It occurs naturally in association with other metals and ores, especially zinc. It is also released by human activities. It is soluble in acids. Some forms of cadmium can dissolve in water, either in rivers and ponds or in soil water.
Plants can take up cadmium from the soil and animals concentrate it in the liver and kidney.
Production and Use Cadmium is produced commercially as a by-product of zinc and lead mining. Waste disposal is a significant source of release of cadmium into the environment. The ash from municipal waste incinerators and sewage sludge contains significant amounts of cadmium or its salts. Transport Pathways Cadmium enters the atmosphere from metal production, smelting, waste combustion, energy production, and industrial applications. Most atmospheric cadmium is cadmium oxide, with small amounts of cadmium salts.