ENVIRONMENTAL MONITORING FOR PUBLIC ACCESS AND COMMUNITY TRACKING
(EMPACT) PROGRAM MICROBIOLOGICAL MONITORING OF RECREATIONAL WATERS

Brenner, K.P.1, J. W. Martinson1, L. J. Wymer1, A. P. Dufour1, W. R. Stutts1, and S. A. Schaub2

1U. S. Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, Ohio. 2U. S. Environmental Protection Agency, Office of Water, Office of Science And Technology, Washington, DC.

Year of
Thirty	Years

Through	Pa

1 Guidelines for the collection of recreational water samples
were last issued in 1968.

1 Water quality is currently determined using the average of the
results from 5 water samples, taken over a 30-day period.

1 Obviously this does not give timely, accurate information for the
public or public health officials.

Develop and evaluate a new monitoring protocol that is scientifically
defensible, takes into account the various sources of variability, has
national applications, and can be translated into a simple system the
public can use to make personal decisions about risks associated with
recreational water activities (swimming, jet skiing, canoeing, surfing,
diving, etc.).

1 Examined 5 representative fresh, estuarine, and marine
water beaches.

1 Sampling design accounted for variations in water depths, length of
beach, permissible swimming area, temporal factors (hourly, daily
and seasonal variations), weather, tides/currents, and number of
bathers/animals on beach.

Samples were collected from each of nine locations within the limits of the beach
bathing area, each location being determined by an associated transect and zone, as
illustrated in Figure 2. A transect is defined as an imaginary line through a fixed
point on the beach and forming a right angle with the shoreline. A zone is defined
as a contour line of equal water depth parallel to the shoreline .

TYPES OF SAMPLES COLLECTED:

. Basic Sampling - Twice a day (9 AM and 2 PM) at each location
for 36 days.

. Hourly Sampling - Ten times a day at each location at hourly
intervals (9 AM - 6 PM) for 14 days (1 week eachmonth).

. Replicate Sampling - Two or ten samples per location for 8 days
(4 days each month).

. Depth Sampling - One to three depths per location for 4 days (2
days each month).

COLLABORATORS

Bacterial levels were highest:

¦	in ankle-deep water; lowest in

chest-deep water.

¦	in the morning vs. the afternoon.

¦	on cloudy days vs. sunny days.

¦	after substantial rainfall.

¦	with onshore winds.

No differences in bacterial levels along the beach at equal
water depth.

Bacterial levels measured on any given day were of little
value in predicting water quality more than one day in the
future.

OS EPA Method 1603
Freshwater beaches

US EPA Method 1600
Estuarine and Marine beaches

Escherichia coli colonies on
modified mTEC agar.

Enterococci on mEI agar.

Partnering


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