by Alisha Davidson, PhD
ML&SA Research & Development Coordinator
As waters warm up this summer, riparians head to the beaches and into the water. While the vast majority of inland and Great Lakes waters are safe for recreation, users should be aware of the potential for contamination and resulting illness. Freshwater lakes and rivers can be contaminated with germs from failing septic systems, animal and human waste deposited near or in the water, and water runoff following rainfall that can bring contaminants from throughout the watershed. Recreational water illnesses (RWIs) are diseases that are spread by swallowing, breathing, or having contact with this contaminated water. RWIs can include a wide variety of infections, including gastrointestinal, skin, ear, respiratory, eye, neurologic and wound infections. The most commonly reported RWI is diarrhea, which can be caused by bacteria, viruses and parasites such as Crypto (short for Cryptosporidium), Giardia, Shigella, norovirus, and E. coli O157:H7.
Incidentally, contact with contaminated water occurs not only in lakes and ponds, but is actually more common in swimming pools. Last year, an incredible 58 percent of pool filters surveyed by the Center for Disease Control were found to contain E. coli. Fifty-nine percent of filters sampled contained Pseudomonas aeruginosa.
Although the risk of contracting a RWI is higher in pools than lakes and rivers, some inland waters do have RWI-causing contaminants. Because of the risk of RWI, public health officials and some lake associations monitor lakes and beaches for contaminants. In 1986, the U.S. Environmental Protection Agency (U.S. EPA) recommended two new indicator organisms for recreational water quality assessment. They were enterococci (for both marine and fresh waters) and Escherichia coli (E. coli, for fresh waters only). These organisms were chosen based on epidemiological studies conducted at various beaches in the United States that showed a strong positive correlation between the organisms and the occurrence of swimming associated gastroenteritiss (diarrhea). As such, Michigan agencies use E. coli levels to assess water safety for recreational purposes. Results of the analysis are available after approximately 28 hours, so water-testing results are reported the following afternoon. E. coli bacteria are counted and judged against standards established by state rules. For more details on how this monitoring is completed and how the results are used to assess beach safety, visit http://www.michigan.gov/deq/0,4561,7-135-3313_3681_3686_3730-11005–,00.html. A beach is closed if monitoring conducted by the county health department determined that levels of bacteria exceed the limits established by the Michigan Public Health Code. If a beach is closed due to bacterial contamination, county health departments will continue to monitor the water quality at the beach and will permit the beach to re-open when bacteria levels fall back within acceptable levels. It is possible that a beach could be closed for swimming but other recreational activities at the beach may still be available.
To find out about lakes and beaches in your area, start with your local county health department. Ask them what beaches they monitor, and how often; what they test for; where can the public view results (and get an explanation of what they mean); and what are the primary sources of pollution for your local beach? Owners of public bathing beaches must post a sign that states whether or not the bathing beach has been tested, and if so, where the test results may be accessed.
While monitoring is voluntary, health departments are required to notify the MI Department of Environmental Quality within 36 hours of conducting a test. Results of local beach and water monitoring are then compiled in the MI Department of Environmental Quality’s BeachGuard System (http://www.deq.state.mi.us/beach/). This website reports beach water quality sampling results and beach advisories and closures for 1221 public beaches and 519 private beaches. In addition to state and local health officials, it may also be useful to contact your lake association; some associations use member funds to protect the health of riparians by testing water more frequently (or testing when local officials do not have sufficient funding).
In addition to monitoring efforts by health officials and lake associations, RWIs can be prevented through responsible action by the public using the water and beaches. With funding from the Great Lakes Restoration Initiative, the Ottawa County Health Department recommends the following ways to prevent RWI:
• NEVER feed birds – that includes seagulls, ducks and mergansers
• Keep pets off the beach and pick up any waste that is near the water (i.e., could wash into the water with rain)
• Use the restroom before swimming
• Do not swallow lake water
• Wash your hands with soap and water before eating
• Do not swim in water that smells foul
• Shower when you return home
• Avoid swimming immediately after heavy rainfall
• Contact your local health official if you think your water is contaminated
This article is intended to inform, not frighten. While there is some risk of RWI when using inland waters, the U.S. (and particularly, Michigan) has some of the cleanest recreational waters in the world, thanks to efforts by the U.S. EPA, MI DEQ and ML&SA over recent decades. Please help continue this improvement by supporting federal, state and local environmental protection efforts!