Black sludge, invasive seaweed, toxic algae: Cape Cod pond, coastal waters get poor marks

If Cape Cod had to be defined by a single element, certainly it would be water, surrounded as it is by ocean, sound, canal and bay, dimpled by scores of ponds and lakes, fringed by marshes and beribboned by streams and rivers.

Its prevalence makes it key to the region's success, but it is a resource in peril — at least as far as coastal embayments and freshwater ponds are concerned. According to the Fifth Annual State of the Waters report just issued by the Association to Preserve Cape Cod, many of the Cape's precious waters continue to be beleaguered by poor water quality.

The one exception: Public water supplies. These, the nonprofit environmental organization says, remain predominantly "excellent," while elsewhere beds of native eelgrass are dead or dying, once abundant bay scallops are gone, oxygen-sucking invasive seaweeds are replacing native species, bay bottoms are carpeted by foul-smelling black sludge, and mats of toxic algae consistently blanket many freshwater ponds, making them health hazards for people, pets and wildlife.

"We've reached this degraded point, which is not any cause for celebration," said Association executive director Andrew Gottlieb, talking about the report's findings.

But every storm cloud has its silver lining and so, too, does this one, he said. While overall water quality in the Cape's embayments and ponds remains subpar since the last report card, it hasn't measurably worsened.

Additionally, no drinking water systems fell into the "poor" category: Especially good news for Yarmouth, which received the lower grade in last year's report because of levels of per- and polyfluoroalkyl substances, or PFAS, that exceeded state standards for six PFAS compounds.

Overall, said Yarmouth Water and Wastewater Superintendent Laurie Ruszala in response to the report, "we've always had good water." But in 2021, she explained, just after the state upped the ante on limitations for PFAS to 20 parts per trillion, samples from three wells showed levels slightly above the new standards: 21 parts per trillion in interconnected wells 4 and 5, and 23 parts per trillion in well 10.

"Those three wells we turned off in 2021 and they have not been on since," she said, noting the remaining wells have all continued to meet the state standards.

In more good news for Yarmouth, Ruszala said the town is now testing a new treatment system for the shut-down wells 4 and 5, located on Long Pond. She expects it will go online in the next month or so, and the wells will be put back into service.

What is the State of the Waters report?

The State of the Waters report is an annual evaluation of water quality in the Cape's coastal waters, freshwater ponds and drinking water supplies. The organization began assessing water quality five years ago to raise public awareness about the issue, as well as to "motivate policy makers to adopt measures that will improve water quality."

Efforts on Cape have progressed since then, too, especially with the state raising the stakes on watershed protection rules here.

"We're at the cusp of seeing some of the towns putting forward some of their wastewater management projects, which will help," Gottlieb said.

Water quality for each type of water body was graded using parameters unique to it and based on sampling and monitoring data and, in the case of drinking water systems, towns' individual consumer confidence reports.

Cape Cod's coastal embayments: Still mostly 'unacceptable'

In all, 90 percent of the 48 embayments and estuaries evaluated got "unacceptable water quality" grades based on data collected from 226 monitoring stations.

Gottlieb said the low water quality in embayments, as well as ponds, is mostly a result of high nutrient loads, primarily inadequately treated wastewater from septic systems. Stormwater runoff and fertilizers also contribute, though to a lesser extent, he said.

This is the first year there was no increase in the number of embayments with "unacceptable" water quality, 43 out of 48, but the organization notes that it's the same 43 water bodies with "unacceptable" grades — in other words, no improvement observed.

"Part of it is, at least on the marine side, there's not much water left to give back; 43 out of 48 exhibit poor water quality. That's pretty bad," Gottlieb said.

Moreover, he said, analysis shows some increase in the number and percentage of monitoring stations that began detecting poor water quality, "which is indicative of further degradation."

"The ones that are getting worse are the ones closer to the estuaries. There's so much load coming down from the headwaters, it's all encroaching further down," he said, explaining this suggests that tidal flushing, which may have been enough in previous years to clear some of the loads out into the ocean, is not working as well.

According to the findings, all of the embayments on the Nantucket Sound side of the Cape have "unacceptable" water quality. The same holds true for the Buzzards Bay side, except for at Quissett Harbor. Cape Cod Bay still has the most embayments with "acceptable" water quality — four.

Study highlights shortage of pond water quality data

Like the embayments and estuaries, the number of evaluated ponds with low water quality grades remained "somewhat stable" from the previous year, Gottlieb said. Some of the evaluated ponds, though, are "marginal."

In all, 139 ponds were evaluated based on total phosphorus, chlorophyll and water clarity measures. The challenge with the Cape's ponds is that very few of them have enough water quality data to make it possible to grade them.

According to the organization, the 139 ponds that had enough data represent just 16 percent of the Cape's 890 freshwater ponds, "indicating that there is an ongoing shortage of recent water quality data available for most of the Cape’s ponds."

More than a third of the ponds that were evaluated — 59 — got "unacceptable" water quality grades.

Through its Cape Cod Freshwater Initiative, established in 2022, the Cape Cod Commission is working toward a wider evaluation of freshwater resoures on Cape with an aim to develop a regional plan to restore and protect them.

On the plus side: Most drinking water supplies get high marks

Data from 21 public water supplies collected after treatment was evaluated, and 19 of them earned "excellent" grades for meeting all state and federal drinking water standards.

The two that just missed rising to excellence, the Buzzards Bay Water District and the Sandwich Water District, were still deemed to have "good" water quality.

According to the report, the "good" rather than "excellent" grade is based on detection of total coliform bacteria, "used as an indicator that harmful enteric bacteria such as E. coli may be present." The organization emphasizes that "both suppliers followed up with appropriate response measures and did not detect E. coli."

In addition to Yarmouth seeing a better assessment over the last report, Otis Air National Guard's water system got a better grade, too. In last year's report it was given a "poor" grade because of detection of total coliform and E. coli that required issuance of a boil order.

On the topic of PFAS, the latest assessment found that 10 of the 19 systems with "excellent" evaluations detected PFAS6 in some groundwater wells, but they met the state's standards. The findings, which cover the second year since the regulations took effect, highlight the proliferation of PFAS in public water supplies and the need to manage them.

According to the Centers for Disease Control and Prevention, PFAS are man-made chemicals that have been used in industry and consumer products since the 1940s. They're found in everything from nonstick cookware, water-repellent clothing, stain- and wrinkle-resistant fabrics and carpets, to some cosmetics, some firefighting foams and products that resist grease and oil.

Spinning it all forward

There is much work ahead to address the Cape's water quality concerns, Gottlieb said, but it's encouraging to see towns actively pursuing plans to correct problem areas.

"The really good evidence of that is that the project volume that's going to be going to town meetings this spring exceeds $600 million in eight towns, with 13 projects," Gottlieb said. "Towns and their voters are doing the things that we need them to do in order to turn things around, so that's a really positive thing in all of this measured misery."

Beyond those measures, it will be important to protect what's left of the Cape's undeveloped land to keep from exacerbating things going forward, he said.

"Only 14 percent is undeveloped and unprotected. It's about 60,000 acres, and about 40,000 of that is critical habitat area," he said.

The call, he stressed, is "to be aggressive about protecting as much of that critical habitat that's in that 14 precent as possible over the next several years."

"We're not anti-housing, but housing in undeveloped green spaces is the wrong place to put density," he said.

The latest water report, he said, "really highlights the need to focus on protecting the landscape while focusing affordable housing on redevelopment and refilling in already disturbed areas."

Heather McCarron writes about climate change, environment, energy, science and the natural world, in addition to news and features in Barnstable and Brewster. Reach her at hmccarron@capecodonline.com, or follow her on X @HMcCarron_CCT

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This article originally appeared on Cape Cod Times: Report: Cape drinking water mostly 'excellent.' Here's the bad news.