Water Nuggets Practice Exam

The choice that identifies bacteria, nitrates, heavy metals, and pesticides as primary contaminants of concern in drinking water is correct because these substances significantly impact public health and safety.

Bacteria can cause various waterborne diseases, leading to outbreaks and serious health issues. Nitrates, often from agricultural runoff, pose risks especially to infants, as they can interfere with the blood's ability to carry oxygen. Heavy metals, such as lead and mercury, are toxic and can accumulate in the body over time, causing severe health problems. Pesticides can contaminate drinking water supplies through agricultural runoff and pose risks to human health even at low concentrations.

In contrast, other options include substances like chlorine and fluoride, which are typically used as disinfectants and for water treatment, thus they are not considered contaminants in the same sense as the substances listed in the correct answer. Algae and sediment may affect water quality but do not pose the same direct health risks associated with the contaminants identified in the correct choice.