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Children’s Vulnerability to Pesticides

Children’s Vulnerability to Pesticides. Photo: H Murphy – Alahanpanjang, West Sumatra Indonesia, 1996. Why?. Behavioral factors Biological factors Bigger doses Long term effects @ low level exposure. Sources – Child/OP Encounters. > ¼ mi.

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Children’s Vulnerability to Pesticides

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  1. Children’s Vulnerability to Pesticides Photo: H Murphy – Alahanpanjang, West Sumatra Indonesia, 1996

  2. Why? • Behavioral factors • Biological factors • Bigger doses • Long term effects @ low level exposure

  3. Sources – Child/OP Encounters > ¼ mi

  4. Proximity to Farmland Data from Washington StatePNASH Center Research Lu C, Fenske RA, Simcox NJ, Kalman D. Pesticide exposure of children in an agricultural community: evidence of household proximity to farmland and take home exposure pathways. Environ Res. 2000 Nov;84(3):290-302.

  5. Child Behavior Question CDC reports from a nationally representative sample of the U.S. population shows thatchildren have twice the amount of pesticide by-products in their urine as adults. How would you describe to a parent the behaviorsin young children that would explain this?

  6. Behaviors • Hand to mouth: Taste their environment • Near the ground: Spend more time on the ground • Outdoors: Spend more time outside

  7. Agricultural Workplace/Playground

  8. Geometric Means (µmol/L) and 95% C.I. for OP Metabolite Concentrations by Sampling Month(Arrows indicate months of OP pesticides spraying) Koch D, Lu C, Fisker-Andersen J, Jolley L, Fenske RA. Temporal association of children's pesticide exposure and agricultural spraying: report of a longitudinal biological monitoring study. Environ Health Perspect. 2002 Aug;110(8):829-33.

  9. Behavior: soil ingestion G. Selevan. EHP 2000;108 Suppl 3:451-455

  10. Maria’s husband is an applicator but his blood test (cholinesterase monitoring program) is normal. She likes to take her baby with her when she picks him up from work but was advised against this. She cannot understand why being around pesticides would be a problem for her baby when her husband who had direct contact is fine. Child Biology Question How would you explain to a parent the biological factors would make a child more vulnerable than an adult?

  11. Biology- Higher Dose By: • Higher Metabolic Rates • Inhales more per day (1.7x) than adult • Dietary consumption/body weight • Drinks 2 x more water per their weight than an adult • Eats 12x more apples per their weight than an adult • Skin • More permeable: highest at birth • 2.7 x more skin surface/weight than adults • Developing organs

  12. Biology: inhalation dose 1.7x

  13. Biology: dermal & dietary dose 2.7 x 2x 12x G. Selevan. EHP 2000;108 Suppl 3:451-455

  14. Biology: skin permeability • Skin permeability Highest at birth Adult permeability by ~ 1 yr.

  15. Vulnerability to Health Effects: Organs Still Developing “A little kid goes from a single cell to a laughing, sociable, intelligent, friendly human being over the course of two years. That’s dramatic growth and development!” Kenneth Olden, PhD, former Director, National Institute of Environmental Health Sciences

  16. Metabolic Vulnerability: e.g. Paraoxonase Paraoxonase (PON1) is an enzyme that acts as a detoxifying system for organophosphate pesticide metabolites Activity of the enzyme is reduced in pregnancy, infancy, childhood Some evidence that PON1 activity can modify risk of adverse health outcomes in children birth outcomes (head circumference) pediatric brain tumors Nielsen SS. Risk of Brain Tumors in Children and Susceptibility to Organophosphorus Insecticides: The Potential Role of Paraoxonase (PON1) . EHP 2005;113:909-913 Berkowitz GS. In Utero Pesticide Exposure, Maternal Paraoxonase Activity, and Head Circumference. EHP 2004;112:388-391.

  17. Ramon and Rosa’s 3 year old has small amounts of OP’s in his urine (he was recruited for a PNASH study). They are asking you how this could occur. The family live 5 miles from the closest orchard. Parent Activities Question Why is this? What things are the parents doing that would account for this? What questions will you ask and what things will you look for in the household

  18. Dependency • Children rely on adults to provide safe environments – indoor and out

  19. Sources – Child/OP Encounters > ¼ mi

  20. Parental Take-Home

  21. Washington State data from PNASH: metabolites of OPs in children’s urine Community Low/Hi Spray Season Applicator Farmworker Seattle Fenske RA, Lu C, Curl CL, Shirai JH, Kissel JC. Biologic monitoring to characterize organophosphorus pesticide exposure among children and workers: an analysis of recent studies in Washington State. Environ Health Perspect. 2005 Nov;113(11):1651-7.

  22. Parent Activity Questions • Source of food and water • Parent occupation? • Shower after working before holding children? • Work clothes and shoes in the house? • Laundry practices ? • Use household pesticides ? • Garden pesticides ? • House and car cleaning ? • Pesticide storage? • Location of day care? • House near fields?

  23. Chlorpyrifos Metabolite Concentrations in the Urine of 22 Children Before, During, and After Organic Diet Intervention Organic diet Conventional diet Conventional diet Lu C, Toepel K, Irish R, Fenske RA, Barr DB, Bravo R. Organic diets significantly lower children's dietary exposure to organophosphorus pesticides. Environ Health Perspect. 2006 Feb;114(2):260-3.

  24. Impacts on ChildrenStudies on low level OP exposures among children • The younger the child the greater consequences of OP exposure on development • Fetus • Soon after birth • Nerve cells affected • Levels so low that they do not affect the cholinesterase but still damage developing nerve cells.

  25. What is the Evidence? Three Studies of Mother-Baby Pairs Mary Wolff, Stephanie Engel, Gertrud Berkowitz Mount Sinai School of Medicine Virginia Rauh, Robin Wyatt, Frederica Perera Columbia University Brenda Eskenazi, Kim Harley, Asa Bradman, Amy Marks University of California, Berkeley

  26. New York Studies Following 700 mother/baby pairs for 7 years. • Mother’s air intake for pesticides • Mother’s blood • Umbilical cord blood of baby Followed 409 mother/baby pairs for 3 years. • Mother’s urine • Birth outcomes • Development to age 2

  27. California Studies 600 pregnant Latina women from working families living in Salinas, a heavy agriculture area. • OP by-products in urine during pregnancy and after delivery • Birth outcomes

  28. Biomarkers of Prenatal OP Pesticide Exposures In Urine In Blood Chlorpyrifos X OP by products (Dialkyl Phosphates) X X Berkeley Mt. Sinai Columbia Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  29. Early Childhood Neurodevelopmental Outcome Measurements Pre-school Intelligence** Infant Development* Behavioral Assessment 5Y X **** X 6M X Neonatal X X 1Y X X X 2Y X X X 3Y X 3.5Y X Berkeley Mt. Sinai Columbia * Baley: Tests motor, cognitive, language development *** Brazelton **Wechsler Preschool and Primary Scale of Intelligence (WPPSI) **** Verbal IQ assessed with PPVT Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  30. Early Childhood Behavioral Outcome Measurements Child Behavior Checklist 2Y X 3Y X 3.5Y X Berkeley Mt. Sinai Columbia Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  31. AGRICULTURAL CALIFORNIA URBAN NEW YORK Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  32. Characteristics of Study Populations Berkeley (%) 1 -- Mexican 97 2 82 81 Mt. Sinai (%) 20 27 Mex, PR 51 1 29 32 Columbia (%) -- 35 Dominican 65 -- 29 35 Race/Ethnicity Non-Hispanic White African-American Hispanic Other Married < High school Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  33. In summary… • Three scientifically-rigorous, cohort studies • Different populations • Different exposure levels and sources • Exposure measured using biomarkers in urine (metabolites) and blood (parent compound) • Despite these differences, some patterns emerge… Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

  34. Prenatal OP exposure associated with …….. • Increased odds of abnormal reflexes in neonates • Poorer mental development in 2 and 3 year olds • Poorer verbal IQ in 3½ and 5 year olds • Increased odds of pervasive developmental disorder Source: Kim Harley, PhD UC Berkeley Center for Children’s Environmental Health Research

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