A brief introduction of water disinfection
Public water systems routinely perform disinfection to protect public health in compliance with standards set by health and environmental regulatory agencies. Water disinfection is a critical process to eliminate pathogens and disease-causing microorganisms in water. Disinfection can be achieved through various methods, including the use of chlorine, chloramine, and/or other oxidation processes.
Among the various methods used, chloramine, a compound formed by mixing chlorine with ammonia, has gained popularity as a disinfectant in the past two decades. Its increased use, however, brings to light the complex interplay of regulations, health implications, and the need for public vigilance.
Chloramine reemergence
Chloramine has been around for decades as a water disinfectant. It was dwarfed by chlorine in use simply because the later is much more effective and lower in cost. But in the last two decades, more and more public water systems moved to chloramine use. But why?
Because the bond of chlorine and ammonia is stable in chloramine (which is the exact reason why chloramine is much harder to be removed), chloramine provides a longer-lasting residual disinfectant effect than chlorine, making it more stable as it travels through the distribution system. It is claimed that this property helps maintain disinfection effectiveness to each serviced household.
But chlorine has been used for more than a century. Does this mean that we had not properly protected public health before? The answer is definitely negative. And the question remains: Why chloramine was used more all of a sudden?
Disinfection byproducts and related regulation
To answer that, we have to learn something about disinfection byproduct. Disinfection byproducts (DBPs) are chemical compounds formed when disinfectants used to purify water react with largely natural organic matters (NOM) present in the water. NOM in nature comes from dead plants, animals or microbes and is common especially in surface water like lakes or rivers. There are two types of widely studied DBPs from chlorine use: THMs and HAAs. Both are linked to animal cancer in lab tests. The discovery of THMs and the subsequent discovery of HAAs had aroused public health concerns and had prompted Environmental Protection Agency (EPA) to establish related regulations.
EPA established the first regulations for THMs under the National Interim Primary Drinking Water Regulations (NIPDWR) around 1980. In 1998, EPA introduced Stage 1 Disinfectants and Disinfection Byproducts Rule (D/DBPR) to address a broader spectrum of DBPs, including HAAs. And in 2006, EPA strengthened its regulations with the Stage 2 D/DBPR.
If THMs regulation only prompted affected public water systems to adjusted the point of chlorination, moving it further along in the treatment process to reduce the time chlorine had to react with organic matters, the two stages of D/DBPR had forced them to start to look for alternative. And chloramine is the answer. In Health Canada's saying: "Chloramines are often used to meet DBP compliance based on HAAs and THMs".
Focus on chloramine use
When doves of public water systems started to move to chloramine use, there were many resistance at the grassroot level. One representative voice has been chloramine.org. But a lot of focus of such grassroot voices had been put on the disinfectant itself in causing respiratory, dermatologic and digestive issues. While chloramine itself may have its own health implications, especially to sensitive group of people, it has been deemed as a safe-to-use disinfectant by itself.
But the research and focus are quickly moving to chloramine related DBPs. And the initial researches are causing great concerns in highlighting that the emerging and unregulated DBPs from chloramine use as a disinfectant is much more toxic than its chlorine counterparts. In an iodo-acids study published in 2007, it is noted that "As part of a recent Nationwide Disinfection By-Product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines." And in an article published by NIH in 2019, it is noted that "I-DBPs are almost always more cytotoxic and genotoxic than their chlorinated and brominated analogues. Iodoacetic acid is the most genotoxic of all DBPs studied to date, and diiodoacetamide and iodoacetamide are the most cytotoxic."
What can you do if your public water system uses chloramine
Two technologies can be used to remove DBPs from water: activated carbon and membrane. Among different types of activated carbons, catalytic carbon has better DBPs removal efficacy. Catalytic carbon is activated carbon with its surface specially modified to promote catalytic property which will help to break down compounds through chemical reaction.
Catalytic carbon can do everything regular activated carbon can, plus:
- Better Reduction of DBPs, Chloramines, Hydrogen Sulfide, VOCs, ferrous Iron, etc.
- Higher Capacity for Chlorine Reduction/Removal.
Our suggestion is to use catalytic carbon filters and/or RO systems for where you fetch your drinking or cooking water at kitchen main water faucet, refrigerator water dispenser, or drinking water faucet. This will create a layer of protection in case there are emerging DBPs from your public water system.