Polluted Rivers and Their Impact

Introduction

• Focus on the Mississippi River, the largest river in the United States.
• Drains a vast area from the Appalachians to the Continental Divide.
• Major tributaries include the Missouri, Ohio, and Tennessee Rivers.
• Carries water to the Gulf of Mexico through the Mississippi Delta near New Orleans.

Sources of Pollution

• Animal and Human Waste: Contributions from agriculture and urban areas.
• Sediment Runoff: Erosion of soil into rivers.
• Pesticides: Used in agriculture, running off into waterways.
• Industrial Waste: Discharges from factories and industrial sites.
• Toxic Heavy Metals: Byproducts from various industrial processes.

Fertilizer: The Biggest Threat

• Usage: Widely used in agriculture and by homeowners for lawns.
• Runoff: Excess fertilizer not absorbed by plants is washed into rivers.

Impact of Fertilizer on Oceans

• Algal Blooms: Fertilizer accelerates plankton growth, leading to large blooms.
• Oxygen Depletion: Rapid growth of microorganisms consumes oxygen.
• Decay Process: Dead plankton decompose, using up remaining oxygen.
• Dead Zones: Areas with zero oxygen and no life, notably the Mississippi Delta.

The Dead Zone

• Size: Can be up to 250 miles long and 50 miles wide.
• Comparison to Oil Spills: Results in more devastation than oil spills.

Global Perspective

• Not Unique to the Mississippi: Many large rivers and agricultural areas worldwide face similar issues.
• Impact on Coastal Ecosystems: Dead zones threaten coastal productivity and resources.

Conclusion

• Dead zones are a growing environmental concern, particularly in coastal areas where ocean resources are heavily relied upon.