Presentation on theme: "The Human Health Effects of Pesticide Exposure"— Presentation transcript:
1The Human Health Effects of Pesticide Exposure Acute EffectsSkin ProblemsRespiratory ProblemsReproductionRisks to ChildrenNervous SystemCancers
2Agriculture in AsiaA Typical North Vietnamese Farming Village
3Focus on OP’s Most commonly used insecticide in agriculture Children at risk for neurodevelopmental problemsMost commonly used insecticide in agricultureCommon cause of poisoning
4Normal Electrical Nerve Impulse Transmission nerve cellElectrical 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.acetatecholineOnce acetylcholine is broken, it can no longer transmit electrical nerve impulses.Electrical nerve impulses stop and the muscles and glands are quietmuscle cell
5Organophosphate-Carbamate Disruption of Electrical Nerve Impulse Transmission Therapeutic Effect of Atropinenerve cellIf 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.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.muscle cellElectrical nerve impulseacetatecholinecholinesteraseorganophosphateatropine
7Signs and Symptoms in Adults MiosisBlurringEyeCNSLungsGIGlandsMuscleHeartFatigueDizzinessHeadacheTremorsAtaxiaSeizuresLOCComaInsomniaMental ΔTightnessWheezingCoughRhinorrheaWeakness CrampsFasciculationsAbd. crampsNauseaVomitingDiarrheaDroolingSweatingTearingTachyBrady BP↓ BPExercise: Body Mapping
8Parathion StoryOn the day her house was sprayed, previously healthy girl 4 months of age became irritable and seemed congested in her upper airway, with a thick whitish nasal discharge. Over the next several days these symptoms persisted, and she began to refuse food, developed a fever, more frequent bowel movements, and decreased sleep. On day 6, she was brought to the emergency department (ED) and was given iv antibiotics, fluids, oxygen, and a series of tests to determine infection status. She was discharged with a diagnosis of upper respiratory infection and a prescription for an antibiotic. That night the child got worse paramedics were called and she was transported by air ambulance to a pediatric intensive care unit . She was sleepy, dehydrated, and had black, foul-smelling stools showing blood coming from the upper intestines. The diagnosis was dehydration and high salt in her blood (sodium). She remained in the hospital for more than 1 week, receiving fluids and antibiotics. She was discharged home without medications, but she continued to have abnormal head movement. Fourteen months later her home was evaluated for methyl parathion contamination, and her urinary metabolite of methyl parathion was 89 . The general population reference range is 0-63.
9Signs of Pesticide Poisoning in a CHILD SeizuresLethargic sleepyComaCan be confused with the flu
10Respiratory ProblemsOrganophosphates and carbamates inhibit cholinesterase resulting inConstriction of the bronchial tubesIncreased secretionsDifficulty in breathingMany pesticides are ‘sensitizers’ causing allergic reactions along with OTHER triggersdusts, pollens, animals, diesel, molds, grains, hay, disinfectants
12Respiratory Problems Insecticide related wheezing with*: parathionchlorpyriphosmalathionHerbicide related wheezing with*:paraquatatrazinealachlorchlorimuron ethyl (Classic)EPTCChildren exposed to pesticides in 1st year of life 4.5x greater risk of developing asthma before age 5.*Source: Agriculture Health Study:
14Skin Disorders Dermatitis with any pesticide AllergicContact12%-68% prevalence of skin problems in agricultureParaquat irritant/burn = 53% applicators in one study*Chloracne from dioxins: 2,4,5 –T (Agent Orange) and possibly 2,4 –D, diuron, linuron (Viktor Yushchenko* Source: Castro-Gutierrez N, McConnell R, Andersson K, Pacheco-Anton F, Hogstedt,C. Respiratory symptoms, spirometry and chronic occupational paraquat exposure. Scand J Work Environ Health 1997;23:421–427.
15Paraquat Application by Burmese Migrant Workers in Thailand Mae Sot, Thailand
16Skin DisordersSoil fumigants can cause irritant dermatitis and chemical burnsmethyl bromidedichloropropene (Telone)Metam sodiumHerbicide induced contact or allergic dermatitismiticide propargiteparaquat and diquatFungicide induced contact or allergic dermatitisManebMancozedZinebSulfurZiramBenomylCaptanSource: Solomon G, Ogunseitan OA, Kirsch A. Pesticides and Human Health: A Resource for Health Care Professionals. PSR
18Severe Contact Dermatitis Cartap + [Fenobucarb, Dimethoate and Methyl Parathion x 20 yrs] Prey Vang, Cambodia
19Pesticides Associated to Allergic Contact Dermatitis* AcephateBenomylCaptanCarbarylChlorothalonilChlorpyrifosDCNADiazinonDienochlorDimethoateEthoxyquinFenbutatin-oxideFluvalinateFolpetMalathionMancozebManebNorflurazonOmethoatePCNBPermethrinPyrethrumSulfurThiramVinclozolinZinebZiram*Source: M.A. O’Malley, Skin reactions to pesticides, Occup Med State Art Rev 12 (2): 327–45.
21Reproductive EffectsBirth defects: Difficult to study but consist findings w/Limb reductions - Uro-genital defectsCentral nervous systemCleft palates/lipsEye – heart defectsGlyphosate: 3.6 risk of neurobehavioral problems in offspringTime to Pregnancy: occupational exposure increase time needed to get pregnant20% in women engaged in pesticide activitiesDicamba, glyphosate, 2,4-D, thiocarbamates, OP’s.Reproductive n=62Congenital defects +: add to the growing body of evidence but still problems in designs. risk limb, urogenital, CNS, orofacial, heart, eye. Glyphosate and pyridil derivativesTime to PG + : n=8 consistent ~ suggest occupational exposure causes time to pregnancyFertility ?: inconclusive-design problemsLBW, prematurity, IUGR:? n=10 7/10 + pyrethroid and chlorpyrifos. One paper mixed and 2 negative. May be an association more study neededFetal death + 9/11 positive assoc c/ SB or NND only 1 neg. Strong assoc w/ SaB or B defect and conventional pesticide prenatally vs IPM…phenoxy herbicides and SAB and hexachlorobenzene contaminated seeds in childhood and SaB
23Reproductive Effects Small for Age Births: 7/10 studies + Fetal and maternal blood samples for Op by products and newborn lengthsChlorpyrifos and diazon residentially ~ lower birth weight and length*Fetal deaths (still births, neonatal death, or miscarriages)9/11 studies +Strong association to miscarriages farming households using conventional pesticides 3 months before conception compared to IPM farms* Source: Whyatt RM et al. Biomarkers in assessing residential insecticide exposures during pregnancy and effects on fetal growth.Tox Applied Pharm 206 (2): AUG
24New York Study Following 700 mother/baby pairs for 7 years. mother’s air intake for pesticidesmother’s bloodumbilical cord blood of baby
25New York City StudyFetal exposure to chlorpyrifos is associated with lower birth-weight and birth lengthSame effect as SMOKING- as if the mother was a heavy smokerAt age 3 those more exposed had delayed movement and mental skills and attention deficits – temporary?
26California Studies600 pregnant Latina women farm working families living in Salinas, a heavy agriculture area.OP by-products in urine during pregnancy and after deliveryBirth outcomes
27California StudyOP pesticide by products in during DURING pregnancy associated to:Shorter pregnancy – early deliveriesAbnormal reflexes at birthNow watching these children’s nervous system as they grow
28Summary Long Term Effects of OP’s Length of gestation is shorter in women with higher organophosphate pesticide exposuresNewborns of mothers with higher organophosphate pesticide exposures have more abnormal reflexesPre-natal chlorpyrifos exposure is associated with reduced birth-weight and birth lengthChildren exposed to highest exposures had significantly higher risk of motor and cognitive delay compared to those with lowest exposuresUsing child behavior checklist, highest exposed group had symptoms of inattentive disorder.
29Some Important FactsThe younger you are the worse the consequences of OP exposure for developmentFetusSoon after birthNerve system affectedLevels so low that they do not inhibit ChE but still effect neural development.
31Risks to ChildrenAsthmaBrain and kidney tumorsLeukemiaNeuro-developmental problemsSmall for age at birthCongenital defects
32Health History Interviewing Batambang Province, Cambodia
33Neurological and Mental Health Depression, emotional disorders and suicidesEarlier poisonings ~ minor depressionCanada suicides ~ pesticide useSubtle diminished function of nervous systemOccur after severe acute poisoningsChronic low level exposureParkinson’s Disease [genetics + environmental exposures]Consistent evidence w/ past occupational exposuresMixed pesticides /herbicides investigated
34Animal Studies (rodents) Rodents exposed to low levels of OP’s over a long time during pregnancy and right after birth:Problems with gaitTremorsBalance problemsRun into cliffsCannot right themselvesEskenazi B. Exposures of children to organophosphate pesticides and their potential adverse health effects.EHP 1999;107 (Suppl 3):
35CancersBrain tumors: 1.7 risk with a dose - response (more pesticide use the higher the risk) 323,292 offspring of Norwegian farmersBreast (?): 1.8 x risk sprayed field, 2.0 x if not use PPEKidney: children of occupationally exposed men 1.59 x risk. Mortality rate 502 in pentachlorophenol chemical company workersBrain: n=11 [5 cohort +, 5 c/c, 1 eco.] 1.7x risk in children associated to prenatal use of tick –flea productsBreast n= 6 [1 cohort, 2 c/c, 3 eco]Cohort: risk abnormal mammography but n/s for malignancy in greenhouse workers vs nonC/C : risk in veg, fruit and crop farmers . OR 1.8 ( ) if in sprayed field 2.0 ( ) if did not use PPE but inverse risk with longer duration of farming (re: physical activity, sunlight or anti-estrogenic pesticides?)Eco: # acres ~ risk of B cancer mortality [rice and catfish], Triazine medium exposure 1.14 and high exposure 1.2Kidney n=6 [2 cohort, 4 c/c]Cohort: 1657,703 kids of occupationally exposed men, PMR 1.59 ( ) + chemical company and death SMR 502 ( )4 c/c + assoc most consistent for longer duration of exposure and kids of parents occupationally exposedPancreatic n=3 (2 c/c, 1 cohort)All + especially with high exposure herbicides and fungicidesCohort male aerial pesticides SMR 2.71 ( ) ? smokingc/c arsenical OR = 3.4 ( ) other OR=3.17 ( ) job matrix fungicides 1.5 ( ) herb 1.6 ( )Non Hodgkin’s Lymphoma n= 27 [cohort 11, c/c 14, Eco 2]2,4-D implicated previously w/ these studies consistent23/27 studies show statist sign association w/pesticides and NHLcohort 9/11 + assoc, 3 ss 2 negc/c 12/14 + assoc, 8 ss, 2 negeco 2/2 +Source: Sanborn M, Cole D, Kerr K, Vakil C, Sanin LH, Bassil K. Pesticides Literature Review. Ontario College of Family Physicians. Toronto 2004.
36CancersPancreatic: Aerial applicators (9,961) 2.71x risk than flight instructors (9969)Prostate: 55,322 male applicators 3.75 risk > age 50 with methyl bromide or chlorinated pesticides (organochlorines like DDT or endosulfan)Non Hodgkin’s Lymphoma [Immunologic + environmental factors]: 23/27 studies positive. 2-4 D a precipitant.Leukemia 14/16 studies positive