The Pesticide Dilemma

1. Chapter 23 The Pesticide Dilemma

2. What is a Pesticide? Pyrethrin is derived from chrysanthemum flowers. • First-Generation Pesticides • Inorganic compounds (e.g., lead, mercury) • Botanicals (e.g., nicotine, pyrethrin)

3. What is a Pesticide? • Second-Generation Pesticides • Synthetic botanicals (e.g., pyrethroids) • DDT

4. What is a Pesticide? • The Major Groups of Insecticides • Chlorinated hydrocarbons (e.g., DDT) • broad spectrum • do not degrade in the environment • Other examples: • -endosulfan • -lindane • -methoxychlor Dichlorodiphenyl-trichloroethane (DDT)

5. What is a Pesticide? • The Major Groups of Insecticides • Organophosphates (e.g., malathion) • More toxic than other pesticides • Less persistent in the environment • Other examples: • -methamidophos • -dimethoate • -malathion

6. What is a Pesticide? • The Major Groups of Insecticides • Carbamates (e.g., carbaryl) • Derived from carbamic acid • Less toxic to mammals

7. What is a Pesticide? • The Major Kinds of Herbicides • Selective herbicides • (e.g., 2,4-D – kills broad-leaved plants) 2,4,5-T

8. What is a Pesticide? • The Major Kinds of Herbicides • Nonselective herbicides • (e.g., glyphosate, aka: Round-UpTM)

9. Benefits and Problems with Pesticides Location of malaria • Benefit: Disease Control

10. Benefits and Problems with Pesticides • Benefit: Crop production • Farmers save ~$3 - $5 in crops for every $1 invested into pesticides

11. Benefits and Problems with Pesticides # of species exhibiting genetic resistance to pesticides • Problem: Evolution of Genetic Resistance

12. Benefits and Problems with Pesticides Kills most pests Resistant survive INCREASE Numbers increase EVEN MORE New population genetically resistant • Problem: Evolution of Genetic Resistance • Creates a pesticide treadmill Pesticide application

13. Benefits and Problems with Pesticides • Problem: Evolution of Genetic Resistance • Resistance Management • Create a “refuge” (no pesticide applied) • Avoid repeated use of same pesticide

14. Benefits and Problems with Pesticides • Problem: Imbalances in the Ecosystem

15. Benefits and Problems with Pesticides • Problem: Imbalances in the Ecosystem • Creation of New Pests

16. Benefits and Problems with Pesticides Biomagnification of DDT • Problem: Persistence, Bioaccumulation, and Biological Magnification

17. Benefits and Problems with Pesticides • Problem: Mobility in the Environment

18. Risks of Pesticides to Human Health • Short-term Effects of Pesticides • Handling of food with pesticide residue

19. Risks of Pesticides to Human Health • Short-term Effects of Pesticides • Case-in-Point: The Bhopal Disaster • 40 tons of methyl isocyanate gas released • 600,000 people exposed • 2,500 immediately killed • 2,500 more killed through time • 50,000-60,000 have serious health problems

20. Risks of Pesticides to Human Health • Long-term Effects of Pesticides • Potentially higher risk of cancer • Sterility • Miscarriage / birth defects • Potentially higher risk for Parkinson’s disease • Endocrine disruption

21. Alternatives to Pesticides • Using Cultivation Methods to Control Pests • Interplant mixtures of plants • Strip cutting • Planting, fertilizing, and irrigating at proper time • Crop rotation

22. Alternatives to Pesticides • Biological Controls • Using naturally occurring diseases, parasites, or predators to control a pest • Pheromones and Hormones • Use pheromones to attract insects to traps • Synthetic hormones induce abnormal development • Reproductive Controls • Sterile-male technique – inundate pest population with large numbers of sterile males

23. Alternatives to Pesticides • Genetic Controls • Using Genetically Modified plants (GMOs) • Case-in-Point: Bt, Its Potential and Problems • Genetically modified corn to produce Bt toxin • Potential problem: may affect non-target species, such as monarch butterfly • Quarantine

24. Alternatives to Pesticides • Integrated Pest Management (IPM)

25. Alternatives to Pesticides IPM introduced • Integrated Pest Management Rice Production in Indonesia

26. Alternatives to Pesticides • Irradiating Foods • used on meats, fruits, and vegetables • Kills many microorganisms

27. Laws Controlling Pesticide Use • Food, Drug, and Cosmetics Act (1938) • Pesticide Chemicals Amendment (1954) • Established unacceptable levels of pesticides in food • Delaney Clause (1958) • No suspected carcinogens in processed food • Problems with laws: • Processed vs. raw foods • Knowledge of pesticides’ toxicity • Detection limits for pesticides

28. Laws Controlling Pesticide Use • Federal Insecticide, Fungicide, and Rodenticide Act (1947) -FIFRA • Originally passed to regulate effectiveness • Amended to protect health from exposure • Banned pesticides include: DDT, aldrin, dieldrin, kepone, chlordane, heptachlor Estimates of Risk of Cancer from Pesticide Residue (1987 study)

29. Laws Controlling Pesticide Use • Food Quality Protection Act (1996) • Amended FDCA and FIFRA • Applied Delaney clause to processed and raw foods • Considered increased effects on children • Pesticide limits established considering all health risks (not just cancer) • Endocrine disrupting properties are considered • Pesticide limits established considering all exposures (including drinking water)

30. The Manufacture and Use of Banned Pesticides • Some US companies still make banned or seriously restricted pesticides and export the product. • This can potentially lead to the importation of food tainted with banned pesticides

31. The Manufacture and Use of Banned Pesticides • The Global Ban of Persistent Organic Pollutants