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Fecal bacteria shuts Cape beaches, but officials say no need to worry

chapoquoit beach
Liz Lerner
/
Chapoquoit Beach in Falmouth on August 4, 2022, a day swimming was closed due to high fecal bacteria.

Kathryn: There have been a number of beach closures in Falmouth, Barnstable, Mashpee and beyond over the last few weeks due to fecal bacteria found in the water. CAI’s climate and environment reporter Eve Zuckoff joins us now to explain what exactly is going on, and whether you need to be worried. Hi Eve.

Eve: Hey there, Kathryn.

Kathryn: So where are we seeing fecal bacteria in the water that's causing beaches to be shut down?

Eve: Right now Santuit Pond in Mashpee and Loop Beach in Barnstable have closures. There are also two beaches in Provincetown that are being re-tested and results will be back later today after some troubling early signs. We started taking a closer look at this because five swimming beaches in Falmouth failed water quality tests on the same day back in July. And exposure to fecal bacteria can lead to skin rashes, vomiting, GI issues, diarrhea, and more.

Kathryn: How is fecal bacteria getting to these beaches?

Eve: Well, there are many routes, but fecal bacteria from birds and mammal poop makes its way to our beaches often through stormwater runoff. When that runoff lands in marshes and harbors, fecal bacteria gets stuck in the sediment, where it grows under the hot sun, until some combination of rain, wind, and outgoing tides can come in and flush it all out into the ocean. Sometimes the bacteria can concentrate in areas where we like to swim, and that can cause beach shutdowns for a day or two.

Now, one county health official theorized that the beach closures in Falmouth are actually the result of the lack of rain. As we know, we’re in an ongoing and worsening drought. That has allowed the fecal bacteria to build up, and not get flushed out as easily. This is the third summer in a row with a drought declared – and I want to point out here that that’s an indicator of climate change. So this issue may become a recurring one in future summers.

Kathryn: We’ve seen and heard people point fingers to faulty septic systems, specifically we've been reporting on Autocamp, which is a luxury camp ground in Falmouth where the leach field is failing. Is pollution from septic systems a factor in this rise of fecal bacteria?

Eve: Actually, town and county health officials say No. Septic systems are terrible — no one really disputes that. But that's when it comes to leaking nutrients like nitrogen and phosphorous, which causes pollution, toxic algae blooms, and fish kills in local waters. But it’s difficult for bacteria and viruses to travel very far through groundwater. The soil acts as a filter for those two. In Fact, Scott McGann, Falmouth’s health agent told me that Autocamp is discharging just about 15-houses worth of effluent in an area that has a thousand-odd homes.

"Autocamp is 3%, …  of the total discharge to that watershed; 97% is from regular residential septic systems," McGann said. "So to blame Autocamp? Maybe we should be looking at the other 97%."

Kathryn: I understand that some of the town and county water quality monitors you've spoken to said they weren’t  too concerned about this latest round of beach closures. Does that mean the fecal bacteria issue is more of a an "ew factor," more of a perception problem?

Eve: Yeah, you’re right about that: they’re not raising flags about public safety at this point — Bethany Traverse, who has years of experience testing water quality for Barnstable County, says she’s not worried because high fecal bacteria levels don't last long around here.

"Especially our ocean beaches," she said, "they clear themselves out really quickly and efficiently because of the tide, right? Tide comes in, takes all that gunk out, clears it out. And then what might have been really high bacteria counts one day could be zero the next."

So she said they’re looking for patterns: if we see days, weeks in a row where there are failed water quality tests in an area, that would trigger much more concern that ‘Hey, there could be a sewer main that’s broken, and sending untreated sewage straight into an area.’

Or there’s something else going on that we need to study.

Kathryn: So how do we know when water is safe to swim in? 

Eve: Well, the main thing is to heed the warnings when signs are posted. But I’ll say it takes at least 18-24 hours for water quality tests to get processed, which means swimmers aren’t immediately notified when there’s a problem.

But if you’re concerned about it, consider swimming further from harbors or marshes. And, finally, it’s important to emphasize here that fecal bacteria is not a widespread problem, and we have extremely clean beaches. Traverse told me: we don't have factory discharge pipes and sewage plants dumping into the water, like other communities around the country.

Nature usually does its job of flushing out any bacteria that may have built up.

Kathryn: Alright well thank you for taking a closer look at fecal bacteria, what it means, and what's happening on our beaches. That’s CAI’s Eve Zuckoff.   Thanks a lot, Eve. 

Eve: Thanks, Kathryn.

Eve Zuckoff covers the environment and human impacts of climate change for CAI.
Kathryn Eident is an award-winning journalist and hosts WCAI's Morning Edition. She began producing stories for WCAI in 2008 as a Boston University graduate student reporting from the Statehouse. Since then, Kathryn’s work has appeared in the Boston Globe, Cape Cod Times, Studio 360, Scientific American, and Cape and Plymouth Business Magazine.