Which pollutant is likely to cause cholera?

Step 1: Analyze the question The question asks which pollutant is likely to cause cholera. Cholera is a disease, so we need to find the pollutant that carries the disease-causing organism.

Step 2: Explain the concept Cholera is caused by the bacterium Vibrio cholerae. It is a water-borne disease, spread when water or food is contaminated with faeces from an infected person. Symptoms include severe watery diarrhoea and dehydration.

So the pollutant we want must contain human faecal matter and pathogens.

Step 3: Evaluate each option

• A. Agricultural wastes: These include fertilizers, pesticides and animal droppings. They mainly cause eutrophication and chemical pollution. They are not the typical source of cholera.
• B. Industrial wastes: These contain toxic chemicals and heavy metals, which cause poisoning, not cholera.
• C. Nuclear fallouts: These cause radiation sickness, cancers and genetic mutations, not infectious diseases.
• D. Oil spillages: These harm aquatic life and ruin water quality, but they do not carry cholera bacteria.
• E. Untreated sewage: This contains human faeces, which may carry Vibrio cholerae. When it contaminates drinking water sources such as wells, streams and rivers, cholera outbreaks follow.

Step 4: Answer The correct option is E. untreated sewage.

Tip: Link disease type to pollutant type:

• Biological pollutant (sewage) → water-borne diseases such as cholera, typhoid and dysentery
• Chemical pollutants (industrial and agricultural) → poisoning
• Radioactive pollutants → cancers and mutations

If you see a disease question about pollution, ask yourself: "Is it infectious?" If so, think of sewage.