Disinfection Byproducts may pose health risks because

• A. They may pose health risks
• B. They always prevent illness
• C. They are always present as solids
• D. They are not monitored

Answer: (A)

Disinfection byproducts form when disinfectants like chlorine react with natural organic matter in water, creating chemical compounds that can be harmful with enough exposure. The key idea here is that disinfection protects against microbes, but it can also introduce chemicals that may pose health risks, especially with long-term or high-level exposure. This is why the statement that they may pose health risks is the best description.

They aren’t always present as solids—many DBPs are dissolved or volatile substances in water. Also, drinking-water systems do monitor DBP levels and regulate them to keep exposure within safe limits, so the notion that they are not monitored isn’t accurate. In short, disinfection reduces microbial illness but carries a potential chemical health risk that regulators watch to minimize.