How do soils become contaminated?
There are many different types of chemicals that can contaminate soil. Some chemicals are gases at room temperature. Some chemicals are liquids at room temperature such as the metal mercury. Other chemicals are solids at room temperature such as the metal lead. Some chemicals, in liquid form, can completely dissolve in water such as ethanol – drinking alcohol. Other chemicals, in liquid form, can dissolve only very slightly such as benzene. Some chemicals, in solid form, dissolve in water but to a limited extent. Other chemicals in solid form dissolve fairly easily, but with limitation such as table salt. Some gases can dissolve in water as carbon dioxide does to a limited extent. Before we can understand how soil becomes contaminated by these different types of chemicals, soils need to be defined. A soil can be divided up into different fractions. The soil contains mineral particles (the mineral fraction), water (soil solution or groundwater), air (soil atmosphere), and organic matter
