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Story Publication logo February 12, 2024

Cape Cod Faces a Rising 'Yellow Tide'

Houses in Cape Cod

Nitrogen pollution and climate change threaten Cape Cod's tourism industry.

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Multiple Authors

Tourism is big business on the cape, but a growing environmental issue could disrupt the lives of tourists and residents, alike.

This story was co-published with WBUR in Boston. Read its coverage on efforts to improve the Cape’s water pollution, including one innovative town considering “pee-cycling. 

Video courtesy of Scientific American. United States, 2024.

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Javier Lloret: There’s going to be bad smells. There’s going to be fish kills. There’s going to be a lot of algae getting entangled in your boat, in your propeller, in everything.  And it’s not a nice view, you know. So in a way, we’re decreasing the value of the land, which is precisely the same value that brought people here to enjoy an enjoyable summer.

Narrator: Javier Lloret is a research scientist at the Marine Biological Laboratory on Cape Cod, a hook-shaped peninsula off Massachusetts, about 70 miles southeast of Boston.

Lloret: One of the things that we’re planning to do here, right in this location, is to collect some groundwater samples ...  just to check on the overall health of the, of the ecosystem there.

And here we go. That’s our filter sample. We will analyze for the nutrients.

Narrator: Nearly 230,000 residents live on the cape year-round. But in 2022 more than four million tourists visited its and beaches and shores. Tourism is big business here, bringing in $1.4 billion to the county.  And generally those numbers grow each year.

But the cape has become a victim of its own success. More visitors and more homeowners have brought unchecked pollution to the area, threatening to permanently destroy its beaches and estuaries.

[CLIP: Reporter: “A new report finds Cape Cod’s bays and ponds continue to suffer from water pollution.”]

[CLIP: Reporter: “Cape Cod’s bays and ponds are polluted with excess nutrients.”]

[CLIP: Reporter: “Decades of pollution continue to threaten both human health and ecosystems.”]

Narrator: According to the Association to Preserve Cape Cod, a nonprofit watchdog group, in 2022, 90 percent of the area’s coastal embayments required, quote, “immediate restoration,” unquote. And beach closures in response to high bacteria levels are now common throughout the busy summer months.

What’s the cause of this situation? Excess loads of nitrogen in the cape’s groundwater.

Lloret: These systems are not adapted to these huge nutrient inputs. Humans have put a lot of nitrogen into the land. Basically what it does is that it makes algae to grow, like, out of control.

Narrator: Uncurbed algal growth has plagued the cape’s estuaries for years. But now residents and scientists such as Lloret fear that if nitrogen pollution isn’t curbed immediately, the water may never recover.

Nitrogen naturally occurs in the environment. But too much nitrogen in saltwater results in massive overgrowths of algae. The algal blooms block light to plants at the bottom of the water and use up oxygen that’s vital to sea life.

Around the world, nitrogen pollution has become a big problem in estuaries such as the Chesapeake Bay.  

But unlike the Chesapeake, the nitrogen on the cape isn’t from chicken feces or agricultural fertilizer. It’s coming from human urine.

Lloret: Probably, like 90 to 95 percent of the nitrogen that is coming to these waterways comes from wastewater.

Narrator: The cape’s nitrogen problem partially comes from its unique geology.

Cape Cod was formed nearly 20,000 years ago when glaciers melted, leaving behind what is essentially a big pile of sand. This sand is extremely porous, and any surface water quickly filters into the groundwater below. This groundwater, including any pollutants, eventually makes its way to the cape’s shores.

For tens of thousands of years, that wasn’t a problem for those who lived on the cape. But since the 1970s, the population has more than doubled.  Tiny towns grew larger, and houses were built with little regulation. No central sewer system was set up, and most homeowners installed self-contained septic systems.

Andrew Gottlieb: Well, what we see now is a cyanobacteria bloom that has been going for about a week to 10 days now.

Narrator: Andrew Gottlieb, director of the Association to Preserve Cape Cod, has lived on the cape his whole life.  

Gottlieb: People like Cape Cod—want to come to Cape Cod. And to a certain extent, they’re loving it to death.... Across the region, we rely on 19th-century technology to get rid of our wastewater, you know—we all basically have a hole in the backyard, and our wastewater flows into it. And there’s no nutrient removal; there’s no even rudimentary treatment of the wastewater. 

Narrator: Gottlieb and other residents are pushing to build more sewers and wastewater treatment plants to replace the septic systems throughout the cape.

A standard septic system has two components. A large container that has an inflow and an outflow, and a leaching field that has perforated pipes surrounded by gravel or sand. The wastewater from toilets or household appliances flows into the large container. Solids settle to the bottom while liquids flow towards the pipes and into the ground.

Gottlieb: What septic systems don’t do, and to which they are not designed to do, is remove pretty much anything from the waste stream.

Narrator: In contrast, sewer systems capture all home wastewater and deliver it to a central treatment facility through a series of pipes and pumping stations. The nitrogen never reaches the groundwater.

But as of now, only six out of the 15 towns on Cape Cod have sewer systems. And even then, only a fraction of the homes in those towns are hooked up. Eighty-five percent of homes on the cape still use septic tanks.

Gottlieb: Our position is that continued reliance on septic systems is no longer acceptable.

Lloret: I mean, we already have the technology. This is nothing new. I mean, we can just sewer the towns; we can just connect everyone to a centralized treatment facility. Now the problem there is that it is extremely costly.

Narrator: Officials estimate that the cost of building sewers throughout the cape will be well over $4 billion. Some of that money will come from the state. Some towns in the county have also imposed a so-called "Airbnb tax" on short-term rentals.  But that will not be enough.

Mark Ells: We’re going to reach a point where there’s still going to be a gap there. And we’re going to need to go to the public and ask them for additional revenue.

Narrator: Mark Ells is the town manager of Barnstable, the largest town on the cape. Barnstable is in the first few years of a 30-year plan to build sewers for all its residents. But the town of Barnstable says that even beyond the cost, the actual construction of the sewers presents a massive engineering puzzle.

Ells: So the challenge is—and we’re already feeling it from our residents—the fatigue from construction.

Narrator: Construction times are limited to the months before and after the high tourism season. Any roadwork chokes the cape’s already snarled traffic. And since the pandemic, construction labor and materials still remain in short supply.

But not all Cape residents are waiting for the sewers to be built. Pat Uhlman, a resident of Barnstable, replaced her old septic tank with an I/A, or innovative/alternative, septic system.

Pat Uhlman: They dug up the whole driveway and there is a 1,500 gallon septic tank underneath where I am standing.

In the town of Barnstable, where I live, they’re expanding their sewer system. But it’s probably a good 20 years before it’s going to get out here where the ponds are. It’s going to take a lot of time. And I’m not so sure our water has that much time.

Narrator: Traditional septic systems on the cape can release 85 milligrams or more per liter of nitrogen into the groundwater. Older I/A systems average 19 mg per liter, while newer “enhanced” I/A technologies, like this one being installed in Uhlman’s neighborhood, are capable of reducing that to less than 5 mg per liter—a big improvement but still short of reducing all nitrogen from wastewater from entering the cape’s groundwater.

Brian Baumgaertel: This is a septic tank. This would be under the ground in your house. Most of the magic here happens underground - you don’t get to see most of it. We see dirty water going in, we see clean water coming out and we know we’ve done the job we set out to do.

Narrator: Brian Baumgaertel is director of the Massachusetts Alternative Septic System Test Center, a program of Barnstable County Government, located on the cape. Here his team tests and certifies I/A septic technology.

Baumgaertel: Well, I think what I would say is that anybody who believes that sewer is the only solution and anybody who believes that alternative septic systems are the only solution—both of them are wrong. What we really need is a blended approach.

You know, use sewer where it makes sense but think about “Where can you supplement sewer....?” So it's a balance of, you know, “How do we, how do we protect the environment?” but “How do we do that in a way that doesn’t really bankrupt the everyday Cape Cod resident?”

Narrator: Other residents, such as Hilda Maingay and Earle Barnhart, are going a step further. The couple live in Falmouth and are pushing to eliminate nitrogen completely by using urine-diversion toilets in their home.

Earl Barnhart: In our house we have a urine diverting composting toilet that will recover all of the nutrients from the human waste.

There’s a urine diverting compartment in the front where the urine is diverted and goes through one pipe to storage. 

The urine from the urine diverting toilet comes down one tube, pipe, and goes into storage. The solid material from the composting toilet goes straight down this tube into these bins.

Hilda Maingay: The sooner we get this nitrogen out of our wastewater or out of our water, the quicker we can maybe restore the ecosystem. The longer we wait, the further the ecosystem has degraded, and the less likely [it] is that we ever can get it back. 

Narrator: For now, Lloret continues to monitor the nitrogen and algal levels in the water, uncertain about Cape Cod’s future.

Lloret: From my own research, the thing that is keeping me up at night right now is the fact that in the background, we have another major driver of change that is right there, which is climate change.

So I’m very concerned that then climate change has the potential to completely change the rules of the game from a scientific perspective but also from a management perspective.

We’re going to have a new set of conditions, new, new set of temperatures, new precipitation ranges that are going to change the delivery of nutrients from land on to these ecosystems, the capacity of the landscape to absorb these nutrients.

It is very difficult to predict what’s going to happen five years from now, 10 years from now, 20 years from now and, of course, 50 years from now. So that's something that I'm very worried about.


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