The concentration of iron, lead ,nitrate, and fluoride in a water sample from an underground lake was found to be 0.18 ppm, 35 ppb, 80 ppm and 1000 ppb, respectively. This water is unsuitable for drinking due to high concentration of

Options

A. Lead
B. Nitrate
C. Iron
D. Fluoride

Answer

To determine which substance makes the water sample unsuitable for drinking, we need to compare the concentrations of iron, lead, nitrate, and fluoride. The concentrations are given in different units (ppm and ppb), so we will convert them to the same unit for comparison.

### Step-by-Step Solution:

1. **Identify the given concentrations:**
- Iron: 0.18 ppm
- Lead: 35 ppb
- Nitrate: 80 ppm
- Fluoride: 1000 ppb

2. **Convert all concentrations to ppm:**
- **Lead:**
\[ 35 \text{ ppb} = \frac{35}{1000} \text{ ppm} = 0.035 \text{ ppm} \]
- **Fluoride:**
\[ 1000 \text{ ppb} = \frac{1000}{1000} \text{ ppm} = 1 \text{ ppm} \]

3. **List the concentrations in ppm:**
- Iron: 0.18 ppm
- Lead: 0.035 ppm
- Nitrate: 80 ppm
- Fluoride: 1 ppm

4. **Compare the concentrations:**
- Iron: 0.18 ppm
- Lead: 0.035 ppm
- Nitrate: 80 ppm
- Fluoride: 1 ppm

5. **Identify the highest concentration:**
- The highest concentration is that of **nitrate**, which is **80 ppm**.

6. **Conclusion:**
- Since nitrate has the highest concentration, the water is unsuitable for drinking due to the high concentration of **nitrate**.

### Final Answer:
The water is unsuitable for drinking due to the high concentration of **nitrate**.