Which of the following is not a group of chemical contaminants monitored?

The choice of "Bacterial Organic Compounds" as the answer is correct because it does not represent a recognized category of chemical contaminants monitored in water quality testing. Water quality regulations generally categorize contaminants for monitoring into various groups, typically including inorganic contaminants (IOC's), volatile organic compounds (VOC's), and synthetic organic compounds (SOC's).

Inorganic contaminants include substances like metals and salts, VOCs refer to various carbon-based chemicals that can evaporate into the air, and SOCs consist of man-made organic chemicals. Bacterial contaminants, on the other hand, are typically categorized separately from chemical contaminants and are usually classified under microbiological contaminants rather than being grouped with organic compounds. Thus, "Bacterial Organic Compounds" does not align with the established categories of chemical contaminants that regulatory bodies focus on monitoring.