TRAINING FOR THE HEALTH SECTOR
[Date …Place …Event…Sponsor…Organizer]
PESTICIDES
Children's Health and the Environment
CHEST Training Package for the Health Sector
1
Pesticides and Children
LEARNING OBJECTIVES
 Learn about pesticides – what they are and what are the
risks they may pose?
 Identify the scenarios – where and when are children
exposed?
 Recognize signs, symptoms and diseases that may be
related to pesticide exposure in children
 Know how to prevent and treat children's pesticide
exposure
2
Pesticides and Children
OVERVIEW
 Origin, environmental transport and fate of pesticides
 Routes and circumstances of exposure
 Toxicokinetics and toxicodynamics
 Target organs and systems
 Diagnosis and treatment of poisoning
 Prevention of pesticide exposure and poisoning
3
Pesticides and Children
PESTICIDES – RISKS AND BENEFITS
BENEFICIAL EFFECTS
NEGATIVE EFFECTS
Toxic properties
 Crop protection
 Human
 Food preservation
 Environmental
 Material preservation
 Disease control
4
Pesticides and Children
USE OF PESTICIDES
Global Pesticide Use 1999
 First synthetic pesticides:
1940
 Consumption increasing
worldwide
herbicide
insecticide
fungicide
other
 2.6 million tons of active
ingredients used in 1999
 25% of the world production
www.epa.gov/oppbead1/pestsales/99pestsales/usage1999.html#3_1
used in developing countries...
where 99% of deaths due to
pesticides occur!
5
Pesticides and Children
USE OF PESTICIDES – TYPES OF PRODUCT
 Pesticides used in different settings: - Agricultural
- Veterinary
- Domestic
- Institutional
 Formulations:
liquid, gel, paste, powder, granules, pellets,
baits...
 Concentrations: from 2% to 80% of active ingredient
 Containers:
glass, plastic or metal flasks, bottles, drums,
plastic bags or paper bags....
6
Pesticides and Children
PESTICIDES – CLASSIFICATION BY USE
Chemicals designed to kill, reduce or repel pests: animals, plants, fungi...
Insecticides
Insect repellents
Herbicides
Fungicides
Rodenticides
Wood preservatives
Fumigants
7
Pesticides and Children
PESTICIDES – CLASSIFICATION BY USE
AND CHEMICAL STRUCTURE
Different chemicals used for different purposes
 INSECTICIDES
•
•
•
•
Pyrethroids
Organophosphorus
Carbamates
Organochlorine
 HERBICIDES
•
•
•
•
•
Bipyridyls
Chlorophenoxy
Glyphosate
Acetanilides
Triazines
 FUNGICIDES
•
•
•
•
•
•
•
•
•
 RODENTICIDES
Thiocarbamates
Dithiocarbamates
Cupric salts
Tiabendazoles

Triazoles
Dicarboximides
Dinitrophenoles
Organotin compounds
Miscellaneous
•
•
Warfarines
Indanodiones
FUMIGANTS
•
•
•
Aluminium and zinc
phosphide
Methyl bromide
Ethylene dibromide
 INSECT REPELLENTS
•
Diethyltoluamide
8
Pesticides and Children
ORIGIN, TRANSPORT AND FATE
1.
Emission
2.
Drift
3.
Deposition
4.
Sedimentation
5.
Leaching
6.
Drainage
7.
Volatilization
Distribution routes and "receptor" organisms
for pesticides used in agriculture
Application
Humans
Wildlife
Plants
1
Spray
Granulate
Or
Seed
Treatment
Air
Target
Pest
6
- Crops
- Soil organisms
- Applicators
- Bystanders
- Wildlife
Terrestrial
organism
3
7
1
Soil
Cattle
Crops
Ground
water
5
2
Surface
water
Aquatic
organisms
4
Sediment
Sediment
organism
A .Laborde
9
Pesticides and Children
PERSISTENCE AND BIO-CONCENTRATION
 PERSISTENT ORGANIC POLLUTANTS (POPs)
 Persist in the environment
 Accumulate in the food-chain
 Lypophilic
 Travel long distances
 Concentrate in marine animals
 May produce toxic effects
 Organochlorine pesticides
PESTICIDES
Aldrin
Dieldrin
Chlordane
DDT
Endrin
Heptachlor
Mirex
Toxaphene
10
Pesticides and Children
PESTICIDES IN THE ATMOSPHERE AND WATER
USGS
11
Pesticides and Children
PESTICIDES IN THE ATMOSPHERE
USGS
12
Pesticides and Children
CHILDREN'S EXPOSURE
A cause of concern

Multiple chemicals

Multiple sources of exposure

Multiple routes of exposure

Multiple effects
WHO
13
Pesticides and Children
CHILDREN’S ENVIRONMENTAL EXPOSURE
 Pesticides used in:
 Children living on:
homes and schools, playgrounds,
parks, fields and other public places
farms, agricultural areas (rural setting)
 Pesticides present in: air, soil, food, water, objects…
Different scenarios:
 ACUTE
high-level exposure, overt poisoning
 CHRONIC
low-level, chronic exposure, various effects
14
Pesticides and Children
SOURCES AND SETTINGS OF EXPOSURE...
HOME, SCHOOL, DAY-CARE, INSTITUTIONS...
Indoor and outdoor application
 Mosquito control
 Professional/domestic application
 Lice or scabies
 Fleas or ticks on pets
Pesticide residues




Dust, soil, furniture, carpets, toys, food…
Playgrounds, playing fields, lawns, gardens
Wood preservatives in play structures
Long range transport of POPs (e.g. DDT)
WHO
15
Pesticides and Children
SOURCES AND SETTINGS OF EXPOSURE
Children living on farms or in agricultural areas are exposed:
 to pesticide drift from sprayed fields
 to contaminated soil around living areas
 to contaminated equipment and clothes
 when playing around treated fields
 while helping parents with spraying
 … or with dips in animal husbandry
 when working as child labour
Corra
16
Pesticides and Children
RURAL SETTINGS
Increase in the
levels of
organophosphorus
(OP)
metabolites
(DAP)
paralleling
pesticide
spraying in a
rural area
Koch EHP, 2002, 110 (8): 829
17
Pesticides and Children
PESTICIDES IN DIFFERENT MEDIA
Air
 Respirable
particles contaminated with pesticides
 Respirable aerosols during spraying
 Vapour from volatile residues of pesticides
Soil
 Hand-to-mouth
behaviour
 Crawling on the ground
18
Pesticides and Children
PESTICIDES IN DIFFERENT MEDIA
Water
 Pesticides in drinking-water: tap, well
Food
 Crops routinely sprayed:
 fruits, vegetables, grains
 Bioaccumulation in animals and products
 fish, meat, eggs, dairy
WHO
19
Pesticides and Children
PESTICIDES IN DIFFERENT MEDIA
Food residues
 Many food products have detectable levels of pesticides
 Guideline levels of pesticides in food (MRL)
 Guidelines to limit the population exposure (ADI)
 Acceptable daily intake (ADI)
 Increasing concern about
cumulative dietary exposure
WHO
20
Pesticides and Children
EXAMPLE OF SEASONAL PESTICIDE USE
APPLE ORCHARD
CALENDAR
AUTUMN
 Herbicides: simazine, paraquat, 2-4D
WINTER
 Fungicides: dinitroorthocresol (DNOC)
 Insecticides: organophosphates
SPRING
 Fungicides: Cu salts, dithiocarbamates
 Insecticides: endosulfan, OPs
NPS
SUMMER
 Insecticides: OPs
Ref: Dr A. Laborde, Uruguay
21
Pesticides and Children
TOXICOKINETICS
 Absorption
 Distribution and storage
 Dermal, ocular, ingestion,
 Fat soluble pesticides are
inhalation, injection
stored in adipose tissue
 Biotransformation
 Into inactive or more
active metabolites
 Elimination
 Urinary excretion
 Biliary / faecal excretion
 Excretion in milk
22
Pesticides and Children
ROUTES OF EXPOSURE
Multiple/simultaneous routes of exposure
 Ingestion




Breastfeeding
Accidental ingestion
Residues in food
Mouthing
 Inhalation
 Indoor and outdoor spraying
 Occupational exposure
 Dermal absorption





 Transplacental
Accidental contact
Occupational exposure
Residues on surfaces
Contaminated clothing
Medical use: scabies, head lice
23
Pesticides and Children
ROUTES OF PERINATAL EXPOSURE
 Mother’s intake and body burden is
transferred across the placenta
 Breast milk may be contaminated
"The very top of the food-chain"
WHO
24
Pesticides and Children
METABOLIC PATHWAYS
 Organophosphates
metabolize into:
oxon
DAP
 Oxones
 Specific inactive
metabolites (ME)
 Non-specific
metabolites:
dialkylphosphates
(DAPs)
DAP
ME
Wessels, EHP (2003) 111 (16): 1939
25
Pesticides and Children
MECHANISMS OF ACUTE TOXICITY
 Irritation (most of the pesticides)
 Allergic sensitization (fungicides)
 Enzyme inhibition (e.g. cholinesterases)
 Oxidative damage (e.g. paraquat)
 Inhibition of neurotransmission (e.g. organochlorines)
 Calcium (Ca2+) homeostasis alteration
 GABA inhibition
 Uncoupling of oxidative phosphorylation (e.g. glyphosate)
26
Pesticides and Children
ACUTE PESTICIDE-RELATED ILLNESS
 Dermal and ocular irritation (or allergic response)
 Upper and lower respiratory tract irritation
 Allergic responses / asthma (fungicides)
 Gastrointestinal symptoms
 Neurological symptoms
 Specific syndromes
 Cholinergic crisis (organophosphorus pesticides)
 Bleeding (warfarin-based rodenticides)
 Caustic lesions and pulmonary fibrosis
(herbicide, paraquat)
Pronczuk
27
Pesticides and Children
ACUTE POISONING
"Accidental" ingestion
 Storage of left-over pesticide in a
medicine or soft-drink bottle
 Confusion with pharmaceutical
 Pesticide container re-used for
storing drinks or food
 Pesticide container present in the
Bottles containing pharmaceuticals and
the pesticide chlorpyriphos
Laborde, CIAT, Montevideo
child's environment
28
Pesticides and Children
ACUTE POISONING
Arizona Household Survey
 107 homes surveyed:
- 148 different pesticide products
- half were stored inside
- less than 1.2 m from ground
- in the kitchen
EPA
29
Pesticides and Children
DIAGNOSIS OF EXPOSURE
 History of exposure
 Availability of pesticides
 Recent application
 Signs and symptoms
 May be misdiagnosed!
 Laboratory tests
WHO
30
Pesticides and Children
ACUTE TOXINDROMES
PESTICIDE
Organo
phosphates
Clorpyriphos
Diazinon
Azinphos
Parathion
Carbamates
Carbaryl
Aldicarb
ACUTE
SYMPTOMS
Irreversible
cholinesterase
inhibition
DIAGNOSIS
TREATMENT
Cholinesterase
levels (red
blood cells)
- Supportive care
- Atropine i/v
- Oximes
- Decontamination
Cholinesterase
levels (RBC)
- Supportive care
- Atropine i/v
- Decontamination
Cholinergic crisis:
- nausea, vomiting
- hypersecretion
- miosis
- fasciculations
- coma
Reversible
cholinesterase
inhibition
31
Pesticides and Children
ACUTE TOXINDROMES
PESTICIDE
ACUTE
SYMPTOMS
DIAGNOSIS
TREATMENT
Type I
Allethrin
Permethrin
Tetrametrhin
- Tremor
- Ataxia
- Iritability
- Supportive care
- Symptomatic
- Decontamination
Type II
Deltamethrin
Cypermetrhin
Fenvalerate
- Salivation
- Temporary
paresthesias
- Seazures
Organo
chlorines
GABA blockade:
- Tremors
- Dizziness
- Seizures
urinary 3phenoxybenzoic
acid is measured
in research
studies
urinary 3phenoxybenzoic
acid is measured
in research
studies
- Detectable in
blood
Pyrethroids
Lindane
Endosulfan
- Supportive care
- Symptomatic
- Decontamination
- Supportive care
- Symptomatic
- Decontamination
32
Pesticides and Children
ACUTE PESTICIDE TOXINDROMES
PESTICIDE
ACUTE
SYMPTOMS
DIAGNOSIS TREATMENT
Chlorophenoxi
compounds
(e.g: 2,4 D)
Nausea, vomiting,
acidosis, mialgia
fever, miopathy,
neurophaty
Vomiting
Corrosive lesions
Hepatotoxicity
Acute tubular
necrosis
Pulmonar fibrosis
Haemorrhage
(from vit. K
antagonism)
Detectable in
urine
Decontamination and
Urine alkalinization
Dithionite test
in urine
Decontamination
Avoid O2
Hemoperfusion
Possibly:
corticosteroids and
ciclophosphamide
Vitamin K1
( fitomenadione)
Bipyridyl
compounds
paraquat
Anticoagulant
Rodenticide
Warfarine
Brodifacoum
Diphacinone
Elevated
Protrombine
Time (PT)
33
Pesticides and Children
LOW-LEVEL CHRONIC EXPOSURE
Growing body of epidemiological and animal data and research
studies suggest a link between long-term exposure and:

Abnormal growth and development
 Impaired neurological development
 Cancer
 Increased susceptibility to infections
34
Pesticides and Children
PRECONCEPTIONAL PRENATAL EXPOSURE
 Pesticide exposure before or during pregnancy
associated with increased risk of:
 Infertility
 Perinatal death
 Spontaneous abortion
 Premature birth
 Fetal growth retardation
 Congenital malformations
 Early childhood cancer
WHO
35
Pesticides and Children
PRENATAL EXPOSURE AND
NEURODEVELOPMENTAL EFFECTS
 Exposure during brain growth has subtle and
permanent effects on:





Brain structure and function
Neuronal and axonal differentiation
Serotoninergic system
Synaptogenesis
Programming of synaptic function
36
Pesticides and Children
PRENATAL EXPOSURE AND
NEURODEVELOPMENTAL EFFECTS
Mechanisms of developmental toxicity may be
different from those of acute toxicity
e.g.: Chlorpyrifos and cholinergic systems
 Parent compound is also toxic
 Non-cholinergic systems are primary targets too
37
Pesticides and Children
CHRONIC NEUROLOGICAL EFFECTS
 Neurological sequelae of acute poisoning
 Neurological symptoms due to high indoor
levels of pesticides
 Subtle changes in memory and attention
38
Pesticides and Children
PESTICIDES AND CHILDHOOD CANCER
Some studies have found an association between
postnatal pesticide exposure and paediatric cancer
 Brain tumours
 Acute lymphocytic leukaemia
 Non-Hodgkin lymphoma
39
Pesticides and Children
PRENATAL EXPOSURE AND CHILDHOOD CANCER
 Maternal exposure to pesticide has been associated
with paediatric cancer – acute lymphocytic leukaemia
 Association with parental occupational exposure
 Leukaemia
 Brain cancer
 Hodgkin and non-Hodgkin lymphomas
 Kidney cancer
40
Pesticides and Children
ENDOCRINE DISRUPTION
 Low doses of certain pesticides may mimic or block
hormones or trigger inappropriate hormone activity
 Endocrine disruption may alter development and
reproduction and induce birth defects





Infertility
Low sperm count
Early puberty
Hormone-dependent cancers (testicular, breast, prostate)
Altered sex ratio
41
Pesticides and Children
IMMUNOTOXICITY
 Immunotoxicity is suspected, but evidence is limited
Studies in Arctic zone:

Higher incidence of ear infections

Cytokine panel abnormalities
www.smithsonianmag.si.edu/smithsonian/issues04/jan04/ima
ges/topdogs_mush_jpg.html
42
Pesticides and Children
PESTICIDES IN CHILDREN'S COMPLEX ENVIRONMENT
PESTICIDES
Agriculture
Veterinary
"Cosmetic"
Human health
Public health
Air, water, food, soil and objects
Eating and drinking contaminated food and beverages
Playing in contaminated areas
Reaching unsafely stored pesticides
House and farm help/child labour






SUSCEPTIBILITIES
Critical windows
Age
Nutritional status
Poverty
WHO
Home
School
Playground
Farms
Fields
Acute effects
Poisoning
Neurotoxicity
Impaired development
Endocrine disruption
Cancer
43
Pesticides and Children
PREVENTION OF EXPOSURE
What can be done to prevent pesticide exposure and
poisoning ?
 Take action at
 Local level
 National level
 International
WHO
44
Pesticides and Children
PREVENTION – LOCAL LEVEL
Use pesticides ONLY when the benefits outweigh the risks
 Avoid cosmetic or scheduled use of pesticides in the home
 Use integrated pest management (IPM), non-chemical pest controls
If pesticides are necessary:
 Store in original containers with child-proof seals, out of reach, in a locked cabinet
 Educate on the safe use of pesticides
 Follow manufacturer’s instructions
 Use protective equipment
 Respect re-entry times
 Pregnant women should not apply pesticides
 Use least hazardous chemicals, least dangerous mode of application
45
Pesticides and Children
PREVENTION – COMMUNITY LEVEL
 Integrated pest management (IPM)





Homes
Schools
Public buildings
Health centres
Public parks
 Community activities





Community campaigns
School activities
Local awards or contests
Pesticide-free "zones"
Support organic farming
WHO
46
Pesticides and Children
PREVENTION – NATIONAL LEVEL
 Education campaigns aimed at pesticide users, general
population and children
 Restrict availability or limit use
 Establish and monitor maximum residue limits
 Surveillance and epidemiological vigilance for acute and
chronic related illness
 Treatment capacities
 Emergency services
 Poison control centres
 Education of health care providers
47
Pesticides and Children
PREVENTION – INTERNATIONAL LEVEL
 Persistent organic pollutants (POPs)
Stockholm Convention
 Hazardous chemicals and pesticides
Rotterdam Convention (PIC)
 International organizations:
WHO, IFCS, FAO, ILO
Pronczuk
48
Pesticides and Children
PESTICIDES AND CHILDREN: ACTIVITIES IN WHO
1. Guidelines for the classification of pesticides by
2.
3.
4.
5.
hazard
Joint FAO/WHO Meeting on Pesticide Residues
International pesticide limits in water
Pesticides Databank on CD-ROM
Poison centres and pesticide exposures
49
Pesticides and Children
CRITICAL ROLE OF
HEALTH AND ENVIRONMENT PROFESSIONALS
 Diagnose and treat
 Publish, research
 Sentinel cases
 Community-based interventions
 Educate
 Patients and families
 Colleagues and students
WHO
 Advocate
 Provide role model
50