that they can arise from many non-human sources and subsequently persist in the
environment [3]. More broadly, FIB in coastal urban regions could arise from a
variety of different sources [7] including leaking sewer lines [24], decaying wrack
[25], beach sands [16], algae [26] and aquatic vegetation [27], or coastal wetlands
with birds and waterfowl [28]. Septic systems in non-sewered areas are sometimes a
source as well [29], as are livestock in agricultural areas [30] and pets in suburbia
[31]. Urban development generally correlates with high FIB in surface waters
arriving via runoff or dry-weather drains, but individual sources are mostly
unknown [32, 33]. Evaluating recreational waters by FIB assays is further complicated because FIB survive differently than most pathogens [34], leading to unnecessary beach closures, and they can become non‐culturable but still viable, giving
an erroneous illusion of safe water [35].
Clearly, with the many different potential FIB sources in recreational waters,
effective water quality management requires more information than FIB monitoring data alone can provide. Fortunately, new MST methodologies and approaches
developed and tested over the past decade are now available that provide reasonably accurate differentiation of specific sources of fecal pollution [3, 5, 36].
2 The Drivers for Microbial Source Tracking
2.1 Total Maximum Daily Load Program
In the USA much of the MST research and application has occurred in the
development of TMDLs to meet the requirements of the US Clean Water Act
[37–39]. A TMDL is a regulatory term that describes the maximum amount of a
pollutant that a body of water can receive and still meet established water quality
standards. Waters that do not meet regulatory standards for designated uses are
listed as impaired waters. Designated uses of waters include fishing, swimming,
aquatic life support, and drinking water. A TMDL assessment report is required for
impaired waters. A TMDL assessment report is followed by developing a TMDL
implementation plan with the goal of improving the quality of a water body listed as
impaired.
High FIB concentrations in the USA are typically the major cause of surface
water impairments and are subject to the TMDL regulatory program. For example,
in Virginia (USA) concentrations of FIB cause the largest number of impairments;
50 % of assessed rivers/streams, 1.3 % of assessed lake areas, and 3.4 % of assessed
estuarine waters are listed as impaired for recreational use [40]. Across a watershed,
a variety of potential FIB sources can exist, including livestock and poultry
operations, urban runoff, leaking sanitary and storm sewers, large wildlife and
migratory bird populations, and pets such as dogs and cats. Identifying the different
sources of fecal contamination in a watershed is needed for developing and
implementing TMDLs and to evaluate the effectiveness of best management
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B. Badgley and C. Hagedorn
environment [3]. More broadly, FIB in coastal urban regions could arise from a
variety of different sources [7] including leaking sewer lines [24], decaying wrack
[25], beach sands [16], algae [26] and aquatic vegetation [27], or coastal wetlands
with birds and waterfowl [28]. Septic systems in non-sewered areas are sometimes a
source as well [29], as are livestock in agricultural areas [30] and pets in suburbia
[31]. Urban development generally correlates with high FIB in surface waters
arriving via runoff or dry-weather drains, but individual sources are mostly
unknown [32, 33]. Evaluating recreational waters by FIB assays is further complicated because FIB survive differently than most pathogens [34], leading to unnecessary beach closures, and they can become non‐culturable but still viable, giving
an erroneous illusion of safe water [35].
Clearly, with the many different potential FIB sources in recreational waters,
effective water quality management requires more information than FIB monitoring data alone can provide. Fortunately, new MST methodologies and approaches
developed and tested over the past decade are now available that provide reasonably accurate differentiation of specific sources of fecal pollution [3, 5, 36].
2 The Drivers for Microbial Source Tracking
2.1 Total Maximum Daily Load Program
In the USA much of the MST research and application has occurred in the
development of TMDLs to meet the requirements of the US Clean Water Act
[37–39]. A TMDL is a regulatory term that describes the maximum amount of a
pollutant that a body of water can receive and still meet established water quality
standards. Waters that do not meet regulatory standards for designated uses are
listed as impaired waters. Designated uses of waters include fishing, swimming,
aquatic life support, and drinking water. A TMDL assessment report is required for
impaired waters. A TMDL assessment report is followed by developing a TMDL
implementation plan with the goal of improving the quality of a water body listed as
impaired.
High FIB concentrations in the USA are typically the major cause of surface
water impairments and are subject to the TMDL regulatory program. For example,
in Virginia (USA) concentrations of FIB cause the largest number of impairments;
50 % of assessed rivers/streams, 1.3 % of assessed lake areas, and 3.4 % of assessed
estuarine waters are listed as impaired for recreational use [40]. Across a watershed,
a variety of potential FIB sources can exist, including livestock and poultry
operations, urban runoff, leaking sanitary and storm sewers, large wildlife and
migratory bird populations, and pets such as dogs and cats. Identifying the different
sources of fecal contamination in a watershed is needed for developing and
implementing TMDLs and to evaluate the effectiveness of best management
270
B. Badgley and C. Hagedorn