What type of substances do combined residual chloramines interact with?

Combined residual chloramines primarily interact with free residual chlorine compounds. When chloramine, which is a compound formed when ammonia is added to chlorine in water treatment, encounters free chlorine, it can undergo reactions that lead to the formation of more complex nitrogen chlorides. This interaction is important to understand because it influences the overall disinfection process and affects the residual levels of both chloramines and free chlorine in the water system.

The presence of free chlorine can lead to the breakdown of original chloramine compounds, and thus monitoring these interactions is crucial for maintaining effective disinfection while minimizing harmful byproducts. Understanding this relationship helps water operators manage water quality effectively in distribution systems.

The other options focus on interactions that do not primarily reflect the nature of chloramines. While various organic pollutants, molecular chlorine, and inorganic ions can be present in water systems and might interact with disinfectants, the specific interaction of combined chloramines is most relevant in the context of its relationship with free residual chlorine.