Question

in some older parts of cities, sewage pipes can leak into rivers and streams due to various reasons. what is one of the reasons?
crushed or broken pipes
soil erosion
volcanic eruptions

Explanation:

Older sewage pipes can be damaged over time. Crushed or broken pipes directly cause leakage into waterways. Soil erosion (usually related to land - surface soil loss) and volcanic eruptions (rare in urban settings) are less likely direct causes for sewage pipe leaks in city older areas compared to pipe structural damage.

Answer:

crushed or broken pipes