What is the Secondary Drinking Water Standard defined by?

The Secondary Drinking Water Standard is defined in 40 CFR 143. This regulation is part of the federal guidelines established by the Environmental Protection Agency (EPA) that outlines non-enforceable standards for contaminants that may cause cosmetic effects (like staining or discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. These standards are important for ensuring that water remains palatable and does not cause issues that would affect public acceptance of drinking water, even though they typically do not pose direct health risks.

The other choices represent different code sections that pertain to other regulatory areas. For example, 40 CFR 141 covers the National Primary Drinking Water Regulations, which set enforceable standards for contaminants that affect health, while 40 CFR 150 addresses environmental impact statements under the National Environmental Policy Act (NEPA). Lastly, 40 CFR 152 is related to the regulatory processes for the registration of pesticides. Thus, only 40 CFR 143 provides the specific framework for the Secondary Drinking Water Standards.