The Element Arsenic

The element arsenic is a steel grey metal-like material. Arsenic is a natural part of our environment and widely distributed in Earth's crust. So living organisms are often exposed to some amount of it. Very low levels of it are always present in soil, water, food, and air. Most arsenic compounds have no smell or special taste, even when present in drinking water. Arsenic has been used in pesticides, poisons, chicken-feed supplements, and wood preservatives. However, the naturally occurring arsenic in the soil can make the water toxic to humans.

Did you know?

The following analogy will illustrate how little of Earth's freshwater is available: If all of Earth's water could fill a 4 liter (about 1 gallon) container, the amount of available fresh water would fill less than a tablespoon out of the 4 liters. As you can see, only a small percentage of freshwater on Earth is available for human use.

Table 8.1 Water Pollutants

Point Sources

Bacteria

Dissolved

Ammonia

Solids

Acids Toxics

Municipal sewage treatment plants

Industrial facilities

Combined sewer overflows

Nonpoint Sources

Agricultural runoff

Urban runoff

Construction runoff

Mining runoff

• •

Septic systems

Landfill spills •

Forestry runoff

Source: U.S. Environmental Protection Agency.

Source: U.S. Environmental Protection Agency.

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