Indiana Pesticide Applicator Core Practice Exam

What is the primary reaction involved in chemical degradation of pesticides?

1. Decomposition by microbes

2. Water or oxygen reacting with the pesticide

3. Absorption by soil

4. Evaporation

The correct answer is: Water or oxygen reacting with the pesticide

The primary reaction involved in the chemical degradation of pesticides often refers to the processes where water or oxygen reacts with the pesticide molecules. This reaction can lead to the breakdown of the pesticide into simpler, less harmful substances. When pesticides are exposed to moisture or oxygen, they can undergo hydrolysis or oxidation reactions, respectively. Hydrolysis involves the chemical breakdown of a compound due to reaction with water, which can be particularly important for many pesticide formulations that are susceptible to this kind of degradation. Similarly, oxidation, a reaction with oxygen, can lead to the transformation of pesticides into non-toxic metabolites. While the actions of microbes and soil absorption are important in the overall degradation process of pesticides, they are considered part of biological degradation and physical processes rather than direct chemical reactions. Microbial decomposition typically involves living organisms that metabolize the chemical, and soil absorption is more about the retention and binding of pesticide molecules in soil rather than their chemical breakdown. Evaporation relates to the loss of pesticides into the atmosphere but does not directly contribute to chemical degradation in the same manner. Thus, the correct answer reflects the fundamental chemical reactions that lead to the breakdown of pesticides into less harmful substances, highlighting the role of water and oxygen in these processes.