Indicators of Pollutants

How can we tell if your water is at risk?

Water is considered “at risk” when it contains materials that can harm people and other organisms. These harmful materials are called pollutants. Pollutants may be chemicals, industrial waste, small particles of soil, or sewage. When you visit your water sampling site, you will look for signs or indicators of pollutants in the water.

What does the Color of the Water Tell Us?

The color or clarity of water can tell you a lot about whether it is polluted. Here are some signs to look for:

Greenish color – May indicate that the water contains fertilizers, sewage or animal waste. The greenish color comes from green algae that eat nitrogen - rich substances (such as fertilizers, sewage or animal waste), which makes them multiply like crazy.

Orange –red color – May indicate that the water contains oil, blood from meat- processing plants or chemicals from mines. But don’t be fooled – orange – red water may just contain a lot of natural tannin from nearby trees and shrubs or iron from surrounding soil.

Multicolor – May indicate that the water contains oil. Dark red, blue and black might mean that dyes from textile mill or leather-tanning factory have gotten into the water.

White foam – May indicate that the water contains detergent.

Milkiness – May indicate that the water contains industrial waste from pulp and paper mills or dairies. But keep in mind that the meltwater from some glaciers is naturally milky looking.

Mudiness – May indicate that the water contains an excess of soil particles, sewage, algae, plankton or industrial waste. Some water, however, is just naturally muddy looking.

What does the Smell of the Water Tell Us?

The smell of water is another good indicator of pollution. Here is what some odors might mean:

Rotten–egg smell – May indicate that the water contains sewage or industrial waste.

Rank or foul smell (like the smell of barn–yard or manure) – May indicate that the water contains sewage, livestock waste, too many algae or decaying matter.

Harsh, bitter or acrid smell (like the smell of ammonia) – May indicate the water contains industrial waste.

Chlorine smell (like household bleach) – May indicate the water contains overheated sewage.

What does the Presence of Aquatic Animals Tell Us?

The presence of animals in water can also reveal a lot about the quality of the water. Generally, the greater the variety of animals in water, the cleaner that water is likely to be.