Many factors should be considered when determining the vulnerability of an aquifer to nitrate pollution from agricultural practices. Nitrate contamination of ground water depends upon climate, fertilizer or manure management, soil, crop, and farming systems. A climate with rainfall exceeding evapo-transpiration often leads to the movement of rainwater to groundwater. In West Virginia, water received though precipitation is more than that lost through evapo-transpiration from soils and plants. A part of the water received through precipitation becomes surface runoff and is lost from the land through rivers or streams.
Nitrates are highly soluble salts.
When water moves on the surface of a soil, it dissolves some nitrates that are present in the surface layers of soils. Another part of the precipitation seeps into the soil and recharges the groundwater. Water that has seeped through the soil is called groundwater. This seeping water dissolves soil nitrates. Any excess nitrates that are present in this groundwater-recharge zone are carried to the groundwater.