You don’t have to be swimming to be vulnerable to water pollution.

Participating in recreational water activities other than swimming does not exempt you from the health risks associated with poor water quality. Recreational water activities with limited water contact can also put you at risk of contracting an illness or infection.

Secondary contact recreational water activities are defined as activities where only your limbs (arms and legs) are in contact with the water. The defining feature of secondary contact is reduced exposure, which is why these activities are also known as limited contact activities. Canoeing, kayaking, boating, sailing, rowing, wading and fishing are examples of secondary contact recreational water activities.

While your exposure to pollutants is reduced while participating in secondary contact activities, your health risk is not nil. Even water activities where your body has very limited exposure to the water, such as fishing or boating, can make you ill.

Health Risks Associated with Secondary Contact Recreational Water Activities

Your exposure to pollutants and contamination is lower when you have secondary rather than primary contact with the water. Your risk of ingesting, inhaling, or coming in skin contact with contaminated water while participating in secondary contact recreational water activities is also reduced. However, there are still health risks associated with secondary contact activities.

There is a very substantive body of research on the health risks associated with recreational water use related to primary contact activities. Primary contact activities, like swimming and surfing, are defined as any water activity where your whole body is submerged.

Studies on the health risks involved with secondary contact recreational water activities is still emerging. It has proven a challenge for researchers to quantify how much exposure people have when engaging in limited contact activities. (Calculating how much water someone ingests while canoeing, or doing yoga on a SUP board is tricky.)

There is, however, enough scientific evidence associating secondary contact with the contraction of illnesses, such as gastrointestinal illnesses, eye infections and respiratory illnesses, for both the EPA and the Canadian Guidelines for Recreational Water Quality to have developed criteria to mitigate our health risks.

Photo by Dave Wilson, A kayak angler prepares to start fishing on Lady Bird Lake in downtown Austin, Texas.

Your level of exposure to contaminated water can increase to primary in a flash. In general your risk of exposure increases:

  • the wetter your body gets
  • the more intense the activity is
  • the closer you are the the surface of the water
  • the longer you spend out on the water
  • Ingestion
    A recent study in the Chicago area found that canoeist, kayakers, rowers, and anglers reported swallowing anywhere from 3-4mL to 10-15mL of water during their activity. While is is hard to know how much water people swallow during a limited contact activity, there is an elevated risk of contracting a gastrointestinal illness associated with these activities. Moreover, the rate of gastrointestinal illness is directly related to the amount of exposure and ingestion that happens during secondary contact.

    Skin contact
    Skin contact with contaminated water can cause rashes and other skin problems. Bacteria can enter the body through openings, such as ears, nose, eyes, and through cuts and scrapes in the skin.

    Inhaling contaminated water can lead to respiratory illnesses, and infections in the eyes, ears, and nose. The longer you are out on the water, the closer you are to the water’s surface, and the intensity of your workout all increase the inhalation of mists and aerosols.

    Photo by Matthew Kenwrick

    In the same boat: the blurry lines of exposure

    Did you just get pulled under by the fish at the end of your line? Were you tossed over board by your crew for a celebratory dunk? Did a wave just crash over your boat? Secondary contact can turn into primary contact in a hurry, depending on your recreational water activity.

    Additionally, if you are trying an activity for the first time, there’s a pretty high chance you’ll accidentally end up in the water. Accidental immersion and splashing can lead to a variety of water exposure scenarios such as illnesses affecting the skin, eyes and ears. Inhaling contaminated water, which can lead to respiratory illnesses, is another means of exposure during secondary contact activities.

    Water Quality Criteria

    The recreational water quality standards for secondary contact are set by local government authorities. These values are a health risk management decision determined by scientists based on the potential exposure and health risks associated with secondary recreational water activities.

    Secondary Contact standards for E. coli in freshwater and enterococci in marine water in Canada and the U.S.

    Canadian Guidelines for Secondary Contact in fresh and marine waters
    In Canada the guidelines for secondary contact was calculated by simply multiplying the primary-contact geometric mean guideline values by 5.

    So, for E. coli secondary contact guideline is 1000 per 100 millilitres. For enterococci is works out to be 175 per 100 millilitres.

    Freshwater – E.coli: (5X200/100mL) = 1000 E.coli/mL
    Marine water – Enterococci: (5X35/100mL) = 175 enterococci/100mL

    Single-sample max concentration of 2000 e.coli/100ml

    Ontario’s Ministry of the Environment set the standard at 500 e.coli/100ml

    EPA secondary contact guidelines
    Secondary contact category 1 : : 630 cfu/100 mL (E. coli) for freshwater and 175 cfu/100 mL (enterococci) for marine water. Secondary contact in this category is defined as activities, such as fishing, commercial and recreational boating, and limited body contact incidental to shoreline activity. These activities do not involve a significant risk of water ingestion.

    Secondary contact category 2 : 1030 cfu/100 mL (E. coli). Secondary contact activities where the risk of water ingestion occur less frequently than for secondary contact recreation 1 due to physical characteristics of the water body and/or limited public access.

    Non-contact recreation : 2060 cfu/100 mL (E. coli) and 350 cfu/100 mL (enterococci). Activities in this category include ship and barge traffic, birding, and the use hike and bike trails near a water body. Non-contact does not involving a significant risk of water ingestion. Waterbodies defined as non-contact are places where primary and secondary contact recreation should not occur because of unsafe conditions.

    Secondary contact standards for blue-green algae

    Specific criteria for reducing you exposure to cyanobacteria (blue-green algae) and toxic algal blooms when participating in a secondary contact recreational water activity does not yet exist.

    Protect yourself from harmful algae blooms by following the standards set forth for primary contact. Read more here on blue-green algae and your health.

    Photo by Dan Thibodeaux

    Research on secondary contact recreational water activities

    Read some of the latest studies on the subject of secondary contact recreational water activities.

    Health risks of limited-contact water recreation, Dorevitch S1, Pratap P, Wroblewski M, Hryhorczuk DO, Li H, Liu LC, Scheff PA., Environ Health Perspect. 2012 Feb;120(2):192-7. doi: 10.1289/ehp.1103934. Epub 2011 Oct 26.

    Water ingestion during water recreation, Dorevitch S1, Panthi S, Huang Y, Li H, Michalek AM, Pratap P, Wroblewski M, Liu L, Scheff PA, Li A., Water Res. 2011 Feb;45(5):2020-8. doi: 10.1016/j.watres.2010.12.006. Epub 2010 Dec 13.

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