Cultural or Accelerated Eutrophication lakes is most often caused by input of -

Options

A. PCBS
B. Nitrates and phosphates
C. Sediment
D. Selenium

Answer

**Step-by-Step Solution:**

1. **Understanding Eutrophication:**
- Eutrophication is the process where water bodies become overly enriched with nutrients, leading to excessive growth of algae and other aquatic plants. This can deplete oxygen in the water, harming aquatic life.

2. **Differentiating between Types of Eutrophication:**
- There are two types of eutrophication: natural and cultural (or accelerated). Cultural eutrophication is primarily driven by human activities.

3. **Identifying Causes of Cultural Eutrophication:**
- Cultural eutrophication is often caused by the input of nutrients from human activities. The most significant contributors are sewage and industrial waste.

4. **Recognizing Key Nutrients:**
- The primary nutrients that lead to accelerated eutrophication are nitrates and phosphates. These nutrients are commonly found in fertilizers, sewage, and industrial effluents.

5. **Evaluating Options:**
- Among the options provided:
- PCBs (Polychlorinated Biphenyls) are not primarily responsible for accelerated eutrophication.
- Nitrates and phosphates are the main contributors to cultural eutrophication.
- Sediments are not a direct cause of accelerated eutrophication.
- Selenium is not relevant in this context.

6. **Conclusion:**
- The correct answer is that cultural or accelerated eutrophication in lakes is most often caused by the input of nitrates and phosphates.