Which statement about contaminated groundwater is true?

• A. Long lasting due to lack of oxygen and sunlight
• B. Quickly purified
• C. Easily accessible
• D. Very expensive to purify

Answer: (A)

Groundwater contamination tends to last a long time because it sits underground where there is little to no oxygen and no sunlight. Those conditions slow the natural processes that break down many pollutants. Without oxygen, aerobic biodegradation happens slowly or not at all, and without sunlight, photolysis doesn’t occur. As a result, contaminants persist and can move slowly with the groundwater through aquifers, spreading the pollution over larger areas before it’s naturally attenuated. Statements that imply rapid purification or easy access don’t fit the reality of underground water; remediation can be challenging and costly, but the main reason contamination sticks around is the lack of oxygen and sunlight that would normally help break it down.