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Water Supply Resources

January 1st, 2020

Welcome to the CEI Water Supply Resources webpage. Feel free to click on the topics below to browse information and resources we hope you find useful. We invite you to also visit our Innovations Download page with even more material and research from our CEI staff.


What is Perfluorooctanoic acid (PFOA)?

Perfluorooctanoic acid (PFOA) is a “flourosurfactant” used as a “surfactant in the emulsion polymerization of flouropolymers.” Simply speaking PFOA is a carbon-fluorine chain based compound (carboxylic acid) used in the production of certain plastics, mostly Teflon. The compound is also used in insulators for electrical wires, firefighting foam, waterproofing for outdoor clothing (Gore-tex), non-stick cooking ware and sealants, among others. PFOA is closely related to other plastic production based compound-contaminants such as Perfluorooctanesulfonic acid (PFOS) and Perfluorononanoic acid (PFNA), which have similar properties but are used to produce different products. The primary distinction between these compounds is that PFOA accumulates much more in humans, while PFOS and PFNA accumulates more in wildlife (though both can be found in either).


Why is it a threat?

PFOA and its sister carboxylic acid compounds persist indefinitely in the environment. They are highly resistant to oxidation due to the strength of the carbon-fluorine bonds. PFOA is toxic and carcinogenic. Specifically, PFOA is toxic to the liver, immune system and is thought to have developmental effects in children. Exposure pathways are not well understood, but food, food packaging, drinking water and air seem to be implicated as the primary pathways. Microwave popcorn bags seem to make up a significant source of exposure.


How common is it?

According to the USEPA, PFOA is found in 99.7% of all Americans at an average of 4 parts per billion (ppb) and is found in the blood serum of every industrialized nation. PFOA is widely detected in fresh surface water bodies. Although less common, it has also been detected in some groundwater drinking water supplies.


What are the regulations?

There are no legally enforceable USEPA drinking water standards for PFOA. In 2009, the USEPA established a provisional health advisory level for PFOA of 0.4 ppb to assess the potential risk from short-term exposure of these chemicals through drinking water.   PFOA was included on the third unregulated drinking water contaminant candidate list to evaluate whether further regulation is required.

The USEPA developed an Emerging Contaminant Fact Sheet for PFOS and PFOA, that can be viewed here.


What can be done?

If PFOA is detected in a drinking water supply above regulatory limits, there are options. Contact CEI for help in solving these issues. Please call Emily DiFranco, PMP at 800-725-2550, or email at [email protected].


Harmful Algal Blooms

Most communities deal with harmful algal blooms (HABs) and their impacts on recreational activities through pond and lake warnings and closures. HABs have been known to cause fish kills and pet deaths, as well as making people sick from swimming in cyanobacteria laden water. In some cases, HABs are so extensive that they can cause disruptions to drinking water supply, as occurred in Toledo, Ohio in August 2014. 

HABs are formed by cyanobacteria, also known as blue-green algae but are actually photosynthetic bacteria. Their primary season runs from June to September, although they can survive all winter in reduced capacity, returning to thrive in warmer temperatures. Since temperature and nutrients, including nitrogen and phosphorus, seem to be a driving force for growth, the increasing water temperatures occurring with climate change and higher levels of stormwater runoff from increasing urbanization of water supply watersheds may exacerbate the problem. Cyanobacteria occur in fresh, brackish and marine waters and thrive in nutrient rich warm waters. When cyanobacteria concentrate, they increase to form HABs at which point they cause aesthetic color issues and may produce taste and odor compounds such as geosmin and methyl isoborneol (MIB) and dangerous cyanotoxins.


Water Supply Disruption in Toledo, August 2014

The fear in Toledo is that the cyanotoxins, produced by cyanobacteria, may have not been removed by conventional treatment facility including filtration and entered the distribution system. Recent advances in the ability to detect lower levels of cyanotoxins and epidemiological studies examining cyanotoxin effects on human health have heightened concerns. Cyanotoxins can cause a range of human health issues such as liver and kidney damage, neurological damage, gastrointestinal issues, and tissue damage. The risks for drinking water supplies is not well known, but likely depends on the treatment process as well as how “slugs” or mats of the cyanobacteria are handled when they enter the treatment facility. 


Current Regulatory Status

Cyanobacteria produce numerous types of cyanotoxins. The cyanotoxins are produced and contained within growing cyanobacteria cells. Generally, release of cyanotoxins occurs during cell death and lysis, however, some types of cyanobacteria release cyanotoxins as a soluble exotoxin in the raw water during growth if light conditions are poor. Research into the frequency and effects of these toxins is ongoing. However, it is generally thought that microcystin-LR is the most frequent and probably most toxic of the microcystins. The United States Environmental Protection Agency (USEPA) now encourages awareness of cyanobacteria in drinking water, and has funded studies examining cyanobacteria and associated health effects caused by cyanotoxins. As a result, the USEPA currently lists three cyanotoxins on the Safe Drinking Water Act’s Contaminant Candidate List (CCL3) and Unregulated Contaminant Monitoring Rules (Anatoxin-a, Microcystin-LR, and Cylindrospermopsin).


New England Cyanobacteria Assessment

Although some water systems are all too familiar with the challenges associated with taste and odor issues caused by some cyanobacteria, concerns about human health effects are more recently coming to light. In an effort to determine the magnitude of the cyanobacteria and cyanotoxin presence in New England drinking water supplies, Comprehensive Environmental Inc. (CEI) conducted an initial assessment on cyanobacteria and microcystins removal at four New England water treatment facilities. CEI is a progressive civil and environmental engineering consulting firm, striving to stay ahead of issues affecting our industry. Through these efforts, we provide our clients with the highest level of service and potentially pass on new information to the drinking water community. For this initial assessment, CEI collaborated with the University of New Hampshire, Center for Freshwater Biology and four New England drinking water systems to determine (for the first time) whether cyanobacteria and microcystins (liver toxins produced by many species of cyanobacteria commonly found in New England) are effectively removed through water treatment processes.

The most effective approach to keeping cyanotoxins out of the water supply is watershed protection and management. Water suppliers are encouraged to develop a monitoring plan for cyanobacteria as well as preventative actions. By preventing cyanobacteria growth within the drinking water supply, operators will not need to rely on treatment removal methods. Water resource protection and management methods involve limitation of nutrient loading from surface runoff and erosion, stormwater discharge and wastewater discharge.

CEI is a leader in the fields of watershed management and water treatment. For more information on HABs, cyanobacteria, cyanotoxins and their control, download the report on our study Cyanobacteria: Initial Assessment of New England Water Supplies  on our Innovations Download Page or contact Bob Hartzel, CLM, CPESC at 1-800-725-2550 x352 or [email protected].


HAB Resources


Manganese in Drinking Water

New Research Highlights Public Health Concerns 

Manganese has long been recognized to cause nuisance and aesthetic issues in drinking water. Concerns about the potential health impacts of manganese in drinking water have renewed in response to new research.

The Massachusetts Department of Environmental Protection (MassDEP) has made changes to the requirements for manganese monitoring and public notification. The MassDEP is also encouraging filtration of water with elevated levels of manganese and/or use of alternative drinking water sources.

CEI is well versed in the issues associated with manganese in drinking water and treatment. This webpage provides links to CEI’s literature on manganese and links to other websites with valuable information. 

CEI Project Spotlight:  Manganese Removal Treatment Facility, Kingston, Massachusetts


MassDEP Updated CCR Language

MassDEP Manganese Monitoring and Fact Sheets


Manganese Resources

For more information on Manganese Treatment, please contact Michael Ohl, P.E., Project Manager at 800-725-2550 x359 or [email protected].

Arsenic in Drinking Water

Arsenic in drinking water has been making headlines lately. You may have seen some articles with the words “poison” and “toxic” in reference to arsenic. A recent USGS press release on a study they completed in 2011 focused on arsenic and other contaminant levels in New England bed rock wells caused a stir. Coincidently, ongoing research into the health effects of arsenic in drinking water has also been making headlines. What’s it all about? Keep reading for more information. What is Arsenic?

Arsenic (As) is a naturally occurring contaminant in drinking water originating from rock and soil deposits containing arsenic. The presence of arsenic can also result from human activities such as use of pesticides or glass and electronic production wastes. It is generally understood that most of the arsenic occurring in New England drinking water wells is associated with naturally occurring bedrock deposits.


Recent USGS Study

A study by USGS released in 2011 highlights the prevalence of arsenic in private and public bedrock wells across the north east due to natural rock formations. Water testing indicated that approximately 13% of the studied wells (mix of public and private) were found to have arsenic in excess of the maximum contaminant level (MCL). Wells located along the eastern portion of New England have even higher levels of arsenic with about 23% of bedrock wells experiencing arsenic above the MCL. While public water supplies are required to routinely test for and treat arsenic to levels below the MCLs, private wells are not regulated and are at risk if this water is not being tested and treated accordingly.


Drinking Water Regulation

Arsenic is an odorless, tasteless, and colorless contaminant detectable only through analytical analysis. Arsenic is a human carcinogen or cancer causing agent with long term exposure potentially causing cancer, cardiovascular disease, immunological disorders, diabetes and other medical issues. In 2001, the US EPA reduced the maximum contaminant level (MCL) of arsenic in drinking water to 10 micrograms per liter (ug/L) or 10 parts per billion (ppb).


Recent Research Suggesting the Need to Re-Evaluate the MCL

Recent research indicates that the current arsenic MCL may not be sufficient. Consumption of low levels of arsenic through drinking water may decrease the amount of nutrients in the blood and breast milk of pregnant women, leading to growth and development deficits in babies. Research also indicates that low levels of arsenic in drinking water may compromise the body’s immunity in these vulnerable groups. Other research indicates that low levels of arsenic (below 10 ug/L) may adversely impact intelligence levels. 

Research on the carcinogenic affects of arsenic in drinking water at lower concentrations are also ongoing.

Based on the recent research, a US EPA advisory panel will be re-evaluating the affects of arsenic in drinking water to determine if the current MCL is sufficient to protect public health. In addition to health impacts, the US EPA considers ability to accurately measure the contaminant and ability to reasonably treat the water, among other factors, when establishing an MCL.


Arsenic in Drinking Water Resources


Arsenic in Drinking Water News

For more information on Arsenic in Drinking Water, please contact Michael Ohl, P.E., Project Manager at 800-725-2550 x359 or [email protected].


1,4 Dioxane

What is 1,4-Dioxane?

1,4-Dioxane is an emerging contaminant of concern as a threat to human health and the environment. 1,4-Dioxane can be found in a variety of products including paints, pesticides, detergents, shampoos, toothpastes, cosmetics and other personal care products. When it enters the environment, it becomes soluble in water and is difficult to remove.


Why is it a threat?

1,4-Dioxane is carcinogenic to humans when enough is ingested through drinking water over many years exposure.


Why now? 

In 2010, the US EPA published a revised toxicological review reducing the level that would cause a one-in-one million cancer risk to 0.35 ppb or ug/L. Why so much lower than the earlier decision? New methodology is available to measure 1,4-dioxane at lower levels down to 0.25 ppb including EPA Method 522; EPA Method 8260B SIM; and EPA Method 8270C SIM.


What are the regulations?

There is no Federal drinking water maximum contaminant level for 1,4-dioxane at this time. However, some New England states are regulating 1,4-dioxane.

New Hampshire – In 2005, the NHDES adopted an Ambient Groundwater Quality Standard (AGQS) of 3.0 ppb, based on available research at the time. In 2011, the NHDES requested that all public water supplies sample for 1,4-dioxane using a reporting limit of 0.25 ppb. NHDES is evaluating the need for more stringent regulations for 1,4-dioxane.

Massachusetts - In 2011, the MassDEP established an Office of Research and Standards Guideline (ORSG) level for 1,4-dioxane in drinking water of 0.3 ppb.

Maine – In 2011, Maine established Maximum Exposure Guideline for 1,4-dioxane in drinking water at 4 ppb.

Connecticut – In 2011, the Connecticut DPH set a drinking water Action Level of 3 ppb and a bathing/showering Action Level of 50 ppb.


What can be done? 

If 1,4-dioxane is detected in a drinking water supply above regulatory limits, there are options. Contact CEI for help in solving your 1,4-dioxane issues.


Current Regulatory Guidelines

  • MassDEP Office of Research and Standards Guideline Level (ORSGL) = 0.0003 mg/L or 0.3 ppb
  • NH Ambient Groundwater Quality Standard (AGQS) = 3 ppb
  • NH Drinking Water and Groundwater Bureau of the Water Division reporting limit = 0.25 ppb
  • Maine Maximum Exposure Guideline = 4 ppb
  • CT DPH Drinking Water Action Level = 3 ppb 


1,4-Dioxane Resources


1,4-Dioxane in Drinking Water News

For more information on 1,4-Dioxane, please contact Rick Cote, P.E., LSP at 800-725-2550 or [email protected].


Drought Management

New England

Climate change and cyclical changes in weather patterns pose challenges to water suppliers.  In New England statistically, droughts tend to occur over periods of several years, as occurred in the mid-1960s and more recently in the late 1990s and early 2000s.  Droughts are unpredictable, one could start at any time, so it is important to have a plan in place to help you be prepared.  Drought management planning can help provide a guide for use when droughts occur to protect resources and inform the public. Having the plan already in place will allow you to respond more quickly when a drought occurs.


CEI Drought Management Plans

Drought management plans provide water suppliers with a tool for monitoring and responding to potential drought conditions through the following:

  • Providing guidelines for monitoring of system specific drought related conditions;

  • Establishing benchmarks for normal and dry conditions;

  • Providing guidelines for assessment of various system specific drought conditions; and

  • Developing standard operating procedures to respond to drought conditions.

Drought management plans are valuable tools for water suppliers in their efforts to be good stewards of the environment and continue to provide an adequate supply of high quality water to customers. They are a great tool to show customers that you have a formal plan to deal with the issue. The plan can also be a tool to communicate with Water Commissioners or Selectmen.

If you would like assistance in developing a drought management plan or have questions, please contact David Roman, P.E., CFM at  800-725-2550 X399 or [email protected].


Drought Management Resources


Drought News

USGS Report: "Low April Streamflows Not Necessarily an Indicator of Summer Drought"


Revised Total Coliform Rule (RTCR)

The Revised Total Coliform Rule (RTCR) was finalized in February 2013 and compliance is required starting April 1, 2016.  However, some states have already started requiring compliance with the RTCR requirements.  The following provides a brief outline of the RTCR requirements.


General RTCR Overview

  • Monthly monitoring for Total Coliforms, used as an indicator of system integrity.

  • Establishes Maximum Contaminant Level (MCL) for E. coli.

  • Each total coliform-positive (TC+) routine sample must be tested for the presence of E. coli.

  • If any TC+ sample is also E. coli-positive (EC+), then the EC+ sample result must be reported to the state by the end of the day that the PWS is notified.

  • If any routine sample is TC+, repeat samples are required, including upstream/downstream sampling.

  • Assessments and Corrective Action requirements for EC+ events and repeat TC+ events.

For more information, please contact Michael Ohl, P.E., Principal at 800-725-2550 x359 or [email protected].


RTCR Resources

Posted in the categories About CEI, Drinking Water.