Aluminum Fact Sheet

Aluminum is an extremely abundant metal in the earth’s crust and is often found in the form of silicates such as feldspar (KAlSi3O8). The oxide of aluminum known as bauxite (Al2O3·nH2O) provides a convenient source of uncontaminated ore. Aluminum can be selectively leached from rock and soil to enter any water source. Al3+ is known to exist in groundwater in concentrations ranging from 0.1 ppm to 8.0 ppm. Aluminum can be present as aluminum hydroxide, a residual from the municipal feeding of alum (aluminum sulfate) or as sodium aluminate from clarification or precipitation softening. It has been known to cause deposits in cooling systems and contributes to boiler scale. Aluminum may precipitate at normal drinking water pH levels and accumulate as a white gelatinous deposit.