MDARD Michigan Core Pesticide Applicator Practice Exam

What is the primary cause of leaching in water affecting pesticides?

1. Solubility

2. Density

3. Temperature

4. pH levels

The correct answer is: Solubility

Leaching refers to the process by which soluble substances, such as pesticides, are washed out from soil into groundwater. The primary factor influencing this process is solubility. When pesticides are highly soluble in water, they can easily dissolve and move through the soil profile when it rains or when irrigation occurs, potentially reaching groundwater. Solubility directly affects how easily pesticides can be transported in soil, and those that are more soluble are more likely to leach into water supplies. Understanding the solubility of a pesticide is critical for determining its environmental impact, especially in agricultural settings where water quality is a concern. The other factors, such as density, temperature, and pH levels, play roles in pesticide behavior in the environment but are not the main drivers of leaching. Density may affect how a substance pools in the soil or interacts with water, temperature can influence chemical reactions and volatility, and pH levels can impact the chemical form of certain pesticides, but these elements do not primarily dictate the movement of pesticides into water through leaching.