Abbreviations & Terms Used in This Document Pesticide Sales Trends and Rank for Select Pesticides of Interest... 3

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1 V2 July 9, Summary of esticide Detections in Grouwater a Surface Water Resources repared for the esticide Management lan Committee, incorporating data from the Minnesota Department of Agriculture (MDA) Water Quality Monitoring Report available at Contents Abbreviations & Terms Used in This Document... 2 esticide Sales Tres a Rank for Select esticides of Interest... 3 recipitation atterns &... 5 esticide Monitoring Regions (MRs)... 5 Analayte List a Detection Summary... 6 MDA Grouwater Data... 9 MDA Surface Water Data MDA Special Monitoring Studies Grouwater Reference Values Surface Water Reference Values Robert Street North St. aul, MN AGRI An Equal Opportunity Employer TTY: 651/ /

2 Abbreviations & Terms Used in This Document MR = esticide Monitoring Region ; established by the MDA to facilitate monitoring activities. µg/l = Micrograms per liter (equivalent to parts per billion when the medium is water). ng/l = Nanograms per liter (equivalent to parts per trillion when the medium is water; = 1,000 ppb). = Not detected ; a pesticide or degradate is not detected by laboratory method used. = resent ; a pesticide or degradate is detected as present during laboratory analysis, but the concentration is below the ability of the laboratory method to quantify. MRL = Method Reporting Limit ; the lowest concentration a given analytical method can quantify. n = Number of samples collected or analyzed. - = A dash iicates a sample was not collected or analyzed. HRL = Health Risk Limit for drinking water; established by Minnesota state rule. HBV = Health Based Value for drinking water; guideline set by the MN Dept of Health. RAA = Risk Assessment Advice for drinking water; guideline set by the MN Dept of Health. Generally, RAAs contains greater uncertainty than HRLs a HBVs. MCL = Maximum Contaminant Level, established by the USEA for the regulation of public water supplies. If available, used in the absence of an HRL, HBV or RAA. Reference = For grouwater, in the absence of an HRL, HBV, RAA or MCL, the lowest value from among available published values a methods from the MDH (MDH Methodology), the USEA Office of esticide rograms (DWLOC: Drinking Water Level of Comparison), the USEA Office of Water (HA: Health Advisory), a the United States Geological Survey (HBSL: Health Based Screening Level, calculated according to EA methods for Health Advisories). Values selected were discussed with MDH, a appropriate human health-based guidance may change. For surface water, either a MN ollution Control Agency Chronic or Acute Staard defined in Minn. Rule Chap or MCA non-promulgated toxicity advice. In the absence of MCA staards or advice, Aquatic Life Benchmarks established during USEA pesticide registration are used. Mean = The mathematical average of a given set of laboratory results. Median = An equal number of laboratory results fall above a below this number. 75 th %tile = 75% of laboratory results fall below the given number. 90 th %tile = 90% of laboratory results fall below the given number. Maximum = Maximum concentration measured. EA = U.S. Environmental rotection Agency MDA = Minnesota Department of Agriculture MDH = Minnesota Health Department MCA = Minnesota ollution Control Agency USDA = United States Department of Agriculture USGS = United States Geological Survey MDA esticide Management lan Committee June 29, age 2 of 52

3 esticide Sales Tres a Rank for Select esticides of Interest MDA esticide Management lan Committee June 29, age 3 of 52

4 For additional information about Minnesota pesticide sales for other crop chemicals a for 12 other product type categories, a for reports on pesticide usage a use practices in specific Minnesota cropproduction scenarios, visit MDA esticide Management lan Committee June 29, age 4 of 52

5 recipitation atterns & esticide movement from the point of application to the broader environment is often related to the timing a magnitude of precipitation events with respect to pesticide application periods. Total annual precipitation a annual precipitation departure from normal for, as reported by the State Climatology Office, are shown in Figures 2 a 3, respectively. The maps are shown for comparison. recipitation Total Jan 1 - Dec 31, inches DNR State Climatology Office, May 1, recipitation Departure Jan 1 - Dec 31, inches DNR State Climatology Office - May 1, esticide Monitoring Regions (MRs) MDA has developed regional water monitoring networks based on ten esticide Monitoring Regions (MRs). MRs are based on areas of similar agricultural practices a hydrologic / geographic characteristics. MR bouaries follow county bouaries, but also generally represent different hydrological regions of Minnesota. MDA esticide Management lan Committee June 29, age 5 of 52

6 Analayte List a Detection Summary esticides analyzed for in the laboratory are referred to as analytes. They are detected by methods using either gas chromatography mass spectrometry (GC-MS with reporting limits in μg/l) or liquid chromatography with taem mass spectrometry (LC-MS/MS with reporting limits in ng/l). The analyte list is shown below, organized by target a non-target analytes. The target analyte list: o Is based on the relative expectation of detecting the pesticide. o Helps MDA focus limited resources on the chemicals of greatest concern to water resources. o Typically includes many of the most commonly used pesticide products or degradates. A non-target analyte: o May also be detected if it falls into the same chemical class as target analytes. o Is quantified (if possible) a reported as non-target analyte detections. KEY: x = monitoring sample detections in surface water or grouwater. Shaded row = Analytes associated with expaed MDA laboratory methods for. 1 μg/l = 1,000 ng/l Common Name Type Detected Target or Non- Target Analyte in Surface Water Detected Target or Non- Target Analyte in Grouwater GC-MS MRL (μg/l) LC-MS/MS MRL (ng/l) target analytes 2,4,5-T Herbicide 50 2,4,5-T Herbicide 50 2,4-D Herbicide x x 8.3 2,4-DB Herbicide 13.3 Acetamiprid Insecticide 25 Acetochlor Herbicide x x 0.05 Acetochlor ESA Degradate x x 30 Acetochlor OXA Degradate x x 33.3 Alachlor Herbicide x x 0.05 Alachlor ESA Degradate x x 41.6 Alachlor OXA Degradate x x 33.3 Aldicarb sulfone Insecticide 15 Aldicarb sulfoxide Insecticide 50 Atrazine Herbicide x x 0.05 DEDI atrazine (DACT) Degradate x x 50 Deisopropylatrazine Degradate x x 0.2 Desethylatrazine Degradate x x 0.05 Hydroxyatrazine Degradate x x 6.7 Azoxystrobin Fungicide x 10 Bensulfuron-methyl Herbicide 16.7 Bentazon Herbicide x x 0.8 Boscalid Fungicide x x 0.3 Bromacil Herbicide x x 20 Carbaryl Insecticide x 25 Carbofuran Insecticide 13.3 Chlorantraniliprole Insecticide 50 Chlorimuron-ethyl Herbicide 20 Chlorothalonil Fungicide 0.12 Chlorpyrifos Insecticide x 0.04 MDA esticide Management lan Committee June 29, age 6 of 52

7 Common Name Type Detected Target or Non- Target Analyte in Surface Water Detected Target or Non- Target Analyte in Grouwater 1 μg/l = 1,000 ng/l GC-MS MRL (μg/l) Clomazone Herbicide x 0.1 LC-MS/MS MRL (ng/l) Clopyralid Herbicide x x 41.6 Clothianidin Insecticide x x 25 Cyanazine Herbicide 0.2 Cyfluthrin Insecticide 0.5 Diazinon Insecticide 0.12 Dicamba Herbicide x x 50 Dichlorprop Herbicide 50 Difenoconazole Fungicide 25 Dimethenamid Herbicide x x 0.05 Dimethenamid ESA Degradate x x 6.7 Dimethenamid OXA Degradate x x 10 Dimethoate Insecticide x 0.22 Disulfoton Insecticide 0.15 Disulfoton Sulfone Insecticide 20 Diuron Herbicide x x 13.3 ETC Herbicide 0.23 Esfenvalerate Insecticide 0.2 Ethalfluralin Herbicide 0.15 Flufenacet OXA Degradate 8.3 Flumetsulam Herbicide x x 50 Fonofos Insecticide 0.1 Halosulfuron-methyl Herbicide 30 Hexazinone Herbicide 10 Imazamethabenz-methyl Herbicide 5 Imazamethabenz Acid Degradate 10 Imazamox Herbicide x x 13.3 Imazapic Herbicide x 10 Imazapyr Herbicide x x 8.3 Imazaquin Herbicide 16.7 Imazethapyr Herbicide x x 6.7 Imidacloprid Insecticide x x 20 Isoxaflutole Herbicide 40 Isoxaflutole DKN Degradate 50 Lambda Cyhalothrin Insecticide 0.2 Linuron Herbicide 20 Malathion Insecticide x 0.09 MCA Herbicide x 5 MCB Herbicide 10 MC Herbicide x 50 Mesotrione Herbicide x 50 Metalaxyl Fungicide x x 8.3 Metolachlor Herbicide x x 0.07 Metolachlor ESA Degradate x x 10 Metolachlor OXA Degradate x x 10 Metribuzin Herbicide x x 0.1 Metribuzin DA Degradate x 1 (estimated) Metribuzin DADK Degradate x x 1 (estimated) MDA esticide Management lan Committee June 29, age 7 of 52

8 1 μg/l = 1,000 ng/l Common Name Type Detected Target or Non- Target Analyte in Surface Water Detected Target or Non- Target Analyte in Grouwater GC-MS MRL (μg/l) LC-MS/MS MRL (ng/l) Metribuzin DK Degradate x 1 (estimated) Metsulfuron-methyl Herbicide 23.3 Myclobutanil Fungicide 0.2 Neburon Herbicide 10 Nicosulfuron Herbicide x 26.6 Norflurazon Herbicide 20 Oxadiazon Herbicide x 0.05 arathion-methyl Insecticide 0.12 eimethalin Herbicide 0.08 horate Insecticide 0.12 icloram Herbicide x 41.6 rometon Herbicide x x 0.1 rometryn Herbicide 3.3 ropachlor Herbicide 0.1 ropachlor ESA Degradate 30 ropachlor OXA Degradate 10 ropazine Herbicide x 0.1 ropiconazole Fungicide x 0.2 ropoxur Insecticide 10 yraclostrobin Fungicide x 0.23 Saflufenacil Herbicide x 15 Siduron Herbicide 6.7 Simazine Herbicide x 0.1 Sulfometuron-methyl Herbicide x 8.3 Tebuconazole Fungicide x 0.2 Tebupirimphos (hostebupirim) Insecticide 0.1 Tembotrione Herbicide x 50 Terbufos Insecticide 0.19 Tetraconazole Fungicide x x 0.15 Thiamethoxam Insecticide x x 25 Thifensulfuron-methyl Herbicide 16.7 Thiobencarb Herbicide 8.3 Triallate Herbicide 0.1 Triasulfuron Herbicide 23.3 Triclopyr Herbicide x x 50 Trifluralin Herbicide 0.17 zeta-cypermethrin Insecticide 0.5 non-target analytes Dichlobenil Herbicide x 0.1 2,6-Dichlorobenzamide Degradate x 0.1 Ethofumesate Herbicide x 0.1 ELISA analyte list Common Name Type Detected in Surface Water Detected in Grouwater Acetochlor Herbicide x na 0.10 MRL (μg/l) Glyphosate Herbicide x na 0.10 MDA esticide Management lan Committee June 29, age 8 of 52

9 MDA Grouwater Data Overview A total of 276 samples were collected from 171 grouwater monitoring sites in, although not all analytes were available for each sample collected due to ongoing laboratory analytical method development. Of the 171 monitoring sites: 143 are comprised of one or more specifically designed a installed monitoring or observation wells; 14 were private drinking water wells; a 14 consisted of naturally occurring springs emerging from bedrock formations of interest in the southeastern karst area of the state (MR 9). All of the locations are considered sensitive to contamination from activities at the la surface. Network design a sampling protocols are available in the program s grouwater design document on the MDA website at: ( Many iividual pesticides were detected in fewer than 10 of the samples collected. The most frequently detected analyte was metolachlor ESA, a metolachlor degradate (227 detections; 82% of the samples). Two atrazine breakdown products, hydroxyatrazine a DEDI atrazine (also known as DACT), were not available analytes prior to a were detected relatively frequently in (19% a 18%, respectively). Bentazon, primarily used as a crop production herbicide, was a newly available target analyte in a was present in 14.8 percent of the samples analyzed that year, a in 18% of samples in. Bentazon occurred most frequently in MR 4 although it did appear in other MRs. No grouwater pesticide (or pesticide plus degradate combinations, where appropriate) exceeded any human health-based drinking water reference values in. MDA esticide Management lan Committee June 29, age 9 of 52

10 MDA Grouwater Data: General Results esticides & degradates detected in grouwater monitoring samples collected by MDA in, along with available drinking water guidance values. No grouwater samples exceeded human health-based drinking water guidance values in. Chemical detected in MDA grouwater samples during Samples Analyzed Detections ercent Detected (%) Maximum Detection (μg/l) Guidance Value (μg/l) Value Type 2,4-D HRL 93 Acetochlor HRL 08 Acetochlor ESA HBV 11 Acetochlor OXA HBV 11 Alachlor HRL 08 Alachlor ESA RAA 09 Alachlor OXA RAA 09 Atrazine HRL MCL DEDI atrazine (DACT) arent HRL MCL Deisopropylatrazine arent HRL MCL Desethylatrazine arent HRL MCL Hydroxyatrazine HBV 05 Bentazon HBV 98 Boscalid <1 1,526 Reference HHB Bromacil Reference HA Clopyralid < ,050 Reference HHB Clothianidin Reference HHB Dicamba HRL 93 Dimethenamid HBV 99 Dimethenamid ESA arent HBV 99 Dimethenamid OXA arent HBV 99 Diuron < Reference HA Flumetsulam ,000 Reference HHB Imazamox ,980 Reference DWLOC Imazapyr ,000 Reference MDH Imazethapyr ,500 Reference HHB Imidacloprid Reference HHB Metalaxyl Reference HBSL Metolachlor HRL 11 Metolachlor ESA HBV 11 Metolachlor OXA HBV 11 Metribuzin /10 HRL 93/HBV 10 Metribuzin DA /10 arent HRL 93/HBV 10 Metribuzin DADK /10 arent HRL 93/HBV 10 Metribuzin DK /10 arent HRL 93/HBV 10 Nicosulfuron < ,000 HBV 97 rometon HRL 93 Tetraconazole <1 246 Reference HHB Thiamethoxam Reference HHB Triclopyr < HBV 99 MDA esticide Management lan Committee June 29, age 10 of 52

11 Common Detection esticides: Five (5) herbicide active ingredients (acetochlor, alachlor, atrazine, metolachlor a metribuzin) have been declared by the MDA to be in common detection in grouwater based on detection frequency of the active ingredient a/or related degradates. The figure below illustrates the number of common detection pesticides detected in grouwater samples per site in. MDA esticide Management lan Committee June 29, age 11 of 52

12 MDA Grouwater Data: Acetochlor a Degradate Detections HRL 08 arent: 9 µg/l HBV 11 Degradates: ESA 300 µg/l; OXA 100 µg/l Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report. *10-new a *11-new results are based upon the lower method reporting limits related to the LC-MS/MS method first available in. This only pertains to the degradate values. MDA esticide Management lan Committee June 29, age 12 of 52

13 Concentration (ppb) Frequency of Detection (%) Frequency of Detection (%) MDA Grouwater Data: Acetochlor a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. MR 9 detection tre graph for 11 springs MR 4 semi-annual values (does not include DNR springs or domestic well data); annual values. State map of grouwater detections 50 Based on acetochlor ESA a acetochlor OXA method reporting limit of 0.07 ug/l 40 MR 9 40 MR Year Acetochlor Acetochlor ESA Acetochlor OXA Acetochlor Acetochlor ESA Acetochlor OXA Notes: MR 4 concentration tre graph uses only spring a autumn datapoints in order to accommodate the shift from quarterly to semi-annual sampling. MR 4 acetochlor a acetochlor OXA 75 th a 90 th percentile concentrations are all below the MRL. Acetochlor ESA HBV = 300 ppb ND Year 75th ercentile 90th ercentile MDA esticide Management lan Committee June 29, age 13 of 52

14 MDA Grouwater Data: Alachlor a Degradate Detections HRL 08 arent: 5 µg/l RAA 09 Degradates: ESA 70 µg/l; OXA 70 µg/l Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report. *10-new a *11-new results are based upon the lower method reporting limits related to the LC-MS/MS method first available in. This only pertains to the degradate values. MDA esticide Management lan Committee June 29, age 14 of 52

15 Concentration (ppb) Concentration (ppb) Frequency of Detection (%) Frequency of Detection (%) MDA Grouwater Data: Alachlor a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. MR 9 detection tre graph for 11 springs MR 4 semi-annual values (does not include DNR springs or domestic well data); annual values. State map of grouwater detections Based on alachlor ESA a alachlor OXA method reporting limit of 0.07 ug/l 100 MR 9 60 MR Year Alachlor Alachlor ESA Alachlor OXA Alachlor Alachlor ESA Alachlor OXA MR Alachlor ESA RAA = 70 ppb 0.15 Alachlor ESA Median RAA = 70 ppb ND ND Year Year 75th %-ile 90th %-ile MDA esticide Management lan Committee June 29, age 15 of 52

16 MDA Grouwater Data: Atrazine a Degradate Detections HRL MCL arent a Degradates Combined: 3.0 µg/l Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report. MDA esticide Management lan Committee June 29, age 16 of 52

17 Frequency of Detection (%) Frequency of Detection (%) MDA Grouwater Data: Atrazine a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. MR 9 detection tre graph for 11 springs MR 4 semi-annual values (does not include DNR springs or domestic well data); annual values. State map of grouwater detections 100 MR MR Year Atrazine Desethylatrazine Deisopropylatrazine Atrazine Desethylatrazine Deisopropylatrazine MR 9 concentration data for 11 springs (does not include DNR springs or domestic well data) MDA esticide Management lan Committee June 29, age 17 of 52

18 Concentration (ppb) Concentration (ppb) Concentration (ppb) Concentration (ppb) Concentration (ppb) Concentration (ppb) MR Atrazine HRL = 3 ppb 0.4 Desethylatrazine Deisopropylatrazine HRL = 3 ppb ND ND ND Year Year Year 75th ercentile 90th ercentile 75th ercentile 90th ercentile 75th ercentile 90th ercentile 0.15 Atrazine Median HRL = 3 ppb Desethylatrazine Median HRL = 3.0 ppb Deisopropylatrazine Median HRL = 3 ppb ND ND ND Year Year Year MDA esticide Management lan Committee June 29, age 18 of 52

19 MDA Grouwater Data: Dimethenamid a Degradate Detections HBV 99 arent a Degradates Combined: 40 µg/l Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report. *10-new a *11-new results are based upon the lower method reporting limits related to the LC-MS/MS method first available in. This only pertains to the degradate values. MDA esticide Management lan Committee June 29, age 19 of 52

20 Concentration (ppb) Concentration (ppb) Frequency of Detection (%) Frequency of Detection (%) MDA Grouwater Data: Dimethenamid a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. MR 9 detection tre graph for 11 springs MR 4 semi-annual values (does not include DNR springs or domestic well data); annual values. State map of grouwater detections MR 9 Based on dimethenamid ESA a dimethenamid OXA method reporting limit of 0.07 ug/l 10 MR Year Dimethenamid Dimethenamid ESA Dimethenamid OXA Dimethenamid Dimethenamid Esa Dimethenamid Oxa MR 4 Dimethenamid median a 90 th percentile values are non-detect. Median values for degradates are below the MRL Dimethenamid ESA HBV = 40 ppb Dimethenamid OXA HBV = 40 ppb ND ND 75th ercentile Year 90th ercentile 75th ercentile Year 90th ercentile MDA esticide Management lan Committee June 29, age 20 of 52

21 MDA Grouwater Data: Metolachlor a Degradate Detections HRL 11 arent: 300 µg/l HBV 11 Degradates: ESA 800 µg/l; OXA Degradate 800 µg/l Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report. *10-new a *11-new results are based upon the lower method reporting limits related to the LC-MS/MS method first available in. This only pertains to the degradate values. MDA esticide Management lan Committee June 29, age 21 of 52

22 MDA Grouwater Data: Metolachlor a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. MR 9 detection tre graph for 11 springs MR 4 semi-annual values (does not include DNR springs or domestic well data); annual values. State map of grouwater detections 100 Based on Metolachlor ESA a Metolachlor OXA method reporting limit of 0.07 ug/l 100 MR 9 Frequency of Detection (%) MR 4 Frequency of Detection (%) Year 0 Year Metolachlor Metolachlor ESA Metolachlor OXA Metolachlor Metolachlor ESA Metolachlor OXA MR 4 Concentration (ppb) Metolachlor ESA HBV = 800 ppb Concentration (ppb) Metolachlor ESA Median HBV = 800 ppb Concentration (ppb) Metolachlor OXA HBV = 800 ppb Median ND Year ND Year ND Year 75th ercentile 90th ercentile MDA esticide Management lan Committee June 29, age 22 of 52

23 MDA Grouwater Data: Metribuzin a Degradate Detections HRL 93 arent a Degradates Combined: 200 µg/l (current promulgation) HBV 10 arent: 10 µg/l (proposed promulgation) RAA 10 Degradates: 10 µg/l (additive with parent) Data comparison to HRLs, HBVs, or RAAs serves to screen data but is not equivalent to a health risk assessment. 75 th ercentile data is provided in the complete monitoring report.. Data for MRs 7 9: non-detect for all percentiles MDA esticide Management lan Committee June 29, age 23 of 52

24 Concentration (ppb) Concentration (ppb) Concentration (ppb) Frequency of Detection (%) MDA Grouwater Data: Metribuzin a Degradate Detections 2000 Note: Frequency of detection is based on pre- MRLs. As shown in the previous tables, metribuzin is almost MR 4 semi-annual values exclusively a grouwater contaminant of MR 4. State map of grouwater detections 40 MR Metribuzin Metribuzin DADK Metribuzin DK Metribuzin DA MR Metribuzin HBV = 10 ppb Metribuzin DK HBV = 10 ppb Metribuzin DADK HBV = 10 ppb ND ND ND Year Year Year 75th ercentile 90th ercentile 90th ercentile 75th ercentile 75th ercentile 90th ercentile MDA esticide Management lan Committee June 29, age 24 of 52

25 Site Season Well Type Acetochlor ESA Alachlor ESA Alachlor OXA Atrazine Bentazon Deisopropylatrazine Desethylatrazine Dimethenamid ESA Dimethenamid OXA Imazamox Imidacloprid Metalaxyl Metolachlor Metolachlor ESA Metolachlor OXA Metribuzin Metribuzin DA Metribuzin DADK Metribuzin DK Thiamethoxam MDA Grouwater Data: Monitoring of deeper wells in MR 4 pesticide results summary from wells at the shallow a deep well nests in MDA MR 4 Deep wells are feet deeper than shallow pairs The deep wells were distributed across MR 4 at sites that had previously shown higher pesticide levels. The purpose of the deeper wells is to determine if pesticides are impacting deeper portions of the aquifer. Sites are sampled twice each year during the normal sampling rous (May a November). 03K4 29A8 80B1 80E8 73A6 61G2 56J10 49D9 Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep Shallow Deep MDA esticide Management lan Committee June 29, age 25 of 52

26 Example comparisons of concentrations between deep a shallow wells for four pesticide breakdown products. d = deep well a s = shallow well. A) atrazine plus degradates B) metolachlor ESA C) metolachlor OXA D) metribuzin plus degradates Similar to, the deeper wells frequently have higher concentrations than the shallow wells. The concentration difference between deep a shallow wells is somewhat unpredictable from site-to-site as well as among the various chemicals. In an effort to provide additional data to help uersta the water quality results from these deep well/shallow well sites, the program has installed automatic water level recorders into the deeper wells. The goal is to answer questions about the optimum timing of sample collection in relation to grouwater recharge events. MDA esticide Management lan Committee June 29, age 26 of 52

27 MDA Grouwater Data: Urban grouwater In, the MDA began a cooperative effort with the MCA to sample wells in urban/suburban or developing urban settings where there is a high likelihood that turf management pesticide products are used. MCA staff collect samples from a select number of MCA monitoring sites based on MDA s review a concurrence. Sites from previous years sampling efforts that had detectable levels of pesticides are given preference for inclusion in sampling for following years, to allow for determination of tre in these wells over time. Urban sampling wells may occur in urban settings throughout Minnesota, not just MR 10 which includes the Twin Cities metro area. Detection frequencies a concentrations te to be quite low for most compous. Compous detected are also detected in rural agricultural settings. The reasons for the detection of agricultural pesticides in urban settings are unknown, but are suggestive of atmospheric transport, deposition a/or historic application uer different la use. The only compou that was detected solely in urban areas was diuron. Maximum detections for bromacil, imazapyr, a prometon came from urban areas. Summary of pesticides detected in urban grouwater samples. esticide or esticide Degradate Detections/Total Samples Detections/Total Samples Detection Frequency (%) Maximum (g/l) Acetochlor ESA 1/ Alachlor ESA 2/ Alachlor OXA 1/ Atrazine 4/20 20 Desethylatrazine 5/ Hydroxyatrazine 1/ Bromacil 1/ Dicamba 1/ Diuron 1/ Imazapyr 6/ Imidacloprid 1/ Metolachlor ESA 12/ Metolachlor OXA 3/ rometon 3/20 15 MDA esticide Management lan Committee June 29, age 27 of 52

28 MDA Surface Water Data MDA Surface Water Data: Stream, River, Lake a recipitation Monitoring Overview In, the MDA began monitoring surface water utilizing the tiered structure (see MDA Surface Water Monitoring Design Document Within the tiered structure, there are three different levels (tiers) of monitoring intensity. Tier 1 site locations are distributed throughout most of the agricultural areas of the state a are sampled four times during an eight week period from May 1st through June 30th. Tier 2 a 3 site locations are subject to an increase in sampling frequency. A pesticide sample is defined as the collection of either a GC-MS or a LC-MS/MS sample which together include analysis for up to 116 pesticide-related chemicals. In some instances, both GC-MS a LC- MS/MS samples are collected during a visit to a site, resulting in the collection of two pesticide samples. During the monitoring season 789 surface water samples were collected as follows: 228 Tier 1 samples; 151 Tier 2 samples; 235 Tier 3 samples; 24 samples as part of MCA s Environmental Monitoring a Assessment rogram (EMA) collected from a raomly selected group of streams in agricultural areas of the state, a 88 samples from other streams that had identified biological impairments as part of an MCA stressor identification effort (STID) [the EMA sampling occurred somewhat later in the year a generally at lower flow coitions]; 42 samples from 21 different lakes across the state; a 21 samples associated with precipitation monitoring at two different locations in the state. A summary of all water quality results can be fou in the Water Quality Monitoring Report available at 4 samples had acetochlor concentrations greater than its chronic aquatic life staard, a two had atrazine concentrations greater than its human health staard; however, these concentrations must also be assessed for duration before establishing whether an exceedance of the staard has occurred. 7 samples had acetochlor concentrations greater than 50% of its staard but less than the staard itself. Two of those were confirmation analysis samples from acetochlor ELISA screening in the Le Sueur River watershed a tributaries. Other than the 2 atrazine samples with concentrations greater than their staard, no samples exceeded 50% of the aquatic life or human health staards for atrazine. Chlorpyrifos, an organophosphate insecticide, was detected 8 times at five stream locations in, with 7 concentrations greater than the chronic aquatic life staard of 0.04 µg/l, a two of those greater than the maximum aquatic life staard of µg/l. µg/l Malathion a dimethoate, also organophosphate insecticides, were detected above or near their chronic reference values. As in, four herbicides (bromacil, diuron, metsulfuron-methyl a sulfometuron-methyl) were detected at concentrations above reference values at a small urban stream in St. aul. The source of the pesticides in this stream is being investigated by MDA s Inspection & Incident Response Units, a thus data from this small stream is not included in this report. MDA esticide Management lan Committee June 29, age 28 of 52

29 MDA Stream a River Monitoring Locations Tier 1 Tier 2 Tier 3 Surface water summary data: The M guidance uses concentration criteria i.e., sample concentrations > 10 to 50% of a reference value along with other criteria (e.g., pesticide use tres locally or statewide), to establish if a pesticide s status should be considered a surface water pesticide of concern. Summary data is presented as follows: 1. General results. 2. Historical data from current Tier 3 sites for any pesticide that is an MDA surface water pesticide of concern or continues to be a potential concern. 3. data from Tier 1, 2 or 3 or other program sites for pesticides that exceed 10 to 50% of a reference value. MDA esticide Management lan Committee June 29, age 29 of 52

30 MDA Surface Water Data: General Results Tier 1 a Tier 2 site location sample analysis was limited to the GC-MS pesticide list in non-urban areas; results (g/l). 1 g/l (ppb) = 1000 ng/l (ppt Tier 1 GC-MS Detected Analytes Total Detects (total n = 138) Total % Detects Total Max (g/l) Total Median (g/l) Base flow Detects Base flow n = 49 Storm flow n = 89 Base flow Base flow Storm Storm Base flow Max Median flow Storm flow flow Max % Detects (g/l) (g/l) Detects % Detects (g/l) Acetochlor 98 71% % % Atrazine % % % Deisopropylatrazine 4 3% 2 4% 2 2% Desethylatrazine % % % 0.23 Dimethenamid 57 41% % % 1.43 Malathion 1 1% % 0.1 Metolachlor % % % Metribuzin 1 1% % Metribuzin DADK 1 1% 1 2% rometon 5 4% % 0.27 ropazine 4 3% % Tier 2 GC-MS Detected Analytes Total Detects (total n = 125) Total % Detects Total Max (g/l) Total Median (g/l) Base flow Detects Base flow n = 56 Storm flow n = 69 Base Base flow Storm Storm Base flow flow Max Median flow Storm flow flow Max % Detects (g/l) (g/l) Detects % Detects (g/l) Storm flow Median (g/l) Storm flow Median (g/l) Acetochlor 71 57% % % Alachlor 1 1% % Atrazine 91 73% % % Deisopropylatrazine 1 1% % Desethylatrazine 91 73% % % 0.09 Boscalid 2 2% % Chlorpyrifos 7 6% % % 0.11 Clomazone 3 2% % Dichlobenil (non-target analyte) 1 1% 1 2% Dimethenamid 67 54% % % 0.82 Dimethoate 1 1% % Ethofumesate (non-target analyte) 16 13% % % 1.94 Metolachlor 95 76% % % 2.36 Metribuzin 5 4% % 0.2 rometon 2 2% % 0.5 ropiconazole 19 15% % % 1.16 yraclostrobin (Total n= 36, storm flow n =19) 1 3% % Simazine 3 2% 1 2% 2 3% Tebuconazole 14 11% % % 3.28 Tetraconazole 19 15% 8 14% 11 16% MDA esticide Management lan Committee June 29, age 30 of 52

31 Tier 3 GC-MS surface water results (g/l). 1 g/l (ppb) = 1000 ng/l (ppt) Tier 3 GC-MS Detected Analytes Total Detects (total n = 155) Total % Detects Total Max (g/l) Total Median (g/l) Base flow Detects Base flow n = 56 Storm flow n = 99 Base Base flow Storm Storm Storm Base flow flow Max Median flow flow % flow Max % Detects (g/l) (g/l) Detects Detects (g/l) Acetochlor 77 50% % % Alachlor 1 1% % Atrazine % % % Deisopropylatrazine 1 1% 1 2% Desethylatrazine % % % Chlorpyrifos 1 1% % Dimethenamid 67 44% % 57 58% 0.63 Dimethoate 1 1% % 0.47 Ethofumesate (non-target analyte) 3 2% % 0.53 Metolachlor % % % Metribuzin 6 4% % 0.35 rometon 1 1% % ropazine 3 2% % ropiconazole 10 6% 1 2% 9 9% Tebuconazole 4 3% % 0.41 Tetraconazole 11 7% % 0.15 Storm flow Median (g/l) MDA esticide Management lan Committee June 29, age 31 of 52

32 Tier 3 LC-MS/MS surface water results (ng/l). 1 g/l (ppb) = 1000 ng/l (ppt) Tier 3 LC-MS/MS Detected Analytes Total Detects (total n = 80) Total % Detects Total Max (ng/l) Total Median (ng/l) Base flow Detects Base flow n = 24 Storm flow n = 56 Base Storm Base flow Base flow Storm Storm flow flow % Max Median flow flow % Max Detects (ng/l) (ng/l) Detects Detects (ng/l) 2 4-D 49 61% % % Acetochlor ESA 72 90% % % Acetochlor OXA 52 65% % % Alachlor ESA 58 73% % % Azoxystrobin 11 14% % % 323 Bentazon 64 80% % % Clopyralid 11 14% % 630 Clothianidin (total n = 34, storm flow n =20) 12 35% % DEDI Atrazine 10 13% % % 86 Dicamba 7 9% % 710 Dimethenamid ESA 55 69% % % Dimethenamid OXA 27 34% % % 80 Diuron 5 6% % 331 Hydroxyatrazine 79 99% % % Imazapyr 1 1% % 9.46 Imazethapyr 33 41% % % Imidacloprid 2 3% % % 21 MCA 12 15% % % 705 Mesotrione 9 11% % 239 Metalaxyl 6 8% % 28.3 Metolachlor ESA % % % Metolachlor OXA 76 95% % % Saflufenacil 21 26% % % 137 Tembotrione 1 1% % 78 Thiamethoxam 16 20% % % 214 Triclopyr 1 1% % 89 Storm flow Median (ng/l) MDA esticide Management lan Committee June 29, age 32 of 52

33 MDA Surface Water Data: Historical Data from Current Tier 3 Locations 1. MDA Surface Water esticides of Concern Acetochlor MCA Chronic Staard = 3.6 µg/l (4-day average) Atrazine MCA Chronic Staard = 10 µg/l (4-day average); = 3.4 µg/l (30-day average Class 2A waters ) 2. MDA Surface Water esticide of otential Concern Metolachlor MCA Chronic Staard = 23 µg/l (4-day average) Acetochlor (g/l) Atrazine (g/l) Metolachlor (g/l) Beauford Ditch Median 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum Buffalo River 90 th %- Median - Georgetown tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum Le Sueur River Median 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum Seven Mile Creek Median 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum N. Branch Root River Median 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum MDA esticide Management lan Committee June 29, age 33 of 52

34 MDA Surface Water Data: Historical Data from Current Tier 3 Locations (continued) S. Branch Root River Median Acetochlor (g /L) Atrazine (g /L) Metolachlor (g /L) 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum Middle Branch Whitewater River Median 90 th %- tile Maximum Median 90 th %-tile Maximum Median 90 th %- tile Maximum MDA esticide Management lan Committee June 29, age 34 of 52

35 MDA Surface Water Data: esticides Concentrations Relative to Reference Values Sample concentrations greater than 10%, 50% or above reference values MDA uses the thresholds of 10% a 50% of applicable water quality staards or reference values for analyzing water quality data in accordance with the Minnesota esticide Management lan (M). These thresholds provide context to historical data a, in some instances, can trigger specific actions by MDA, such as increased monitoring or initiating the development of pesticide-specific best management practices. IMORTANT NOTE: The following summary does not consider the duration component of staards or reference values. The summary simply notes whether a concentration was detected at a level above 10%, 50% or 100% of the staard or reference value. All MDA data is provided to the MCA for further assessment. Acetochlor (herbicide) Tier 1 or 2 sites o 3 samples exceeded 50% of the chronic aquatic life staard for acetochlor (3.6 µg/l). o 3 samples above the staard (one at South Fork Root River-Houston a two at Bridge Creek). Tier 3 sites o From to, the number of occurrences above 10% or 50% of the staard increased from 7 to 22, with increases occurring at five of seven Tier 3 site locations. o 2 samples (Buffalo River a Seven Mile Creek) were above 50% of the staard. o One sample (Beauford Ditch) was above the staard. ELISA screening o 2 confirmation analyses from ELISA screening in the Le Sueur River watershed a tributaries had concentrations exceeding 50% of the staard. Atrazine (herbicide) Tier 1 or 2 sites o 2 samples (Little Cannon River a South Fork Root River-Houston) were above the human health staard for atrazine in Class 2A streams (3.4 µg/l). Tier 3 sites o There were 3 occurrences of atrazine above 10% of the aquatic life staard (10 µg/l): 2 at Buffalo River a one at Middle Branch of the Whitewater River. o 4 samples were measured above 10% of the human health staard for Class 2A streams (3.4 µg/l); one from Seven Mile Creek, 2 from Middle Branch of the Whitewater River, a one from South Branch of the Root River. No samples were measured above 50% of the staard. Chlorpyrifos (organophosphate insecticide) Tier 2 sites o 4 samples above the chronic aquatic life staard (0.04 µg/l) but below the maximum staard. o 3 samples above the maximum staard (0.083 µg/l). Tier 3 site o Detected at Buffalo River-Georgetown. Malathion (organophosphate insecticide) Tier 2 site o Detected above the applicable reference value (0.035 µg/l) in one sample from the South Fork Crow River-Mayer. (Note: Sales of malathion averaged about 14,000 lbs annually between a.) Dimethoate (organophosphate insecticide) Tier 3 site o One sample collected very nearly exceeded the applicable reference value (0.50 µg/l) in Whitewater River-Middle Branch. (Note: Sales of dimethoate were at their lowest in decades at 10,416 lbs in.) MDA esticide Management lan Committee June 29, age 35 of 52

36 MDA Surface Water Data: Chlorpyrifos rior to, chlorpyrifos had never been detected at concentrations above the MRL. However, there had been several detections qualified by the laboratory as present as iicated in the table below. Starting in, the concentration a frequency of chlorpyrifos detections has increased. There were eight detections of chlorpyrifos in both a. Although the Buffalo River detection was the only detection at a Tier 3 site in, there were several detections at Tier 2 sites. These detections included three different detections above the maximum staard a two just below it. The MDA is investigating the increased number a magnitude of chlorpyrifos detections in south central a northwestern parts of Minnesota a has respoed with increased monitoring in several watersheds. In April, the Commissioner of the Department of Agriculture proposed that chlorpyrifos to be determined a pesticide of concern for surface water in Minnesota. Detections of chlorpyrifos in Minnesota surface waters since Site MR a County Date Chlorpyrifos Concentratio ns (g/l) Method Reporting Limit (g/l) Beauford Ditch 8 (Blue Earth) 5/13/ * 0.1 Snake River 1 (Marshall) 7/5/ 0.1 Buffalo River-Georgetown 1 (Clay) 7/17/ 0.1 Snake River 1 (Marshall) 7/18/ 0.1 Buffalo River-Georgetown 1 (Clay) 5/23/ 0.1 Le Sueur River-Hwy 66 8 (Blue Earth) 8/2/ 0.1 Buffalo River-Georgetown 1 (Clay) 6/9/ 0.04** Buffalo River-Georgetown 1 (Clay) 9/3/ 0.04 Snake River 1 (Marshall) 6/28/ Snake River 1 (Marshall) 6/30/ 0.04 Gra Marais Creek 1 (olk) 5/25/ Tamarac River-Stephen 1 (Marshall) 6/23/ Unnamed Ditch-Tamarac River (EMA) 1 (Marshall) 6/30/ 0.04 Black River near Thief River Falls (EMA) 1 (ennington) 6/30/ Unnamed Ditch-South Fork Crow River (EMA) 4 (Kaiyohi) 8/5/ Seven Mile Creek 8 (Nicollet) 9/2/ Tamarac River-Stephen 1 (Marshall) 6/23/ Tamarac River-Stephen 1 (Marshall) 7/12/ Buffalo River-Georgetown 1 (Clay) 7/21/ 0.04 Gra Marais Creek 1 (olk) 7/25/ Gra Marais Creek 1 (olk) 7/27/ Gra Marais Creek 1 (olk) 8/11/ Snake River 1 (Marshall) 8/11/ Jack Creek 8 (Jackson) 8/15/ MDA esticide Management lan Committee June 29, age 36 of 52

37 MDA Surface Water Data: Urban surface water Urban watershed sampling is coucted to evaluate the concentrations of commonly used pesticides in runoff from urban watersheds. These sites are sampled essentially in the same manner as the other Tier 1 a Tier 2 sites, except that the monitoring season is slightly longer. A time frame adjustment occurred in to further exte the monitoring season: Mid-April through the e of August, to capture the main application period for pesticides applied to turf, lascapes, structures as well as other sites within urban locations. All urban surface water monitoring sites were located in the Twin Cities Metropolitan area (MR 10). 5 sites sampled using the Urban Tier 1 protocol 1 site sampled using the Urban Tier 2 protocol. Samples were collected for both GC-MS a LC-MS/MS pesticide analyses at these six monitoring sites. Results overview: 38 different pesticide compous a breakdown products were detected in the urban streams. Of the 116 pesticide samples collected from the six urban tiered streams in, none iicated pesticide concentrations above applicable reference values. A comparison with agricultural tiered surface water samples show that eight compous were detected only in urban tiered surface water samples: Herbicides 2,6-dichlorobenzamide (degradate of the herbicide dichlobenil, which was detected in an agricultural Tier 1 surface water samples a also in urban Tier 1 a Tier 2 samples) bromacil imazapic MC oxadiazon sulfometuron-methyl Insecticides carbaryl Fungicides pyraclostrobin MDA esticide Management lan Committee June 29, age 37 of 52

38 Summary of GC-MS a LC-MS/MS pesticide detections in Urban Tier 1 a Tier 2 surface water monitoring samples,. Urban Tier 1 a Urban Tier 2 GC-MS (g/l) Detected Analyte Total n = 58 Number of Detections a Detection % Maximum (g/l) Date of Maximum 90th ercentile (g/l) Median (g/l) Of Total Samples, Number Exceeding 50% of a Surface Water Reference Value (a %) 2,6-Dichlorobenzamide (not a target analyte) 5 (9%) 0.14 August NA* Acetochlor 27 (41%) 0.23 May (0%) Atrazine 39 (67%) 0.15 multiple (0%) Desethylatrazine 30 (52%) 0.13 May (0%) Boscalid 6 (10%) 2.05 June 15 0 (0%) Dichlobenil (not a target analyte) 7 (12%) 0.52 April (0%) Dimethenamid 12 (21%) 1.29 June 21 0 (0%) Metolachlor 36 (62%) 0.36 June (0%) Oxadiazon 3 (5%) 0.11 July 11 0 (0%) rometon 2 (3%) multiple 0 (0%) ropiconazole 3 (5%) multiple 0 (0%) Urban Tier 1 a Urban Tier 2 LC-MS/MS (ng/l) Detected Analyte Total n = 58 Maximum (ng/l) 90th ercentile (ng/l) Median (ng/l) 2,4-D 58 (100%) 2090 August (0%) Acetochlor ESA 9 (16%) 975 June (0%) Acetochlor OXA 9 (16%) 699 June NA* Alachlor ESA 8 (14%) 157 June (0%) Azoxystrobin 5 (9%) 411 July 11 0 (0%) Bentazon 9 (16%) 7.25 August (0%) Bromacil 9 (16%) 441 June (0%) Carbaryl 1 (2%) 25 June 15 0 (0%) Dicamba 4 (7%) 255 August 15 0 (0%) Dimethenamid ESA 12 (21%) 127 July (0%) Dimethenamid OXA 8 (14%) 220 July NA* Diuron 18 (31%) 194 June (0%) Hydroxyatrazine 57 (98%) 58.1 August (0%) Imazapic 4 (7%) 81.1 August 17 0 (0%) Imazapyr 9 (16%) 11.8 July (0%) Imazethapyr 2 (3%) 19.9 June 30 0 (0%) Imidacloprid 7 (12%) 399 June (0%) MCA 21 (36%) 294 August (0%) MC 19 (33%) 516 August (0%) Metalaxyl 4 (7%) 80.9 July 11 0 (0%) Metolachlor ESA 19 (33%) 628 June (0%) Metolachlor OXA 17 (29%) 171 July (0%) Saflufenacil 1 (2%) 32.1 June 30 0 (0%) Sulfometuron-methyl 4 (7%) 20.6 June 21 0 (0%) Thiamethoxam 1 (2%) 298 July 11 0 (0%) Triclopyr 4 (7%) 230 July 11 0 (0%) MDA esticide Management lan Committee June 29, age 38 of 52

39 MDA Surface Water Data: Lake Sampling in In, twenty lakes were sampled for pesticides in collaboration with MCA s Sentinel Lakes a Intensive Watershed Monitoring efforts. At least one lake was sampled from all ten MRs in. This sampling follows annual cooperative efforts with MCA a USGS since. The sampling was part of the National Lakes Assessment rogram sponsored by EA where 53 raomly selected lakes were sampled across the state. A report was produced by MDA in titled esticides in Minnesota Lakes which summarizes the results from the study. The report is available at: ( The table below shows summary statistics for GC-MS pesticide compous detected in lake sampling efforts. All pesticide detections in lakes in were well below applicable water quality staards. Metolachlor was the most frequently detected GC-MS pesticide compou in. Hydroxyatrazine was the most commonly detected pesticide compou in lakes in among both GC-MS a LC-MS/MS analytes. Summary statistics for GC-MS pesticide compous detected in lake sampling, GC-MS Detected Median Detections Detection Maximum (μg/l) Analyte (μg/l) (21 samples) Frequency Acetochlor 6 29% Atrazine % Desethylatrazine % Dimethenamid 2 10% Metolachlor % ropiconazole 1 5% Summary statistics for LC-MS/MS pesticide compous detected in lake sampling, LC-MS/MS Median Detections Detection Maximum (ng/l) Detected Analyte (ng/l) (21 samples) Frequency 2,4-D % Acetochlor ESA % Acetochlor OXA % Alachlor ESA % Alachlor OXA % Azoxystrobin % Bentazon % Dimethenamid ESA % Dimethenamid OXA % Diuron % Hydroxyatrazine % Imazethapyr % MCA % Metolachlor ESA % Metolachlor OXA % MDA esticide Management lan Committee June 29, age 39 of 52

40 MDA Surface Water Data: recipitation Sampling recipitation monitoring for pesticides a nutrients began in south central Minnesota in at the Little Cobb River (agricultural area) near Beauford a in southeastern Minnesota in at the MDA Rochester office (urban area). Differences in detection frequency a concentrations between the sites may be related to their relative location a associated pesticide applications within close proximity of the collectors. Samples were collected via wet precipitation collectors for rainfall sampling from May through late September. These collectors automatically open a collection vessel at the onset of rainfall. The Little Cobb River collector was stuck in the open position for all of due to equipment malfunction, so the pesticide data represents both dry a wet fall sampling. GC-MS Detected Analyte Location MR Detections/ Total Samples Detection Frequency Median (g/l) Maximum (g/l) Date of Maximum Acetochlor Little Cobb 8 8/9 89% May 18 Rochester 9 8/8 100% May 24 Atrazine Little Cobb 8 7/9 78% May 18 Rochester 9 6/8 75% June 15 Deisopropylatrazine Little Cobb 8 1/9 11% 0.35 May 18 Rochester 9 0/8 0% -- Desethylatrazine Little Cobb 8 7/9 78% May 18 Rochester 9 3/8 38% 0.08 May 24 Chlorpyrifos Little Cobb 8 1/9 11% 0.09 August 23 Rochester 9 0/8 0% -- Dimethenamid Little Cobb 8 4/9 44% 0.05 multiple Rochester 9 4/8 50% multiple Metolachlor Little Cobb 8 8/9 89% May 18 Rochester 9 8/8 100% June 15 ropazine Little Cobb 8 1/9 11% May 18 Rochester 9 0/8 0% -- ropiconazole Little Cobb 8 0/9 0% -- Rochester 9 1/8 13% August 19 LC-MS/MS Detected Analyte Location MR Detections/ Total Samples Detection Frequency Median (ng/l) Maximum (ng/l) Date of Maximum 2,4-D Little Cobb 8 1/1 100% June 15 Rochester 9 2/3 67% August 19 Azoxystrobin Little Cobb 8 0/1 0% Rochester 9 1/3 33% August 19 MDA esticide Management lan Committee June 29, age 40 of 52

41 Concentration pesticide results from rainfall precipitation collected at Little Cobb River, Concentration pesticide results from rainfall precipitation collected in Rochester, MDA esticide Management lan Committee June 29, age 41 of 52

42 - GC-MS pesticide data summary from rainfall precipitation sampling recipitation monitoring for pesticides began in for the Little Cobb site a in for the Rochester site. The table below presents all detected GC-MS pesticides from the Little Cobb site a the Rochester site since precipitation site establishment. In, the highest atrazine median a maximum concentrations were measured at both sites for the period of record. Acetochlor a metolachlor were detected in 100 percent (8/8 samples) at the Rochester location, a atrazine was detected relatively frequently at both locations in. Metolachlor was detected in 16 of 17 samples in. Desethylatrazine was detected more frequently, a at higher concentrations, than deisopropylatrazine at both locations. Chlorpyrifos has been detected in three out of the last four years (,, a ), in a single sample each year, at the Little Cobb location only. For the third consecutive year, propiconazole was detected at present levels at the Little Cobb location. GC-MS Detected Analyte Acetochlor Alachlor Atrazine Deisopropylatrazine Desethylatrazine Chlorpyrifos Dimethenamid Metolachlor ropazine ropiconazole Location M R Detections / Total Samples Detections Detections Detections Median Maximum Median Maximum Median Maximum Median / Total / Total / Total (g/l) (g/l) (g/l) (g/l) (g/l) (g/l) (g/l) Samples Samples Samples Little Cobb 8 6/ / / / Rochester / / / Little Cobb 8 0/ /7 1/10 0/ Rochester / / / Little Cobb 8 6/ / / / Rochester / / / Little Cobb 8 0/ /7 0/ / Rochester / /7 0/8 Little Cobb 8 4/ / / / Rochester / / / Little Cobb 8 1/ / / / Rochester / / /8 Little Cobb 8 1/9 1/7 2/ / Rochester / /7 4/8 Little Cobb 8 6/ / / / Rochester / / / Little Cobb 8 0/ / / /9 Rochester / / / Little Cobb /7 2/10 0/9 Rochester / / /8 Maximum (g/l) MDA esticide Management lan Committee June 29, age 42 of 52

43 MDA Special Monitoring Studies Acetochlor evaluation in the Le Sueur River Watershed a tributaries Since, the MDA has been utilizing an ELISA based screening analysis for acetochlor in surface water samples collected from within the Le Sueur River Watershed in south central Minnesota. Both composite a grab samples were collected from a network of existing stream gage locations a submitted to the UW-Stevens oint Water a Environmental Analysis Laboratory (WEAL) for ELISA analysis. 136 surface water samples were collected between May a September of. Le Sueur River outlet a sub-watershed monitoring locations. Based on ELISA method results, duplicate samples delivered to the MDA Laboratory for confirmation analysis by GC-MS. 2 confirmation analysis samples iicated acetochlor concentrations above 50% of the acetochlor chronic aquatic life staard. Results from the season suggest the ELISA method continues to be a suitable low cost screening method for the presence of acetochlor. The test tes to over-predict acetochlor concentrations when metolachlor is also present. LS1 LS2 LS3 BCR LT1 BD1 MR1 MR2 Watershed Acres 710, , , ,145 82,868 5, , ,362 Sample # Sample # Sample # Median (g/l) Median (g/l) Median (g/l) Max (g/l) Max (g/l) Max (g/l) Min (g/l) <0.10 Min (g/l) < <0.10 <0.10 Min (g/l) <0.10 < <0.10 <0.10 <0.10 MDA esticide Management lan Committee June 29, age 43 of 52

44 Evaluation of glyphosate laboratory methodologies In the summer of, the MDA evaluated two different laboratory methods in a pilot study to assess options for monitoring glyphosate in Minnesota waters. Utilizing the results from this pilot study, the MDA Laboratory has established LC-MS/MS method to analyze for the compou at low levels in water. Limited water samples will be submitted to the MDA Laboratory in for the analysis of glyphosate a its primary environmental degradate aminomethylphosphonic acid (AMA). Two methods were evaluated: An enzyme-linked immunosorbent assay (ELISA) kit, referred to as GLY-ELISA An LC-MS/MS developed by Monsanto Co., a registrant of glyphosate in Minnesota, referred to as GLY-LC Two matrix coitions were examined: low sediment high sediment Other coitions: Filtering in the field a in the laboratory to address sampling methodologies All laboratory analyses performed in triplicate, with the adjusted mean value compared to the spike concentration Samples collected on May 25, from two streams in southeast Minnesota. The GLY-LC method performed better than the GLY-ELISA method for all environmental samples. Both methods appeared to uer-predict glyphosate concentrations in environmental matrix samples. MDA esticide Management lan Committee June 29, age 44 of 52

45 Expaed sampling with MCA In, MDA worked cooperatively with the MCA on two additional pesticide sampling projects. These projects were possible due to expaed MDA Laboratory capacity created by fus provided to MDA through the Clean Water Legacy Fu a a Legislative-Citizen Commission on Minnesota Resources (LCCMR) grant. Environmental Monitoring a Assessment rogram (EMA) EMA sampling, part of a USEA program, was coucted by MCA in completing an effort that began in. EMA s goal: Monitor the coition of the Nation's ecological resources to evaluate the cumulative success of current policies a programs a to identify emerging problems before they become widespread or irreversible. 12 sites; sampling coucted in August a September of Site selection raomized to include all stretches of streams a rivers in Minnesota esticide sampling generally limited to watersheds with agricultural la use Sites ranged from small drainage ditches to large river systems esticide sampling was completed in conjunction with other chemical, physical, a biological sampling Sampling biased toward base flow coitions because wading access in the stream was required Biological Stressor Identification (STID) STID pesticide sampling was coucted by MCA in. STID is completed yearly in conjunction with MCA s Intensive Watershed Investigation efforts, a occurs in the third a fourth years of the Intensive Watershed Investigation. sampling occurred in the following major watersheds between July 27, a September 27, : Cedar, Shell Rock, Chippewa, Mustinka, a St. Croix-Stillwater. Sampling included both storm a base flow coitions. rior to the EMA a STID projects in, MDA had not coucted a statewide stream survey effort of a magnitude that included streams of varying orders with many ungaged locations. Stream gaging allows for flow characterization during water quality assessment periods. Most of the locations sampled in EMA a STID were only sampled once, a limited emphasis was placed on targeting storm flow periods. Also, the sampling periods ranged from July through September, which is later in the year than the period the MDA Tier 1 a Tier 2 typically target. All EMA a STID samples included both a GC-MS a LC-MS/MS sample. MDA esticide Management lan Committee June 29, age 45 of 52