Grantee Research Project Results
2011 Progress Report: Measures of Distribution System Water Quality and Their Relation to Health Outcomes in Atlanta
EPA Grant Number: R834250Title: Measures of Distribution System Water Quality and Their Relation to Health Outcomes in Atlanta
Investigators: Moe, Christine L. , Uber, Jim , Klein, Mitchel , Tolbert, Paige , Tinker, Sarah , Hooper, Stuart
Current Investigators: Moe, Christine L. , Sarnat, Stefanie Ebelt , Kirby, Amy , Levy, Karen , Klein, Mitchel , Tolbert, Paige
Institution: Rollins School of Public Health, Emory University , University of Cincinnati
Current Institution: Rollins School of Public Health, Emory University
EPA Project Officer: Page, Angela
Project Period: July 1, 2009 through June 30, 2012 (Extended to June 30, 2014)
Project Period Covered by this Report: July 1, 2010 through June 30,2011
Project Amount: $599,756
RFA: Innovative and Integrative Approaches for Advancing Public Health Protection Through Water Infrastructure Sustainability (2008) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities , Water
Objective:
The investigators proposed research to link health outcomes, quantified through emergency department (ED) visits for gastrointestinal (GI) illness, to distribution system water quality and infrastructure characteristics. In addition, the investigators proposed an integrative approach for characterizing health risks associated with microbial contamination of drinking water distribution systems through the development of vulnerability assessments and the implementation of an innovative automated continuous water quality monitor for use in distribution systems.
This study has four aims:
Aim A (Spatially refined analysis): Refine the previously conducted analyses assessing the association between rates of ED visits for GI illness and estimated residence times of drinking water serving the study area of two utilities, using geocoded patient address data to identify the closest node in the distribution system.
Aim B (1993-2004, 2005-2009, 1993-2009 analysis): Extend the previously conducted analyses assessing the association between rates of ED visits for GI illness and estimated residence times of drinking water serving the service area of two utilities by considering data from these utilities covering 2005 through 2009.
Aim C (Vulnerability assessment): Assess the association between rates of ED visits for GI illness and exposure metrics derived from the results of the vulnerability assessment. Compare these associations to those observed when only chlorine residual or water age metrics are considered as the exposure. One distribution system will be studied.
Aim D (AMS evaluation of vulnerability assessment results): Use an automated monitoring system (AMS) to examine the results of the vulnerability assessment by comparing continuously monitored water quality in areas of the distribution system predicted to be “high risk” for microbial contamination to areas predicted to be “low risk.”
In the second year of the study, we developed goals for each of the four aims to streamline the progress of the project. In the following sections, we will discuss the progress toward these goals, and we will also outline the goals for the third year of the project.
In the second year of this grant, our major goals, as outlined in our Year 1 Annual Report, were to:
- Complete analysis for Aim A: to refine the previously conducted analyses assessing the association between rates of ED visits for GI and estimated residence times of drinking water using geocoded patient address data to identify the closest node in the distribution system.
- Develop water residence time estimates for two drinking water utilities in metro Atlanta through 2009 under Aim B.
- Perform analysis for Aim B: to extend the previously conducted analyses assessing the association between rates of ED visits for GI illness and estimated residence times of drinking water serving the service area of the two utilities by considering data from these utilities covering 2005 through 2009.
- Complete a vulnerability assessment of the distribution system to pathogen contamination for one selected utility (Aim C).
- Initiate continuous monitoring of distribution system water quality at the same utility for which the vulnerability assessment was conducted (Aim D).
- Write a manuscript that describes the results for Aims A and B and submit for publication.
Progress Summary:
Aim A
We have made substantial progress on completing the analyses for Aim A. Much of Year 2 was devoted to data processing, checking, and merging of datasets (i.e., data on estimates of water age at nodes in the hydraulic model with data with geocoded emergency department visits). This took longer than expected because we had to reconcile some unexpected differences between the datasets. These problems have been resolved, and the epidemiologic model to assess the association between water age and emergency department visits for GI has now been developed. We are seeking additional information from both of our collaborating metro Atlanta water utilities about the specific geographic regions serviced by each prior to finalizing the analyses of Aim A. We expect to write up these results for publication in the coming year.
Aim B
We have made significant progress on the activities for Aim B.
- We have obtained water production data from both of our collaborating metro Atlanta water utilities. This was facilitated by meetings during the 2010 WQTC conference and during site visits in October 2010. Water residence time analyses have been completed and are ready to be formatted in a manner suitable for subsequent epidemiological analyses.
- Emergency department visit data for the 2004-2009 period, for use in Aim B analyses, were obtained from the Georgia Hospital Association (GHA) in May 2011. We are currently processing these data.
We expect to complete the analyses for Aim B in early 2012. We have begun drafting a manuscript for Aims A and B and will finish the manuscript once analyses for these aims have been finalized. We anticipate submitting this manuscript for publication in spring 2012.
Aim C
We have selected the City of Atlanta water utility for performing the vulnerability assessment. The assessment of microbial health risks due to low-pressure intrusion events has received increased attention in recent years, due to concerns that drinking water may contribute a significant fraction of gastrointestinal disease burden within a community. While recent efforts to estimate the health risks from low-pressure intrusion events have shown impressive progress, they would benefit from a general risk assessment framework for water distribution systems. We have initiated the development of such a framework, based on distribution system hydraulic and water quality models, that is now 90 percent complete. The framework includes the following features:
- Simulation of pathogen transport using general, multi-species fate and transport models;
- General specification of the key characteristics of the vulnerability assessment model, using a specialized language for Monte Carlo simulation
- Database support for flexible and efficient storage of Monte Carlo ensemble results, for post-processing of vulnerability assessment model results
- Efficient, yet accurate, simulation of large numbers of intrusion scenarios, using the theory of linear superposition
- Support for accurate and efficient simulation of short duration intrusion events (as required for low pressure events, ranging in duration from seconds to minutes), and accurate capture of instantaneous concentrations as well as statistical descriptions of concentration variations.
- Development of an open-source programming project to ensure that the framework continues to meet changing research needs.
In May 2011, we presented an update on progress on this framework at the American Society of Civil Engineers World Water Congress in Palm Springs, CA. Current work is devoted to the completion of the framework, and then to application to the City of Atlanta distribution system, as the first comprehensive analysis.
Aim D
We have been preparing for the field deployment of the Automated Monitoring System (AMS).
- We held meetings with the City of Atlanta (CoA) water utility to provide them with the information related to this study and secure their cooperation for the installation of the AMS device in their distribution system.
- With the assistance of the CoA utility, we identified a location at the main water treatment plant for the installation of the AMS to collect baseline water quality data and samples of finished water before it enters the distribution system.
- The new Research Project Coordinator was trained on the AMS installation, operation, and maintenance.
- We developed a water sampling and microbiological analyses plan to supplement the information from the AMS device. The water sample collection and microbiological analyses will be supported by funding from the Water Research Foundation (WaterRF #4350 – awarded in March 2011).
We expect the installation of the AMS at the water treatment plant will take place in October 2011.
We have primarily focused on data collection and cleaning in this period, as well as refinement of epidemiologic modeling approaches. For Aim A, we have produced preliminary descriptive statistics and preliminary epidemiologic modeling results.
Future Activities:
Year 3 goals:
- Complete analyses for Aims A, B, and C.
- Complete distribution system monitoring and sampling (Aim D).
- Write manuscripts for Aims A, B, C, and D and submit for publication.
Journal Articles:
No journal articles submitted with this report: View all 14 publications for this projectSupplemental Keywords:
Water, drinking water, exposure, risk, health effects, human health, vulnerability, population, indicators, public policy, epidemiology, engineering, modeling, monitoring, GeorgiaProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- Final Report
- 2013 Progress Report
- 2012 Progress Report
- 2010 Progress Report
- 2009 Progress Report
- Original Abstract
1 journal articles for this project