Recreational water
    in the Great Lakes
Beaches | Boating | Swimming
Critical contaminants

Swimming
Erie | Huron | Michigan | Ontario | Superior

Lake Erie
The major human health concern for recreational use of Lake Erie waters is microbiological contamination (bacteria, fungi, viruses, and parasites). Human exposure occurs primarily through ingestion of polluted water, and can also occur through the entry of water into the ears, eyes, nose, broken skin, and through contact with the skin. Gastrointestinal disorders and minor skin, eye, ear, nose and throat infections have been associated with microbiological contamination.

Recreational water quality impairment includes situations where partial body contact recreation standards are exceeded. To be complete, an assessment needs to evaluate all recreational water use activities where total or partial body water contact may occur. This includes primary activities such as swimming, windsurfing and water skiing, and also situations where swimming may occur in open waters during secondary contact activities, such as boating and fishing.

Federal, state and provincial recreational water quality guidelines recommend bacterial levels below which the risk of human illness is considered to be minimal. When contaminant indicator levels in the bathing beach water reach levels that indicate contaminants may pose a risk to health, public beaches are posted with a sign warning bathers of the potential health risk.

Lake Huron
For more information about the recreational use of Lake Huron water, please see the beaches section.

Lake Michigan
The Great Lakes are an important resource for recreation, including activities such as swimming and sailboarding which involve direct bodily contact with the water. Apart from the risks of accidental injuries, the major human health concern for recreational waters is microbial contamination by bacteria, viruses, and protozoa. Chemical pollutants may also pose health risks, but exposure to disease-causing microorganisms from sources such as untreated or poorly treated sewage is a greater risk.

Studies have shown that swimmers and people engaging in other recreational water sports have a higher incidence of symptomatic illnesses such as gastroenteritis, otitis, skin infection, conjunctivitis, and acute febrile respiratory illness (AFRI) following activities in recreational waters. Although current studies are not sufficiently validated to allow calculation of risk levels, there is some evidence that swimmers and bathers tend to be at a significantly elevated risk of contracting certain illnesses (most frequently upper respiratory or gastro-intestinal illness) compared with people who do not enter the water. In addition, children, the elderly, and people with weakened immune systems are those most likely to develop illnesses or infections after swimming in polluted water.

Despite these studies, there are challenges in establishing a clear relationship between recreational water exposure and disease outcomes. Less severe symptoms resulting from exposure to microorganisms are not usually reported, which makes statistics on cases related to recreational water exposure difficult to determine. In addition, the implicated body of water is not often tested for the responsible organism and when it is tested the organism is not usually recovered from the water. With the exception of gastro-intestinal illness, a direct relationship between bacteriological quality of the water and symptoms has not been shown -- a causal relationship exists between gastrointestinal symptoms and recreational water quality as measured by indicator-bacteria concentration. Therefore, research efforts are focusing on conducting epidemiological studies to better establish the relationships between diseases and the presence of microorganisms in the water.

Lake Ontario
For more information about the recreational use of Lake Ontario water, please see the beaches section.

Lake Superior
Chemical contaminants such as polycyclic aromatic hydrocarbons (PAHs) have been identified as a possible concern for dermal (skin) exposure in recreational waters. Dermal exposure to contaminants such as PAHs in sediment may occur when people swim in the water or come into contact with suspended sediment particulates in the water. PAHs adsorbed to these particulates would adhere to the skin. Research is ongoing to evaluate potential health effects of this route of exposure, including skin rashes and the potential to cause systemic effects, such as cancer.

A lifetime risk assessment from dermal exposure to PAHs in the St. Mary’s River (Ontario, Canada) indicates that a lifetime health risk of skin cancer was well below the negligible risk range at inshore locations, but that some upstream sites had risk values higher than the negligible risk range and this may be cause for some concern. Strategies to reduce risk were developed with communities where the risk of exposure to PAH from recreational water use was increased.

A key risk reduction recommendation was to take a bath or shower within 24 hours after a swim, thereby removing virtually all of the PAHs on the skin. Other sites in the Lake Superior basin where there are concerns about dermal contact with PAHs through swimming or wading include: two sites that are part of the St. Louis River Area of Concern (AOC) -- Stryker Bay (part of the Interlake Superfund site in Duluth, Minnesota) and Hog Island inlet of Superior Bay in Superior Wisconsin; and a section of the Ashland, Wisconsin waterfront -- due to contamination from the Ashland coal tar site.

Human Health and the Great Lakes design and maintenance provided by
the Great Lakes Commission

Photos: Great Lakes National Program Office of the U.S. EPA
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