镉为人体不需要的元素，人体中的镉是出生后从外环境经呼吸道和消化道摄取而蓄积的。慢性镉中毒的临床表现为肺气肿、骨质改变与贫血。日本发现某些地区由于长期食用被污染的、含镉量很高的米和水而发生痛痛病（骨痛病），主要病变为骨软化，疼痛始于下肢，后遍及全身直至卧床 Cadmium is an unwanted element of the human body. Cadmium in the human body is accumulated from the external environment through the respiratory and gastrointestinal channels after birth. Chronic cadmium poisoning clinical manifestations of emphysema, bone changes and anemia. In Japan, some areas have been found to suffer from toxication (osteoarthritis) due to long-term consumption of polluted, heavily cadmium-containing rice and water. The main pathological changes are osteomalacia, with pain beginning in the lower extremities and throughout the body until bed rest