Which of the following is a site condition associated with groundwater contamination?

• A. Depth of water table
• B. Soil color
• C. Ambient temperature
• D. Humidity

Answer: (A)

The main factor here is how far the groundwater is beneath the surface. The depth to the water table controls how much unsaturated soil a contaminant must travel through before reaching groundwater. A shallower water table means a shorter path and less natural filtration, so surface spills or improper disposal of pesticides can more quickly enter the aquifer. Conversely, a deeper water table provides a longer, more protective buffer as soils can adsorb or dilute contaminants before they reach groundwater.

Soil color, ambient temperature, and humidity don’t directly determine groundwater contamination risk. Soil color can hint at drainage or composition but doesn’t by itself indicate vulnerability to contamination. Temperature and humidity affect reaction rates rather than the fundamental transport path into groundwater.