MDA Pest Nitrate Overview

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Joseph Zachmann, Ph.D.Research Scientist

Pesticide & Fertilizer Management Division

Pesticides & Risk

Pesticides control insect pests, weeds and diseases andmay 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 likeexposure to pesticides in mixtures, endocrine disruption and

other concerns?


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Groundwater Monitoring for Pesticides

MDA monitoring networks aredesigned for agricultural pesticides

Wells are located adjacent tooperating farm fields

Central Sand Plainmonitoring well nest

Far from non-agricultural contaminant sources; intersect water

table to represent worst-case scenario

Southeast karst bedrock aquifers are monitored viasprings

Extremely rare long-term data set entering 29th year

Statewide Network


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What are we looking for?

In 2011 276 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 ordegradates = 30,000 analyses annually

As new pesticides are registered they are reviewed forrisk and may be added to the analytical list

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 MDHdrinking water risk levels


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Metolachlor in Central Sands

Atrazine and its degradates are frequently detected, but concentrationshave decreased significantly in recent years

Atrazine and degradate concentrations: 2000-2012

Atrazine and its Degradates in Central Sands


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Atrazine in Southeast Karst

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 croppests

Climate change effects on increased precipitationintensity and greater leaching and runoff


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All MDA monitoring data is:

Reviewed, compiled and reported annually Submitted to MDH, MPCA and EPA for evaluation

Available and stored long-term in MPCAs EQuISdatabase

QUESTIONS?

Joseph Zachmann, Ph.D.

Research ScientistPesticide Management Unit

Minnesota Department of [email protected]


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Nitrates in Groundwater within

Agricultural Regions of Minnesota

Senate Legislative Briefing:Environment and Energy Committee

April 9, 2013

Bruce MontgomerySection Manager

Fertilizer Non-Point Section

Pesticide and Fertilizer Management DivisionMN Department of Agriculture

A groundwater/drinking watercontaminate of major concern

NitrateNO3-N


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Potentially Lost to Groundwater,Surface Water or Tile Drainage

Nitratemovement togroundwater,springs, andtile drainagewaters can be

appreciable

The ManyEscape Routesof Nitrogen

Whats Grown on the LandStrongly Influences Nitrate

Loss to the Aquifer

Groundwater Stressors

Cropping Systems areNOT created equal


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Crops with Low N Loss Leaching Potential

Alfalfa and CloverVegetated Pasture

Native Prairie/CRP Plantings Perennial Crops

Acreage Trends in Minnesotas Legume Crops(All Hay and Soybeans)

SoybeansAlfalfa,Clover, etc

The Last 90 Years..


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Acreage Trends for Minnesotas Major NitrogenDemanding Crops

All Small Grain Crops

Corn

The Last 90 Years..

Crops with High N Loss Leaching Potential

Potatoes

Edible Beans

Grain Corn

Silage Corn


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Data Source: MDA, TVA, and AAPFCO

Commercial Nitrogen Fertilizer SalesTrends in U.S.& Minnesota: 1965-2011

1960s 1970s 1980s 1990s 2000s 2010s

MN Farmers Continue to Increase Efficiencyfrom Their Nutrient Inputs

Bushels of Corn Produced perLb of N Fertilizer

1992 to 2011


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County Well Index DataNitrates in Private Drinking Wells

Most elevatedconditions are found inthe Central Sands regionand Washington/DakotaCounties;

(Note that only wells with nitrate-N> than 3 mg/L are illustrated here)

Two Home Owner Nitrate Monitoring Networks havebeen Recently Established

Networks have beendesigned to provide low-cost nitrate trendinformation;

Private wells selected ona pre-determined grid;

Multi-Agency support;

SWCD and/or LocalEnvironmental Healthshoulder much of work


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Homeowner Participation is the Cornerstone ofthe Design

Nitrates in Private Drinking Wells in theCentral Sands

Home Owner NetworkApproach included1,555 Minnesotafamilies;

This recent data(2011) suggests that

about 5% > HealthStandard (10 mg/L);

Approx. 500-600wells will be used forlong-term trends


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Southeast Nitrate Monitoring Network

2008 to 2011

Data Source: MDH

This Type of Information will be ExtremelyValuable to Future Generations

Recent AnalysisSuggests that

between 200-300Agricultural

Townships Are atPotential Risk

(based upon GIS layering ofsensitive surficial geologyand row crop density)


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Nitrates in PublicWater Supplies

Nitrates in Public Water Supplies

Based upon MDHdata, less that 1% ofMinnesotas publicwater supplies exceedthe MCL;

(Note that only wells with

nitrate-N > than 3 mg/Lare 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


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Roughly 20-25 Public Water Suppliers in AgriculturalAreas are Dealing with Nitrate Issues

y = 0.0012x - 40.114

R = 0.688

0

2

4

6

8

10

12

14

Jan-93 Oct-95 Jul-98 Apr-01 Jan-04 Oct-06 Jul-09

Nitrate-N(mg/L)

PARK RAPIDS WELL 4

Rapidly Increasing Nitrate Levels Are NotUncommon in These Highly Sensitive Landscapes

1993 1998 2003 2008


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Whats at Stake for Community WaterSuppliers Dealing with Nitrate Problems?

Nitrate removal systemstypically cost more than $3Million for upfront constructioncosts and also maintenance costs

Costs of drilling new and/ordeeper wells;

Costs of blending multiplewells to achieve get acceptablewater quality;

Consumer costs are 2-6 times

higher than non-impacted watersupplies

LESSONS LEARNED: MDA, MDH, and our

partners have tools and case studies to share

http://www.mda.state.mn.us/protecting/waterprotection/drinkingwater.aspx

MDA Pest Nitrate Overview

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