Which substances in water can cause yellow to black discoloration when present?

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Discoloration from waterborne metals happens when dissolved metals oxidize and form solid compounds that tint the water. Iron and manganese are the substances that most commonly produce colors ranging from yellow to black. Iron in dissolved form can oxidize to ferric iron, forming insoluble iron oxides and hydroxides that color water yellow, orange, or reddish-brown. Manganese oxidizes to manganese oxides that appear brown to black, especially at higher concentrations. When both metals are present and oxidation conditions vary, the water can show a spectrum from yellowish to dark or black tones. Other metals tend to produce different colors (for example, copper can cause blue-green discoloration), and calcium and magnesium mainly cause taste and hardness rather than noticeable color.