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Neurological and Long-Term Effects of Pesticides Exposure

Neurological and Long-Term Effects of Pesticides Exposure. A Small Dose of Pesticide. “Out of Harm’s Way: Preventing Toxic Threats to our Children’s Health” October 15, 2005 Spokane, WA. Steven G. Gilbert, PhD, DABT www.asmalldoseof.org.

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Neurological and Long-Term Effects of Pesticides Exposure

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  1. Neurological and Long-Term Effects of Pesticides Exposure A Small Dose of Pesticide “Out of Harm’s Way: Preventing Toxic Threats to our Children’s Health” October 15, 2005 Spokane, WA Steven G. Gilbert, PhD, DABT www.asmalldoseof.org

  2. The function of a pesticide is to kill or harm some form of life. Definition - Simple

  3. “…a pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.” “…a pest is any harmful, destructive, or troublesome animal, plant or microorganism.” US Environmental Protection Agency (EPA) Definition - EPA

  4. “… any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any insects, rodents, nematodes, fungi, or weeds or any other form of life declared to be pests. … and any substance or mixture of substances intended for use as a plant regulator, defoliant or desiccant.” Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA – 1947) Definition - FIFRA

  5. Pesticide Application

  6. Risk = Hazard X Exposure Key Words Dose / Response Individual Sensitivity

  7. What Is This Pesticide? O CH3 CH3 N N 7 1 3 O N N CH3

  8. What Is This Pesticide? CH3 N N

  9. Effects of Amount on Response

  10. Effects of Size on Response

  11. Insecticides (kill insects) Organochlorines Organophosphates Carbamates Synthetic Pyrethroids Insecticides

  12. 10 mg/kg is lethal Adult 70 kg (150 lbs) 700 mg Child 10 kg (22 lbs) 100 mg Insect 1 mg 0.00001 mg Example – killing fleas on pets Dose / Response

  13. Examples DDT, methoxychlor, aldrin, dieldrin, endrin, heptachlor, kepone, lindane, chlordane, endosulfan Toxicity Acute toxicity variable, CNS – convulsions, coma Environmental characteristics Highly persistent in environment, fat soluble, bioaccumulation, biomagnification Mostly banned in US and Europe Organochlorines

  14. Examples Malathion, parathion, guthion, diazinon, Chlorpyrifos (Lorsban) TPN, TOCP, nerve gases – tabun, sarin, soman, VX Toxicity Acute toxicity highly variable – Parathion, TPN, sarin very toxic, malathion much less Environmental characteristics Rapidly degrade in outdoor environment (last longer in doors), do not bioaccumulate Organophosphates-1

  15. Chlorpyrifos (Lorsban) Organophosphorus Insecticide

  16. Mechanism of toxicity Inhibition of acetylcholinesterase (AchE) in nerve tissue Symptoms Over-stimulation of parasympathetic nervous system --- salivation, constricted pupils, diarrhea, sweating, muscle twitching, CNS disturbances – coma and death Treatment Reverse AchE inhibition effects – use Atropine to block Ach receptors or AchE inhibiton with 2-PAM Organophosphates-2

  17. Other Toxic Effects Delayed peripheral neuropathy (TOCP) Generally not carcinogenic Long term neurological consequences from repeated exposures Organophosphates-3

  18. Mechanism of Action Oganochlorines & Pyrethroids - Enzymes, axonal membranes (Na+, K+, Ca++, Cl-) Organophosphates & Carbamates - excess acetylcholine

  19. Multiple Exposures • Neurotoxicological and Statistical Analyses of a Mixture of Five Organophosphorus Pesticides Using a Ray Design V. C. Moser, M. Casey, A. Hamm, W. H. Carter, Jr., J. E. Simmons, and C. Gennings TOXICOLOGICAL SCIENCES 86(1), 101–115 (2005)

  20. Multiple Generational Effects • Epigenetic Transgenerational Actions of Endocrine Disruptors and Male Fertility Matthew D. Anway, Andrea S. Cupp,* Mehmet Uzumcu,.Michael K. Skinner SCIENCE3 JUNE 2005 VOL 308 “The ability of an environmental factor (for example, endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and disease etiology.”

  21. Worker Exposure Issues • Cholinesterase Levels – • depressed by CPF and other organophosphate/carbamate pesticides • Monitoring indicates that works have depressed cholinesterase levels

  22. Health & Pesticide - Summary • Acute effects are major concern for pesticides used widely in WA agriculture • Chronic effects of concern, too. • Children of workers as well as workers are exposed and are at greater risk. • Multiple exposures are occurring, potentially increasing risks. • There may be multiple generation effects. • Precaution is a prudent approach

  23. A Small Dose of ™ Pesticide

  24. Additional Information • WSU – Washington State Pest Management Resources Service (WSPMRS) • - http://wsprs.wsu.edu/ • UW – Welcome to the Pacific Northwest Agricultural Safety and Health Center (PNASH) - http://depts.washington.edu/pnash/ • Pesticide ActionNetwork North America - http://www.panna.org • Washington Toxics Coalition - http://www.watoxics.org • Pesticide Database site - http://www.pesticideinfo.org/ • US EPA Office of Pesticides - http://www.epa.gov/pesticides/ • USGS - NAWQA Pesticide National Synthesis Project - http://water.wr.usgs.gov/pnsp/ • University of Illinois – Pesticide Impact Assessment - http://ext.agn.uiuc.edu/piap/

  25. Authorship Information This presentation is supplement to “A Small Dose of Toxicology” For Additional Information Contact Steven G. Gilbert, PhD, DABT E-mail: smdose@asmalldoseof.org Web: www.asmalldoseof.org

  26. Integrated Pest Management (IPM) • Focus – long-term prevention of pest problems • Reduce or eliminate chemical pest control methods • Monitor for the presence of pests before treating • Nonchemical strategies (make habitat less attractive, physical controls) • Learn about your pests

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