There are two forms of impurities found in drinking water, suspended and dissolved: a) Suspended impurities such as mud, dust, sand, bacteria, viruses etc b) Dissolved impurities that are soluble in water such as; pesticides, industrial pollutants, chlorine, arsenic, fluoride, other chemicals and heavy metals salts like mercury, lead, copper, cadmium. These impurities can affect the taste, odor, and safety of the water.