Which one of the following is the heavy toxic metal present in waste water from industries?

Options

A. mercury
B. cadmium
C. lead
D. all of these

Answer

To answer the question regarding which heavy toxic metal is present in wastewater from industries, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Heavy Metals**: The question asks for heavy toxic metals found in industrial wastewater. Common heavy metals include mercury, cadmium, and lead.

2. **Discuss Mercury**: Mercury is a heavy metal that can enter wastewater. It often appears in its methylated form, which is toxic to aquatic life and can lead to bioaccumulation in the food chain, affecting both aquatic organisms and humans.

3. **Discuss Cadmium**: Cadmium is another heavy metal that is toxic and can be found in industrial wastewater. It is known to cause serious health issues in humans, including kidney damage, liver damage, and brain damage when ingested through contaminated water.

4. **Discuss Lead**: Lead is also a heavy metal that industries release into wastewater. It has been associated with severe health problems, particularly in areas where lead pipes were used. Lead poisoning can affect the liver, kidneys, and brain, and can also lead to anemia.

5. **Conclusion**: Since all three metals (mercury, cadmium, and lead) are present in wastewater from industries and are known to be toxic, the answer to the question is that all of these metals are heavy toxic metals present in industrial wastewater.

### Final Answer:
**All of these (mercury, cadmium, and lead) are heavy toxic metals present in wastewater from industries.**

---