticide analyte. Figures 56 and 57 display the pesticide concentration results by date for all detections in 2013. Table 38. GC-MS/MS pesticide data summary from rainfall precipitation sampling in 2013. GC-MS/MS Detected Analyte Acetochlor Atrazine Deisopropylatrazine Desethylatrazine Metolachlor

Location Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester

P M R 8 9 8 9 8 9 8 9 8 9

Detections/ Total Samples

Detection Frequency

Median (ng/L)

Maximum (ng/L)

Date of Maximum

4/10 4/9 5/10 4/9 3/10 1/9 4/10 2/9 4/10 4/9

40% 44% 50% 44% 30% 11% 40% 22% 40% 44%


262 214 458 453 223 167 127 113 496 474

June 14 June 25 June 24 June 25 July 15 June 25 June 24 June 25 June 24 June 25

LC-MS/MS pesticide results from rainfall precipitation samples are presented in Table 39.  2,4-D was detected in all samples (four from Little Cobb and three from Rochester).  DEDI atrazine and hydroxyatrazine, both degradates of atrazine, were detected once at each location in June. Table 39. LC-MS/MS pesticide data summary from rainfall precipitation sampling in 2013. LC-MS/MS Detected Analyte 2,4-D DEDI atrazine Hydroxyatrazine

Location

PMR

Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester

8 9 8 9 8 9

Detections/ Total Samples 4/4 3/3 1/4 1/3 1/4 1/3

Detection Frequency

Median (ng/L)

Maximum (ng/L)

Date of Maximum

100% 100% 25% 33% 25% 33%

193 56.9 nd nd nd nd

110 123 104 87.9 12.5 7.24

August 23 July 17 June 14 June 25 June 24 June 25

Limited wet precipitation glyphosate monitoring was completed in 2013. Two samples were collected at the Little Cobb location, and three were collected at the Rochester location. Neither glyphosate nor AMPA were detected in wet precipitation in 2013.


Page 133

Figure 56. Concentration pesticide results from rainfall precipitation collected at the Little Cobb River precipitation monitoring station, 2013.

Figure 57. Concentration pesticide results from rainfall precipitation collected at the Rochester precipitation monitoring station, 2013. Precipitation monitoring for pesticides began in 2008 for the Little Cobb site and in 2009 for the Rochester site. Table 40 presents all detected GC-MS/MS pesticides from the Little Cobb site and the Rochester site since 2010. Detection frequency and median concentrations were less in 2013 than 2012. Alachlor, chlorpyrifos, dimethenamid, propazine and propiconazole were not detected in 2013.


Page 134

Table 40. 2010-2013 GC-MS/MS pesticide data summary from rainfall precipitation sampling. GC-MS/MS Detected Analyte Acetochlor Alachlor Atrazine Chlorpyrifos Deisopropylatrazine Desethylatrazine Dimethenamid Metolachlor Propazine Propiconazole

Location Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester Little Cobb Rochester

P M R 8 9 8 9 8 9 8 9 8 9 8 9 8 9 8 9 8 9 8 9

2010 Detections / Total Samples 5/10 7/7 1/10 0/7 7/10 7/7 0/10 0/7 0/10 1/7 5/10 4/7 2/10 2/7 6/10 6/7 0/10 0/7 2/10 0/7

2011

Median

Max

(ng/L)

(ng/L)

nd 70 nd nd 260 120 nd nd nd nd nd P nd nd nd 90 nd nd nd nd

2,520 340 P nd 370 230 nd nd nd P 90 60 50 P 340 180 nd nd P nd

Detections / Total Samples 8/9 8/8 0/9 0/8 7/9 6/8 1/9 0/8 1/9 0/8 7/9 3/8 4/9 4/8 8/9 8/8 1/9 0/8 0/9 1/8

2012

Median (ng/L)

Max (ng/L)

180 190 nd nd 170 100 nd nd nd nd 70 nd nd nd 150 60 nd nd nd nd

1,890 610 nd nd 1,510 320 90 nd 350 nd 720 80 50 P 480 250 P nd nd P

Detections / Total Samples 4/5 4/8 0/5 0/8 5/5 4/8 1/5 0/8 3/5 1/8 5/5 4/8 2/5 3/8 4/5 4/8 0/5 0/8 1/5 0/8

Median (ng/L)

Max (ng/L)

150 50 nd nd 220 70 nd nd P nd 130 P nd nd 80 P nd nd nd nd

720 300 nd nd 870 640 P nd P P 310 120 P P 210 150 nd nd 360 nd

2013* Detections / Median Total (ng/L) Samples 4/10 nd 4/9 nd 0/10 nd 0/9 nd 5/10 nd 4/9 nd 0/10 nd 0/9 nd 3/10 nd 1/9 nd 4/10 nd 2/9 nd 0/10 nd 0/9 nd 4/10 nd 4/9 nd 0/10 nd 0/9 nd 0/10 nd 0/9 nd

Max (ng/L) 262 214 nd nd 458 453 nd nd 223 167 127 113 nd nd 496 474 nd nd nd nd

*Present (P) are no longer reported from the laboratory starting in 2013


Page 135

3.6 Glyphosate monitoring Glyphosate is the most commonly used pesticide in Minnesota and until 2012, the MDA Laboratory had been unable to analyze for glyphosate at low concentrations in water. Utilizing the results from a 2011 pilot study and assistance from Monsanto Corporation, the MDA Laboratory developed an LC-MS/MS method to analyze for glyphosate and its degradate, AMPA, at low concentrations in water. Water samples were submitted to the MDA Laboratory in 2013 for glyphosate analysis (MRL= 3,040 ng/L) and its primary environmental degradate aminomethylphosphonic acid (AMPA) (MRL= 5,060 ng/L). Glyphosate results are presented in Table 41 and monitoring locations are displayed in Figure 58. Highlights of the 2013 glyphosate monitoring season are as follows:     

56 samples were collected by MDA staff from 20 different river and stream locations from PMR’s 1, 8, 9, 10, and urban sites. 27 samples were collected at Tier 3 locations and included a combination of grab samples and equal-time based composites. A single glyphosate detection (11,900 ng/L) was reported from a grab sample collected from the Cedar River (PMR 9) on August 15, 2013. AMPA was not detected in 2013. Five samples were collected by MDA staff from two different wet precipitation collectors. Neither glyphosate nor AMPA were detected in wet precipitation in 2013.

Table 41. 2013 river and stream glyphosate and AMPA results.

Glyphosate

AMPA

PMR

Total Samples

Detections

Detection Frequency

Median (ng/L)

Maximum (ng/L)

1

4

0

0%

nd

nd

8

19

0

0%

nd

nd

9

27

1

4%

nd

11,900

10

2

0

0%

nd

nd

Urban

4

0

0%

nd

nd

1

4

0

0%

nd

nd

8

19

0

0%

nd

nd

9

27

0

0%

nd

nd

10

2

0

0%

nd

nd

Urban

4

0

0%

nd

nd


Page 136

Figure 58. 2013 glyphosate monitoring locations. 3.7 2013 Nutrients and Total Suspended Solids monitoring 3.7.1 Surface water Tier 1 and Tier 2 monitoring Table 42 summarizes inorganic results by PMR for Tier 1, Tier 2 and Urban Tier 1 and 2 sites sampled in 2013.  Nitrate-nitrogen (NO3-N), total phosphorus (TP) and dissolved orthophosphorus (DOP) samples were collected with each pesticide sample at 49 tiered locations.  A limited number of samples were collected in PMR 3 (eight samples) and no samples were collected in PMR 2 during 2013.  Nitrate-nitrogen, TP, and DOP each had 455 samples collected in 2013; more samples were collected during base flow conditions than storm flow conditions. Nitrate-nitrogen (NO3-N) o Limited sampling in PMR 3 resulted in non-detection of NO3-N for all samples collected during both base and storm event periods. o NO3-N was detected for all samples collected in PMR 9. o During base flow conditions, the highest median NO3-N concentration occurred in PMR 9. The base flow median concentrations were non-detect in PMRs 1, 3, 4, and Urban.


Page 137

o During storm event conditions, the highest median NO3-N concentration occurred in PMR 8. The storm flow median concentrations were non-detect in PMRs 3, 4, 5, and Urban. o PMR 3 and Urban locations had NO3-N non-detect medians for both base flow and storm flow conditions. Dissolved orthophosphorus (DOP) o Every sample collected from PMRs 1, 5, 6, 7, 8, 9, 10 and Urban had DOP detected. o Median DOP concentrations for storm event samples ranged from 0.022 mg/L (PMR 4) to 0.182 mg/L (PMR 1) and from non-detect (PMR 3) to 0.071 mg/L (PMR 1) for base flow samples. Total phosphorus (TP) o TP was detected in 100 percent of samples collected in 2013. o Median TP concentrations for storm event samples ranged from 0.019 mg/L (PMR 3) to 0.370 mg/L (PMR 1) and from 0.017 mg/L (PMR 3) to 0.175 mg/L (PMR 1) for base flow samples.


Page 138

Table 42. Tier 1 and Tier 2 inorganic results for surface water samples by PMR, 2013. Inorganic Analyte

Nitrate/Nitrite-Nitrogen

Dissolved Orthophosphorus

Total Phosphorus

Tier 1 and Tier 2 Surface Water Monitoring Region

PMR 1

Base Flow Samples

Storm Event Samples

No. of samples

% Detection

Maximum Value Detected (mg/L)

Median Value of Samples (mg/L)

No. of samples

% Detection

Maximum Value Detected (mg/L)

Median Value of Samples (mg/L)

49

12%

0.76

nd

13

69%

2.50

1.30

PMR 3

4

0%

nd

nd

3

0%

nd

nd

PMR 4

21

33%

10.1

nd

11

36%

6.86

nd

PMR 5

14

57%

1.61

0.83

20

50%

1.16

nd

PMR 6

28

61%

14.1

0.51

6

100%

15.0

9.39

PMR 7

22

86%

12.9

3.52

20

100%

17.7

10.9

PMR 8

55

71%

23.3

2.82

54

100%

23.1

12.8

PMR 9

40

100%

25.3

7.20

24

100%

18.7

5.47

PMR 10

12

83%

13.6

2.70

18

100%

17.6

9.45

Urban

14

14%

0.71

nd

27

11%

0.86

nd

PMR 1

49

100%

0.888

0.071

13

100%

0.377

0.182

PMR 3

4

50%

0.006

nd

3

67%

0.007

0.005

PMR 4

21

90%

0.248

0.017

11

100%

0.091

0.022

PMR 5

14

100%

0.096

0.037

20

100%

0.302

0.043

PMR 6

28

100%

0.292

0.059

6

100%

0.216

0.170

PMR 7

22

100%

0.103

0.027

20

100%

0.230

0.079

PMR 8

55

100%

0.254

0.039

54

100%

0.258

0.077

PMR 9

40

100%

0.555

0.028

24

100%

0.214

0.061

PMR 10

12

100%

0.194

0.053

18

100%

0.369

0.107

Urban

14

100%

0.039

0.022

27

100%

0.178

0.023

PMR 1

49

100%

1.16

0.175

13

100%

1.11

0.370

PMR 3

4

100%

0.018

0.017

3

100%

0.021

0.019

PMR 4

21

100%

0.262

0.041

11

100%

0.288

0.065

PMR 5

14

100%

0.133

0.057

20

100%

0.681

0.134

PMR 6

28

100%

0.475

0.134

6

100%

0.435

0.288

PMR 7

22

100%

0.211

0.111

20

100%

0.452

0.238

PMR 8

55

100%

0.407

0.132

54

100%

0.540

0.220

PMR 9

40

100%

0.626

0.097

24

100%

2.86

0.246

PMR 10

12

100%

0.322

0.094

18

100%

0.558

0.208

Urban

14

100%

0.123

0.053

27

100%

0.427

0.096


Page 139

3.7.2 Surface water Tier 3 monitoring Tier 3 nutrient and total suspended solids results from 2013 are shown in Table 43. 

Nutrient and total suspended solids samples are not always collected with pesticide samples at Tier 3 sites. Field personnel determine whether or not a collection should take place based on a variety of factors, including current field conditions and volume of water available (if collecting from composite samplers).

Nitrate-nitrogen o A total of 167 NO3-N samples were collected (71 base flow and 96 storm flow) in 2013. o Tier 3 median values during base flow periods ranged from non-detect at the Buffalo River near Georgetown to 10.0 mg/L at the Whitewater River at Middle Branch. o The maximum NO3-N concentration in 2013 was detected at Seven Mile Creek with a concentration of 33.3 mg/L. o The Buffalo River near Georgetown exhibited the lowest maximum and median NO3-N concentrations of all the Tier 3 stations for both base and storm flow samples. o In southeast Minnesota, base flow NO3-N levels in streams are heavily influenced by the source aquifer that discharges to the stream, which can result in annual maximum NO3-N levels occurring during base flow periods. For example, the Whitewater River at Middle Branch had a median NO3-N concentration of 10.0 mg/L during base flow and 7.67 mg/L during storm flow. Total phosphorus/dissolved orthophosphorus o TP and DOP each had 167 (71 base flow and 96 storm flow) samples collected in 2013 at Tier 3 sites. o There was a 100 percent detection frequency for all TP samples collected at all Tier 3 sites. o The maximum TP concentration was detected during a storm flow period (9.27 mg/L) at the Whitewater River at Middle Branch. Total suspended solids o A total of 108 TSS samples were collected (38 base flow and 70 storm flow) from Tier 3 locations in 2013. There were no TSS samples collected at Beauford Ditch or Seven Mile Creek in 2013. o The maximum TSS concentration was detected during a storm flow period (8,990 mg/L) at the Whitewater River at Middle Branch.


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Table 43. Inorganic analyte detections in storm event and base flow samples for MDA Tier 3 surface water monitoring sites, 2013. Base Flow Samples Inorganic Analyte

Nitrate/Nitrite

Dissolved Orthophosphorus

Total Phosphorus

Tier 3 Surface Water Monitoring Site

No. of samples

% Detection

Beauford Ditch

7

86%


11

45%

Le Sueur River-Hwy66

6

83%

Root River-North Branch

12

Root River-South Branch-Carimona

12

Seven Mile Creek #3 Whitewater River-Middle Branch Beauford Ditch

Storm Event Samples

Maximum Value Detected

Median Value of Samples



(mg/L)

(mg/L)

20.9

(mg/L)

(mg/L)

31.6

24.3

82%

1.57

0.64

100%

22.5

17.4

100%

14.4

8.20

100%

13.1

7.34

5

100%

33.3

15.5

19

100%

9.26

7.67

11

100%

0.385

0.100

0.055

11

100%

0.232

0.173

0.021

11

100%

0.425

0.097

0.205

0.014

18

100%

0.468

0.094

0.127

0.017

21

100%

0.371

0.079

No. of samples

% Detection

2.23

11

100%

0.82

nd

11

12.3

2.79

11

100%

13.2

5.92

18

100%

12.7

7.40

21

9

100%

17.3

7.31

14

100%

10.9

10.0

7

100%

0.340

0.118


11

100%

0.140


6

100%

0.102


12

100%


12

100%

Seven Mile Creek #3

9

78%

0.034

0.007

5

100%

0.404

0.096

Whitewater River-Middle Branch

14

100%

0.290

0.017

19

100%

0.633

0.098

Beauford Ditch

7

100%

0.446

0.197

11

100%

0.548

0.239


11

100%

0.278

0.173

11

100%

0.608

0.347


6

100%

0.238

0.087

11

100%

1.03

0.349


12

100%

0.275

0.055

18

100%

1.85

0.758


12

100%

0.182

0.043

21

100%

2.97

0.858

Seven Mile Creek #3

9

100%

0.062

0.020

5

100%

0.492

0.169


14

100%

0.414

0.050

19

100%

9.27

0.651


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Table 43 continued. Inorganic analyte detections in storm event and base flow samples for MDA Tier 3 surface water monitoring sites, 2013. Base Flow Samples Inorganic Analyte

Total Suspended Solids

Tier 3 Surface Water Monitoring Site

No. of samples

% Detection

Storm Event Samples



(mg/L)

(mg/L)

No. of samples

% Detection



(mg/L)

(mg/L)

Beauford Ditch

0

--

--

--

0

--

--

--


10

100%

101

62.2

11

100%

366

177


0

--

--

--

1

100%

123

123


8

100%

52.0

11.9

18

100%

1,500

494


9

100%

32.0

6.5

21

100%

4,000

531

Seven Mile Creek #3

0

--

--

--

0

--

--

--


11

100%

29.5

9.6

19

100%

8,990

509


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Section 4: SPECIAL MONITORING STUDIES IN 2013 4.1 Plot and field scale evaluation The MDA Pesticide and Fertilizer Management Units, in cooperation with the Discovery Farms Minnesota, the Minnesota Agricultural Water Resources Center, the Acetochlor Registration Partnership and/or the University of Wisconsin-Platteville, conducted edge of field and BMP effectiveness monitoring projects in 2013 (Table 44). Staff from the MAU plays a critical role in all of these efforts. Demonstration sites include surface water run-off sites monitored with flumes, as well as subsurface tile monitoring sites. The objective of most of these studies is to evaluate nutrients, sediment and/or pesticide BMP effectiveness and loadings from surface and subsurface agricultural drainage systems. Detailed information was collected about agricultural inputs and interpreted with water quality results to determine the impact of particular practices. The field scale sites are located at several locations throughout the state (Figure 59). The exception to BMP effectiveness monitoring is the “Edge-of-Field low cost monitoring assessment.” The primary objective of this project is to evaluate a new low-cost monitoring system to potentially use with the new Natural Resources Conservation Service (NRCS) monitoring and evaluation practice standards (Codes 201 and 202). A brief description of each project listed in Table 44 is provided below. More information on MDA plot and field scale projects can be found at the respective websites shown in Table 44 and is also available from MAU staff upon request.


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Figure 59. MDA field scale monitoring sites.


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Table 44. 2013 plot and field scale monitoring projects.

Project

County(s)

Clay County Drainage Demonstration Site

Clay

Discovery Farms Minnesota

Edge-of-Field Low Cost Monitoring Assessment

Term/ End Date

Type

Analytes

Website

Surface and www.mda.state.mn.us/pr Nutrients and Long-term Subsurface otecting/cleanwaterfund/ sediment tile onfarmprojects.aspx

Blue Earth, Chisago, Surface and Dodge, Goodhue, Nutrients and www.discoveryfarmsmn. Long-term Subsurface Norman, Renville, Rock, sediment org/ tile Stearns, Wilkin, Wright Dodge, Goodhue, 3 years / Olmsted, Rice, Wabasha, Through Winona 2014

Surface

www.mda.state.mn.us/pr Nutrients and otecting/cleanwaterfund/ sediment onfarmprojects.aspx

Highway 90 Drainage Demonstration

Blue Earth

Through Subsurface 2013 tile

St. Clair Vegetative Filter Strip Study

Blue Earth

5 years / Surface Nutrients, Through Flow to sediment and 2015 side-inlets acetochlor

Root River Field to Stream Partnership

Mower, Fillmore, Houston

Nutrients

www.mda.state.mn.us/pr otecting/cleanwaterfund/ onfarmprojects.aspx

None

Surface and www.mda.state.mn.us/pr Nutrients and Long-term Subsurface otecting/cleanwaterfund/ sediment tile onfarmprojects.aspx

Clay County Drainage Demonstration site The Clay County Drainage Demonstration site is located in the Red River Valley where subsurface tile drainage is becoming increasingly common. This demonstration site is designed to evaluate the environmental impact of both surface and subsurface drainage from agricultural fields. This site includes six subsurface plots and one surface runoff plot, each approximately 24 acres in size. 2012 was the first full year that data were collected. Table 45 provides information on the location and type of field that is monitored. Discovery Farms Minnesota Discovery Farms Minnesota (DFM) is a producer-led effort organized by the Minnesota Agricultural Water Resources Center (MAWRC) in partnership with MDA. DFM involves the edge of field collection of water quality and quantity data from overland runoff and/or subsurface tile drainage. Sample collection began in 2011 at five farms. In 2013, nine locations were Minnesota Department of Agriculture 2013 Annual Monitoring Report

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monitored, comprising 17 monitoring sites. Additionally, one site was installed in the autumn of 2013 and is fully operational for the 2014 monitoring season. Table 45 provides information on the location and type of fields that are monitored. Edge of Field low cost monitoring assessment This project is part of a three-state partnership (Wisconsin, Minnesota & Iowa) to test, demonstrate and promote a simple and inexpensive new system for edge-of-field water monitoring. This project is being funded through a NRCS Conservation Innovation Grant (CIG) received by the University of Wisconsin-Platteville. Monitoring equipment was installed throughout the monitoring season in 2013 and the first full season of data collection will begin in 2014. Table 45 provides information on the location and type of fields that are monitored. Highway 90 drainage demonstration This demonstration site provides information on the characteristics of agricultural drainage from a typical field in south-central Minnesota. This project compares different tile spacing, as well as different fertilizer application rates and how these factors relate to grain production rates. Results will help researchers evaluate the environmental and economic impacts of specific management practices. This project began in 2007 and ended in 2013. Table 45 provides information on the location and type of fields that are monitored. St. Clair Vegetative Filter Strip study A paired watershed study design is being used to quantify the effect of vegetative filter strips (VFS) at side-inlet drains on acetochlor concentrations and loads in runoff from cropland treated with a registered acetochlor product. The data acquired in this study will be used by MDA to evaluate and inform the Water Quality Best Management Practices for Acetochlor. Baseline monitoring began in 2010, filter strip planting was completed in the fall of 2010, and effectiveness monitoring is planned through 2015. Table 45 provides information on the location and type of fields that are monitored. Root River Field to Stream Partnership The primary objective of the Root River Field to Stream Partnership is to conduct intensive water monitoring at multiple scales in order to provide an assessment of the amount and sources of pollution within the Root River Watershed. The two scales of monitoring are at individual agricultural fields and within small streams (subwatersheds) of the Root River. This data will help to improve the understanding of how agricultural practices affect water quality on a larger scale. Table 45 provides information on the location and type of fields that are monitored.


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Table 45. MDA field scale monitoring sites.

Discovery Farms Minnesota

Clay County Drainage Demonstration

Project

Drainage Area* (acres) 24.0 T (each site) 24.0 T (each site)

Station Type

Crops Grown

Subsurface (3 sites) Subsurface (3 sites)

Corn-Sugar Beets Corn-Sugar Beets

Red River of the North

24 S

Surface

Corn-Sugar Beets

Le Sueur

Minnesota

14.3 S 26.2 T

Surface & Subsurface

Grain

Lower St. Croix

St. Croix

6.1 S

Surface

Dodge

Swine

Zumbro

Lower Mississippi

13.9 S 13.9 T


Corn Soybean

Goodhue

BeefSwine

Mississippi River – Lake Pepin

Lower Mississippi

6.3 S

Surface

CornAlfalfa

County

Farm Type

Major Watershed

Clay

Grain

Buffalo

Clay

Grain

Buffalo

SDS7

Clay

Grain

Buffalo

BE1

Blue Earth

Swine

CH1

Chisago

DO1

GO1

Site ID EDS 1-3 (3 sites) WDS 4-6 (3 sites)

Major Basin Red River of the North Red River of the North

CornSoybean CornSoybean

Edible BeanSoybeanCornWheat,Sugar Beets Edible BeanSoybeanCornWheat,Sugar Beets CornSoybean

NO1-E

Norman

Grain

Eastern Wild Rice


87.2 S 120.9 T


NO1-W

Norman

Grain

Eastern Wild Rice


312.5 T 258.3 T

Subsurface

RE1

Renville

Grain

Middle Minnesota

Minnesota

81.0 T

Subsurface

RO1‡

Rock

BeefGrain

Lower Big Sioux

Missouri

25.5 S

Surface

CornSoybeanAlfalfa

ST1

Stearns

Dairy

Sauk

Upper Mississippi

28.2 S 24.2 T


CornAlfalfa

WI1

Wilkin

Dairy

Upper Red


160 S

Subsurface

CornSoybean

WR1

Wright

Dairy

North Fork Crow

Upper Mississippi

23.9 S 23.9 T


CornSoybean

* S = Surface watershed, T = Tile-shed watershed † = Site in-line with Discovery Farms Minnesota site GO1 ‡ = Site established in 2013, but monitoring will begin in 2014


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Table 45 continued. MDA field scale monitoring sites.

Root River Field to Stream Partnership

St. Clair Vegetative Filter Strip

Highway 90 Drainage Demonstration Site

Edge of Field Low Cost Monitoring Assessment

Project

Site ID

County

Farm Type

Major Watershed

Nearest Town

Drainage Area* (acres)

Station Type

Crops Grown

MDO1

Dodge

Grain

Zumbro

Mantorville

15.1 S

Surface

CornSoybean

Goodhue

BeefSwine

Mississippi River – Lake Pepin

Goodhue

6.3 S

Surface

CornAlfalfa

MGO2

Goodhue

Grain

Cannon

Goodhue

20.6 S

Surface

MOL1

Olmsted

Grain

Zumbro

Rochester

19.1 S

Surface

MRI1

Rice

SwineGrain

Cannon

Northfield

27.3 S

Surface

MWA1

Wabasha

Dairy

Whitewater

Plainview

11.8 S

Surface

CornAlfalfa

MWI1

Winona

Beef

Rushford

2.9 S

Surface

Pasture

MWI2

Winona

Beef

Lewiston

30.8 S

Surface

MGO1

N1 N2 S1 S2 SI-A SI-B SI-C

†

Blue Earth Blue Earth Blue Earth Blue Earth Blue Earth Blue Earth Blue Earth

Mississippi River Winona Mississippi River Winona

CornSoybean CornSoybean CornSoybean

CornSoybeanAlfalfa Corn Soybean Corn Soybean Corn Soybean Corn Soybean

Grain

Le Sueur

Mankato

5.8 T

Subsurface

Grain

Le Sueur

Mankato

5.3 T

Subsurface

Grain

Le Sueur

Mankato

7.5 T

Subsurface

Grain

Le Sueur

Mankato

5.8 T

Subsurface

Grain

Le Sueur

St. Clair

6.6 S

Surface

Corn

Grain

Le Sueur

St. Clair

15.6 S

Surface

Corn

Grain

Le Sueur

St. Clair

10.0 S

Surface

Corn

BCE

Fillmore

DairySwine

Root

Rushford

21.0 S

Surface

CornAlfalfa CornSoybeanAlfalfa CornAlfalfa

CFE

Fillmore

GrainSwine

Root

Harmony

95.4 S

Surface

CFW

Fillmore

Dairy

Root

Harmony

16.7 S

Surface

SRF

Mower

Grain

Root

Grand Meadow

27.3 S

Surface

CornSoybean

SRT

Mower

Grain

Root

Grand Meadow

58.8 T

SubSurface

CornSoybean

* S = Surface watershed, T = Tile-shed watershed † = Site in-line with Discovery Farms Minnesota site GO1 ‡ = Site established in 2013, but monitoring will begin in 2014


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4.2. Root River Pesticide Pilot Study In 2012, MDA teamed with the Root River Field to Stream Partnership to develop a better understanding of pesticide movement in agricultural watersheds of southeastern Minnesota. In-stream monitoring sites are located at the outlet of three small watersheds (South Branch of the Root River Headwaters, Crystal Creek and Bridge Creek; Figure 60 below). Each site has a drainage area ranging from 2,800 – 4,700 acres. In early 2012, MDA enhanced its pesticide monitoring because the partnership provides a unique opportunity to assess the relationship between pesticide management, climate, and water quality. This enhanced monitoring, known as the Root River Pesticide Pilot Study, features automated sampling for pesticides. The goal is to develop a better understanding of the conditions that can potentially lead to an exceedance of water quality standards for pesticides in Minnesota streams.

Figure 60. Sub-watershed locations being monitored as part of the Root River Field to Stream Partnership.


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The objectives of this study include: Assess relationships between: o Pesticide management activities and observed water quality. o Climate factors (rainfall timing and intensity) and observed water quality. o Soil and agronomic conditions as they relate to observed water quality.  Discover opportunities to “tune” Pesticide Best Management Practices (BMP’s) to be more effective. 4.2.1 Root River Pesticide Pilot Study results In 2013, 93 samples were collected and analyzed with MDA’s GC-MS/MS method from the three small watershed monitoring locations. Samples were collected between March 8th and December 16th, 2013. Samples were collected as a combination of equal-time based composites, equal-flow based composites, and grab samples. In general, storm flow was sampled with the use of composite samples, and base flow was sampled with grab samples. The data from this Pilot Project are not included in the routine monitoring summary presented earlier in this report. The spring of 2013 was extremely wet in southeast Minnesota. As a result, several storm events were sampled. This is in stark contrast to the spring and summer of 2012 when precipitation driven storm events did not occur. At the time of this report, annual watershed pesticide loads were not completed. The pesticide loads will be calculated in the summer of 2014 and will be analyzed with farm practice survey data when it becomes available. Table 46 presents summary statistics for detected GC-MS/MS pesticide compounds in the Root River Pesticide Pilot Study. 2013 GC-MS Root River Pesticide Pilot Study sampling summary:  Several storms events were sampled in May and June in 2013; no storm events occurred in 2012.  Metolachlor and desethylatrazine were detected in 70 percent of the samples collected in 2013.  Atrazine was detected in 69 percent of the samples collected in 2013.  The 90th percentiles of all detected compounds were well below applicable water quality values.  Maximum concentrations of acetochlor, atrazine, and metolachlor exceeded numeric four-day water quality standards. The maximum concentrations occurred in composite samples from storm events in June. Further analysis will occur with these samples when associated farm practice survey data is available.  Bifenthrin was only detected once; however, it exceeded the chronic USEPA/OPP chronic value benchmark for invertebrates. This sample was collected as a short duration (