Description:
Currently, the quality of drinking and recreational waters is estimated through the measurement of fecal bacteria such as Escherichia coli and Enterococci. However, since it takes time for the microorganisms to grow and be detected, their utility as indicators of human fecal contamination and their ability to minimize contact with contaminated waters is limited (by the time you get results, people will have long been in contact with the contaminated water). One way of decreasing the analysis time is to examine chemical indicators, which do not require the many hours to detect or measure the analyte. Chemical indicators may also be useful in tracing sources of fecal contaminations in watersheds in which the total maximum daily loads (TMDLs) of fecal organisms exceed the established limits. Compounds from a variety of classes, such as those which are produced and excreted by humans (coprostanol, urobilin, bile acids), those which are ingested nearly exclusively by humans (certain pharmaceuticals, caffeine, nicotine), and those which can enter the human waste stream (surfactants, fluorescent whitening agents, musks) have all been individually suggested for use as chemical indicators of human fecal contamination, but no one has tried to unite all of the variety of compounds in a single method. Most of the published studies did not investigate if there were a relationship between the concentrations of the compounds and illnesses caused by human fecal material, or even to compare the concentrations of the chemical indicators to the microbial ones, so there is no measure of the utility of the compounds to act as indicators.
The purpose of this task is to analyze for a suite of the above mentioned chemical indicators. Once the method has been developed (or ascertained), a sampling study will determine if the chosen compounds are found in water known to be impacted by human fecal contamination (for example, directly downstream from a sewage outfall), as well as to determine if they are too persistent to be useful as indicators of occurrence (by measuring their concentrations in relatively pristine areas). At all studied locations, additional water samples will be collected and analyzed for E. coli and Enterococci to determine if there is there is any correlation between the concentration of chemicals and microorganisms. This research will utilize liquid chromatography/ mass spectrometry as the method of analysis. Once the method has been satisfactorily developed, the relationship between the concentration of the compounds and human health impacts will be investigated in association with NHEERL in an epidemiological study; the bulk of this epidemiological work will be completed in a separate task. Ultimately, the method would be used by the Office of Ground Water and Drinking Water, as well as other federal, state and local agencies, to protect the public's health by screening recreational and drinking waters.
Keywords:
HUMAN FECAL CONTAMINATION, PHARMACEUTICALS. CAFFEINE, COPROSTANOL, SURFACTANTS, CHEMICAL INDICATORS,
Project Information:
Progress
: In the first year of this task, the Interagency Agreement (IAG) with USGS was established, and samples were collected and analyzed at nineteen predominantly rural locations, to obtain an understanding of the spatial distribution of compounds.
In FY02, the sampling plan was focused on understanding the environmental persistence and transport of the chemical tracers, as well as the microorganisms E. coli and Enterococci. Sample sites in Arizona, Colorado, Georgia, Iowa, Minnesota, Missouri, Nevada, New Jersey, New York and South Dakota were chosen because they are known to be impacted by waste water and the USGS regional staff in the area were interested and willing to perform the additional sampling needed. At these locations, water samples were taken upstream from a waste water treatment plant effluent point, at the discharge point, as well as two samples from further downstream of the plant, to get an idea of the longitudinal distribution of the microbial and chemical contaminants. To contrast with these urban samples, samples were collected in Montana in a watershed impacted by a cattle ranch (following the same upstream/ at the point of discharge/ two downstream sampling regime), as well as a single sample at an un-impacted site in Michigan. Samples were also collected and analyzed for the chemical indicators at nine recreational water locations as part of another NERL/MCEARD contracted study "Determination of Contamination Levels of Water at Potential Beach Sites for Future Research Studies" (the microbial analyses were included in the contract).
The sampling in FY03 focused on intensive Lagrangian sampling at two locations in Iowa and Colorado. The flow of the sampled rivers were determined by a dye tracer study. This information was used to track and sample the same parcel of water, which will help to determine the environmental persistence of these compounds. Additionally, samples were collected at two recreational areas as part of the National Epidemiological and Environmental Assessment of Recreational Water Study. At each location, two samples were collected, one on Saturday and one on Sunday; personnel at the beaches interviewed swimmers, and collected data on health effects/ illness that could be attributed to the swimmer's exposure at the beach. This epidemiology study is a vital test to determine if these chemicals have merit as indicators of human fecal pollution.
In FY04, the sampling and analysis activities were shifted to another task, "Correlation of Chemical Indicators of Human Fecal Contamination to Health Effects via Epidemiology Studies" (Task 18179). The primary activities attributed to this task focused on completing manuscripts describing the research. The first of these entitled "Transport of Chemical and Microbial Compounds from Known Wastewater Discharges: Potential for Use as Indicators of Human Fecal Contamination" has undergone internal review within the EPA and USGS and will be submitted to Environmental Science and Technology in November 2004. This paper describes the results from the 2002 sampling activities. The USGS took the lead on compiling the data from the 2003 sampling year. This data set will be available early in FY05.
Relevance
:The purpose of this task is to develop, in conjunction with the USGS, a method that utilizes chemical indicators, instead of the traditional microbial indicators, to monitor both recreational and drinking water source waters for pathogens. The chemical indicators are desirable, since the analysis time is significantly shorter (2- 3 hours versus 24 hours), and it should be possible to determine source specificity (human versus animal). These two traits will help minimize human exposure to potentially dangerous pathogens. The faster one can determine if a water body is tainted, the earlier steps can be taken to minimize contact/ consumption, resulting in fewer people being exposed. The quick analysis time of the chemical indicators will also allow a faster determination of when it is safe to resume contact/ consumption. Additionally, since most waterborne pathogens that cause human illness result from contact with human fecal material, the ability to discriminate between human and animal waste will prevent unnecessary measures (beach closures, boil advisories, increased chlorine use at treatment facilities) when the contamination is zoonotic, and not anthropogenic. The Office of Ground Water and Drinking Water (OGWDW), as well as other federal, state and local agencies, should be able to use this method to protect the public's health by screening recreational and drinking waters. Since many of the compounds being focused on in this task are pharmaceuticals, it also meets one the Office of Wastewater Management's research needs: Characterizing the Presence of Pharmaceuticals in Water and Wastewater. A third benefit is that pharmaceuticals have been listed as candidates for a future Contaminant Candidate List. This project will provide occurrence information to OGWDW for some pharmaceuticals. Throughout the course of the project, oral and poster presentations at a wide variety of conferences, as well as publications as certain phases of the task are completed, should keep the scientific and regulatory community informed of our progress.
Clients
:Office of Ground Water and Drinking Water (Hiba Shukairy, Valerie Blank, Kesha Forrest)
Research Component
:CCL (CHEMICAL)
Risk Paradigm
:EXPOSURE
Project IDs:
ID Code
:none
Project type
:ORD-DW Plan
ID Code
:9421
Project type
:OMIS