The highest DDT concentration in aquatic food chain shall occur in

Options

A. Phytoplankton
B. Seagull
C. Crab
D. eel

Answer

To determine where the highest DDT concentration in an aquatic food chain occurs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand DDT and its Properties**:
- DDT (Dichloro-Diphenyl-Trichloroethane) is a fat-soluble pesticide. This means it can accumulate in the fatty tissues of organisms.

**Hint**: Remember that fat-soluble substances tend to accumulate in the body rather than being excreted.

2. **Define Bio-magnification**:
- Bio-magnification refers to the increasing concentration of toxins, such as DDT, as you move up the food chain. Organisms at higher trophic levels accumulate more toxins because they consume multiple organisms from lower levels.

**Hint**: Think of bio-magnification as a snowball effect where toxins build up as you go up each level of the food chain.

3. **Identify the Trophic Levels**:
- In the given options:
- **Phytoplankton**: Primary producers (first trophic level).
- **Crab**: Primary consumers (second trophic level).
- **Eel**: Secondary consumers (third trophic level).
- **Seagull**: Top consumers (fourth trophic level).

**Hint**: Identify which organisms are producers and which are consumers to understand their position in the food chain.

4. **Analyze Each Organism's Role**:
- Phytoplankton will have the lowest concentration of DDT since they are at the base of the food chain.
- Crabs, as primary consumers, will have a higher concentration than phytoplankton but lower than secondary and tertiary consumers.
- Eels, being secondary consumers, will accumulate more DDT than crabs.
- Seagulls, as top consumers, will have the highest concentration of DDT because they consume organisms from multiple lower trophic levels.

**Hint**: The higher up the food chain you go, the more DDT accumulates in the organisms.

5. **Conclusion**:
- Based on the analysis, the highest DDT concentration in the aquatic food chain will occur in the **seagull** (the top consumer).

**Final Answer**: The highest DDT concentration in the aquatic food chain shall occur in the **seagull**.