How can groundwater be contaminated?
As groundwater infiltrates it can pick up contaminants from the surface of the ground or from the surrounding soil. The water may dissolve the contaminant or just carry it in to the aquifer. Some contaminants can be transported great distances from their source. Groundwater travels very slowly; therefore, little dilution or dispersion of the contaminant usually occurs. The contaminant forms a concentrated plume that follows the groundwater flow path.