How Safe Are Lakes, Beaches And Rivers For Swimming And Boating?

ACROSS AMERICA — With summer kicking off, many families are planning getaways to lakes and rivers for swimming, paddling and fishing.

But is it safe to dip your toe in the wate?

There's no simple answer. But there are resources residents should check before heading out to the beach or launching a kayak or canoe in a river.

For starters, check with with your state's Department of Natural Resources or equivalent agency for beach closing and other notices about water quality.

Next, consult the Environmental Protection Agency's inventory of impaired waterways to determine if they exceed the "total maximum daily load," or TMDL, standards set forth in the Clean Water Act.

What does that mean?

The term relates to the amount of nitrogen and phosphorus pollution in freshwaters. The nutrients are essential for plant growth, but an overabundance of them causes algae to grow faster than ecosystems can handle, harming water quality and decreasing the oxygen fish and other aquatic life need to survive.

Common sources of excess nitrate that reaches lakes and streams include septic systems, animal feedlots, agricultural fertilizers, manure, industrial waste waters, sanitary landfills, and garbage dumps. At elevated levels, nitrates can cause severe illnesses in infants and domestic animals.

Algae blooms also allow so-called "rough fish" — carp and bullhead — populations to increase at the expense of game fish populations. Severe algae blooms result in stinky, unattractive lake water, undesirable for swimming, boating or fishing.

Nitrates added to the soil in agricultural states contribute to the infamous Gulf of Mexico "dead zone," where fish and aquatic life can no longer survive. Freshwater is less dense than the saline seawater, so the nitrogen and phosphorus-laden runoff sits on top of the ocean surface and doesn't mix, spurring an overgrowth of algae that consumes oxygen as the plants decompose.

The low-oxygen waters create the condition called hypoxia, and marine life suffocates and dies. These waters are warmer than the deeper ocean water, further contributing to the stratification. When the waters don't mix, oxygen in the bottom waters is limited.

If your favorite swimming hole isn't posted as closed, you may want to test it yourself for E. coli bacteria to calculate the swimming risk. County health departments can often help residents test freshwater bodies for bacteria or nitrates. Help finding a state-certified lab is available at the EPA's Safe Drinking Water Hotline at 800-426-4791 or online.

America's rivers aren't the playground for canoers and kayakers they once were. The EPA estimates that 44 percent of U.S. waterways are too polluted for swimming or fishing.

As a result, "freshwater species are going extinct faster than ocean or land species, and rivers are among the most threatened ecosystems on the planet," America's Rivers said with the release earlier this year of its America's 10 Most Endangered Rivers report.

Topping the list is the Colorado River at the Grand Canyon, one of the Seven Natural Wonders of the World and a vacation destination favorite for many Americans.

Others on that list, ranked according to the level of endangerment, include:

Placement on the list doesn't automatically mean those rivers shouldn't be used for recreation, but it underscores the threats to rivers by climate change, pollution, dams and other uses, according to American Rivers.

One other thing to be aware of if you're swimming in a freshwater lake, especially in warmer climates as summer and during the late summer months: The Centers for Disease Control and Prevention says that swimmers in freshwater lakes should assume that the organism Naegleria fowleri better known as brain-eating amoeba are present, although actual cases of infection are extremely rare.

How rare? From 1962 to 2022, there have been only 157 known infected individuals. But Naegleria fowleri illnesses are fatal 97 percent of the time, with only four known survivors during that time, according to the CDC.

The organism is most often found in warm, Southern states, but a warming climate increases the likelihood of encountering the organism farther north.

Other swimming-related illnesses, including skin, ear, respiratory, eye, and other infections — can be caused by germs that naturally live in the water and soil.

One other thing to be aware of if you're swimming in a freshwater lake, especially in warmer climates: The Centers for Disease Control and Prevention says that swimmers in freshwater lakes should assume brain-eating amoeba are present, although actual cases of infection are extremely rare.

The organism is most often found in warm, Southern states, but a warming climate increases the likelihood of encountering the organism farther north.

The CDC estimates about 7.2 million people get sick with waterborne diseases every year, though the agency said it can't say how many infections stem from freshwater exposure versus drinking water exposure.