Chloramine water disinfection creates toxic compound.
Richardson SD, F Fasano, JJ Ellington, FG Crumley, KM Buettner, JJ Evans, BC Blount, LK Silva, TJ Waite, GW Luther, AB McKague, RJ Miltner, ED Wagner and MJ Plewa. 2008. Occurrence and mammalian cell toxicity of iodinated disinfection byproducts in drinking water. Environmental Science and Technology doi:10.1021/es801169k.
Disinfecting compounds used by water treatment plants are creating a potentially hazardous byproduct, called iodoacetic acid, that is highly toxic to mammalian cells. A change is the length of time the plants treat the water can still disinfect the water yet produce much less of the toxic chemical.
Chloramine, a mixture of chlorine and ammonia, is replacing traditional chlorine disinfection in water treatment plants in the US. The switch is occuring because chloramines produce less trihalomethane, a harmful compound that is made when chlorine is used as a disinfectant.
This study shows that chloramine produces iodoacetic acid, which causes developmental abnormalities in mouse embryos.
It turns out that chloramine treatment methods differ in detail from one plant to another. Some add the chlorine and ammonia at the same time while other plants add the chlorine first and the ammonia later.
The process the plants used to treat the water significantly affected the presence of the toxic acid. The treatment plants that allows chlorine to have a longer contact time with water before the ammonia is added produce much less iodoacetic acid. The results suggest that many plants could reduce potential health risks of the acid with a simple change in their process.