There are acute and chronic poisoning. Inhalation of cadmium-containing gas can cause respiratory symptoms, and oral cadmium can cause liver and kidney symptoms.
Cadmium is not an essential element for human body. Cadmium in the human body is absorbed from the external environment after birth, and mainly enters the body through food, water and air for accumulation.
Cadmium absorption and metabolism: Cadmium dust can be inhaled through the respiratory tract. The absorption of cadmium by the lungs accounts for about 25 ~ 40% of the total intake. Smoking 20 cigarettes a day can inhale 2 ~ 4ug of cadmium. The absorption rate of cadmium through digestive tract is related to the type and intake of cadmium compounds, and also to whether other metals are ingested. For example, when the intake of calcium and iron is low, the absorption of cadmium can be significantly increased, while when zinc is ingested, the absorption of cadmium can be inhibited. Cadmium absorbed into the blood is mainly combined with red blood cells. Liver and kidney are two organs that store cadmium in the body, and the cadmium contained in them accounts for about 60% of the total cadmium in the body. It is estimated that the total amount of cadmium in normal people aged 40 ~ 60 is about 30mg, of which 10mg is in the kidney, 4mg is in the liver, and the rest is distributed in the lungs, pancreas, thyroid, testis, hair, etc. The content of cadmium in organs and tissues varies greatly with different regions and environmental pollution, and increases with age.
Cadmium entering the body is mainly excreted through kidney and urine, but a considerable part is excreted through liver and bile with feces. The excretion rate of cadmium is very slow, and the biological half-life of cadmium in human renal cortex is 10 ~ 30 years.
Clinical cadmium poisoning cadmium and its compounds have certain toxicity. Inhalation of cadmium oxide smoke can cause acute poisoning. At the initial stage of poisoning, symptoms such as sore throat, cough, chest tightness, shortness of breath, dizziness, nausea, body aches, weakness, fever, etc. In severe cases, toxic pulmonary edema or chemical pneumonia may occur, with obvious dyspnea, chest pain and a lot of foamy blood sputum, and may die of acute respiratory failure. Using cadmium-plated utensils to prepare or store acidic foods or drinks may contain cadmium in the diet, which may also cause acute cadmium poisoning after ingestion. The incubation period is short, usually after 10 ~ 20 minutes, symptoms such as nausea, vomiting, abdominal pain and diarrhea may occur. Severe cases are accompanied by dizziness, sweating, collapse, numbness of upper limbs, and even convulsions and shock. It usually takes 3 to 5 days to recover.
Long-term inhalation of cadmium will lead to chronic poisoning and kidney damage, mainly manifested in the large amount of low molecular weight proteins in urine. Although the filtration function of glomerulus is mostly normal, the recovery function of renal tubules decreases and the excretion of cadmium in urine increases.
Emphysema, anemia and bone changes of workers exposed to cadmium were also reported, but the exact relationship between these changes and cadmium exposure is still uncertain. It has also been reported abroad that workers exposed to cadmium oxide have a higher incidence of prostate cancer.