Grantee Research Project Results

2004 Progress Report: A Prospective Epidemiological Study of Gastrointestinal Health Effects Associated with Consumption of Conventionally Treated Groundwater

EPA Grant Number: R830376
Title: A Prospective Epidemiological Study of Gastrointestinal Health Effects Associated with Consumption of Conventionally Treated Groundwater
Investigators: Moe, Christine L. , Rose, Joan B. , Moll, Deborah , Payment, Pierre
Current Investigators: Moe, Christine L. , Moll, Deborah , Nilsson, Kenneth , Hooper, Stuart
Institution: Emory University , INRS - Institut Armand-Frappier , Centers for Disease Control and Prevention , Michigan State University
Current Institution: Emory University , Centers for Disease Control and Prevention , University of South Florida
EPA Project Officer: Page, Angela
Project Period: October 1, 2002 through September 30, 2005 (Extended to September 30, 2008)
Project Period Covered by this Report: October 1, 2003 through September 30,2004
Project Amount: $1,820,900
RFA: Microbial Risk in Drinking Water (2001) RFA Text |  Recipients Lists
Research Category: Water , Drinking Water , Human Health

Objective:

The overall goal of this study is to estimate the risks of endemic gastrointestinal illness (GI) associated with the consumption of conventionally treated groundwater (GW) in the U.S. and to determine the relative contributions of source water quality, treatment efficacy and distribution system vulnerability to endemic waterborne disease. During the first half of the reporting period, we continued efforts to launch an epidemiological study to address this goal by recruiting and randomizing 1,000 households (HH) in an area served by a large GW distribution system into one of three study groups: 1) HH who drink tap water, 2) HH provided with bottled treated water collected at the water treatment plant effluent, or 3) HH provided treated water collected at the water treatment plant effluent and then bottled after ozonation and reverse osmosis (RO). Families were asked to record information on their health symptoms in health diaries, and this information was to be collected via bi-weekly telephone calls for 12 months. In addition, we proposed extensive sampling of the source water, the treated water, and water throughout the distribution system to be tested for a panel of microbial indicator organisms (total coliforms, heterotrophic plate count bacteria, E. coli, C. perfringens, P. aeruginosa, H. hydrophila) and residual chlorine.

Because of the difficulty encountered in recruiting the target number of families in the study area who drink tap water (without any point-of-use treatment device), we modified our study design in December 2004 to recruit HH and provide them with either 1) bottled tap water collected from the distribution system, 2) bottled treated water collected at the treatment plant effluent, or 3) treated water collected at the treatment plant effluent and bottled after ozonation and RO. Because of the increased cost of this modified design and the need to restart the recruitment process, the EPA asked us to discontinue the epidemiology study and pursue alternative designs to achieve the study goal.

The current study design (as of August 2005) focuses on estimating the risks of endemic GI associated with the distribution system vulnerability, monitoring changes in distribution system water quality, and identifying risk factors that impact distribution system water quality.

Specific Aims:

• Monitor the GW distribution system for low pressure events using high-resolution pressure loggers.
• Collect water samples immediately after identified low pressure events or other water quality deviations and analyze these water samples for physical and microbial indicators of water quality.
• Continuously monitor physical and chemical water quality in association with event-triggered sample collection.
• Monitor water quality immediately after main breaks, repairs, scheduled flushing, and fire flow tests
• Compare the water quality results obtained from the event samples to the vulnerability assessment model previously completed for this distribution system, so that the model can be evaluated and specific improvements to the vulnerability assessment methodology can be proposed.

Secondary Objectives:

• Compare results from grab samples collected to satisfy regulatory requirements to those collected by continuous flow methods from the same location at the same time (such as for total coliforms).
• Assess various methods of measuring microbiological water quality after a pressure loss event.

Approach:

The proposed study is a 12-month, double-blinded, randomized intervention trial of 900 households in a large metropolitan area in the southeastern US with a community GW system that uses conventional treatment methods, meets current water quality standards and has a well-characterized distribution system with areas of vulnerability. Study households will be randomly divided into three groups of 300 households: Group 1 = Households that drink bottled water that has been treated with reverse osmosis and other advanced treatment methods, Group 2 = Households that drink bottled municipal water collected at the water treatment plant, and Group 3 = Households that drink municipal tap water. Groups 1 and 2 will be blinded to their group assignment. Half of the households within each group will be recruited from vulnerable areas in the distribution system in order to examine the health risks from distribution system contamination. Study participants will report GI symptoms and selected risk factors in a weekly health diary and biweekly telephone interview. Samples will be routinely collected from raw source water, treated water, distribution system water and bottled water and analyzed for microbial indicators. Data analyses will compare GI rates and water quality between the three study groups and between study households in different parts of the distribution system.

Progress Summary:

The modified epidemiological study design yielded a much higher rate of recruitment than the previous design. However, we determined we would not be able to complete the project with our remaining funds and recruitment was suspended to evaluate possible options.

In July, EPA requested we discontinue the human subjects portion of the study and focus the remaining resources on further characterization of pressure changes in the distribution system and their impact on microbiological water quality. EPA requested we submit a modified scope of work to address the study goals and a revised budget justification.

Notice was given to the recruitment team, student interviewers, field nurses, and the telephone schedulers of the cancellation of the epidemiological part of the study. The subcontract with the University of South Florida was cancelled, and the USF staff were notified of the cancellation of the epidemiological part of the study.

A letter was mailed to the recruited households explaining that the study was cancelled. So that participants would not be discouraged from future participation in research studies, and as a token of appreciation for their participation in our study, a $20 gift certificate was included with each letter.

We dismantled the infrastructure for the human subjects part of the study, modified the scope of work to shift the emphasis on examining risks from distribution system vulnerability, and prepared a modified budget and justification detailing what we will do with the remaining funds.

We have researched equipment for water sampling, and designed a unit to automatically collect water samples from the distribution system after a low pressure event. The parts needed to build this unit have been researched, priced, and worked into the revised budget.

Expected Results:

This is the first study to measure the risk of GI associated with the consumption of conventionally treated GW and to distinguish between the risk from source water and treatment vs. the risk from the distribution system. The results of this study will provide valuable information on the magnitude of endemic GI associated with drinking water in the US.

Future Activities:

We propose to monitor the GW distribution system for 9-10 months using electronic pressure loggers and build two automated water monitoring and sampling (AMS) units that will continuously monitor pressure, turbidity, chlorine residual, pH, and temperature. The AMS units will have the ability to automatically collect water samples immediately after a low pressure event or other unusual change in water quality, and to alert the field operator that sample collection is occurring. The samples will be analyzed for total coliform, E. coli, heterotrophic plate count, P. aeruginosa, A. hydrophilia, C. perfringens and coliphage. Both plant effluent water and distribution system locations will be monitored using the AMS units. Routine water samples of the treatment plant effluent water and from strategic points in the distribution system will be collected and analyzed to provide a basis for comparison to post-event samples.

Journal Articles:

No journal articles submitted with this report: View all 12 publications for this project

Supplemental Keywords:

water, drinking water, distribution system, exposure, risk, health effects, human health, pathogens, epidemiology, modeling,, RFA, Scientific Discipline, Health, Water, Environmental Chemistry, Health Risk Assessment, Epidemiology, Risk Assessments, Biochemistry, Drinking Water, groundwater disinfection, health effects, microbial contamination, bacteria, human health effects, waterborne disease, other - risk assessment, exposure, microbial effects, treatment, human exposure, microbial risk, water disinfection, groundwater contamination, water quality, dietary ingestion exposures, drinking water contaminants, drinking water treatment, human health, gastrointestinal health, groundwater, gastrointestinal health effects, exposure assessment

Progress and Final Reports:

Original Abstract

2003 Progress Report

2005 Progress Report

2006 Progress Report

2007

Final Report