Which factor does NOT contribute to the formation of TTHMs?

The formation of Trihalomethanes (TTHMs) is primarily influenced by factors such as water temperature, chlorine concentration, and the presence of organic matter. Among the choices, high water temperature, high levels of free chlorine, and high organic content all foster conditions that increase the formation of TTHMs.

High water temperature accelerates the chemical reactions necessary for TTHM formation. Warm temperatures provide energy that enhances the reactivity of the chlorine with organic precursors present in the water. Similarly, high levels of free chlorine are critical because chlorine is the disinfectant that reacts with organic compounds to form TTHMs. The more free chlorine available, the more potential there is for these reactions to take place. Additionally, high organic content provides the necessary precursors that react with chlorine to produce TTHMs.

On the other hand, low pH does not contribute to TTHM formation in the same way. While pH can affect the reaction rates and the speciation of chlorine in water, it does not directly enhance the formation of TTHMs like the other factors do. In fact, a lower pH can impede the chlorination reaction efficiency, leading to less TTHM formation.

Thus, among the options provided, low