Seasick: What lurks in America's recreational waters?

Seasick: What lurks in America's recreational waters?
Jul 27, 2017
3 Min. Read

According to the National Resources Defense Council (NRDC), there were 22,571 days of beach closures or advisories nationwide last year  — among the highest in two decades.

South Beach, Miami: tourist destination, nightlife hub, and recurrent setting of annually regurgitated Shark Week programs. However, state officials have recently scanned the waters for a less detectable threat than the ones beachgoers tend to worry about, like sharks or riptides. The Florida Department of Health issued a public advisory in March warning swimmers to steer clear of the shore on the southern end of the beach.  


The cause? In a word, feces.

“If you see a bunch of seagulls, you might be disgusted thinking about all of their poop floating in your swimming water,” said Audrey Ichida, Senior Manager and microbial water expert at ICF. “But it’s nothing compared to human sewage.”


Ichida works closely with the Environmental Protection Agency (EPA) in developing safe criteria recommendations by paying attention to high-traffic recreational water destinations like Miami. The city draws around 15.5 million annual visitors, bringing pets and all associated waste with them. As vacation season continues, it wasn’t the first time this year the water fell under federal and state safety thresholds.

Enter the Enterococci

Sunny Isles beach, one of the beaches flagged as unsafe, failed to meet the recreational water quality standard for enterococci, a bacteria found in human or animal intestines (not to be confused with an authentic Italian antipasti). An ‘excessive’ relative amount of feces, especially from humans, in public waters can cause gastrointestinal sickness that can threaten your weekend plans — or potentially your life.


The Centers for Disease Control ( CDC) last recorded that in one year, 90 outbreaks from recreational waterborne diseases resulted in at least 1,788 cases, 95 hospitalizations, and one death. Public health officials and the EPA help minimize outbreaks by monitoring the most common one-two punch that leads to contaminated water: excess rain and faulty infrastructure.

“Repair or Replace”

In 2016, for instance, Los Angeles officials shut down all of Long Beach and Seal Beach following a severely damaged sewer leak. 2.4 million gallons of untreated waste overflowed into the Los Angeles River, prompting a midsummer beach evacuation as city sanitation workers stemmed the flow of sewage into the ocean. Local authorities monitored water samples until they could register two consecutive days of clean results.


In July, excess rainfall caused millions of gallons of untreated human waste to spill into New York’s Hudson River — affecting over 150,000 homes and businesses in the upstate region.

sewage water treatment plant

Both instances of contaminated waters occurred as a result of infrastructural breakdowns, indicating a need for massive repairs. The LA leak was caused by one broken five-foot pipe; its larger sewer line was built in 1929. In 2014, the NY Department of Environmental Conservation and US EPA announced a $136 million,15-year plan to reduce the amount of combined sewer overflows.

"This happening is just a part of the maintenance system,” Adel Hagekhalil, assistant director of Los Angeles Sanitation, told the LA Times. “Something grows old, you have to repair it or replace it."

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"When you see a beach is posted [as contaminated], you’re actually looking at yesterday’s data," - Audrey Ichida

Better Buildings, Better Beaches

To reduce stress on city systems, the Natural Resource Defense Council encourages government officials to opt for green infrastructure—permeable pavement, grassy traffic medians, pocket parks, and green roofs. It captures rain where it falls and sends it back into the ground instead of into sewage drains and waterways.

However, outdated municipal sewage systems aren’t the only reason for water contamination. According to Ichida, the caliber and capacity of water treatment plants can determine the extent to which pathogens reach the water. When sewage treatment plants operate at their designed capacity, they can effectively lower amounts of pathogens and fecal indicator bacteria. But if a plant is designed to treat 10 million waste gallons per day, it may not effectively remove viruses if it takes on, say, 20 or 30 million gallons.

The EPA has historically deferred to state and local officials under the federal Clean Water Act, providing guidance -- rather than regulations or requirements -- on ensuring water quality. Scientists and microbial water experts at ICF support the EPA in writing the criteria by providing the scientific assessments to create the criteria.  

With states taking guidances as suggestions and adopting the criteria into their state standards to varying degrees, though, the question is:

How Closely Are Your Public Waters Being Monitored?

According to the NRDC, there were 22,571 days of beach closures or advisories nationwide last year -- close to the highest in two decades. The EPA recommends that officials keep a closer eye on enterococci levels during ‘beach season’, but monitoring public waters is especially tricky.

“Another part of the picture is that once these bacteria get into the coastal ocean, they are tenacious and try to survive any way they can in their new environment,” writes Elizabeth Halliday, an oceanography researcher for MIT’s joint program.

Several factors can set off false alarms and cause misinterpretations of bacteria test results. Because of the size of the ocean, a bucket-sized sample of water may not be representative of an entire beach. Bacteria can cling to algae or even sand, and can therefore go undetected until later reintroduced into the water. According to Ichida, water quality can also change rapidly — sometimes within a matter of hours.

“So when you see a beach is posted [as contaminated], you’re actually looking at yesterday’s data,” she says. And although models are available to predict water quality based on variables like wave height and sun visibility (and rapid same-day methods are becoming more common), there’s still a lag time between when the water is monitored and when the data becomes available.

Avoiding Waterborne Illness: Tools and Resources

For those savoring the final weeks of summer swimming, it’s important to plan for more than the weather forecast. Check out this interactive tool to get an up-to-date status on the water conditions in your area. Aside from checking the water for unusual colors (e.g. visible slime formally known as harmful algal blooms) or odors, it’s difficult to draw any accurate conclusions on microbial water quality yourself.

Hawaii’s Clean Water Branch, which oversees 303 miles of recreational shoreline, has its own criteria for a ‘perfect storm’ of pathogen-packed water:

High human use, a breakwater, a nearby stream and a nearby storm drain make for a tier-one, high-risk beach.

For tourism bureaus, for fishermen and pet-owners, for vacationers and weekenders and everyone in between, taking the right precautions before heading out for a swim can make all the difference this summer.


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