---
title: "Polluted, contaminated water; function in body"
subject: "Water Supply Engineering"
chapter: 1
key: "semester_5/water_supply_engineering:define-polluted-contaminated-function"
source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/define-polluted-contaminated-function
site: BCT Engineering
---

# Polluted, contaminated water; function in body

Water Supply Engineering · Chapter 1: Introduction

- Asked in: 2080 Baisakh, 2+2 marks
- Video: [Water Pollution & It's Effects - No Lives without Water - Kesara Productions](https://www.youtube.com/watch?v=0PjuPbGXayo) — Kesara Productions කේසර
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/define-polluted-contaminated-function
- Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-1

## Question

Define polluted and contaminated water. Also describe the function of water in the human body.

## Short answer

Polluted water is degraded by sewage, industrial waste, oil, or detergents, making it unfit for use but not necessarily harmful; contaminated water contains pathogens, toxic chemicals, or radioactive matter and is always a health hazard. Water forms 60-70% of body weight, carries nutrients, aids digestion, removes wastes, regulates temperature, and lubricates joints.

## Answer

#### Polluted water
Polluted water is water whose quality has been degraded by the addition of unwanted matter such as sewage, industrial effluent, oil, detergents or agricultural run-off, so that it becomes unfit for its intended use. It may or may not be harmful to health.

#### Contaminated water
Contaminated water is water that contains harmful micro-organisms (bacteria, viruses, protozoa), toxic chemicals or radioactive substances in amounts that can cause disease. Contamination is always a health hazard.

#### Function of water in the human body
- Forms about 60 to 70 percent of body weight.
- Carries nutrients, oxygen and hormones through blood.
- Helps digestion and absorption of food.
- Removes wastes through urine and sweat.
- Regulates body temperature.
- Lubricates joints, eyes and mucous membranes.
- Provides the medium for all chemical reactions in cells.

A person needs roughly 2 to 3 litres of drinking water per day.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Polluted water is best described as:
   A. Water with unwanted matter making it unfit for its use, maybe not harmful to health
   B. Water always carrying cholera
   C. Pure water
   D. Water with radioactive matter only
   Answer: A. Pollution degrades quality and may or may not be harmful. (Key point: Polluted definition)

2. Which makes water contaminated?
   A. Detergents only
   B. Harmful micro-organisms, toxic chemicals or radioactive substances causing disease
   C. Slight colour
   D. High temperature
   Answer: B. Contamination involves disease-causing agents and is always a health hazard. (Key point: Contaminated definition)

3. Water in the body provides:
   A. Only energy
   B. Only bulk
   C. The medium for all chemical reactions in cells
   D. No role in blood
   Answer: C. Water is the medium for cellular chemical reactions; it also carries nutrients and oxygen. (Key point: Role in cells)

## Related in Water Supply Engineering

- [Potable, wholesome, polluted, contaminated water](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apotable-wholesome-polluted-contaminated) — Water Supply Engineering, chapter 1
- [Pure/impure, potable/wholesome, polluted/contaminated](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Adifferentiate-water-types) — Water Supply Engineering, chapter 1
- [Potable, wholesome water; function in body](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Adefine-potable-wholesome-function) — Water Supply Engineering, chapter 1

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