The Effects of Atrazine
Application to the
Environment.
By: Perry Loken, Tim Weisbrod, Nick
Taylor, Sara Schmidt
What is Atrazine?

Atrazine is a 6-carbon S-chlorotriazine.
 Atrazine is the most widely used S-triazine.
 Other S-triazines used as herbicides are
Symazine and cyromazine.
 Atrazine is not very volatile, reactive or
flammable but dissolves readily in water.
How Atrazine is released into
the environment.

Atrazine is a selective herbicide used
primarily in the agriculture industry
 Atrazine is primarily applied to corn,
sorghum and sugar cane.
 Atrazine is a Restricted Use Pesticide
(RUP).
Amounts of Atrazine released
into the environment.

In 1993 the total amount of atrazine used in
the whole country was 35,000 tons.
 Atrazine usage have been increasing
steadily since the 1960’s to the current level
of 70,000-90,000 tons per year.
 Environmental levels of atrazine in
countries that use it average 5ug/L
Map of Atrazine application by
agriculture in the U.S.
How Atrazine Works

Atrazine was designed to block
photosynthesis.
 Crop plants are able to detoxify the atrazine.
 Atrazine works well as both a pre- and post
emergent herbicide.
Why Atrazine may be a threat
to the environment
The complete effects of Atrazine’s ability to block
normal functions of plants and animals (expecially
humans) is unknown.
 Atrazine is being found in surface and drinking
water reserves in areas of atrazine use
 It takes considerable time to biodegrade out of the
an aqueous system.
 Because of our extensive reliance on herbicides.

Outline of Atrazine’s course
through the environment
Atrazine application
Amount left in soil
Amount of atrazine in the Air
Amount washed into surface water
Amount going into drinking water supply
Amount going ending up in the ocean
Amount ending up in humans
Amount staying in plants
Atrazine in the soil

Degradation effects of Atrazine while it is in
the soil.
– Microbial degradation is the principle
mechanism.
– The kinetics is based on the nitrogen avalibility
in the soil.
Application history

Two types of fields
– Adapted
 Has had atrazine applied on a consistent basis.
– Non-adapted
 Has not had atrazine applied to the soil.
Nitrogen rich soils

Nitrogen rich soils contain nitrogen
molecules that are easier for the microbial
to break down.
– So Atrazine will be less likely attacked.
– If nitrogen is deficient, then Atrazine would be
a source of nitrogen for the microbial.
Movement through the soil

Clay and silty soil
– Movement is limited to soil layers of minimal
depth.
Sandy soil movement reaches depths greater than
clay and silty soil.
Atrazine in the air

Highest Concentration is in Summer,
Lowest Concentration is in Winter

Remains in the air more in enclosed areas
Atrazine run-off to surface
water

In the spring Atrazine levels are highest.
 Most of the Atrazine in the soil eventually
runs off into surface water.
 Once in surface water it can be transported
long distances before it has time to degrade.
Atrazine’s effect on animals

Once in surface water, atrazine is in direct
contact with many species which drink or
live in the water.
 Atrazine does not bioaccumulate up the
food chain.
 The major effects of atrazine on animals
are: Endocrine/Reproductive effects and
Neurological effects
Endocrine and Reproductive
Effects

Atrazine disrupts pregnancy by inhibiting
normal ovulatory surges.
 Which include a release in luteinizing
hormone (LH), Prolactin (PRL) and
testosterone (in males).
 Also atrazine has been known to cause
detoxification problems.
Nerveous system problems

Atrazine effects the Purkije cells of the
nerveous system.
 Cellular activity is lowered by 50% in 60
minutes.
 The exact mechanism of this is unknown.
 Atrazine causes motor disorders in animals.
Human Exposure
 2-3
million people are exposed
 0.2
ppb exposed to in drinking water
 Minimal
amounts from food
Chemical Affects

Atrazine has aromatic activities
Estrogen levels reduce

Underlying reason for hormonal
disruption and tumor promoting
properties
The Future
 Womb
Exposure
– Suffer permanent brain defects
 Breast
Feeding Exposure
Children
 Sonora,
Mexico
 Compared preschoolers that were
exposed to Atrazine to the students
that were not.
 Differences is:
– Hand-eye coordination
– Metal and Physical skills
Long Term Exposure
 Increase
Risk of Ovarian Cancer
 Increase Risk of Breast Cancer
 Increase Infertility
 Increase Reproductive Disorder
Modeling with Stella

Model Logic
 Method to find Atrazine sink
 Predict environmental degradation
 Compare soil, Air, Water degradation
 Interpretation of Stella
Graph 1
Model
Table 1
Degradation Rate
Aplication Rate
Degredation in Soil
Volatization
Atr in Soil
App Rate
Ev aporization
Microbial Degradation
half lif e oxidation
Atr inOxidation
Air
Rained out into Soil
Half Lif e in soil
Atrazine Air Degradation
half lif e Photodegradation
Rained Out into Water Source
Landmass ratio
Condensation Rate
Half Lif e Aquatic degraqdation
Atr in Water
Erosion
Runof f
Aquatic Degradation
Ev aporation Rate
Ingestion Rate
Sedimentation
Ingestion
DegradationExcrtetion Rate
Sedimentation Half Lif e
Atr in Humans
Atrazine and
Deriv ativ es excreted
Atrazine In Soil

Outflows
– Biological Degradation, Half-life 42.5 days
– Erosion, 55% immediately lost
– Evaporation, Half-life 97 days

Inflows
– Application of 34 million kg
– Condensation from Air
Atrazine In Air

Inflows
– Evaporation, Half Life 97 days
– initial applicationspraying

Outflows
– Oxidation, Half life 0.11 Days
– Photodegradation, Half life 0.796 days
– Condensation
– Take into account 30% of Earth land
Atrazine In Water

Inflows
– Erosion, 55%
– Condensation, F(x) of Air

Outflows
– Sedimentation, Half life 14 days
– Aquatic Degradation, Half life 3.2 days
– Ingestion
Atrazine Movement
1: Atr in Soil
2: Atr in Air
1:
2:
3:
1.387e+013
4.624e+013
2e+013.
1:
2:
3:
6.93502e+012
2.312e+013
1e+013.
3: Atr in Water
3
2
3
1
3
1:
2:
3:
34000000
1
0
1
1990.00
Page 1
3
1992.50
2
1
1995.00
Y ears
Untitled
2
1
1997.50
2
2000.00
4:49 PM Wed, Feb 27, 2002
Water as the Sink

Air is not:Degradation less than 1 day
 Soil, initially a sink, long run NO
 The Data suggest that water is the sink
– the sink is draining, does not acumulate
– Warning: decrease with one application after
years steady increase
Degradation Routes

1: Atr in Soil
2: Atr in Air
1:
2:
3:
1.387e+013
4.624e+013
2e+013.
1:
2:
3:
6.93502e+012
2.312e+013
1e+013.
Air initial spike
degrades quickly
 Water Spikes later and
degrades slower
 Soil initial spike but
degrades out
3: Atr in Water
3
2
3
1
3
1:
2:
3:
34000000
1
0
1
1990.00
Page 1
3
1992.50
2
1
1995.00
Y ears
Untitled
2
1
1997.50
2
2000.00
4:49 PM Wed, Feb 27, 2002
Future Projection

1: Atr in Air
2: Atr in Soil
1:
2:
3:
4.624e+013
1.387e+013
2e+013.
1:
2:
3:
2.312e+013
6.93502e+012
1e+013.
3: Atr in Water
3
1
3
1:
2:
3:
Page 1
17
34000000
0
2
1990.00
1
1997.50
1
2
2005.00
Y ears
Untitled
2
3
1
2012.50
2
3
2020.00
Projected to 2020
 It can be seen that it
would take until 2012
or 22 years to be
nearly rid of Atrazine
 Indicates steadily
rising levels of ATR
over time with yearly
application
6:49 PM Wed, Feb 27, 2002
Demonstration

Atrazine Movement
Through the
Environment
– Begins with
application, mainly
crops
Stella Agreement

Stella agrees with the literature in that
atrazine does not persist relatively long in
the environment
 Stella is also in agreement in terms of water
being the final sink.
Demonstration

It then works its way to the water supply, by
runoff and other mechaisms
 then it follows tributaries and streams
 Ends up in Large rivers, Lakes and Oceans
Conclusions

Banning atrazine would decrease the
environmental problem but could increase health
and environmental risks.
 Corn and Sorghum crop yields would be reduced.
 The banning would increase the use of atrazine
alternatives, which are less well understood.
 A better plan might be to find alternative methods
of crop management in order to get the best yeilds
with the smallest amount of pesticides.
THANK YOU