About Wisconsin Beach Health Website
A number of Lake Michigan communities
have monitored the water quality at their beaches for several decades. Many,
including Milwaukee, Racine, Kenosha, and Manitowoc have been working together
for several years to address the challenges of pollution and beach closings. In
1999, the City of
Milwaukee Health Department received a grant from the U.S. Environmental Protection Agency's (USEPA)
Environmental Monitoring for Public Access for Community Tracking (EMPACT)
program to enhance the efforts of this group and expand beach monitoring efforts
in the Milwaukee-Racine area. The Beach Health website was created in order to
improve public notification and outreach.
During 2001-02, Beach Health
was funded by the Wisconsin Department of
Natural Resources (WDNR) and Wisconsin
Coastal Management Program (WCMP). Beach Health grew with the addition of
data from several more Lake Michigan coastal municipalities to the site. In
addition, an in-water automated monitoring station transmits real-time data to
the Beach Health website. The Milwaukee Health Department uses these data in a
pilot water-quality predictive model.
2003 was the start of the full
implementation of the Wisconsin coastal beach program. The Wisconsin coastal
beach program is a collaboration between state and local environmental and
health agencies to monitor recreational waters for health risks to help people
make informed choices when they go to the beach. The Wisconsin Department of Natural Resources
coordinates the program, but local health departments have authority over public
beaches within their jurisdictions. The statewide beach monitoring program is
funded by the US Environmental Protection
Agency by a grant under the federal Beach Act of 2000.
Water-quality data from approximately 100 public beaches are listed on
the Beach Health website. Maps of beaches by
county are available along with monitoring information on the WDNR website. The Beach Health website gives the public an opportunity to view water quality data and beach advisories for Great Lakes beaches all across Wisconsin.
Advisory signs posted on the
website and at beaches throughout the state
Advisory signs were developed in 2004 to inform the public about the
current water conditions based on testing for E. coli bacteria.
The U.S. Environmental Protection Agency requires that beaches be posted with
an advisory sign informing the public of increased health risk when a water
sample exceeds 235 colony-forming units of E. coli per 100 milliliters of
The Workgroup approved that the green informational sign shall be posted at all
monitored beaches when water tests are below the USEPA standard. Local health
departments have the option of posting the blue
"Good" sign together with the green sign, if they so choose.
Some health departments, against the Workgroup's recommendation, have chosen not
to post the green sign.
The Workgroup approved that the yellow
"Caution" sign shall be posted when the USEPA health standard is
exceeded. This sign remains posted until the next daily sample shows the
conditions have changed.
The Workgroup approved that the red
"Closed" sign shall be posted when a water sample shows more
than 1000 colony-forming units of E. coli per 100 mL are present, or under any
other conditions that the local health department considers there to be an
increased public health risk at the beach. This sign remains posted until the
next daily sample shows conditions have improved.
Beach Water Quality Monitoring; Applicability of Results
The results from E. coli tests can take 18 to 24 hours. It is important
to note that an advisory for a given day is based on the results of samples
taken the previous day. E. coli levels can also vary from hour to hour and from
meter to meter in the lake environment. Consequently, the posted advisory sign
may not reflect the actual conditions present in the water.
"Fast" vs "Traditional" E. coli Testing
"Fast Test" is based on a technology that allows the "most probable number
(MPN)" of E. coli to be calculated in as few as 18 hours. Currently, many
labs use IDEXX Colilert as a fast test.
The "Traditional" membrane
filter method is based on E. coli growth on a special nutrient surface.
The number of colonies that grow on the surface are a direct count of the number
of E. coli present in a sample and are called "colony forming units" or
So why 235 CFU/100 mL and 1000 CFU/100 mL?
What is the difference between CFU/mL and MPN/mL? CFU means “Colony Forming Unit” and MPN is “Most Probable Number”. The traditional membrane filtration tests for bacterial water quality actually count ‘colonies’ of bacteria and thus is reported as CFU. However, the newer defined substrate tests such as Colisure or Colilert report data as MPN which is a statistical representation of what level of
E. coli is likely present in a sample. For the purposes of reporting, these terms have been used interchangeably.
The “Advisory” standard of 235 CFU/100 mL (E. coli in water) was adopted based upon data from three USEPA studies conducted in the late 1970s (2-4). These studies indicate that
E. coli and/or Enterococci are the best bacterial indicators to assess the risk of acquiring a gastrointestinal illness as a result of using recreational waters. These levels are the original recommendation of USEPA and they were reaffirmed in a revisiting of the issue in 2002 (1).
Additional epidemiological studies are set to take place during the BEACH program and should be completed by 2006. These studies are detailed in the following reports and are available free in *.*.pdf format from the USEPA website (www.epa.gov).
1) USEPA, 2002. Implementation Guidance for Ambient Water Quality Criteria for Bacteria. U.S. Environmental Protection Agency. EPA-823-B-02-003. May 2002 Draft.
2) USEPA, 1986. Ambient Water Quality Criteria for Bacteria–1986. U.S. Environmental Protection Agency. EPA-440/5-84-002.
3) USEPA. 1984. Health Effects Criteria for Fresh Recreational Waters. U.S. Environmental Protection Agency. EPA-600/1-84-004.
4) Cabelli, V. J. 1983. Health effects criteria for marine recreational waters. U. S.
Environmental Protection Agency, Cincinnati, OH. EPA-600/1-80-031.
The epidemiological studies indicated that a level of 235 CFU of E. coli/100mL of recreational water is approximately equal to 8 cases of gastrointestinal illness per 1000 recreational water users.
The “Closure” level of 1000 CFU E. coli/100mL was adopted by the WDNR based upon data from the studies mentioned above and represent a risk of approximately 14 cases of gastrointestinal illness per 1000 recreational water users.
Why E. coli and not Enterococci?
In the study listed as #2 above, E. coli levels were found to have the best correlation with highly credible cases of gastrointestinal illness in freshwater systems. While Enterococci had the best correlation in marine systems, either
E. coli or Enterococci were deemed acceptable fecal indicators in freshwater systems. In addition to the USEPA studies, the WDNR conducted a study prior to the first BEACH season of 2003 in which 3 state park beaches were monitored for
E. coli and Enterococci. The E. coli yielded the most reliable and consistent results in their study
For questions regarding beach advisory or monitoring, contact:
Gregory T. Kleinheinz, R.S., Ph.D.
Director, Environmental and Public Health Microbiology Laboratory
Oshkosh B'Gosh Associate Professor of Microbiology
Department of Biology and Microbiology
University of Wisconsin - Oshkosh
For questions regarding the website, contact:
Wisconsin Beach Health Support Staff
U.S. Geological Survey