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USING GIS FOR EXPOSURE ASSESSMENT

USING GIS FOR EXPOSURE ASSESSMENT

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USING GIS FOR EXPOSURE ASSESSMENT

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  1. USING GIS FOR EXPOSURE ASSESSMENT J.R. NUCKOLS, PhD COLORADO STATE UNIVERSITY, FORT COLLINS, COLORADO, USA http://ehasl.cvmbs.colostate.edu

  2. GOALS • FUNDAMENTAL PRINCIPLES • GEOSPATIAL SCIENCE • HEALTH SCIENCE • ENVIRONMENTAL SCIENCE • EXPOSURE ASSESSMENT PROCESS - ENVIRONMENTAL EPIDEMIOLOGY • STATE OF THE SCIENCE – GIS AND ENVIRONMENTAL EPIDEMIOLOGY

  3. FUNDAMENTALS • GEOSPATIAL SCIENCE • SCALE • RESOLUTION • VALIDATION • ENVIRONMENTAL SCIENCE • GEOPHYSICAL PLAUSIBILITY • MEAUREMENT DATA • ALGORITHMS • VALIDATION • EPIDEMIOLOGY • BIOLOGICAL PLAUSIBILITY • CONFOUNDING FACTORS • STATISTICAL POWER

  4. ENVIRONMENTAL = SPATIAL • ENVIRONMENTAL EPIDEMIOLOGY: • Evaluates associations between environmental exposures and health outcomes, with the purpose of further understanding the etiology of disease

  5. EPIDEMIOLOGY CONTAMINANT OF INTEREST STUDY POPULATION DEMOGRAPHICS INCIDENCE OF DISEASE EXPOSURE ASSMT SOURCE ID SYSTEM BOUNDARY FATE/TRANSPORT EXPOSURE METRIC COMMON SPATIAL FACTORS

  6. GIS-Based Exposure Assessment: Agricultural Chemicals and Childhood Cancer Principal Co-Investigators: Dr. Mary H. Ward, NCI-OEB Dr. Peggy Reynolds, CDHS-EHIB Mr. Robert Guiner, CDHS-EHIB Mr. Ryan Miller, USDA-APHIS Funding: USDHHS-NIH-NCI grants RO3 CA83071, RO1CA71745, and RO1CA92683, and USDHHS-NIH-NCI Occupational and Environmental Epidemiology Branch.

  7. STATE OF CALIFORNIA, USA Sacramento San Francicso Fresno Kilometers 0 200 400

  8. The Problem… landscape trends Highly integrated landscapes… …with multiple applications to many fields. Complex landscapes = Complex Processes … … Pesticide Use Patterns are Complex … Variable in time and space • … Variable application method • Aerial • Ground • Orchard Blast • Fumigation • Chemgation

  9. CONTAMINANT OF INTEREST SOURCE IDENTIFICATION

  10. Selection of Pesticides • 850 Pesticides in California Pesticide Use Reporting Database • Prioritized Study Pesticides based on: • Carcenogenicity • Transportability • Use in our study area • 6 Pesticides in initial study, Approx 30 will be analyzed in validation study

  11. California Pesticide Use Reporting Database Fresno, Madera, Kings, and Tulare Counties Fresno

  12. STUDY POPULATION FATE/TRANSPORT

  13. CPUR Expossure Metric Section B Section A 1,400 lbs - Methyl Bromide Applied to Grapes CASE/CONTROL RESIDENCE

  14. California Department of Water Resources Database Fresno, Madera, Kings, and Tulare Counties Fresno Urban Land Surface Water Pasture Orchards Rice Grain and Hay Crops Row and Field Crops Vineyards

  15. Vineyard Spatial Refinement of Pesticide Use Data • CDWR Metric Section B Section A 1,400 lbs - Methyl Bromide Applied to Grapes Residences

  16. 1,230 0.4

  17. EPIDEMIOLOGICAL RISK EXPOSURE METRIC

  18. SENSITVITY AND SPECIFICITY OF THE PUR EXPOSURE METRIC USING THE CDWR METRIC AS THE “GOLD STANDARD”

  19. Non-differential exposure misclassificationExample: 2% exposure prevalence, true RR = 2 Sensitivity Specificity Source: Norell SE, 1987

  20. VALIDATION

  21. IOWA NHL STUDY: Satellite image boundaries & residences (from Ward et al., 2003)

  22. Odds Ratio (OR) of detecting ≥ 1 of 9 herbicides in house dustResidences with vs without corn or soybean fields in buffer N = 112 residences 750 m 500 Residence 250 100 OR = 11.0 OR = 3.5 OR = 2.8 OR = 1.6* Ref: Ward et al. (2003) *Not statistically significant

  23. SCORECARD • GEOSPATIAL SCIENCE • SCALE • RESOLUTION • VALIDATION • ENVIRONMENTAL SCIENCE • GEOPHYSICAL PLAUSIBILITY • MEAUREMENT DATA • ALGORITHMS • VALIDATION • EPIDEMIOLOGY • BIOLOGICAL PLAUSIBILITY • CONFOUNDING FACTORS • STATISTICAL POWER

  24. STATE OF THE SCIENCE • EDUCATIONAL OPPORTUNITIES • INSTITUTIONAL SUPPORT • RESEARCH

  25. INSTITUTIONAL SUPPORT IN THE USA • PROGRAMS • Agency for Toxic Substances and Disease Registry • National Cancer Institute • Unites States Environmental Protection Agency • Centers for Disease Control and Prevention • ISSUES • FEASIBILITY • COST • IMPLEMENTATION

  26. PROPOSED RESEARCH INITIATIVES • MORE CASE STUDIES / METHODS DEVEL AND VALIDATION • ROLE OF SPATIAL ANALYSIS AND STATISTICS • UNCERTAINTY IN EXPOSURE ASSESSMENT • RETROSPECTIVE ANALYSIS – INCORPORATING TEMPORAL ASPECT • LONG TERM STUDY SITES

  27. NSF Long Term Ecological Research Network • Understanding ecological phenomena over long temporal and large spatial scales. • Create a legacy of well-designed and documented long-term experiments. • Conducting major synthetic and theoretical efforts. • Providing information for the identification and solution of ecological problems.

  28. International LTER Network Currently 21 Countries Actively Contribute

  29. Proposed NCI Geographic-Based Surveillance Project Ecological Information Understanding Long Term Influence of Environmental Factors. Disease Incidence

  30. CONCLUSIONS • USE OF GIS IS FEASIBLE FOR EXPOSURE ASSESSMENT • USE OF GIS CAN IMPROVE EXPOSURE ASSESSMENT • INTERDISCIPLINARY APPROACH ESSENTIAL • MUST CONSIDER FUNDAMENTALS OF EACH SCIENTIFIC DISCIPLINE • NEED EXPANDED EDUCATIONAL AND INSTITUTIONAL SUPPORT