Why is groundwater contamination difficult to purify?

Groundwater contamination is indeed difficult to purify primarily due to the slower breakdown rates of contaminants in groundwater, which is a result of the limited oxygen levels. In aquifers, the movement of water is significantly slower compared to surface water systems. This reduced flow means that contaminants can persist for extended periods, allowing them to remain in the groundwater without undergoing natural degradation processes.

Most biological processes that break down pollutants require oxygen, and groundwater environments often have lower levels of dissolved oxygen, especially in deeper aquifers. As a result, contaminants can accumulate, making it challenging to eliminate them effectively.

In contrast, surface waters are exposed to more oxygen and have greater microbial activity that can aid in the breakdown of contaminants more rapidly. Additionally, the importance of groundwater as a source of drinking water underscores the significance of effectively addressing contamination, contrary to the idea that it is not used for drinking, which is not relevant to the issue of purifying contaminated groundwater.