Chemistry · Ch 15 — Environmental Chemistry
Water Pollution
Water Pollution
Water is essential for life; without water, life would have been impossible. The slogan 'Save Water, Water will save you' tells us the importance of water -- such slogans remind us to save water. But apart from saving water, maintaining its quality is equally important.
Today, water is getting polluted because of human activities, and the availability of potable water in nature is becoming rarer day by day. Water pollution is defined as "the addition of foreign substances or factors like heat which degrades the quality of water, so that it becomes a health hazard or unfit to use."
Water pollutants originate from both natural and human activities, and the source of water pollution is classified as point or non-point source. An easily identified source or place of pollution is called a point source -- for example, municipal and industrial discharge pipes. A non-point source cannot be identified easily -- for example, agricultural run-off, mining wastes, acid rain, and storm-water drainage and construction sediments.
Major water pollutants and their sources:
| No | Pollutant | Sources |
|---|---|---|
| 1 | Microorganisms | Domestic sewage, domestic waste water, dung heap |
| 2 | Organic wastes | Domestic sewage, animal excreta, food processing factory waste, detergents and decayed animals and plants |
| 3 | Plant nutrients | Chemical fertilisers |
| 4 | Heavy metals | Heavy metal producing factories |
| 5 | Sediments | Soil erosion by agriculture and strip-mining |
What this figure shows. A photograph of two large rusted industrial outfall pipes discharging a heavy torrent of turbid, foaming brownish water directly into a river or canal, with industrial buildings visible in the background -- an example of a point-source discharge …
| No | Pollutant | Sources |
|---|---|---|
| 1 | Microorganisms | Domestic sewage, domestic waste water, dung heap |
| 2 | Organic wastes | Domestic sewage, animal excreta, food processing factory waste, detergents and decayed animals and plants |
| 3 | Plant nutrients | Chemical fertilisers |
| 4 | Heavy metals | Heavy metal producing factories |
| 5 | Sediments | Soil erosion by agriculture and strip-mining |
| 6 | Pesticides | Chemicals used for killing insects, fungi and weeds |