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.
The small particles are transported by wind and deposited in either wet or dry form. Aquatic animals, notably fish and invertebrates, absorb cadmium directly from the water, as well as from food. Cadmium is taken up directly from seawater by absorption through the cell membrane. However, a new detailed study indicates that these values may be too high. These authors attribute the very low concentration to restricted human activity over the drainage basin and low annual temperatures that limit weathering and erosion of natural metal sources.