pesticide basics uses, exposures, types and acute effects
TRANSCRIPT
Pesticide BasicsUses, 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
• 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
Aerial
Air blast sprayer
Enclosed cab
Backpack wand
Boom sprayer
Agriculture Jobs
Orchard thinner
Mixer loader
Flagger Picker
Professions Exposed to Pesticides
• Aerial equipment Aerial equipment maintenancemaintenance
• AgronomistsAgronomists• Building Building maintenance workmaintenance work• Emergency respondersEmergency responders• EntomologistsEntomologists• FirefightersFirefighters• ForestryForestry workers workers• Formulating end productFormulating end product• Greenhouse- nursery Greenhouse- nursery
workersworkers• Hazardous Hazardous waste waste workersworkers• LandscapersLandscapers• Livestock dippers and Livestock dippers and
veterinariansveterinarians
• Marina Marina workersworkers• Medical Medical personnelpersonnel• ParkPark workers workers• Plant pathologistsPlant pathologists• Research Research chemistrychemistry• SewerSewer work work• Storage/warehouse workStorage/warehouse work• Structural applicationStructural application• Transporting pesticidesTransporting pesticides• Treating Treating contaminated contaminated
workersworkers• Vector control workersVector control workers• Wood treatment workersWood treatment workers• Work on Work on highway highway or or
railroad rights of wayrailroad rights of way
Key Household Safety Points
1. Proximity2. Take home3. Garden4. Animals5. Recycle6. Decant7. Storage8. Disposal9. Child
play/daycare
“ Partly Trained Gorillas Always Run Down Streets Doing Cartwheels”
ROUTES OF EXPOSURE
Source: EPA Protect Yourself from Pesticides-Guide of Agricultural Workers
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
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)
• 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
Source: H Murphy - Indonesia
Preventing Pesticide Illness
Non-chemical Alternatives
Engineering Controls
Personal Protective Equipment
[PPE]
Primary
Secondary
Tertiary
It’s the law
Risk factors for pesticide exposures
at home
• 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 non-pesticide chemicals (aromatic solvents).
Agricultural vs. Non-Agricultural Cases of
Poisonings
Source: 2004 Pesticide Incident Reporting and Tracking (PIRT) Annual Report
19992000
20012002
2003
Agricultural
Non Agricultural
72
90
62
99
111
68
113
58
75
73
0
20
40
60
80
100
120
case
s
Occupational versus Non-Occupational Cases of
Pesticide Poisoning
Occupational
52%
Non-
Occupational
48%
Source: 2004 Pesticide Incident Reporting and Tracking (PIRT) Annual Report
Proportion of PoisoningsRanked 8th Cause of Poisonings = 102,754 cases in 2005 (4.2%)
Source: Watson WA. 2004 Annual Report of the American Association of Poison Control Centers Toxic Exposure Surveillance System
Children Adults
US: Intentional vs. Accidental
6 suicide attempts used pesticides out of 196,164
8%
84%Accidental
Suicide
WHO Sentinel Surveillance
Country INDIA NEPAL INDONESIA THAILAND MYANMAR PHILIPPINESTime period 12 mo 6 mo 6 mo 6 mo 12 mo 10 moReporting sites 10 5 8 9 8 38Cases 1531 256 126 130 208 327Circumstances identified 95% 93% 96% 98% 94% 99%Intentional 89% 92% 43% 62% 86% 87%Accidental 5% 1% 16% 8% 8% 8%Occupational 6% 0% 37% 28% 0% 4%
Pesticide
Types of Pesticides
Insecticides Herbicides Fungicides Rodenticides
‘cide = to kill
DisinfectantsFumigants
Pesticide Chemical Families
-grouping based on similarities-
1. Similar chemically (similar structure)2. Attacks pests in a similar way (toxicity)3. Common treatment + antidote
OrganophosphateOP
CarbamateC
PyrethroidPY
OrganochlorineOC
Chlorophenoxy Paraquat
Diquat
Pesticide Sample Label
Type of pesticide (used for?)Company nameBrand nameCommon/generic name (active ingredient)Chemical family (? atropine under 1st aid)Signal word (hazard level)
Pesticide Classification Table
# Type Company
Name
BrandName
CommonName
Chemical Family
SignalClass
1.
Insecticide
Gowen Supracide
methidathion
OP(Organophospha
te)
Danger-PoisonIb
COMPANY BRAND COMMON TYPE FAMILY SIGNAL Who
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Pesticide Labels
Bayer Temik Aldicarb Insecticide Carbamate Danger-poison la
Verdicon Sevin Carbaryl Insecticide Carbamate Caution ll
UCP Alliance Thiodan Endosulfan Insecticide Organochlorine Warning ll
Bayer Guthion Azinophos methyl Insecticide Organophospate Danger-poison lb
Dow Dursban Chlorpyrifos Insecticide Warning ll
Syngenta Gramoxone Paraquat Herbicide Paraquat Danger-poison ll
Helena Weed Rhap 2, 4-D Herbicide Chlorophenoxy Danger-poison ll
DuPont Asana Esfenverlate Insecticide Pyrethroid Warning lV
Bayer Captan Captan Fungicide Danger-poison
Max Roundup Glyphosate Herbicide Caution U-IV
II
Dow Dithane Mancozeb Fungicide Caution U-IV
Cerexagri-Nisso Ziram Ziram Fungicide Danger III
Exercise: Classifying Pesticides
Organophospate
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
Adapted from Richards, Kerry Penn State University Extension Service
DANGER/POISON = extremely toxic by ingestion DANGER = extremely toxic high potential for skin and eye irritation
*
*
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)
• 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
• Hexachlorobenzene• Thiram • Maneb• Methylmercury compounds
Fumigants
• Cyanide • 1, 3-dichloropropane• Metam sodium• Methyl bromide• Naphthalene• Phosphine gas (from
aluminum phosphide)
Rodenticides
• Warfarin-related compounds: – 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
– Alcohols – Chlorhexidine – Hypochlorites – Iodines – Phenols – Pine oil
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
Organophosphates: 30”-240 & Carbamates: 15”-30
PyrethroidsPyrethroids: 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: • Loss of consciousness/coma • Seizures (cyno-pyrethroids)
High doses: • 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
ParaquatParaquat 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: • dryness, cracks• erythema • blistering• ulcerations
• Nails: • discoloration• splitting nails• loss of nails
• Respiratory tract: • cough• nosebleeds• sore throat
• Eyes: • conjunctivitis • ulceration, scarring, blindness
• Ingestion: • lung fibrosis (stiff lungs)• multi-system organ failure,
specifically • respiratory failure• kidney failure
DEETDIETHYLTOLUAMIDE
• 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 AcidAnts, 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
muscle cell
Once acetylcholine is broken, it can no longer transmit electrical nerve impulses.
Electrical nerve impulses stop and the muscles and glands are quiet
Electrical nerve impulse coming from nerve cell stimulates the body to produce acetylcholine.
Acetylcholine acts as a bridge transmitting the electrical charge to the muscle cell.
Muscles and glands contract.
After electrical nerve impulse transmission is completed, the body produces cholinesterase.
Cholinesterase breaks up acetylcholine into acetate and choline.
acetate
choline
Organophosphate-Carbamate Disruption of Electrical Nerve Impulse Transmission Therapeutic Effect of Atropine
nerve cell
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.
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]
The bound cholinesterase cannot penetrate acetylcholine to break it up.
The body continues to produce acetylcholine unimpeded.
This results in a build up of acetylcholine with continuous electrical nerve impulse transmission and over stimulation of muscle and glands.
muscle cell
Electrical nerve impulse
acetate
choline
cholinesterase
organophosphate
atropine
Signs and Symptoms in Adults
• Miosis• Blurring
Eye CNS Lungs GI Glands Muscle Heart
Exercise: Body Mapping
• Fatigue• Dizziness• Headache• Tremors• Ataxia • Seizures• LOC• Coma • Insomnia• Mental Δ
TightnessWheezingCoughRhinorrhea
Abd. crampsNauseaVomitingDiarrhea
Drooling
Sweating
Tearing
Weakness CrampsFasciculations
Tachy
Brady
BP
↓ BP
Signs of Pesticide Poisoning in Children
Lethargic sleepy
Seizures
Coma
Can be confused with the flu