What types of chemicals may be regulated under drinking water standards?

The regulation of drinking water standards encompasses a broad range of contaminants to ensure the safety and quality of drinking water. The correct answer lists microbial contaminants, disinfectants, volatile organic compounds, and heavy metals, all of which are critical categories regulated to protect public health.

Microbial contaminants include pathogens such as bacteria, viruses, and protozoa, which can cause serious health issues if ingested. Disinfectants are chemicals used in the treatment process to eliminate harmful microorganisms, and their levels must be monitored to prevent potential harmful by-products.

Volatile organic compounds (VOCs), which can originate from various sources including industrial processes and agricultural runoff, are also regulated due to their potential health risks. Heavy metals, such as lead and arsenic, are naturally occurring elements that can enter water supply systems and pose serious health risks, especially to vulnerable populations like children and pregnant women.

The other options focus on narrower or less relevant sets of chemicals. For instance, pesticides and fertilizers are indeed important in water safety but do not encompass the full range of regulated contaminants like the correct choice. Similarly, aromatic hydrocarbons, semi-volatile organic compounds, and radioactive materials are significant but alone do not cover the diverse set of substances included in drinking water standards as thoroughly as the first