Presentation on theme: "The Effects of Atrazine Application to the Environment. By: Perry Loken, Tim Weisbrod, Nick Taylor, Sara Schmidt."— Presentation transcript:
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 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
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 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
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 Air initial spike degrades quickly Water Spikes later and degrades slower Soil initial spike but degrades out
Future Projection 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
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.