Which is not a pathway for contaminants?

• A. Ingestion
• B. Surface water
• C. Groundwater
• D. Wind

Answer: (A)

Contaminant transport pathways describe how pollutants move from a source through the environment to a receptor. Water and air pathways are about the physical movement of contaminants—through surface water, groundwater, and by wind. Ingestion is not a transport mechanism; it’s a route of exposure where a person or organism takes in contaminants that have already reached a medium such as water or food. So while you can later ingest contaminated water or produce, the act of ingestion itself does not transport the contaminant through the environment. That’s why ingestion is not considered a transport pathway.