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projects > preliminary characterization of the microbial ecology of the Upper Florida Aquifer and literature review > scope of work

Project Scope of Work

Project Scope of Work 2003

Preliminary Characterization of the Microbial Ecology and Literature Review of Microbe-induced Changes in Metal Mobility and Toxicity in Aquifer Storage and Recovery Waters

1. Recently, as part of the Comprehensive Everglades Restoration Plan (CERP) Aquifer Storage and Recovery (ASR) Regional Study project, the project delivery team (PDT) has proposed that microbiological studies be performed during the different phases of ASR well field planning, development, and use. The focus of ongoing research in ASR microbiology is from the perspective of public health and these efforts are designed to address regulatory issues, such as survival of indicator microorganisms and pathogens. This scope of work includes a suite of assays that will compliment the ongoing public health microbiology investigations and address concerns about the impact of injected waters on the native microbial ecology and biogeochemistry. Additionally, a literature review will be conducted to compile, synthesize and assess the published literature on microbially induced changes in mobility and toxicity of metals associated with the aquifer matrices in geologic formations that have been designated as storage zones for ASR systems located in south Florida.

2. The effort proposed here will provide baseline genetic and physiological characterizations of the native microbial populations in selected aquifer waters. These data will be of critical importance during the monitoring of ASR systems if issues other than those of regulatory interest (e.g., arsenic mobilization, decreased well production, pathogen survival) are to be addressed. Collectively, these baseline data will provide a standard to which samples collected after the ASR systems are in operation can be compared.

3. Ideally, characterization of microbial ecology would be performed for native, injected, and recovered water to fully understand the impacts of ASR on the native ecology. At this time, only native water is available for this preliminary characterization. If water samples can be taken from water treatment systems with similar processes expected for the injected water, this scope of work could be modified to add analysis of these samples.

4. Currently, discussions on and decisions about the influence of injected waters on the native microbial population's ability to alter geochemical processes is proceeding without an organized summary of the literature that pertains strictly to the aquifers in south Florida that have been designated for potential use in the CERP. A document that provides such a summary will assist in the development of ASR well development and monitoring strategies.

5. Objectives.

a. Task 1 - Preliminary Characterization of Microbial Ecology of ASR Waters.

1) Characterize the diversity of the microbial communities in native waters associated with CERP ASR wells -

Provides an inventory of the native microbial communities present.

2) Characterize the physiological capacity of the microbial communities in native waters associated with CERP ASR wells -

Provides a measure of which types of nutritional substrates (e.g., proteins, carbohydrates, fatty acids) the native microbes are capable of using for growth and maintenance.

3) Determine the secondary productivity (i.e., bacterial productivity) in the microbial communities in native waters associated with ASR well systems -

Provides rates of metabolism for the native microbe communities.

4) Determine the bacterial abundances and biomass in native waters associated with ASR well systems -

Provides counts and sizes of the native microbe communities.

b. Task 2 - Literature Review of Microbe-induced Changes in Metal Mobility and Toxicity in ASR Waters.

1) Review the literature on microbial interactions with geologic substrates and how these interactions facilitate the mobilization and toxicity of associated metals.

2) Review the literature on the geology and associated geochemistry from studies on aquifers that are currently being used or are projected to be used for ASR systems in south Florida.

6. Preliminary Characterization of the Microbial Ecology.

a. Sampling scheme and parameter list:

1) Collection of a native water sample from each well during the time when sampling of the wells is conducted for the ASR Pilot Project Source Water Characterization task. The collection of the samples will be coordinated with

Mr. Jeff Hendel, Corps, and Mr. Mike Bennett, SFWMD.

For the Hillsboro site, a contractor (Foster Wheeler) procured by the Corps will be responsible for purging the well associated with the scope of work (SOW). For the remaining sites, the drilling contractor(s) currently installing the wells will be responsible for purging the wells associated with this SOW.

Sampling of the wells is dependent upon completion of the wells presented on Table 1. Table 1 also provides an estimated timeframe for completion of the wells to be sampled as part of the SOW. The actual completion dates are contingent on the drill crew's progress each day of drilling, weather, and problems encountered in the field.



Well Location Sampling Schedule Number of Samples
Hillsboro September/October 2003 1
Caloosahatchee (Labelle) November 2003 1
Port Mayaca September/October 2003 1
Moore Haven March/April 2004 1
Kissimmee March/April 2004 1

One primary sample from each exploratory well will be collected and analyzed by USGS as part of the SOW. In addition to the primary samples, one field duplicate sample will be collected at random from one exploratory well for a total of six samples to be collected and analyzed for Task 1.

a) Parameters to meet the objectives outlined above:

(1) Community DNA extraction and diversity assessment using PCR and denaturing gradient gel electrophoresis (DGGE) (Objective 1).

(2) Assessment of community physiological capacities using BioLog EcoPlates (aerobic & facultative anaerobic heterotrophic bacteria) and AN plates (anaerobic bacteria) (Objective 2).

(3) Assessment of secondary bacterial productivity using 3H-leucine as a measurement of protein turnover (Objective 3).

(4) Perform total direct counts using fluorescent stains and microscopy to determine bacterial abundances. These same samples will be used to measure the volume of individual bacterial cells and these data will be used to calculate the bacterial biomass in each sample. All data will be normalized to biomass units so all data will be directly comparable (Objective 4).

b. Methods:

The methods listed that address each of the stated objectives will provide a suite of data that can be used to not only assess the microbial community structure and function in each type of water sampled, but also provide baselines to which future samples can be compared. This multi-phase approach provides a tool with which changes in the microbial communities can be monitored. If changes in the microbial community structures in native and stored waters are occurring, the microbial ecology approach will detect and quantify these changes. These data in conjunction with geochemical data from the same waters will also provide an assessment tool that will assist in the determination of the influence that injected waters and the associated microbial community may have on geochemical processes, such as release of trace metals from geologic features in the aquifer.

The underlying hypothesis of this SOW is the organic carbon, nutrient, and oxygen concentrations that are being injected into the native aquifer are at relatively high concentrations. These increases will shift the microbial community structure to one that favors those bacteria that can more rapidly utilize the new nutrient and oxygen sources. Such shifts in the community and chemical equilibria in the native and stored waters may enhance geochemical processes, such as trace metal mobilization, and contribute to the deterioration of the quality of the stored water and reduction in ASR well productivity.

The USGS will provide the necessary personnel, sampling equipment, and analytical equipment necessary to perform the microbial ecology work associated with this SOW. The sampling procedures for the microbial ecology analyses are derived from non-routine procedures. The sampling procedures are research based and are not discussed in this SOW. However, the sample handling and equipment must be performed in as sterile as possible an environment to prevent cross contamination of microbiological organisms.

7. Literature Review. Peer reviewed literature that describes microbial interactions with geologic substrates and how these interactions promote the mobilization and changes in toxicity of metals will be collected and systematically reviewed. Non-peer-reviewed literature will also be included when pertinent to the topic, but will not be the focus of the literature review. Literature sources will be searched and collected -using internet search engines (e.g., ScienceDirect, USGS Intranet Library, ISI Web of Science, PubMed, Z39.50) and personal communications and possible visits with federal, state and private organizations that are involved with the types of research that would compile publications and reports pertinent to these topics. The final product will be a reference tool that can be used in the development of subsequent tasks that address this issue. The product of this review will be a synthesis of this body of literature and will focus on the following areas:

a. Background information of how microbes interact with geological material to enhance mobilization and alter toxicity in selected metals.

b. Specific examples of geochemical analyses of groundwaters in south Florida that have shown increases in specific metals over time.

c. Synthesis and interpretation of this body of literature.

d. Identify concepts that are of critical importance to our understanding of how injected waters may alter the mobilization and toxicity of metals in aquifer matrices.

e. Identify concepts that need to be addressed but have not yet been studied.

f. Provide recommendations on what and where problems associated with microbially induced mobilization of metals may occur.

g. Provide a bibliography of pertinent references that can be used as a resource by researchers, planners and administrators.

8. Reports. The USGS will provide the Corps with quarterly status reports that are brief summaries of the tasks completed during the quarter and status of the ongoing effort. These reports should describe any issues or concerns that may impact completion of tasks. Generally, the quarterly status report is no more than one page.

A final report for Task 1, an USGS Open-File Report, will be ready for distribution within 4 months following the last sampling event. This report will present the results that meet the objectives of the study, describe the methods used, and provide tables of the sampling results. To reduce report costs, the final report may be a web-based report only with no hard-copy publication. In the future, the USGS may use the results of this effort to publish one or more journal articles at no additional cost to the CERP project.

Mr. John Lisle can present preliminary results of the Task 1, September 2003 sampling event at a PDT meeting as requested prior to the distribution of the final report.

The final report for Task 2 will be a second USGS Open-File Report that will be ready for distribution in March 2004. This report will present results that meet the objectives of Task 2 of this scope of work. To reduce report costs, the final report may be a web-based report only with no hard-copy publication.

9. Schedule.

Task 1
Work Order Issued August 2003
Collection of water samples September 2003 - April 2004
Analysis of water samples October 2003 - May 2004
Presentation to PDT To be determined
Documentation of results 4 months following the last sampling event (to be coordinated with the Final Report)
Final Report 4 months following last sampling event

Task 2
Work Order Issued August 2003
Final Report March 2004

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