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About the Great Lakes LaMPs study...
Glossary of terms
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.
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.
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.
Last modified: April 29, 2003