Question

Chlorinated xenobiotics can ONLY be degraded aerobically, thus making them very recalcitrant if they accumulate in anoxic environments.

A. True
B. False

Answer 1

False. Chlorinated xenobiotics can be degraded aerobically and anaerobically. Their recalcitrance in anoxic environments is not solely due to the inability for anaerobic degradation.

Step-by-step explanation:

False. Chlorinated xenobiotics are compounds that have been synthesized by humans and introduced into the environment at high concentrations. These compounds are problematic because they are difficult to degrade and can accumulate in anoxic (oxygen-depleted) environments. However, while aerobic degradation is one mechanism for breaking down chlorinated xenobiotics, it is not the only one.

There are anaerobic bacteria that have the ability to degrade chlorinated xenobiotics. These bacteria use different mechanisms, such as reductive dechlorination, which does not require oxygen. Anaerobic degradation of chlorinated xenobiotics typically occurs in environments such as groundwater, sediments, or anaerobic digesters.

Therefore, chlorinated xenobiotics can be degraded both aerobically and anaerobically, and their recalcitrance in anoxic environments is not solely due to the inability for anaerobic degradation.