Final answer:
Groundwater contamination can be difficult and sometimes impossible to purify due to the slow natural cleaning process. Examples of contaminants include chemicals from leaking storage tanks and careless disposal of household chemicals.
Step-by-step explanation:
Groundwater contamination can indeed be difficult and sometimes impossible to purify. Groundwater is located beneath the surface of the Earth and is often found in aquifers. When pollutants or contaminants enter the ground, they can seep into the groundwater and contaminate it. Due to the natural cleaning process of groundwater being slower than surface water, it can be challenging to remove the contaminants and purify the groundwater effectively. Examples of groundwater contamination sources include leaking underground storage tanks, agricultural chemicals, and careless disposal of hazardous household chemicals.