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Joseph Zachmann, Ph.D. Research Scientist Pesticide & Fertilizer Management Division.

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Presentation on theme: "Joseph Zachmann, Ph.D. Research Scientist Pesticide & Fertilizer Management Division."— Presentation transcript:

1 Joseph Zachmann, Ph.D. Research Scientist Pesticide & Fertilizer Management Division

2 Pesticides & Risk  Pesticides control insect pests, weeds and diseases and may pose risk to human health and the environment  Some pesticides leach to groundwater  People are concerned about exposure risks Are there pesticides in my drinking water? How high are the concentrations relative to known risk? Even if concentrations are low, what about unknown risks like exposure to pesticides in mixtures, endocrine disruption and other concerns?

3 Groundwater Monitoring for Pesticides  MDA monitoring networks are designed for agricultural pesticides  Wells are located adjacent to operating farm fields Central Sand Plain monitoring well nest Far from non-agricultural contaminant sources; intersect water table to represent worst-case scenario  Southeast karst bedrock aquifers are monitored via springs  Extremely rare long-term data set – entering 29 th year

4 Statewide Network

5 What are we looking for?  In groundwater samples From 171 wells/sites  CWF helped purchase state-of- the-art LC/MS-MS equipment to: Find pesticides at lower concentrations Increase number of pesticides & samples analyzed  Each sample analyzed for 110 different pesticides or degradates = 30,000 analyses annually  As new pesticides are registered they are reviewed for risk and may be added to the analytical list

6 What do we find? 40 pesticides or degradates detected Most are found in fewer than 4% of samples Commonly detected in vulnerable areas: Acetochlor Alachlor Atrazine Metolachlor Metribuzin No pesticide concentrations exceeded MDH drinking water risk levels

7 Metolachlor in Central Sands

8 Atrazine and its degradates are frequently detected, but concentrations have decreased significantly in recent years Atrazine and degradate concentrations: Atrazine and its Degradates in Central Sands

9 Atrazine in Southeast Karst

10 Uncertainties and Groundwater Risks Possible changes in pesticide use patterns & groundwater impacts due to: –New pesticide-resistant crop technologies –Weed resistance to current pesticides –Invasive species control –Climate change effects (warming) on economic crop pests –Climate change effects on increased precipitation intensity and greater leaching and runoff

11 All MDA monitoring data is: Reviewed, compiled and reported annually Submitted to MDH, MPCA and EPA for evaluation Available and stored long-term in MPCA’s EQuIS database

12 QUESTIONS? Joseph Zachmann, Ph.D. Research Scientist Pesticide Management Unit Minnesota Department of Agriculture

13 Nitrates in Groundwater within Agricultural Regions of Minnesota Senate Legislative Briefing: Environment and Energy Committee April 9, 2013 Bruce Montgomery Section Manager Fertilizer Non-Point Section Pesticide and Fertilizer Management Division MN Department of Agriculture

14 A groundwater/drinking water contaminate of major concern Nitrate NO 3 -N

15 Why the Concerns?

16 Nitrate Loading to Groundwater Can Be Significant In Sensitive Geologic Areas These Areas Tend to Be Very Localized

17 Potentially Lost to Groundwater, Surface Water or Tile Drainage Nitrate movement to groundwater, springs, and tile drainage waters can be appreciable The Many Escape Routes of Nitrogen

18 What’s Grown on the Land Strongly Influences Nitrate Loss to the Aquifer Groundwater Stressors Cropping Systems are NOT created equal

19 Crops with Low N Loss Leaching Potential Alfalfa and Clover Vegetated Pasture Native Prairie/CRP Plantings Perennial Crops

20 Acreage Trends in Minnesota’s “Legume” Crops (All Hay and Soybeans) SoybeansAlfalfa, Clover, etc The Last 90 Years…..

21 Acreage Trends for Minnesota’s Major Nitrogen Demanding Crops All Small Grain Crops Corn The Last 90 Years…..

22 Crops with High N Loss Leaching Potential Potatoes Edible Beans Grain Corn Silage Corn

23 Data Source: MDA, TVA, and AAPFCO Commercial Nitrogen Fertilizer Sales Trends in U.S.& Minnesota: ’s 1970’s 1980’s 1990’s 2000’s 2010’s

24 MN Farmers Continue to Increase Efficiency from Their Nutrient Inputs Bushels of Corn Produced per Lb of N Fertilizer 1992 to 2011

25 County Well Index Data Nitrates in Private Drinking Wells Most elevated conditions are found in the Central Sands region and Washington/Dakota Counties; (Note that only wells with nitrate-N > than 3 mg/L are illustrated here)

26 Two “Home Owner” Nitrate Monitoring Networks have been Recently Established Networks have been designed to provide low- cost nitrate trend information; Private wells selected on a pre-determined grid; Multi-Agency support; SWCD and/or Local Environmental Health shoulder much of work

27 Homeowner Participation is the Cornerstone of the Design

28 Nitrates in Private Drinking Wells in the Central Sands Home Owner Network Approach included 1,555 Minnesota families; This recent data (2011) suggests that about 5% > Health Standard (10 mg/L); Approx wells will be used for long-term trends

29 Southeast Nitrate Monitoring Network 2008 to 2011 Data Source: MDH This Type of Information will be Extremely Valuable to Future Generations

30 Recent Analysis Suggests that between Agricultural Townships Are at Potential Risk (based upon GIS layering of sensitive surficial geology and row crop density)

31 Nitrates in Public Water Supplies

32 Based upon MDH data, less that 1% of Minnesota’s public water supplies exceed the MCL ; (Note that only wells with nitrate-N > than 3 mg/L are illustrated here) Figure 10. Distribution of public water supply wells in the County Well Index with nitrate-N greater than 3 mg/L Data Source: MDH

33 Roughly Public Water Suppliers in Agricultural Areas are Dealing with Nitrate Issues

34 Rapidly Increasing Nitrate Levels Are Not Uncommon in These Highly Sensitive Landscapes

35 What’s at Stake for Community Water Suppliers Dealing with Nitrate Problems? Nitrate removal systems typically cost more than $3 Million for upfront construction costs and also maintenance costs Costs of drilling new and/or deeper wells; Costs of ‘blending” multiple wells to achieve get acceptable water quality; Consumer costs are 2-6 times higher than non-impacted water supplies

36 LESSONS LEARNED: MDA, MDH, and our partners have tools and case studies to share


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