Which contaminants are primarily regulated by the EPA in drinking water?

The Environmental Protection Agency (EPA) regulates a wide range of contaminants in drinking water to ensure public health and safety. The correct choice encompasses microorganisms, disinfectants, and organic chemicals, which are significant categories monitored under the Safe Drinking Water Act.

Microorganisms include pathogens such as bacteria, viruses, and protozoa, which can pose serious health risks if present in drinking water. Disinfectants, while used to kill harmful organisms, can form byproducts that may also be harmful; thus, their levels are regulated. Organic chemicals encompass a broad class of substances, including volatile organic compounds and synthetic organic chemicals, many of which can originate from industrial practices, agricultural runoff, and household products.

Regulating these contaminants is crucial for protecting public health, as they can vary widely in sources and effects. In contrast, the other options offered do not capture the full scope of contamination types that the EPA is tasked with regulating, which is why they do not provide a complete picture of the standards set for drinking water safety.