The following links are to State of Florida Department of Health (DOH) webpages with information about water quality sampling at local beaches in and near Key Biscayne.
Main Page: DOH "Florida Healthy Beaches Program"
Since August 2002, the health deparment in Miami-Dade County and other coastal counties have collected water samples at local beaches on a weekly basis. These beach water samples are analyzed for enterococci and fecal coliform bacteria. High concentrations of these bacteria may indicate the presence of microorganisms that could cause disease, infections, or rashes. County health departments issue health advisories or warnings when these conditions are confirmed.
Miami Dade County Beach Water Quality Sampling Locations and Results
Beach Water Quality Sampling locations within Miami-Dade County are shown on an interactive map. Weekly results of tests are given in tabular form below the map for each location and descriptions of sampling/result parameters are given below the results. Four sampling points (SPs) are located in Key Biscayne: Cape Florida Park, Crandon Park - Key Biscayne (North), Crandon Park South and Key Biscayne Beach. Two sampling points are located in Virginia Key: Dog Beach and Virginia Beach.
Beach Water Sampling Result History for Key Biscayne Beach (Sampling location is at the Key Biscayne Beach Club)
Why should I be concerned about water quality?
Water quality is a concern because bacteria and viruses associated with fecal indicator bacteria (FIBs) affect human health, particularly the very young, the elderly, and those with weakened immune systems. Swimming in water with high levels of FIBs can cause illnesses such as:
Florida Department of Health Beach Water Sampling Program
Lab tests conducted on water samples collected weekly by the FDOH from the four Key Biscayne ocean beach locations look for the presence of enterococci bacteria (FDOH Florida Healthy Beaches Program, 2018). The presence of enterococci is used as a saltwater quality indicator on the recommendation of the U.S. Environmental Protection Agency (USEPA; EPA, 2015).
If enterococci are present above a certain number after a 24-hour incubation period, FDOH staff returns to the same location to take another sample. If the results are again above the threshold for recreational water quality, the FDOH is required by law to issue a Swimming Advisory to the municipality in the vicinity of the beach.
Florida Healthy Beaches Program testing result categories as reported by the Miami-Dade County FDOH are:
- Good = 0-35.4 enterococci per 100 milliliters of marine water
- Moderate = 35.5-70.4 enterococci per 100 milliliters of marine water
- Poor = 70.5 or greater enterococci per 100 milliliters of marine water
This process is codified in State of Florida Statute 514.023 Sampling of beach waters; and public bathing places; health advisories. This means the FDOH, including its County offices, have the jurisdiction to issue beach swimming advisories (Florida Statutes, 2018).
What Do Enterococci Levels Tell Us About Water Quality and Safety?
Statewide beach water quality tests look for enterococci because these bacteria are a indicator for other harmful bacteria associated with the human intestinal tract. (Herrin, 2018). It is these other bacteria that can make people sick. However, “enterococci have a greater correlation with swimming-associated gastrointestinal illness in both marine and fresh waters than other bacterial indicator organisms, and are less likely to "die off" in saltwater” and “it is difficult to test waters for every possible type of disease-causing bacteria” (USEPA, 2015).
The presence of enterococci does not mean that the water is contaminated with human sewage. According to Boehm and Sassubre (2014), “The use of enterococci as indicators of human fecal pollution or contamination can be problematic, however, because enterococci are also found in animal feces and on plants.” Enterococci species are found in the guts of mammals and birds as well as in soils, land and marine plants and beach sand. It is possible that some of the bacteria are associated with the decay of sargassum seaweed that has accumulated in large amounts in recent months.
Additional sampling and testing (“source tracking”) is required to identify the sources of enterococci (e.g., human, bird) in beach water samples. These analyses look for bacteroides shown to be closely associated with certain mammals and birds and generally take longer than the 24-hour FDOH analyses (Herrin, 2018).
If the FDOH issues a beach advisory, it is required by law to notify the local office of the Florida Department of Environmental Protection (DEP) who “shall promptly investigate wastewater treatment facilities within 1 mile of the affected beach waters … to determine if a facility experienced an incident that may have contributed to the contamination …” (Florida Statutes, 2018).
How to Find Water Sampling Info for Key Biscayne
The Florida Healthy Beaches Program webpage allows users to search for beach sampling info by County (note: Dade is used instead of Miami-Dade) and then by beach sampling location from a table or via a Google map of the area of interest. Blue symbols on the map represent each sampling location. A mouseover of the symbol gives the location name, last sample date, whether an advisory is active, and a link to view samples.
Follow this link for data for Cape Florida Park, Crandon Park South and Crandon Park North on page 1 of 5 for Dade sampling locations. Follow this link for Key Biscayne Beach (the Beach Club) on page 2. Click on “View Samples” to see the sampling and analytical result history for each location.
Boehm A.B. and Sassoubre L.M. 2014 Feb 5. Enterococci as Indicators of Environmental Fecal Contamination. In: Gilmore MS, Clewell DB, Ike Y, et al., editors. Enterococci: From Commensals to Leading Causes of Drug Resistant Infection [Internet]. Boston: Massachusetts Eye and Ear Infirmary; 2014-. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24649503
Florida Department of Health, 2018. Florida Healthy Beaches Program
Florida Statutes, 2018. Chapter 514.023 Sampling of beach waters; and public bathing places; health advisories
Herrin, J., 2018. Personal Communication, Source Molecular Laboratories (September 12-13, 2018).
US Environmental Protection Agency, 2015. Recreational Water Quality Criteria, OFFICE OF WATER 820-F-12-058 (PDF)