Examples of typical complexed metals in wastewater include which of the following?

The correct choice includes cadmium, copper, lead, and zinc because these metals are commonly found in wastewater and tend to form complexes with organic molecules in the environment. Complexed metals are often present due to industrial activities, wastewater discharges, and other anthropogenic sources. These metals can become soluble and interact with other substances in the wastewater, making them more challenging to remove during treatment processes.

The presence of these metals in wastewater poses environmental and health risks, as they can be toxic to aquatic life and humans, even at low concentrations. Understanding the presence and behavior of these complexed metals is crucial for effective wastewater management and treatment strategies.

Other choices represent metals that may also be found in various contexts or are not typically associated with wastewater in the same manner. Gold, silver, and palladium, for instance, are precious metals primarily associated with electrical and electronics industries, while iron, magnesium, and sodium are more abundant and essential elements rather than being typical complexed metals in wastewater. Chromium, arsenic, and mercury, although also found in wastewater, may not be categorized the same way in terms of being typical complexed metals as seen with cadmium, copper, lead, and zinc.