# Explain why the presence of nitrates in drinking water is considered harmful to human health, and state one agricultural practice that causes nitrates to enter water supplies.

> Cambridge International IGCSE Chemistry (0620) — 10.1 Water · Explain · 4 marks

## Mark scheme (4 marks)

1. Nitrates in drinking water can be converted to nitrites in the body / gut
2. Nitrites reduce the ability of haemoglobin / blood to carry oxygen
3. This is particularly dangerous for infants / young babies (blue baby syndrome)
4. Nitrates enter water supplies due to the use of (artificial / excess) fertilisers on agricultural land (which are washed into rivers / groundwater by rain)

## Key terms

- [nitrates](https://www.gradenine.co.uk/glossary/nitrates)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-presence-of-nitrates-bf1ddfc0) · Published by Druglandscape Ltd.