Which pesticide characteristic would likely lead to the most groundwater pollution?

Little absorption by colloids is a characteristic that would lead to the most groundwater pollution because when a pesticide has low absorption, it means that it does not easily adhere to soil particles. This allows the pesticide to more readily leach through the soil profile and enter groundwater systems, especially in areas with sandy or well-drained soils.

High absorption by colloids would typically result in more retention within the soil, thus minimizing the likelihood of reaching groundwater. High volatility can facilitate the pesticide evaporating into the atmosphere rather than moving through the soil. Low water solubility also reduces the movement of the pesticide into groundwater, as compounds that do not dissolve well in water tend to remain in the soil or bind tightly to soil particles. Therefore, low absorption by colloids poses a significant risk for groundwater contamination due to its increased potential for leaching.