As triathletes, we’re no strangers to jumping into roaring rivers, murky lakes, and churning oceans. Open-water swimming is part of the swim-bike-run deal. We talk a lot about taking the proper safety precautions when it comes to the actual act of swimming in a big body of water, but before you jump into your local swimming hole, you should also be aware of the potential microscopic dangers of water quality for swimming.
Dr. Rasha Maal-Bared, microbiologist and member of the Edmonton ITU Water Quality Committee in Edmonton, Alberta, Canada, said, “When you think of freshwater bodies or marine beaches, all of those can potentially be contaminated, and those contaminants can be microbiological or chemical in nature.”
Dr. Maal-Bared noted that swimmers can be exposed to water contaminants by swallowing them, making skin contact, and even inhaling the barely-visible water vapor mist that rises from the water’s surface. The worry most triathletes likely have regarding water quality surrounds the ever-important GI system.
“Recreational water use is actually associated with a higher rate of gastrointestinal illness, but can cause a range of respiratory illnesses and skin infections,” said Dr. Maal-Bared of the importance of paying attention to water quality for swimming. “That’s why we have to monitor recreational water usage so closely.”
The types of pathogens water specialists are concerned about vary. Some of the ones microbiologists focus on are Cryptosporidium, Campylobacter, pathogenic E. coli, and Salmonella, along with hundreds of environmental degradation-resistant viruses.
Lance Panigutti, a Colorado-based race director of 12 years who has put on over 450 endurance events and 120 triathlons, has lucked out with water quality during his career.
“I’ve only had to adjust a race due to water quality one time,” remembered Panigutti. “It was a late May race in Colorado and it rained for a week straight before the race. The runoff caused high E. coli levels, so we had to cancel the swim.”
Even still, Panigutti is also focused on things like water temperatures, debris, and working with local officials to meet their standards of water safety. Each state in the U.S. is required to report swim beach contaminant levels to its Department of Public Health. The bacterial and chemical levels must fall within state and federal guidelines for what is safe to swim in, otherwise, the swim beach must close (or the swim portion of a race must be canceled) until water testing returns to approved measurements.
“Most of our venues are municipal venues, and they do their own water testing because they have swim beaches,” said Panigutti. “But I’m also looking out for things at the swim start and exit like rocks, fish hooks, glass, and other things that can visually affect water quality.”
Speaking of hydro-disturbances we can see, algal blooms are something to avoid at all costs as a swimmer.
“If the water has algae, you probably want to stay out of it,” said Dr. Maal-Bared. “Certain algal toxins are neurotoxins and can affect brain function.”
The swim portion of the 2019 Ironman Louisville triathlon was canceled due to a miles-long toxic algae bloom in the Ohio River. It may have seemed frustrating at the time, but race directors simply can’t allow athletes to put themselves at risk in this way.
“We have a triathlon in Steamboat Springs, Colorado, in mid-August, and there can be algae blooms there at that time,” said Panigutti. “We will adjust our swim course to avoid the algae blooms and send athletes through the clearest and safest possible water.”
Some race directors, however, like Gerry Rott of Lavaman in Waikoloa Village, Hawaii, are blessed with untainted water for race day.
“The Lavaman swim is at a resort venue, and the swim bay’s water quality is monitored by the nearby hotel because it also serves as their swim beach,” said Rott.
Many often think ocean swims are more dangerous than lake or river swims, but diving into a protected bay like the one offered by the Lavaman race can be healthier and less choppy than some large freshwater bodies.
“It is such a pristine bay we’ve never had an issue with water quality. There are very few boats in that area—you can even see the bottom for much of the swim,” commented Rott. “I don’t know if in as long as I’ve lived here there’s ever been an issue with Waikoloa.”
With so much talk of testing, bacterial levels, and municipal officials, it may seem daunting to find a swimming location that is safe. As more of us seek out open water as an alternative to a pool during the pandemic, there are a few things you can do to self-assess the quality of the water.
“Try to figure out what watershed [i.e. where did the water originate?] your body of water falls under, and then work to figure out what occurs in that watershed,” suggested Dr. Maal-Bared. “Take a look and figure out if this open water is close to a sewer outfall, water treatment plant, or mouth of a river. If those things apply—or if it’s in an agricultural area—then maybe reconsider.”
Panigutti echoed Dr. Maal-Bared’s thoughts, adding that “boating activity can lead to high levels of gasoline and chemicals in the water,” so it’s not a bad idea to consider motorized traffic’s impact on your favorite place to splash around, too.
“The number one thing we tell swimmers is we recommend you don’t swim in open waters if there’s been rainfall in the past 24 hours,” cautioned Dr. Maal-Bared. “There’s a significant correlation between rainfall and potential for pathogens to get back into waterways.”
If you’re sitting here wishing you hadn’t just swam in that murky local lake, you can monitor for signs of infection or illness at home.
Dr. Maal-Bared warned that triathletes should keep an eye out for infection. Symptoms usually include GI-distress, skin rashes, ear pain, cough and congestion, and pink eye. However, the microbiologist reminded us the “reality is that exposure does not mean you’re going to get sick.”
As triathletes everywhere make the most of the final weeks of open-water swim season, remember to evaluate the water in which you plan to dunk yourself. While COVID-19 has not been found to thrive in water, there may be other nasty microscopic factors at play.
Once you know the local swim hole is safe, have at it, but maybe limit the number of times you pee in your wetsuit, for the rest of our sakes.
Water Quality for Swimming Cheat Sheet
Assess how close your swim location is to agricultural environments like crops and livestock pastures. If the swim location is directly next to or within a few miles of an agricultural site, consider diving in elsewhere due to chemical and animal waste runoff. You can also check with local parks and recreation authorities to ask about your watershed’s bacterial and microbial concerns.
Only swim the day after rainfall if the body of water has been tested for E.coli since the rain ended. Otherwise, wait a couple days before diving in.
If there is green or blueish-green “muck” on the water’s surface, avoid swimming—that’s algae and it can be harmful to your health. Also, check with local governing bodies on their recent testing for the presence of algae, like the sometimes less-visible blue algae microbes.
Seeing is believing. If there is debris, trash, heavy boat traffic, or dog-doo near the swim hole you’re considering, use common sense to pack up and head elsewhere.
Use Local Resources
There’s a solid chance your local government or a local organization is providing updates on water quality in your area. Get to know these sites and reference them often. Some to consider include beachreportcard.org (in Los Angeles), the CDC’s Water Quality Information Page, your local parks and recreation department, your local department of public health’s water quality division, and individual state and parks’ websites.