What can happen if low volume/slow recovery wells are over-purged?

Over-purging low volume or slow recovery wells can lead to aeration of the formation water. When a well is purged excessively, it can create a vacuum effect that draws air into the well and disturbs the natural water table and the equilibrium between the water and the surrounding geological materials. This aeration can introduce dissolved gases, such as oxygen, into the water, which can adversely affect the water quality and the behavior of contaminants that may be present.

This situation can be especially problematic for sensitive aquifers or when sampling for specific contaminants, as the presence of air can alter chemical reactions and the solubility of various compounds. Therefore, controlling the purging process is vital to maintaining the integrity of the water sample and the conditions within the aquifer.