Water Disinfection: Beneficial or Detrimental?

Water pouring into glass

By: Asayah Barnwell 

Waterborne disease is the cause for an estimated 2.2 million deaths per year and about 1.4 million are deaths of children. The estimated economic cost associated with waterborne disease is 1 billion dollars annually in the USA and 12 billion worldwide. Waterborne infections occur when a person is exposed to contaminated water via inhalation, ingestion, and dermal contact.  

Chlorination is the process in which chlorine is added to water to disinfect it. Chlorination has been shown to reduce the majority of bacteria and viruses found in the water and its low in cost, easy to use, has residual protection, etc. Due to the adoption of chlorination to disinfect water around the world, waterborne diseases and related deaths have significantly decreased around the world. 

The water disinfection process is associated with many positives, but what about the negatives? How safe is the water disinfection process? In the early 1970s, the EPA determined chlorination had the ability to form disinfection byproducts (DBPs). During chlorination, chlorine reacts with the organic matter that is present within the water.  

More than 600 DBPs have been discovered in drinking water. We are exposed to DBPs through inhalation, dermal contact, and ingestion. In short, we are exposed to these by-products in all the ways we use water daily.  

How does this exposure affect our health? 

Studies have shown that DBPs are associated with: 

toxicology study I conducted in 2019 at the University of Illinois at Urbana-Champaign looked at the effects of iodoacetic acid on cell proliferation, uterine morphology, and cell viability in mouse uteri. Iodoacetic acid (IAA) is a water disinfection by-product that is found in chlorine-treated water. At the time of this study, there were very few studies involving the effects of IAA in relation to reproductive health. Before working on this study, I had no knowledge of disinfection by-products and their effects on human health. I found this topic extremely interesting and it caused me to think deeper about the water we drink as well as any other objects or substances we use in our daily lives. The study found that there was a significant decrease in cell viability and cell number in cultured stromal cells that were exposed to IAA concentrations of 2µm and 15µm. There was also a noticeable trending decrease in the luminal epithelium of uteri in mice that were exposed to IAA for 30 days. These results were favorable, but also shocking. I didn’t expect the results to be as significant as they were, and it was interesting to see the physical effects when looking at the histological results.  

Further studies may lead to safer alternatives or an improved water disinfection process to potentially lessen the amount of DBPs found in water or eliminate them altogether.  There are alternatives to disinfection, but I’ve not found anything better than chlorine. I’ve also given thought to creating a method in the process to remove the DBPs after the initial disinfection, and am still thinking through it. I’d love to hear your comments and ideas: abarnwell@scitovation.com


  • Gonsioroski, A. V. (n.d.). The effects of iodoacetic acid on mouse ovarian follicles. 
    Jeong, C. H., Gao, L., Dettro, T., Wagner, E. D., Ricke, W. A., Plewa, M. J., & Flaws, J. A. (2016). Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro. Reproductive Toxicology, 62, 71–76. https://doi.org/10.1016/j.reprotox.2016.04.028 
  • Narotsky, M. G., Klinefelter, G. R., Goldman, J. M., DeAngelo, A. B., Best, D. S., McDonald, A., … Simmons, J. E. (2015). Reproductive toxicity of a mixture of regulated drinking-water disinfection by-products in a multigenerational rat bioassay. Environmental Health Perspectives, 123(6), 564–570. https://doi.org/10.1289/ehp.1408579 
  • National Toxicology Program. (2017). Report on Carcinogens Monograph on Haloacetic Acids Found as Water Disinfection. National Toxicology Program, (March). 
  •  https://doi.org/10.1021/acs.est.8b01802 
  • Barnwell, A., “The Effects of Iodoacetic Acid on Cell Proliferation, Uterine Morphology, and Cell Viability in Mice Uteri .” The Graduate College at the University of Illinois at Urbana-Champaign, 2019, grad.illinois.edu/effects-iodoacetic-acid-cell-proliferation-uterine-morphology-and-cell-viability-mice-uteri. 
  • Ramírez-Castillo, Flor Yazmín et al. “Waterborne pathogens: detection methods and challenges.” Pathogens (Basel, Switzerland) vol. 4,2 307-34. 21 May. 2015, doi:10.3390/pathogens4020307 
  • “Chlorination.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 23 Apr. 2014, www.cdc.gov/safewater/chlorination.html.