When assessing water quality, which of the following is part of secondary regulations?

When assessing water quality, odor and taste are considered part of secondary regulations because these aspects are primarily focused on aesthetic qualities rather than direct health risks. Secondary regulations are established by agencies to address concerns that affect the aesthetic quality of drinking water, including its odor, taste, and appearance. These regulations aim to ensure that water is not only safe to drink but also pleasant to consume, as poor taste or odor can lead to public dissatisfaction and potentially result in them opting for alternative water sources.

In contrast, options such as pathogen control, heavy metal concentration, and microbial limits are related to primary regulations, which are designed to protect public health by limiting contaminants that can pose immediate health risks. Pathogens and microbial limits directly address harmful microorganisms in the water, while heavy metal concentration pertains to the presence of toxic metals that can have serious biological implications. Thus, option C is correct because it aligns with the aesthetic-focused nature of secondary regulations.