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
Central Sand Plain
monitoring well nest
 Wells are located adjacent to
operating farm fields
 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-ofthe-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 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 in Southeast Karst
0 .3
A tr a z in e + D e is o p r o p y la tr a z in e + D e s e th y la tr a z in e
0 .2
0 .1
100
2
1
1
0
P M R 9
80
A ll s p r in g s
60
40
20
A tr a z in e
D e s e t h y la tr a z in e
D e is o p r o p y la tr a z in e
2
2
0
1
1
2
0
1
0
2
0
2
Y ear
1
0
9
0
8
0
2
0
2
0
7
0
6
2
0
0
5
0
2
0
0
0
4
0
2
F r e q u e n c y o f D e te c tio n (% )
2
2
0
1
0
2
0
1
9
2
0
0
8
2
0
0
0
2
Y ear
0
7
6
2
0
0
0
2
0
2
0
5
4
0
3
0
2
0
2
0
2
0
1
0
0
2
0
0
0
N D
2
C o n c e n tr a tio n ( p p b )
D N R F is h H a tc h e r y S p r in g s M e d ia n
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 Scientist
Pesticide Management Unit
Minnesota Department of Agriculture
651-201-6588
joseph.zachmann@state.mn.us
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
A groundwater/drinking water
contaminate of major concern
Nitrate
NO3-N
Why the Concerns?
Why the Concerns?
Nitrate Loading to Groundwater Can Be
Significant In Sensitive Geologic Areas
PARK RAPIDS WELL 4
14
12
Nitrate-N (mg/L)
10
8
6
4
y = 0,0012x - 40,114
R² = 0,688
2
0
Jan-93
1993
Oct-95
1998
Jul-98
2003
Apr-01
Jan-04
2008
Oct-06
These Areas Tend to Be
Very Localized
Jul-09
The Many
Escape Routes
of Nitrogen
Nitrate
movement to
groundwater,
springs, and
tile drainage
waters can be
appreciable
Potentially Lost to Groundwater,
Surface Water or Tile Drainage
Groundwater Stressors
What’s Grown on the Land
Strongly Influences Nitrate
Loss to the Aquifer
Cropping Systems are
NOT created equal
Crops with Low N Loss Leaching Potential
Alfalfa and Clover
Native Prairie/CRP Plantings
Vegetated Pasture
Perennial Crops
The Last 90 Years…..
Acreage Trends in Minnesota’s “Legume” Crops
(All Hay and Soybeans)
8
7
Millions of Acres
6
Alfalfa,
Soybean
Clover, etc
Soybeans
Hay
5
4
3
2
1
0
1921 1931 1941 1951 1961 1971 1981 1991 2001 2011
Year
The Last 90 Years…..
Acreage Trends for Minnesota’s Major Nitrogen
Demanding Crops
All Small Grain Crops
Millions of Acres
10
Corn
8
Corn
6
Small Grains
Potatoes
Sugarbeet
Sunflower
4
Edible Beans
2
0
1920
1930
1940
1950
1960
1970
Year
1980
1990
2000
2010
Crops with High N Loss Leaching Potential
Grain Corn
Potatoes
Silage Corn
Edible Beans
Commercial Nitrogen Fertilizer Sales
Trends in U.S.& Minnesota: 1965-2011
Data Source: MDA, TVA, and AAPFCO
900,000
14,000,000
800,000
12,000,000
10,000,000
600,000
8,000,000
500,000
400,000
6,000,000
MN Sales (left axis)
300,000
200,000
4,000,000
US Sales (right axis)
2,000,000
100,000
0
1960’s
1970’s
1980’s
1990’s
2000’s
0
2010’s
Tons of N Sold in the U.S.
Tons of N Sold in Minnesota
700,000
Ratio of Bushels Produced per Lb N
Fertilizer Input
MN Farmers Continue to Increase Efficiency
from Their Nutrient Inputs
1.4
Statewide "NUE" on Corn Using the N Balance Method
1.2
1.0
0.8
0.6
0.4
Bushels of Corn Produced per
Lb of N Fertilizer
1992 to 2011
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)
Two “Home Owner” Nitrate Monitoring Networks have
been Recently Established
• Networks have been
designed to provide lowcost 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
This Type of Information will be Extremely
Valuable to Future Generations
Southeast Nitrate Monitoring Network
2008 to 2011
% Over 10 mg/L
16
14
12
10
8
6
4
2
0
Feb'08
Aug'08
Feb'09
Aug'09
Data Source: MDH
Aug'10
Aug'11
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
Rapidly Increasing Nitrate Levels Are Not
Uncommon in These Highly Sensitive Landscapes
PARK RAPIDS WELL 4
14
12
Nitrate-N (mg/L)
10
8
6
4
y = 0,0012x - 40,114
R² = 0,688
2
0
Jan-93
1993
Oct-95
1998
Jul-98
2003
Apr-01
Jan-04
2008
Oct-06
Jul-09
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