ABSTRACT
Aluminium is the third most common element – and the most abundant metal – in the Earth's crust. The metalloid boron occurs in nature mainly as borates and is essential to plants and some animals. Cyanide is very toxic and its release into the environment, for example from ore processing, electroplating factories, gas works and coke plants, can have serious impacts. Manganese is abundant in the Earth's crust and in soils and is an essential element. Molybdenum is present at low levels in most rocks and soils and is concentrated in its main ore minerals: molybdenite and the molybdate mineral, powellite. Vanadium is essential in some organisms, particularly species of algae. The elements included in this text are limited to those that are added to the natural environment by human activities in sufficient quantities to have observable environmental and health impacts. Cooling waters from industry, particularly power plants, can create unnaturally high water temperatures in watercourses close to the effluent source.
