Should I be worried about chloramines?
Though the two words sound similar, chlorine and chloramine are very different. Chloramine is a compound that is created when chlorine and ammonia are combined.
Most often, chloramine is used in the form of monochloramine as a disinfectant for drinking water. However, it is much less effective than pure chlorine and accordingly, is generally only used for secondary disinfection. Secondary disinfection is like the "maintenance" phase of disinfection--its purpose is to kill anything that was not killed by the primary disinfectant and prevent new pathogens from gaining a foothold.
Chloramines can also form organically through the combination of nitrogen and chlorine in solution. This most commonly occurs in water sources contaminated with organic material; as chlorine is added to the water, it reacts with the nitrogen present to form dichloramine, trichloramine, and organic chloramine. The type of chloramine that is formed is dependent on the ammonia-nitrogen weight ratio in the water and the pH level.
What are the health risks associated with chloramines?
There is limited research on the specific health risks of exposure to dichloramine and trichloramine, mainly because it is not common to be repeatedly exposed to high levels of these compounds. Both dichloramine and trichloramine evaporate from water quickly. The gaseous nature of chloramine means you would need to be in an enclosed environment where they were continually being produced in order to inhale a significantly high concentration. This is a concern for pool and food industry workers, who are surrounded by water with high levels of organic material and chlorine for long periods every day. There have been some studies which have shown that trichloramine can be irritating to the respiratory system and eyes, particularly in people who already suffer from asthma. However, no other health correlations have been discovered and only trichloramine is regulated as a workplace health exposure risk.
Does hypochlorous acid produce chloramine?
Hypochlorous acid is a form of chlorine, so chloramine formation is an expected result of combining hypochlorous with high nitrogen sources. In fact, just like hypochlorous, chloramines are also produced by the human body as part of the neutrophil response. To reduce the likelihood of chloramine formation, we recommend cleaning your surfaces with soap and water prior to adding hypochlorous, as it reduces the organic matter load (which is the main source of nitrogen). Additionally, if you are adding hypochlorous to a hydroponic water system in a greenhouse it is important to coordinate your nutrient schedule so you are not adding hypochlorous and fertilizers at the same time. The hypochlorous will be converted to chloramine and lost through evaporation, rendering it useless.
However, it is important to note that both dichloramine and trichloramine require a low pH in order to form--dichloramine forms between 4-6 pH and trichloramine only occurs below 4 pH. Because the ideal pH range for hypochlorous is between 6-7, it is highly unlikely that your solution will produce either of these if made correctly. So, while it's good to be aware of chloramines, unless you are a grower or a pool worker, it's probably not something you need to worry about.
Photo by Enis Yavuz on Unsplash
References
Wastensson, G., & Eriksson, K. (2020). Inorganic chloramines: a critical review of the toxicological and epidemiological evidence as a basis for occupational exposure limit setting. Critical Reviews in Toxicology, 50(3), 219–271. https://doi.org/10.1080/10408444.2020.1744514
Kim, C., & Cha, Y.-N. (2013). Taurine chloramine produced from taurine under inflammation provides anti-inflammatory and cytoprotective effects. Amino Acids, 46(1), 89–100. https://doi.org/10.1007/s00726-013-1545-6
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