What is a major concern about runoff water from a pesticide storage area?

Runoff water from a pesticide storage area poses a significant risk because it can carry harmful pesticide residues into nearby ground or surface water. This contamination can have detrimental effects on aquatic ecosystems, drinking water supplies, and overall environmental health. When pesticides enter water bodies, they can disrupt aquatic life, harm fish populations, and impact the quality of water used for agricultural and recreational purposes.

The other options, while they may be concerns in different contexts, do not directly address the primary issue associated with runoff from pesticide storage areas. For instance, evaporation does not directly relate to the effect of pesticide residues on water sources. Contamination of the air is generally linked to pesticide application rather than runoff, and soil erosion, while a serious agricultural concern, does not specifically relate to the contamination threats posed by stored pesticides in runoff scenarios.