Perspective on the 2017 Clarke Prize Lecture Topic. Professor Joan B. Rose Homer Nowlin Chair

Transcription

1 Perspective on the 2017 Clarke Prize Lecture Topic Professor Joan B. Rose Homer Nowlin Chair

2 Global trends in the era of the Anthropocene THE GREAT ACCELERATION 844 million people lack even a basic drinking-water service, including 159 million people who are dependent on surface water. Globally, at least 2 billion people use a drinking water source contaminated with faeces. Contaminated drinking water is estimated to cause diarrhoeal deaths each year.

3 Billions lack effective sewage treatment Africa Asia Europe North and Central America South America Oceania 11% 5% 4% 12% 68% Distribution of the 1.5 billion people by continent whose sewage is discharged without treatment

4 THE CHANGING LANDSCAPE IS CONTRIBUTING TO THE RISK Cultivated areas of the world. Brown regions indicate areas in which at least 30% of the landscape is cultivated. Reproduced from the Millennium Ecosystem Assessment 2005 ( UNEP. Loss of wetlands (km 2 ) from 1950s to 1990s in the US Verhoeven et al. TRENDS in Ecology and Evolution Vol.21 No.2 February

5 BIG PROBLEMS IMPACT PUBLIC HEALTH Climate Change Restoration of Water Infrastructure

6 Waterborne Diseases Reported Cholera Cases in 1993 Cryptosporidium Typhoid Fever

7 NATIONAL ACADEMY OF SCIENCES RISK ASSESSMENT PARADIGM HAZARD IDENTIFICATION: Types of microorganisms and disease end-points DOSE-RESPONSE: Human feeding studies, clinical studies, less virulent microbes and health adults EXPOSURE: Monitoring data, indicators and modeling used to address exposure RISK CHARACTERIZATION: Magnitude of the risk, uncertainty and variability SCIENCE AND DECISIONS: Advancing Risk Assessment, (2009) Committee on Improving Risk Analysis Approaches Used by the EPA NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES THE NATIONAL ACADEMIES PRESS, DC.

8 PROBLEM FORMULATION With Stakeholders ANALYSIS Exposure Pathways Address HAZARDS Dose-Response Human Health Effects RISK CHARACTERIZATION Uncertainty Analysis RISK MANAGEMENT OPTIONS

9 HUNDREDS OF HAZARDS Viruses Bacteria Parasites THE DISEASES: diarrhea, respiratory illness, liver damage, kidney failure, heart disease, cancer, nervous system disorders; birth defects, death.

10 Methods changed over time as technology advanced. It is now well recognized that fecal coliforms and E.coli can not provide the information needed. Failure to correlate with occurrence or removal of pathogens. The Indictor Total Coliforms 1914 Fecal Coliforms 1940s E. coli 1986 GLOBAL Universal Indicator for drinking water E.coli <1/100ml

11 Improving Water Diagnostics Escherichia coli (E. coli) General indicator of fecal contamination Linked to gastrointestinal illness through epidemiological studies (DuFour et al. 1982; Wade et al. 2006, 2008, 2010) USEPA recreational freshwater criterion: 2.5 log CFU/100 ml IDEXX Colilert Quanti-Tray 2000

12 Pathogen Water Diagnostics Polymerase chain reaction (PCR): Small amount of DNA amplified in a thermal cycler Amplified products are measured at the end point of amplification by agarose gel electrophoresis Quantitative PCR (qpcr) Digital droplet PCR 12

13 An example of 3 rd generation sequencer - Real-time sequence analysis - Rapid - Cost effective - Field potential Images from University of Oxford

14 EXPOSURE ASSESSMENT IS KEY The distribution of the human sewage marker Bacteroides was associated with on-site sewage treatment

15 Transport of animal feacal source tracking markers during summer rains 64 watersheds a) Base flow b) Summer rain

16 Global data bases on population Demographics Sewage coverage, Type of treatment Cryptosporidium emissions Pathogen specific information Incidence of disease Excretion rates Concentrations in sewage Removal by Treatment Hofstra, Bouwman, Beusen and Medema, STOTEN 2013

17 Downscale the Diagnostic Data: Move from emissions linked to global hydrology to concentrations and then risk Hotspot regions with high RV emissions are urban areas in densely populated parts of the world, such as Bangladesh and Nigeria, while low emissions are found in rural areas in North Russia and the Australian desert. Even for industrialized regions with high population density and without tertiary treatment (disinfection), such as the UK, substantial emissions are estimated.

18 Produce interactive global maps with high resolution; Address scenario planning Nynke Hofstra ssp3 assumes improvement to sewers but no treatment Nynke Hofstra et al. 2016

19 Must use Microbial Risk Assessment Water Diagnostics Risk Assessment Management Water Safety Hazard ID Dose Response Exposure Characterization Management

20 Recommendations Use the risk assessment framework integrate quantitative science and management/policy and promote the translation of science into action around sewage sources. Use advanced technology for water diagnostics to improve spatial and temporal resolution of the evidence for decision making, including MST tools for the identification of the source of contamination. Support the development of water diagnostic laboratories and develop microbial data bases particularly in to fill data gaps in developing regions of the world.

21 THANK YOU Joan B. Rose ROSE GANG Major contributors: Dr. Nynke Hofstra Dr. Marc Verhougstraete, Dr. Sherry Martin, Dr. David Hyndman, Dr. Tiong Aw, Dr. Yiseul Kim, Mr. Matthew Flood, Ms. Becca Ives