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 ------- |