Guanabara bay qmra final

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  1. 1. Guanabara Bay QMRA Rachel Sklar Anna Gitter Alexandre Chabrelie
  2. 2. Problem Sailing Competitions scheduled in heavily polluted body of water Guanabara Bay o Trash/sewage from Favelas along rivers o 35 rivers, 9 million inhabitants (5.5 t/day garbage), 6,000 industries (150 t/day industrial effluents) o Pollution gradient + tidal pollution variability Bottles, dead fishes, sewages & garbages Authorities received $1 billion over last 2 decades to depollute 32t dead fish removed, garbages vs. eco-boats & eco-barriers, 35% average in 2013 (some spikes: 7% treated sewages)
  3. 3. Removing 80% of the pollutants? Its not going to happen From the point of view of the Olympics, the point of view of water quality, what Ive said about the 80% does not at all affect the courses for the sailing events, Correa said. Theres no big risk for sailors having troubles with illnesses and such things. Andre Correa, Rio State Environmental Secretary
  4. 4. What is the risk of contracting Highly Credible Gastroenteric Disease to sailors during one hour of an olympic race? QMRA Question
  5. 5. Hazard ID Olympic Games - Sport map Source: Canoe slalom Marathon swimming Sailing Rowing, Canoe sprint Diving Many potential pathogens concerned - F/T coliforms, E. coli, Enterococci, giardia, cryptosporidium Fecal Coliforms serve as an Indicator Bacteria presence of sewage and other waste Concern for athletes contracting a HCGI (1) vomiting; (2) diarrhea with a fever or disabling enough for remaining at home; (3) stomachache or nausea accompanied by a fever.
  6. 6. Paranhos et al. 1998
  7. 7. Exposure Assessment Incidental ingestion o Assumptions recreational contact routes: inhalation and entrapment of mists in the nose and mouth with swallowing; secondary contact of water (Geosyntec 2008; Sunger 2012) Duration of sailing events: one hour (worst-case scenario assumption) Distribution Lognormal Mean 5 Standard Deviation 5 Fixed Intake Median (50th Percentile) 100th Percentile 4 mL/hr 7.52 mL/hr 34 mL/hr Table 1: Canoeist Ingestion Rates (mL/hr) (Geosyntec 2008)
  8. 8. Environmental Samples Guanabara Bay (Carreira 2015 unpublished) FC:Ecoli Ratio Bathing Waters,Israel (Fattal et al.,1987) Dose Response Bathing waters in NY, LA, and MA (Cabelli et al.,1982)
  9. 9. Dose Response Exponential DR Model fit to data from Cabelli et al. 1982 Kcalculated=0.001254263
  10. 10. Risk Characterization Crystal Ball method Risk of HCGI risk for sailors during one hour of an olympic sailing race: 6.24999E-06 Very Low!
  11. 11. Risk
  12. 12. Sensitivity Analysis most sensitive variable according to the quantitative model was for ingestion volume
  13. 13. Modelling Limitations sensitivity analysis: greatest uncertainty is ingestion rate ??? FC:E.Coli Ratio for a different environment, Israel vs. Brazil Dose-Response curve derived from epi studies in N. America bathing waters
  14. 14. Risk Management
  15. 15. Risk Mitigation Current: o New Sewage Treatment Plants o Floating Garbage Barriers o Trash Collecting Vessels called Ecoboats Potential o Education & economic incentives to bring trash and other waste to a centralized disposal location o Limit unnecessary recreation by athletes in the water o Consider relocating event to a less polluted area of the bay or out of Brazil
  16. 16. It can get really disgusting, with dog carcasses in some places and the water turning brown from sewage contamination Thomas Low-Beer, 24, a Brazilian sailor Guanabara Bay was exaggerated, contending that recent tests had shown that fecal contamination in the Olympic regatta area was within satisfactory standards in Brazil. Carlos Portinho, Rios top environmental advisor
  17. 17. Future Work Hazard ID: look at presence of geographically specific pathogens Exposure Assessment: sailing specific ingestion rates via observation Dose-Response: o indicator to pathogen ratio specific to geographic region o dose-response curve derived from epi studies in geographically similar area Risk Management: o risk would be significantly lower in another bay in Brazil? o model risk reduction: cost o survey athletes to gauge risk perception
  18. 18. Risk Management Relocation Scenario: loss of revenue for Brazil/local communities Cleanup Scenario: o investment in prevention and cleanup (infrastructure) o Local leaders, CBO, Brazilian Govt, Olympic Committee o incentive schemes that involve benefits for local people
  19. 19. Sources Aquece Rio-International Sailing Regatta 2015. (n.d.). Retrieved June 11, 2015, from Cabelli, V. J., Dufour, A. P., McCabe, L. J., & Levin, M. A. (1982). SWIMMING-ASSOCIATED GASTROENTERITIS AND WATER QUALITY1. American journal of epidemiology, 115(4), 606-616. Francy, D. S., Myers, D. N., & Metzker, K. D. (1993). Escherichia coli and fecal-coliform bacteria as indicators of recreational water quality. US Department of the Interior, US Geological Survey. Geosyntec. (2008). Dry and wet weather risk assessment of human health impacts of disinfection v. no disinfection of the Chicago Area Waterways System (CWS). Retrieved June 8, 2015, from nal.pdf Kjerfve, B., Ribeiro, C. H., Dias, G. T., Filippo, A. M., & Quaresma, V. D. S. (1997). Oceanographic characteristics of an impacted coastal bay: Baa de Guanabara, Rio de Janeiro, Brazil. Continental Shelf Research, 17(13), 1609-1643. Paranhos, R., Pereira, A. P., & Mayr, L. M. (1998). Diel variability of water quality in a tropical polluted bay. Environmental Monitoring and Assessment, 50(2), 131-141. Kirkpatrick, N. (2015, March 19). 2016 Rio Olympics: Sailing with Sewage. The Washington Post. Retrieved June 10, 2015, from cesspool/ Sunger, N. 2013. Quantitative Health Risk Assessment of Recreational Water Users in Philadelphia. (Doctoral Dissertation). Accessed from Google Scholar. Texas Commission for Environmental Quality. (2007). Texas Water Quality Standards: Criteria for Recreation. Available from:


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