Pesticide Basics Uses, Exposures, Types and Acute Effects

Did you know?  5 million at risk population (U.S. EPA, 1992)  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 maintenanceAerial equipment maintenance AgronomistsAgronomists Building maintenance workBuilding maintenance work Emergency respondersEmergency responders EntomologistsEntomologists FirefightersFirefighters Forestry workersForestry workers Formulating end productFormulating end product Greenhouse- nursery workersGreenhouse- nursery workers Hazardous waste workersHazardous waste workers LandscapersLandscapers Livestock dippers and veterinariansLivestock dippers and veterinarians Marina workers Marina workers Medical personnel Medical personnel Park workers Park workers Plant pathologists Plant pathologists Research chemistry Research chemistry Sewer work Sewer work Storage/warehouse work Storage/warehouse work Structural application Structural application Transporting pesticides Transporting pesticides Treating contaminated workers Treating contaminated workers Vector control workers Vector control workers Wood treatment workers Wood treatment workers Work on highway or railroad rights of way Work on highway or railroad rights of way

Key Household Safety Points 1.Proximity 2.Take home 3.Garden 4.Animals 5.Recycle 6.Decant 7.Storage 8.Disposal 9.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: 1 st 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

Occupational versus Non-Occupational Cases of Pesticide Poisoning Source: 2004 Pesticide Incident Reporting and Tracking (PIRT) Annual Report

Proportion of Poisonings Ranked 8 th Cause of Poisonings = 102,754 cases in 2005 (4.2%) Source: Watson WA 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

Pesticide Types of Pesticides InsecticidesHerbicidesFungicidesRodenticides ‘cide = to kill Disinfectants Fumigants

Pesticide Chemical Families - grouping based on similarities- 1.Similar chemically (similar structure) 2.Attacks pests in a similar way (toxicity) 3.Common treatment + antidote Organophosphate OP Carbamate C Pyrethroid PY Organochlorine OC Chlorophenoxy Paraquat Diquat

Pesticide Sample Label Type of pesticide (used for?) Company name Brand name Common/generic name (active ingredient) Chemical family (? atropine under 1 st aid) Signal word (hazard level)

Pesticide Classification Table #TypeCompany Name Brand Name Common Name Chemical Family Signal Class 1.Insecticide Gowen Supracide methidathion OP (Organophosphate) Danger- Poison Ib

COMPANYBRANDCOMMONTYPEFAMILYSIGNALWho Pesticide Labels BayerTemikAldicarbInsecticideCarbamateDanger-poisonla VerdiconSevinCarbarylInsecticideCarbamateCautionll UCP AllianceThiodanEndosulfanInsecticideOrganochlorineWarningll BayerGuthionAzinophos methylInsecticideOrganophospateDanger-poisonlb DowDursbanChlorpyrifosInsecticideWarningll SyngentaGramoxoneParaquatHerbicideParaquatDanger-poisonll HelenaWeed Rhap2, 4-DHerbicideChlorophenoxyDanger-poisonll DuPontAsanaEsfenverlateInsecticidePyrethroidWarninglV BayerCaptan FungicideDanger-poison MaxRoundupGlyphosateHerbicideCautionU-IV II DowDithane Mancozeb Fungicide Caution U-IV Cerexagri-Nisso Ziram Fungicide DangerIII Exercise: Classifying Pesticides Organophospate

How toxic is it? Source: Richards, Kerry Penn State University Extension Service

LD 50 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”-24 0 & Carbamates: 15”-3 0

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: 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: 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: 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

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 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 EyeCNSLungs GI GlandsMuscle Heart Exercise: Body Mapping Fatigue Dizziness Headache Tremors Ataxia Seizures LOC Coma Insomnia Mental Δ Tightness Wheezing Cough Rhinorrhea Abd. cramps Nausea Vomiting Diarrhea Drooling Sweating Tearing Weakness Cramps Fasciculations Tachy Brady  BP ↓ BP

Signs of Pesticide Poisoning in Children Lethargic sleepy Seizures Coma Can be confused with the flu