Texas Pesticide Applicator Practice Exam

Which process is NOT responsible for the breakdown of pesticides after application?

1. Photodegradation

2. Microbial degradation

3. Chemical degradation

4. Atmospheric degradation

The correct answer is: Atmospheric degradation

The correct answer is atmospheric degradation. This term typically refers to the processes that occur in the atmosphere, such as the interaction of chemicals with sunlight and other atmospheric components, which can lead to changes in their chemical structure. However, atmospheric degradation is not usually considered a primary mechanism for the breakdown of pesticides post-application. In contrast, photodegradation involves the breakdown of pesticides through the energy of sunlight, which can result in the transformation of pesticide compounds. Microbial degradation relies on the activity of soil microorganisms, which can metabolize and break down pesticides, making them less harmful. Chemical degradation encompasses various chemical reactions, such as hydrolysis or oxidation, that can also lead to the breakdown of pesticides after they have been applied. Thus, while atmospheric conditions can affect pesticides, they are not a main pathway for their degradation in a way that directly contributes to their dissipation in the soil or on target organisms.