MDARD Michigan Core Pesticide Applicator Practice Exam

Which chemical property of pesticides is directly associated with its potential for surface water runoff?

1. High volatility

2. High absorption

3. High solubility

4. Low solubility

The correct answer is: High solubility

The potential for surface water runoff is closely related to the solubility of a pesticide in water. When a pesticide has high solubility, it means that it dissolves easily in water. This increased solubility allows the chemical to be transported more readily into surface water bodies during rainfall or irrigation events. Pesticides that dissolve well in water can be carried away from the application site and into streams, ponds, or lakes, especially during heavy rains or when soil saturation occurs. This can lead to potential risks for aquatic organisms and contribute to water quality issues. Understanding solubility is crucial for predicting how pesticides move through the environment and their potential impact on surface water resources. On the other hand, other properties such as volatility affect how pesticides evaporate into the air rather than how they move through water. Absorption refers to how well a pesticide binds to soil particles, which typically decreases the likelihood of it being washed away. Low solubility would mean less likelihood of runoff, as the chemical would remain more bound to the soil rather than being transported in water. Thus, high solubility is the key factor that directly influences the potential for surface water runoff.