Which of the following is the most common form of pollution found in rivers and streams?

• A. Sewage
• B. Heavy metals
• C. Radioactive waste
• D. Oil spills

Answer: (A)

Verified step by step guidance

1. Understand the types of pollution listed: sewage, heavy metals, radioactive waste, and oil spills. Each represents a different source and impact on aquatic environments.
2. Recall that rivers and streams are often impacted by pollutants that originate from human settlements and agricultural runoff, which commonly include organic waste and pathogens.
3. Recognize that sewage pollution involves the discharge of untreated or partially treated human waste into water bodies, which is a widespread issue due to inadequate sanitation infrastructure in many areas.
4. Compare the frequency and sources of the other pollutants: heavy metals and radioactive waste are typically localized and less common, while oil spills usually affect larger bodies of water like oceans rather than small rivers and streams.
5. Conclude that sewage is the most common form of pollution in rivers and streams because it is directly linked to human activity and is more frequently discharged into these freshwater systems.