Neurological and Long-Term Effects of Pesticides Exposure
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Neurotox – Pesticides – 9/8/05 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. 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. - PowerPoint PPT Presentation
Transcript of Neurological and Long-Term Effects of Pesticides Exposure
Neurotox – Pesticides – 9/8/05
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, 2005Spokane, WA
Steven G. Gilbert, PhD, DABTwww.asmalldoseof.org
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Definition - Simple
The function of a pesticide is to kill or
harm some form of life.
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Definition - EPA
“…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)
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Definition - FIFRA
“… 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)
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Pesticide Application
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Key Words
Risk =
Hazard X Exposure
Dose / Response
Individual Sensitivity
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
What Is This Pesticide?
N
NN
N
CH3
CH3
CH3
O
O
1
3
7
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
N
CH3N
What Is This Pesticide?
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Effects of Amount on Response
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Effects of Size on Response
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Insecticides
Insecticides (kill insects)• Organochlorines• Organophosphates• Carbamates• Synthetic Pyrethroids
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Dose / Response
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
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Organochlorines
ExamplesDDT, methoxychlor, aldrin, dieldrin, endrin,
heptachlor, kepone, lindane, chlordane, endosulfan
ToxicityAcute toxicity variable, CNS – convulsions,
coma
Environmental characteristicsHighly persistent in environment, fat
soluble, bioaccumulation, biomagnification
Mostly banned in US and Europe
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Organophosphates-1
ExamplesMalathion, parathion, guthion, diazinon,
Chlorpyrifos (Lorsban) TPN, TOCP, nerve gases – tabun, sarin, soman, VX
ToxicityAcute toxicity highly variable – Parathion, TPN,
sarin very toxic, malathion much less
Environmental characteristicsRapidly degrade in outdoor environment (last
longer in doors), do not bioaccumulate
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Chlorpyrifos (Lorsban)
Organophosphorus Insecticide
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Organophosphates-2
Mechanism of toxicityInhibition of acetylcholinesterase (AchE) in
nerve tissue
SymptomsOver-stimulation of parasympathetic nervous
system --- salivation, constricted pupils, diarrhea, sweating, muscle twitching, CNS disturbances – coma and death
TreatmentReverse AchE inhibition effects – use
Atropine to block Ach receptors or AchE inhibiton with 2-PAM
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Organophosphates-3
Other Toxic Effects• Delayed peripheral neuropathy (TOCP)• Generally not carcinogenic• Long term neurological consequences
from repeated exposures
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Mechanism of Action
Oganochlorines & Pyrethroids - Enzymes, axonal membranes (Na+, K+, Ca++, Cl-)
Organophosphates & Carbamates - excess acetylcholine
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Neurotoxicological and Statistical Analyses of a Mixture of Five Organophosphorus Pesticides Using a Ray DesignV. C. Moser, M. Casey, A. Hamm, W. H.
Carter, Jr., J. E. Simmons, and C. Gennings
TOXICOLOGICAL SCIENCES 86(1), 101–115 (2005)
Multiple Exposures
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Epigenetic Transgenerational Actions of Endocrine Disruptors and Male FertilityMatthew D. Anway, Andrea S. Cupp,*
Mehmet Uzumcu,.Michael K. Skinner
SCIENCE 3 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.”
Multiple Generational Effects
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Worker Exposure Issues
• Cholinesterase Levels – depressed by CPF and other
organophosphate/carbamate pesticides
• Monitoring indicates that works have depressed cholinesterase levels
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
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
Health & Pesticide - Summary
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
A Small Dose of ™ Pesticide
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
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/
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
Authorship Information
For Additional Information ContactSteven G. Gilbert, PhD, DABT
E-mail: [email protected]: www.asmalldoseof.org
This presentation is supplement to “A Small Dose of Toxicology”
A Small Dose of Toxicology Neurotox – Pesticides – 9/8/05
• 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
Integrated Pest Management (IPM)
