Why do we disinfect water?
Water is disinfected to protect public health. Disinfection kills or inactivates bacteria, viruses, and other potentially harmful organisms found in drinking water. Proir to the widespread use of disinfectants, many people became ill or died because of contaminated water. The Hanover DPW currently uses chlorine to disinfect its drinking water. The EPA and the Center for Disease Control and Prevention (CDC) believes the benefits of drinking water disinfection outweigh the potential risks from disinfection byproducts. (EPA 3)
What are disinfection byproducts?
Drinking water research indicates that certain byproducts of water disinfection have the potential to be harmful. EPA has adopted enforceable regulations on the following byproducts; total trihalomethanes (TTHMs), Haloacetic Acids (HAA5), chlorite, and bromate. Drinking water in Hanover has periodically exceeded the regulatory limit for TTHMs requiring the Town to take mitigative actions. (EPA 7)
What are chloramines?
According to the U.S. Environmental Protection Agency (EPA), chloramines are disinfectants used to treat drinking water. They are most commonly formed when ammonia is added to chlorine to treat drinking water. Water that contains chloramines and meets EPA regulatory standards is safe to use for drinking, cooking, bathing, and other household uses. (EPA 1)
Are there different forms of chloramines?
The different types of chloramines are monochloramine, dichloramine, trichloramine, and organic chloramines, When chloramines are used to disinfect water, monochloramine is the most common form. Dichloramine, trichloramine, and organic chloramines are produced when treating drinking water but at much lower levels than monochloramine. To ensure primarily monochloramines are being formed, a target pH is maintained throughout the system. (EPA 1)
How long has monochloramine been used as a drinking water disinfectant?
Monochloramine has been used as a drinking water disinfectant for more than 90 years. More than one in five Americans use drinking water teated with monochloramine. The MWRA, the provider of drinking water to the Boston metropolitan area, has been using chloramines for many years. (EPA 2)
How do the kinds and concentrations of disinfection byproducts formed by monochloramine compare to those formed by chlorine?
Compared to water treated with chlorine, water treated with monochloramine contains lower concentrations of total trihalomethanes (TTHMs) and Haloacetic Acids (HAA5). EPA and other organizations continue to conduct research on unregulated byproducts that may form in water treated with monochloramine. (EPA 9)
What disinfectants are available for drinking water?
- Chlorine: Most water utilities use chlorine as a primary disinfectant because of its effectiveness in killing potentially harmful bacteria. However, chlorine can react with natural organic matter present in water to form potentially harmful disinfection byproducts. (EPA 4)
- Monochloramine: This is commonly used as a secondary disinfectant to protect water as it travels from the treatment plant to consumers. Monochloramine also helps lower levels of potentially harmful regulated disinfectant byproducts compared to chlorine. (EPA 4)
- Ozone, UV light, and chlorine dioxide: These are effective at killing bacteria, viruses, and other potentially harmful organisms in water at the water treatment plant. However, they do not provide protection as water travels through pipes of the distribution system. The EPA recommends that chlorine or monochloramine still be used in addition to these processes to protect the quality of trreated water as it travels from the treatment plant to the customer. (EPA 4)
Is monochloramine as effective as chlorine in disinfecting drinking water?
Monochloramine is effective in killing bacteria, viruses, and other potentially harmful organisms but takes much longer to act than chlorine. Therefore, we will continue to use chlorine as a primary disinfectant in our water treatment plants. Monochloramine is more stable and longer lasting than chlorine and therefore will be used as a secondary disinfectant as the water exits the treatment plants and travels into the water distribution system. (EPA general).
Other than chlorine and monochloramine, what options could we have considered to control the levels of disinfection byproducts?
- Reducing water age in system - significantly reducing time in pipes is not practical for the Hanover system. Installation and use of bleeders at dead ends or areas with known water age/low usage issues would push Hanover's usage above the available supplies.
- Reducing storage volumes in tanks is feasible but can result in pressure problems during periods of high demand as well as strain the ability to supply adequate volumes to fight fires.
- Reduce/minimize pumping from well sources with high total organic carbon (TOC) during lower demand periods such as the winter. The Town has adopted this strategy during winter months, but it is not feasible during the higher demands of the summer.
- Installation of in-tank mixing systems. Contracts have been awarded and this work is scheduled for the fall and winter of 2019-2020.
- Reducing pre-chlorination to the greatest extent possible. The Town adopted this strategy several years ago and continues to not pre-chlorinate today.
- Use or potasium permanganate for pre-filter oxidation instead of chlorine. The Town uses potassium permanganate at all three of its water treatment plants for pre-filter oxidation.
- Improving filtration (Granular Activated Carbon GAC media) - There are a high capital and operation and maintenance costs associated with this strategy as regular replacement of filter media is required (typically every 1-2 years depending on water quality).
- Ozone and UV light - Requires regular maintenance and replacement of expensive bulbs making it impractical to employ at three separate treatment facilities.
- Replacement of any known cast-iron unlined water mains as feasible. The Town is considering this option as a factor in its water main replacement program.
How did EPA evaluate the safety of monochloramine for use as a drinking water disinfectant?
EPA evaluated monochloramine primarily through an analysis of human health and animal data. Research reviewed in EPA's safety analysis is contained in EPA's Drinking Water Criteria Document for Chloramines. (link to EPA's chloramine related research), Publication No. ECAO-CIN-D002. EPA coninues to work with other organizations on research related to the safe use of monochloramine. (EPA 14/15/16)
Does monochloramine cause skin problems?
EPA believes that water disinfected with monochloramine that meets regulatory standards has no known or anticipates adverse health effects, including skin problems. CDC's investigation of reports of monochloramine-related skin problems associated with drinking water use was unable to draw any conclusions about monochloramine and health effects. Trichloramine, a chemical related to monochloramine that often forms in swimming pools has been linked to skin problems. (EPA 24)
Is it safe to drink and cook with chloraminated water?
Chloraminated water that meets EPA regulatory standards is safe to use for drinking and cooking. EPA regulations limit chloramines to levels where no adverse health effects are anticipated. EPA's risk assessment process includes a review of available research and historical data focused on health outcomes that scientists consider to be the most critical. Special populations, such as people with weak immune systems, should check with their physicians before consuming any type of drinking water, including bottled water. (EPA 20)
Can I shower in chloraminated water?
Showering with chloraminated water poses little risk because monochloramine does not easily enter the air. Trichloramine, a chemical related to monochloramine and often found in swimming pools enters the air more easily and has been linked to breathing problems. Trichloramine formation does not usually occur during normal drinking water treatment conditions. (EPA 21).
Can I use a humidifier with chloraminated water?
The use of chloraminated water in humidifiers poses little risk because monochloramine does not easily enter the air. (EPA 21)
Do chloramines cause breathing problems?
EPA believes that water disinfected with monochloramine that meets regulatory standards has no known or anticipated adverse health effects, including breathing problems. Monochloramine does not enter the air easily and therefore would be difficult to inhale. CDC's investigation of reports of monochloramine-related breathing problems associated with drinking water use was unable to draw any conclusions about monochloramine use and health effects. Breathing problems associated with trichloramine and indoor swimming pools have been reported. (EPA 25)
Does monochloramine cause digestive problems?
EPA believes that water disinfected with monochloramine that meets regulatory standards has no known or anticipated adverse health effects, including digestive problems. EPA's regulatory standard for monochloramine is based primarily on risk assessments focussed on drinking water which provides a wide range of safety to offset uncertainties in risk assessments. People who believe their digestive problems are related to monochloramine should consult with their doctors. (EPA 26)
Does monochloramine use contribute to the release of lead or other contaminants in drinking water?
Changes in water chemistry from monochloramine use may impact lead or other contaminant levels. As a result we may need to adjust our treatment processes to reduce lead or other unregulated contaminants to meet EPA regulations. The Town's approval permit with DEP requires increased monitoring of the water distribution system for lead and copper. (EPA 27)
Does monochloramine cause cancer?
EPA believes that water disinfected with monochloramine that meets regulatory standards has no known or anticipated adverse health effects, including cancer. EPA's regulatory standard for monochloramine provides a wide range of safety to offset uncertainties in risk assessments. For additional information regarding how uncertainty factors (also known as safety factors) are applied to risk-assessments to provide a wide margin of safety see: (http://epa.gov/risk/dose-response.htm). EPA continues to support research on the safety of monochloramine use. (EPA 23)
Can chloraminated water be used for dialysis?
If chloramine enters the blood stream directly, it combines with hemoglobin (red blood cells) so it can no longer carry oxygen. This can occur if chloramine is not removed from water used in dialysis machines but cannot happen by drinking chloraminated water. Both chlorine and chloramines need to be removed from kidney dialysis water.
Prior to activating our chloramination system, we must demonstrate to the Massachusetts Department of Environmental Protection (DEP) that adequate public notification and education has been provided to Hanover residents, businesses, and health care providers including comprehensive information about changeover impacts for kidney dialysis patients. As a result, we will soon be providing all Hanover residents, area hospitals, health clinics, and the Hanover Board of Health with chloramine information material through direct mail. In addition, we will be updating the Town's website with similar educational material. (EPA 22)
Can chloraminated water be used in an aquarium?
Chlorine and monochloramine can be harmful to fish because they directly enter the bloodstream through their gills. Chlorinated and chloraminated water can be safely used in aquariums by using products readily available from aquarium supply stores.
Similar to dialysis, we must demonstrate to DEP that adeqaute public notification and education has been provided to Hanover residents, area pet stores and veterinarians including comprehensive information about changeover impacts for aquariums. This information will also be provided to all Hanover residents, area pet stores, and veterinarians through direct mail and through updates to the Town's web site. (EPA 22)
Can I remove monochloramine from my drinking water?
EPA believes that drinking water disinfected with monochloramine that meets regulatory standards is safe to use and it does not need to be removed. The Hanover DPW (Water Division) will be testing the drinking water regularly to make sure it is within EPA regulatory limits. (EPA29)
The footnote codes (EPA 1...29) refer to question numbers and answers in the EPA Chloramine Q&A document (EPA 815-B-09-001 March 2009). Click the following link for the full text of the EPA's Chloramine Q&A document. (EPA Chloramine Document)