Which of the following contaminants is specifically regulated due to its impact on public health?

The regulation of specific contaminants in drinking water is crucial for protecting public health, and both nitrites and heavy metals fall into this category. Nitrites, for example, are particularly harmful because they can interfere with the ability of the blood to carry oxygen in infants, leading to a condition known as methemoglobinemia or "blue baby syndrome." Due to this serious health risk, nitrites are closely regulated to ensure that their levels remain below harmful thresholds in drinking water.

Heavy metals, such as lead, mercury, and arsenic, are also heavily regulated due to their toxic properties and long-term health effects, which can include neurological damage, cancer, and developmental issues in children. Because these contaminants can accumulate in the human body over time, even low levels can pose significant health risks.

Phosphates, while they can contribute to water quality issues like eutrophication in aquatic environments, are not specifically regulated due to direct impacts on human health in drinking water supplies. Therefore, while they may have environmental consequences, they do not carry the same level of health risk that warrants stringent regulation as nitrites and heavy metals do.

In summary, the correct choice encompasses both nitrites and heavy metals, highlighting the importance of regulation in ensuring public safety from serious health