Joseph Zachmann, Ph.D.Research Scientist

Pesticide & Fertilizer Management Division

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?

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 29th year

Statewide Network

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 or degradates = 30,000 analyses annually

As new pesticides are registered they are reviewed for risk 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 MDH drinking water risk levels

Metolachlor in Central Sands

• Atrazine and its degradates are frequently detected, but concentrations have decreased significantly in recent years

• Atrazine and degradate concentrations: 2000-2012

Atrazine and its Degradates in Central Sands

Atrazine in Southeast Karst

Year

Con

cent

ratio

n (p

pb)

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

0.1

0.2

0.3

Atrazine + Deisopropylatrazine + DesethylatrazineDNR Fish Hatchery Springs Median

ND

Year

Fre

qu

ency

of

Det

ecti

on

(%

)

2004

2005

2006

2007

2008

2009

2010

2011

2012

0

20

40

60

80

100

Atrazine Desethylatrazine Deisopropylatrazine

PMR 9

All springs

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

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

QUESTIONS?Joseph Zachmann, Ph.D.Research ScientistPesticide Management UnitMinnesota Department of Agriculture651-201-6588joseph.zachmann@state.mn.us

Nitrates in Groundwater within Agricultural Regions of Minnesota

Senate Legislative Briefing:Environment and Energy Committee

April 9, 2013

Bruce MontgomerySection Manager

Fertilizer Non-Point SectionPesticide and Fertilizer Management Division

MN Department of Agriculture

A groundwater/drinking water contaminate of major concern

NitrateNO3-N

Why the Concerns?Why the Concerns?

Jan-93 Oct-95 Jul-98 Apr-01 Jan-04 Oct-06 Jul-090

2

4

6

8

10

12

14

f(x) = 0.0012186044487809 x − 40.1144766920416R² = 0.687982949899093

PARK RAPIDS WELL 4

Nit

rate

-N (

mg

/L)

Nitrate Loading to Groundwater Can Be Significant In Sensitive Geologic Areas

These Areas Tend to Be Very Localized

1993 1998 2003 2008

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

What’s Grown on the Land Strongly Influences Nitrate

Loss to the Aquifer

Groundwater Stressors

Cropping Systems are NOT created

equal

Crops with Low N Loss Leaching Potential

Alfalfa and CloverVegetated Pasture

Native Prairie/CRP Plantings Perennial Crops

0

1

2

3

4

5

6

7

8

1921 1931 1941 1951 1961 1971 1981 1991 2001 2011

Millio

ns o

f A

cre

s

Year

Hay Soybean

Acreage Trends in Minnesota’s “Legume” Crops

(All Hay and Soybeans)

Soybeans

Alfalfa, Clover, etc

The Last 90 Years…..

Acreage Trends for Minnesota’s Major Nitrogen Demanding Crops

0

2

4

6

8

10

1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Millio

ns o

f A

cre

s

Year

Corn

Small Grains

Potatoes

Sugarbeet

Sunflower

Edible Beans

All Small Grain Crops Cor

n

The Last 90 Years…..

Crops with High N Loss Leaching Potential

Potatoes

Edible Beans

Grain Corn

Silage Corn

Data Source: MDA, TVA, and AAPFCO

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

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

MN Sales (left axis)

US Sales (right axis)

Ton

sof

N S

old in

Min

neso

ta

Ton

sof

N S

old in

the

U.S

.

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

0.4

0.6

0.8

1.0

1.2

1.4

Ra

tio

of

Bu

sh

els

Pro

du

ce

d p

er

Lb

N

Fe

rtil

ize

r In

pu

t

Statewide "NUE" on Corn Using the N Balance Method

MN Farmers Continue to Increase Efficiency from Their Nutrient Inputs

Bushels of Corn Produced per Lb of N Fertilizer

1992 to 2011

County Well Index DataNitrates 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)

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

Homeowner Participation is the Cornerstone of the Design

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. 500-600 wells will be used for long-term trends

Southeast Nitrate Monitoring Network2008 to 2011

Data Source: MDH

This Type of Information will be Extremely Valuable to Future Generations

0

2

4

6

8

10

12

14

16

Feb'08 Aug'08 Feb'09 Aug'09 Aug'10 Aug'11

% Over 10 mg/L

Recent Analysis Suggests that between 200-300 Agricultural Townships Are at Potential Risk

(based upon GIS layering of sensitive surficial geology and row crop density)

Nitrates in Public Water Supplies

Nitrates in Public Water Supplies

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

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

Jan-93 Oct-95 Jul-98 Apr-01 Jan-04 Oct-06 Jul-090

2

4

6

8

10

12

14

f(x) = 0.0012186044487809 x − 40.1144766920416R² = 0.687982949899093

PARK RAPIDS WELL 4

Nit

rate

-N (

mg

/L)

Rapidly Increasing Nitrate Levels Are Not Uncommon in These Highly Sensitive

Landscapes

1993 1998 2003 2008

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

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

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