DC environmental group looks at the safety of Charlestown water

Environmental Working Group (EWG) includes Charlestown in national assessment of US drinking water

By Will Collette

Like much of rural Rhode Island, Charlestown does not have a public water utility – no water mains, sewers or fire hydrants. But according to a new report issued by the Environmental Working Group (EWG), Charlestown does have a surprising number of households whose drinking water comes from public sources, perhaps best thought of as community supplies.

These are shared water supplies in our fake fire districts (homeowner associations such as the Central Quonnie Fire District), trailer parks, subdivisions like Castle Rock and even the nonprofit senior affordable housing complex Churchwoods.

EWG lists 9 such systems that they identify as serving 1,869 Charlestown residents. If that number is accurate, that’s close to a quarter of our population. But if you live near any of these systems and draw your water from the same source, you might have similar findings in your own home.

According to EWG, all these systems contain toxic chemicals that cause some level of danger to public health.

Those nine systems are:

Border Hill Mobile Home Park, 75 people

Castle Rock Condominiums, 292

Central Beach Fire District, 470

Church Woods, 98

Indian Cedar Mobile Home Park, 150

Ninigret Realty, 109

Quonochontaug East Beach Water Association, 300

Shady Harbor Fire District, 300

Shannock Water District, 75

Some unspecified number of Charlestown residents may be tapped into either the South Kingstown-south Shore (e.g. Green Hill Cove) or Westerly Water Department

If you click on the link for each site, you get a breakdown of what showed up in that site’s water supply.

The most common toxics found are nitrates, PFAS and radon generally under the EPA’s legal limits. As EWG argues,

“Legal does not necessarily equal safe."

• Getting a passing grade from the federal government does not mean the water meets the latest health guidelines.
• Legal limits for contaminants in tap water have not been updated in almost 20 years.
• The best way to ensure clean tap water is to keep pollution out of source water in the first place.”

Should you care if you don’t live in a shared-water community?

Those of us with private wells probably have similar levels of chemicals in our water to nearby community water systems, especially if we are drawing from the same water source.

Charlestown water quality official Matt Dowling says that nearly all Charlestown water contains some levels of nitrates:

“Nitrate is nearly ubiquitous in groundwater, out of 360 private well sampling events across Charlestown for issuances of Certificates of Occupancy, only ~16% of nitrate samples were below the method detection limits of 0.05 mg/L.  Sources of nitrate in groundwater in Charlestown is primarily from septic system effluent (~80%). There is a significant relationship of the number of septic systems in an area to the concentration of nitrate in potable groundwater in the shallow coastal aquifers of Charlestown.” 

Matt notes that EWG’s report used a much lower trigger level than the EPA, at least for now before the Trump administration alters (or eliminates) the standard.

“The EWG has developed a guideline for which they are comparing drinking water nitrate concentrations of 0.14 mg/L which is 70 times less than the national maximum contaminant level of 10 mg/L.  They have developed this guideline based on the following 2019 finding:

“’With the meta-analysis of eight studies of drinking water nitrate and colorectal cancer, we observed a statistically significant positive association for nitrate exposure and colorectal cancer risk and calculated a one-in-one million cancer risk level of 0.14 mg/L nitrate in drinking water.” https://www.sciencedirect.com/science/article/pii/S001393511930218X#!’”

Matt continued, noting that his own review showed an increased cancer risk from nitrates at one-quarter of EPA’s standard:

“I have reviewed papers that find enhanced cancer risks at potable water concentrations of nitrate at 2.5 mg/L in potable water, Dowling et al 2024 stated that ‘concentrations as low as 2.5 mg/L have been shown to have adverse health effects, including different types of cancer (Nolan and Hitt 2006).’”

That’s just for nitrates. EWG found other toxic chemicals, especially PFAS, in Charlestown water supplies. PFAS are plastic-related compounds and lots of PFAS contamination got into Charlestown water from the fire-firing activity at the old Ninigret Naval Auxiliary Air Station (now Ninigret Park and the Ninigret National Wildlife Refuge).

Matt said:

“I know much, much less about PFAS only that the standard is about to be reduced, and it seems that PFAS is also nearly ubiquitous.  The EWG is also using a very low guideline when compared to the current and proposed standards.  I have found that granular activated carbon filtration can be effective in removing PFAS from potable water.” 

The Trump regime isn’t helping by the recently reported shut down of EPA’s on-going effort to assess the risks of PFAS, meaning the standard probably won’t be reduced as Matt anticipated and may even be eliminated entirely.

Shoreline development’s role

The almost universal nitrate problem is a hard one to solve especially in the densely packed up-scale neighborhoods right on the coast. The two approaches with the most promise are (1) upgrade conventional septic systems to state-of-the-art denitrification systems and (2) allow no more development – no new buildings, added bedrooms or accessory dwelling units (ADUs) in those areas.

According to Matt:

At septic system densities of over 2-3 per acre (in glacial till groundwater aquifer and based on dwelling units per acre with individual OWTS where over 75% use conventional systems), we can expect to see groundwater concentrations of nitrate at Extreme Risk for source water impairment >5 mg/L. 

Over 75% of the septic systems in the coastal area use older conventional technologies that do not adequately treat nitrogen in the effluent.  We have been promoting, through grant cost sharing funding, for in-kind system replacements in this area, but the pace is slow and grant funding has dried up. [Emphasis added]

Additional housing density in the areas designated by CRMC as Lands Developed Beyond Carrying Capacity from the new ADU bill adds further pressure in reducing nitrogen impairment to groundwater (and surface water).

Even with new ADUs using nitrogen reducing technologies, they still contribute additional nitrogen loading.  In 2010 the RIDEM stated that in order for Eastern Ninigret Pond and Green Hill Pond to meet surface water quality goals, watershed nitrogen loading had to be reduced by 61%, If Charlestown facilitated the upgrade of all ~75% of the remaining conventional septic systems to modern nitrogen reducing technology as in-kind and allow no more additional bedrooms in the subwatershed that is wholly developed beyond carrying capacity in Charlestown, we could reduce total N load by 40%, not bad since there are also other mechanism to manage other N inputs like fertilizers etc.  But adding ADU to these areas reduces that %.”

What does this all mean?

First, don’t panic. There are virtually no pure and pristine water sources anywhere on the planet, especially now that PFAS pollution is being found everywhere.

I spent 20 years working with communities around the country on water protection issues. Fear of water contamination is universal and largely justified. During those 20 years, I’ve known some people who cracked under the pressure of feeling they had to come up with pure water for their families, so much so that they committed suicide. Please – don’t do that! Don’t despair because you can’t achieve the unachievable.

The more relevant questions include what contaminants and at what levels are present in your water, how do those levels compare with scientific standards and most importantly, what do YOU consider to be a reasonable risk?

For every water contaminant, especially those linked to cancer, opinions will range from higher levels preferred by industry and regulators as opposed to those held by public health experts and environmental scientists who argue that for some cancer-causing chemicals, there is no safe level.

Ultimately, you must decide what you consider acceptable for you and your family. Given the realities we all face, you may find yourself having to choose among choices that are far from perfect.

You have time to think it through. I saw nothing in EWG’s data showing any immediate threat to life.

Measures to consider include getting your water tested, installing a whole house water filter, upgrading your septic system and if you have radon in your basement, installing a venting system. Read up and do your research. Matt Dowling in Town Hall (401) 364-5030) can advise you on your options.

You can find answers to many of your questions on the town’s wastewater web page. It's loaded with links and information about water quality that can help you make informed decisions. CLICK HERE.