Pesticide Basics
Uses, Exposures, Types and Acute Effects
Did you know?
 5 million at risk population (U.S. EPA, 1992)
 250-500 physician-diagnosed cases occur per 100,000 agricultural
workers (Blondell, 1997).
 Migrant and seasonal farmworkers are especially at high risk
 84% of American households used pesticides, most commonly
insecticides (Whitmore et al, 1992)
 Homeowners use 5-10 lbs/acre/yr on their lawns and gardens,
many x greater than farmers apply to corn and soybean fields
(Robinson et al, 1994).
Did you know?
 Non -agricultural pesticide exposure as disinfectants
widespread: (e.g., pine oil cleaners, bathroom cleaning
products, and cleaning materials for swimming pools).
 Non-Ag Sector a concern = pest control, nurseries,
greenhouses, and landscaping.
 The medical profession uses disinfectants to sanitize and
sterilize surfaces and instruments.
 Organophosphate and pyrethroid insecticides most
implicated for poisonings.
 Water chlorination is one of the largest (by tonnage) uses of
pesticides.
Where Are Pesticides Used?
 Forests to control insects and under-story
vegetation;
 Landscapes, parks, and recreational areas to
control weeds, insects, and disease pests;
 Rights-of-way along railroads and under
electric wires to control vegetation;
 Houses, schools, and commercial and office
buildings to control insects, rodents, and fungi;
 Boat hulls to control fouling organisms;
Where Are Pesticides Used?
 Aquatic sites to control mosquitoes and weeds
 Wood products to control wood-destroying organisms
 Food preparation areas to control insects and rodents
 Human skin to kill or repel insects
 Household pets to control fleas and ticks
 Livestock to control insects and other pests.
Non Occupational Pesticide
Encounters
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Accidental or intentional ingestion
Food and water residues
Contaminated clothing
Treated wood/structures
Residues on animals/carpets
Garden residues
Termite control
Hazardous waste sites/spills
Agriculture Pesticide Applications
Boom sprayer
Aerial
Enclosed cab
Air blast sprayer
Backpack wand
Agriculture Jobs
Orchard thinner
Flagger
Mixer loader
Picker
Professions Exposed to Pesticides
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Aerial equipment maintenance
Agronomists
Building maintenance work
Emergency responders
Entomologists
Firefighters
Forestry workers
Formulating end product
Greenhouse- nursery workers
Hazardous waste workers
Landscapers
Livestock dippers and
veterinarians
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Marina workers
Medical personnel
Park workers
Plant pathologists
Research chemistry
Sewer work
Storage/warehouse work
Structural application
Transporting pesticides
Treating contaminated workers
Vector control workers
Wood treatment workers
Work on highway or railroad
rights of way
Key Household Safety Points
“ Partly Trained Gorillas Always Run Down Streets Doing Cartwheels”
1.
2.
3.
4.
5.
6.
7.
8.
9.
Proximity
Take home
Garden
Animals
Recycle
Decant
Storage
Disposal
Child play/daycare
ROUTES OF EXPOSURE
OP’s are readily absorbed:
Across the SKIN with skin contact
In the lungs with INHALATION
of pesticide contaminated air/dust
In the gut by INGESTION of
pesticide residue on food/dirt/dust
Source: EPA Protect Yourself from Pesticides-Guide of Agricultural Workers
Risk Factors for Occupational
Pesticide Exposures
 Concentration of commercial
preparations > than diluted final
product = greater risk
 AG workers highest exposure risk in
mixing, loading, applying, and flagging.
Source: H Murphy - Cambodia
Occupational Risk Factors
• Pregnant Women: 1st trimester
• Field workers entering sprayed field before re-entry interval
[REI]
• Residuals on skin and clothes
– How to remove PPE
– How to clean PPE
– Showering after use
Evidence?
Agriculture Risk Factors
• Indonesia:
–
–
–
–
Cocktail mixture of multiple products
Spray frequency
Skin contact > wet clothing
Use of toxic products (1a/Ib, II)
Source: H Murphy - Indonesia
• Washington state:
–
–
–
–
–
Protective: Chemically resistant boots
Protective: Full face respirators
Risk: Mixing and loading pesticides
Risk: Cleaning equipment
Protective: Using a workplace locker for PPE
Preventing Pesticide Illness
Primary
Non-chemical Alternatives
Secondary
Engineering Controls
Tertiary
It’s the
law
Personal
Protective Equipment
[PPE]
Risk factors for pesticide
exposures at home
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•
•
•
•
•
Migrant families > risk
Children’s vulnerability
Location near fields
Take home pathway
Pesticide storage and use in homes
Multiple chemical sensitivities (MCS)
Migrant Families
• Living conditions: quality
and location
• Communication: language
and literacy
• Immigration status
• Access to health care
• Diet
Unintentional (Accidental)
• GI absorption from accidental ingestion = acute
poisonings
• Respiratory and dermal absorption from
surrounding environment
• Hand to mouth activity in children
Occupational
• Dermal is most important
• Inhalation is a common
pathway
• Ingestion less common but
can occur if not use gloves or
poor hygiene
Intentional
(Suicide/Homicide/Abuse)
• Ingestion is primary
pathway
• Inhalation is another
pathway, although
primary agents of abuse
in this manner are nonpesticide chemicals
(aromatic solvents).
Agricultural vs. Non-Agricultural
Cases of Poisonings
120
113
100
111
99
90
72
80
cases
68
62
75
73
60
58
40
20
0
Non Agricultural
1999
2000
Agricultural
2001
2002
2003
Source: 2004 Pesticide Incident Reporting and Tracking (PIRT) Annual Report
Occupational versus Non-Occupational
Cases of Pesticide Poisoning
NonOccupational
48%
Source: 2004 Pesticide Incident Reporting and Tracking (PIRT) Annual Report
Occupational
52%
Proportion of Poisonings
Ranked 8th Cause of Poisonings = 102,754 cases in 2005 (4.2%)
Children
Adults
Source: Watson WA. 2004 Annual Report of the American Association of Poison Control Centers Toxic
Exposure Surveillance System
US: Intentional vs. Accidental
Accidental
84%
Suicide
8%
6 suicide attempts
used pesticides out
of 196,164
WHO Sentinel Surveillance
Country
Time period
Reporting sites
Cases
Circumstances identified
Intentional
Accidental
Occupational
INDIA
12 mo
10
1531
95%
89%
5%
6%
NEPAL INDONESIA THAILAND MYANMAR PHILIPPINES
10 mo
12 mo
6 mo
6 mo
6 mo
38
8
9
8
5
327
208
130
126
256
99%
94%
98%
96%
93%
87%
86%
62%
43%
92%
8%
8%
8%
16%
1%
4%
0%
28%
37%
0%
Pesticide
‘cide = to kill
Fumigants
Insecticides
Types of
Pesticides
Herbicides
Fungicides
Disinfectants
Rodenticides
Pesticide Chemical Families
-grouping based on similarities1.
2.
3.
Similar chemically (similar structure)
Attacks pests in a similar way (toxicity)
Common treatment + antidote
Organophosphate
OP
Organochlorine
OC
Carbamate
C
Chlorophenoxy
Pyrethroid
PY
Paraquat
Diquat
Pesticide Sample Label
 Type of pesticide (used for?)
 Company name
 Brand name
 Common/generic name (active ingredient)
 Chemical family (? atropine under 1st aid)
 Signal word (hazard level)
Pesticide Classification Table
#
Type
1. Insecticide
Company
Name
Gowen
Brand
Name
Common
Name
Supracide
methidathion
Chemical
Family
OP
(Organophosphate)
Signal
Class
DangerPoison
Ib
Exercise: Classifying Pesticides
Pesticide Labels
COMPANY
BRAND
COMMON
TYPE
FAMILY
SIGNAL
Who
1.
Bayer
Temik
Aldicarb
Insecticide
Carbamate
Danger-poison
la
2.
Verdicon
Sevin
Carbaryl
Insecticide
Carbamate
Caution
ll
3.
UCP Alliance
Thiodan
Endosulfan
Insecticide
Organochlorine
Warning
ll
4.
Bayer
Guthion
Azinophos methyl
Insecticide
Organophospate
Danger-poison
lb
5.
Dow
Dursban
Chlorpyrifos
Insecticide
Organophospate
Warning
ll
6.
Syngenta
Gramoxone
Paraquat
Herbicide
Paraquat
Danger-poison
ll
7.
Helena
Weed Rhap
2, 4-D
Herbicide
Chlorophenoxy
Danger-poison
ll
8.
DuPont
Asana
Esfenverlate
Insecticide
Pyrethroid
Warning
lV
9.
Bayer
Captan
Captan
Fungicide
Danger-poison
II
10.
Max
Roundup
Glyphosate
Herbicide
Caution
U-IV
11.
Dow
Dithane
Mancozeb
Fungicide
Caution
U-IV
Ziram
Fungicide
Danger
III
12.
Cerexagri-Nisso
Ziram
How toxic is it?
Source: Richards, Kerry Penn State University Extension Service
Source: Richards, Kerry Penn State University Extension Service
LD50
Lethal dose = Amount of
chemical it takes to kill 50% of an
experimental population
Source: Richards, Kerry Penn State University Extension Service
*
*
DANGER/POISON = extremely toxic by ingestion
DANGER = extremely toxic high potential for skin and eye irritation
Adapted from Richards, Kerry Penn State University Extension Service
Source: Richards, Kerry Penn State University Extension Service
Insecticides
• ChE Inhibitors:
– Organophosphates
– n-methyl carbamates
• Pyrethroids
– Pyrethrins (ocloresin extract of chrysanthemum)
– Pyrethroids (the synthetic derivative)
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Organochlorines (e.g. DDT)
DEET
Boric Acid
Fluorides
Nicotine
Arsenicals
Herbicides
• Chlorophenoxy herbicides (e.g. 2-4D)
• Paraquat and diquat
• Pentachlorophenol and dinitrocresol
(wood preservatives)
• Copper chromium arsenate ( decks, fences,
and children’s wood playground sets – d/c
2003)
Fungicides
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Hexachlorobenzene
Thiram
Maneb
Methylmercury compounds
Fumigants
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Cyanide
1, 3-dichloropropane
Metam sodium
Methyl bromide
Naphthalene
Phosphine gas (from
aluminum phosphide)
Rodenticides
• Warfarin-related
compounds:
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–
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Warfarin
Coumarins
Brodifacoum
Difenacoum (so-called
“super warfarins”)
• Others:
– Thallium
– Zinc phosphide
– Sodium fluoroacetate
Disinfectants
• Agents used for sanitization and sterilization in the
home and hospital
• Registered as pesticides by the U.S. EPA
• Examples include
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Alcohols
Chlorhexidine
Hypochlorites
Iodines
Phenols
Pine oil
Organophosphates: 30”-240 & Carbamates: 15”-30
General central nervous system
• Fatigue
• Dizziness
• Headache
• Tremors
• Ataxia
• Convulsions (uncommon w/carbamate)
• LOC (uncommon w/carbamate)
• Coma (uncommon w/carbamate)
From muscle over stimulation:
• Muscle weakness
• Muscle cramps
• Muscle fasciculations
From gland over stimulation:
• Salivary gland- excessive salivation
• Sweat gland- excessive sweating
• Lachrymal gland-excessive eye tearing
From organ over-stimulation:
• Eyes
• Gastrointestinal
• Pulmonary
•Blurred vision (constricted pupils)
• Stomach cramps
• Nausea
• Vomiting
• Diarrhea
• Chest tightness
• Wheezing
• Cough
• Runny nose
Pyrethroids
Pyrethroids: are irritants to the eyes, skin and respiratory tract. The
symptoms last from 1-2 hours. Systemic toxicity from inhalation or dermal
absorption is low.
Normal use:
*
*
*
*
Paresthesias (cyno pyrethroids)
Shortness of breath (wheezing)
Mucous membrane irritation (throat nose)
Skin itching
If ingested:
•
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Loss of consciousness/coma
Seizures (cyno-pyrethroids)
High doses:
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Vomiting
Diarrhea
Excessive saliva
Muscle fasciculation
Ataxia
•
Irritability: to sound ~ touch
Cyno-pyrethroids: fenverlate, flucythrinate, fluvalinate cypermethrine, deltapermethrin,
Organochlorines: 10 - 480
lipophylic
The nerves stimulating glands
are not affected so you will
NOT see:
• excessive salivation
• excessive sweating
• excessive eye tearing
(or over-stimulation of small
muscles like)
• twitching eyelids
CNS Effects
• Muscle Weakness
• Dizziness
• Headache
• Numbness
• Nausea/vomiting
• LOC
• Seizures
• Tremors
•
Ataxia
• Anxiety/restlessness
• Confusion
Paraquat
Paraquat is very toxic to the skin and mucous membranes. Particles are too large
to get deep into the lungs*, but once in the blood it collects in the lungs. If ingested
high case fatality rate.
•
Skin:
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dryness, cracks
erythema
blistering
ulcerations
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Nails:
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discoloration
splitting nails
loss of nails
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Respiratory tract:
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cough
nosebleeds
sore throat
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Eyes:
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conjunctivitis
ulceration, scarring, blindness
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Ingestion:
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lung fibrosis (stiff lungs)
multi-system organ failure,
specifically
respiratory failure
kidney failure
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•
DEET
DIETHYLTOLUAMIDE
• Few toxic cases - given the widespread use
• Toxic if ingested
• Children: toxic encephalopathy w/ heavy use on large
surface area on kids (+ ETOH - isopropyl or ethyl)
• Dermal problems: tingling, irritation, desquamination,
contact dermatitis, exacerbate pre-existing skin dz
• Kids: use 5-6.5% formulations
Boric Acid
Ants, Cockroaches in Residences
“broiled lobster appearance”
Boric Acid
Respiratory tract irritant
Moderate skin irritant
Historic antibacterial: poisonings from burn
compresses, diaper powder, irrigation solutions
 Targets:
GI tract, skin, vasculature, brain
 Chronic ingestion more toxic than acute (13 ½ life)
 Absorption: via gut and abraded skin
Fluorides
• Transformed in stomach to corrosive hydrofluoric
acid:  thirst, nausea-vomiting,
diarrhea, abdominal pain
• Fluoride ion reduces extra-cellular fluid
concentrations of Ca+ and Mg  hypocalcemic
tetany
• Cardiac arrythmias- shock  2ndary to fluid/electrolyte
imbalances, hypokalemia and the fluoride itself
• CNS  H.A. muscle weakness, stupor, seizures and coma
Focus on OP’s
 Children at risk for neurodevelopmental problems
 Most commonly used insecticide in agriculture
 Common cause of poisoning
Normal Electrical Nerve Impulse Transmission
nerve cell
After electrical nerve
impulse transmission is
completed, the body
produces
cholinesterase.
Electrical nerve impulse
coming from nerve cell
stimulates the body to
produce acetylcholine.
Cholinesterase breaks
up acetylcholine into
acetate and choline.
Acetylcholine acts as a
bridge transmitting the
electrical charge to the
muscle cell.
acetate
choline
Muscles and glands
contract.
Once acetylcholine is
broken, it can no
longer transmit
electrical nerve
impulses.
Electrical nerve
impulses stop and the
muscles and glands
are quiet
muscle cell
Organophosphate-Carbamate Disruption of Electrical Nerve Impulse
Transmission Therapeutic Effect of Atropine
nerve cell
If an organophosphate (Op)
or carbamate is present,
they bind with
cholinesterase. [This is an
irreversible effect with an
Op but not with a
carbamate]
Atropine relieves the over
stimulation of the muscles
and glands by reducing the
amounts of acetylcholine.
The effect only lasts 15
minutes. Therefore the
dose must be repeated
until the organophosphate
binding effect has worn off.
The bound cholinesterase
cannot penetrate
acetylcholine to break it up.
The body continues to
produce acetylcholine
unimpeded.
Electrical nerve
impulse
acetate
This results in a build up of
acetylcholine with
continuous electrical nerve
impulse transmission and
over stimulation of muscle
and glands.
choline
cholinesterase
organophosphate
atropine
muscle cell
Signs and Symptoms in Adults
Exercise: Body Mapping
Eye
• Miosis
• Blurring
CNS
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Fatigue
Dizziness
Headache
Tremors
Ataxia
Seizures
LOC
Coma
Insomnia
Mental Δ
Lungs
Tightness
Wheezing
Cough
Rhinorrhea
GI
Abd. cramps
Nausea
Vomiting
Diarrhea
Glands
Drooling
Muscle
Heart
Weakness Cramps Tachy
Fasciculations
Sweating
Brady
Tearing
 BP
↓ BP
Signs of Pesticide Poisoning in Children
Lethargic
sleepy
Seizures
Coma
Can be confused with the flu