Which of the following contaminants is commonly removed using ion exchange technology?

Ion exchange technology is highly effective for removing certain types of contaminants from water, particularly dissolved ions. Lead, as a heavy metal, is often targeted by this method because it can be exchanged with other, less harmful ions in the resin used in ion-exchange processes. The resin typically contains a high concentration of ions, and when water is passed through it, lead ions are exchanged for sodium or potassium ions. This process significantly reduces the concentration of lead in the water, making it safer for consumption.

While other contaminants listed might be discussed in the context of water treatment, they are commonly addressed using different methods. For instance, nitrates can be removed through biological processes or reverse osmosis, while sulfate removal often involves chemical precipitation or other filtration techniques. Calcium, being a common hardness ion, is frequently dealt with through water softening, not strictly ion exchange in the context of targeting heavy metals like lead.