Pathways for contaminants include which of the following?

• A. Ingestion and inhalation
• B. Groundwater and soil moisture
• C. Airflow only
• D. Surface water, groundwater, and wind

Answer: (D)

Pathways describe how contaminants move through the environment from a source to receptors, by traveling in environmental media. The major transport media are water and air. Contaminants can move with surface water in rivers, lakes, and streams, and they can also move with groundwater through aquifers, delivering contaminants to water supplies and ecosystems. The atmosphere carries contaminants as airborne particles or gases, allowing them to disperse over distances and eventually deposit elsewhere.

This is why surface water, groundwater, and wind capture the key transport routes. Ingestion and inhalation are exposure routes—ways people or organisms come into contact with contaminants after they’ve moved through the environment—not the transport media themselves. Focusing only on airflow omits important waterborne pathways, and mentioning only groundwater and soil moisture leaves out surface water and the role of the atmosphere.