Grantee Research Project Results

2014 Progress Report: Water Infrastructure Sustainability and Health in Alabama’s Black Belt

Objective:

Objectives of this study are to: (1) assess public health impacts associated with rural water supply system performance and water quality across a range of small public and private utilities in rural Alabama; (2) conduct a quantitative microbial risk assessment using measured water quality exposure data; (3) identify possible transmission pathways for waterborne pathogens in rural water supply systems; and (4) identify low-cost, practicable risk mitigation strategies to protect public health.

Progress Summary:

This project includes active surveillance of water quality across 14 different systems in a three-county area over a total period of 3 years. During this reporting period, we have concluded system-level, large-volume field sampling (household-level water quality and survey data collection; refined methods for pathogen sampling, storage, and processing; and have completed system-level sampling using dead-end ultrafiltration for indicator and molecular work). We also have concluded our planned work with water system operators.

Twelve water supplies were sampled in participating counties (two water supplies declined to participate in system-level sampling). Water samples were collected from 10 locations within each system on three sample collection rounds. All initial time point samples were collected September 2013 to January 2014, with the second and third collections taking place January 2014 to March 2014 and March 2014 to May 2014, respectively. Each water sample was assigned to one of the six possible location categories and analyzed initially for several physical-chemical parameters and microbial indicators (Figure 1). Each system had a slightly different combination of sampling locations due to variability between system infrastructure components and willingness of operators to cooperate and abide by the predetermined parameters. Sample collection locations included 26 wellhead pump stations, 1 surface water extraction point, 21 fire hydrants, 1 clean out (i.e., designated entry points into the water service used for maintenance and sampling), 7 water tower outlets, and 64 outside faucets at public buildings and private homes. Our goal was include a diversity of sample locations that then will inform the quantitative microbial risk assessment (QMRA) analysis as the primary objective of this study.

Figure 1. Sample processing of dead-end ultrafiltration samples and completed analysis to date.

We have obtained approval for our QAPP; obtained IRB approval from the University of Alabama and Georgia State University; created a field laboratory for the processing of samples and as the operational base for field data collection; trained data collection assistants; refined methods and established a library for the proposed microbial source tracking of Escherichia coli (E. coli) isolates; established communication and coordination with partners, including operators, water boards, the Alabama Department of Public Health, the U.S. Centers for Disease Control and Prevention, and local nonprofit organizations; and obtained maps and system information from operators. We have produced two publications and one dissertation, and have two more manuscripts in draft form. We have conducted a 1-day workshop with operators and managers from local water supplies on Water Safety Plans and microbial risks in drinking waters as part of our commitment to work with systems who have an interest in managing microbial risks.

Year 3 Summary Results 

Temporal and spatial trends for key water quality measures were evaluated in12 rural drinking water systems via large-volume water sampling from 10 locations within each system on three sampling dates. Tests for normality on all continuous water quality measures were performed using histograms and normal probability plots. Values for turbidity and HPC were log transformed to make patterns in these highly skewed, non-normally distributed data more interpretable. To compare the continuous variables of measured water quality (free chlorine, total chlorine, pH, turbidity, pressure and HPC) across location groups and time points, Kruskal-Wallis tests were used and box plots were generated to visualize trends. Four water quality variables (total coliforms, E. coli, enterococci, F+ RNA coliphage) are reported below as principal microbial indicators.

Future Activities:

Work in Y4 will focus on molecular analysis of these 360 system-level samples for 15 pathogens by multiple methods and using these data in integrated, stochastic risk assessment models.

Future activities include pathogen analysis of all sample concentrates. QMRA models will be constructed to make use of microbial data. 

Planned activities in Y4:

References:

[1] Claas EC, Burnham CA, Mazzulli T, Templeton K, Topin F. Performance of the xTAG^® gastrointestinal pathogen panel, a multiplex molecular assay for simultaneous detection of bacterial, viral, and parasitic causes of infectious gastroenteritis. Journal of Microbiology and Biotechnology 2013;23(7):1041-1045.

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Progress and Final Reports: