Which of the following contaminants are often tested in drinking water for health risks?

Benzene and polychlorinated biphenyls (PCBs) are known for their significant health risks and are commonly tested in drinking water. Benzene is a volatile organic compound that can cause serious health issues, including cancer, when consumed over long periods. PCBs are industrial chemicals that have been linked to effects on the immune system, reproductive system, and potential carcinogenicity.

Testing for these contaminants is critical because they can be found in drinking water as a result of industrial discharge, improper waste disposal, and other environmental factors. Monitoring water supplies for these substances helps ensure that public health is protected, as they can pose long-term health risks to populations if present above allowable levels.

In contrast, while microplastics and phenols, silica and chlorine, or carbon and nitrogen may have their implications for water quality, they are typically not prioritized as direct health risks in the same way that benzene and PCBs are. Microplastics are currently being studied for potential effects, but standards and methods for assessment are still developing. Furthermore, while silica and chlorine do play roles in water chemistry and treatment, they aren't necessarily linked to the severe health outcomes associated with benzene and PCBs. Carbon and nitrogen are elements found in many natural and