Which of the following is a natural source of pollution that can eventually contaminate all groundwater?

• A. Arsenic leaching from rocks and soil
• B. Industrial chemical spills
• C. Oil leakage from underground storage tanks
• D. Fertilizer runoff from agriculture

Answer: (A)

Verified step by step guidance

1. Understand the difference between natural and anthropogenic (human-made) sources of pollution. Natural sources originate from natural processes, while anthropogenic sources result from human activities.
2. Identify the options that are natural sources. Arsenic leaching from rocks and soil is a natural process where arsenic naturally present in the earth's crust dissolves into groundwater.
3. Recognize that industrial chemical spills, oil leakage from underground storage tanks, and fertilizer runoff are all human-related activities and thus are anthropogenic sources of pollution.
4. Consider how arsenic leaching can contaminate groundwater over large areas because it occurs naturally in many types of rocks and soils, making it a widespread natural contaminant.
5. Conclude that among the given options, arsenic leaching from rocks and soil is the natural source of pollution that can eventually contaminate all groundwater.