After water, superphosphate is probably the substance added in greatest quantity to Australia's soil. Phosphorus deficiency is a fact of life in most of Australia's food-producing areas, and fertilizers that remedy it — mainly superphosphate — account for at least 85% of our fertilizer consumption. Unfortunately, when superphosphate is spread across the land, so are small amounts of the impurities it contains, one of which is the toxic metal cadmium.