Under normal circumstances, exposure to rare earths will not bring direct harm to human health. Appropriate amount of rare earth can also play a role in human body: ① anticoagulant effect; ② burn treatment; ③ Anti-inflammatory and bactericidal effects; ④ Hypoglycemic effect; ⑤ Anti-cancer effect; ⑥ Prevent or delay the formation of atherosclerosis; ⑦ Participate in the immune process.
However, related reports have confirmed that rare earth elements are non-essential trace elements in human body, and long-term low-dose exposure or intake may have adverse consequences on human health or metabolism. Especially after a report "tieguanyin rare earth exceeds the standard, excessive intake is harmful to human body", whether rare earth is really harmful to human body or toxic has gradually become the focus of attention. Therefore, experts began to study the "safe dose" of human exposure to rare earths. Some researchers have suggested that for an adult weighing 60 kg, the daily intake of rare earth from food should not exceed 36 mg; However, the facts show that the intake of rare earth in adult residents in heavy rare earth areas and light rare earth areas is 6.7 mg/day and 6.0 mg/day, respectively, and local residents are suspected to have abnormal central nervous system detection indicators.
The more serious consequences appear in the Bayan Obo mining area, where the villagers have a high proportion of cancer, the sheep's hair is ugly, and some sheep have internal and external teeth.
Foreign countries are no exception. 20 1 1 the cost of the mine disaster in Bukit Merah, Malaysia 1 100 million dollars to deal with the aftermath is also a sensation. It is precisely because there has been no case of leukemia in nearby villages for many years, but the establishment of rare earth mines led to birth defects of residents, and 8 leukemia patients, 7 of whom died of the disease. The reason is that a large number of nuclear radiation pollutants have been brought near the mine, which has affected people's living environment and human health.
Ways of rare earth entering and discharging in vitro
Ways of rare earth entering human body: oral cavity, respiratory tract, skin and injection.
Excretion: Ln is mainly excreted through urine, bile and gastrointestinal tract. Usually, light Ln from La to Sm is mainly excreted with bile; Ln, which is as heavy as Tb and Lu, is mainly excreted by urine through the kidney.
In order to avoid the adverse effects of rare earth on human body, the following suggestions are put forward:
Personnel working in relevant factories should have regular physical examinations, and relevant units and departments should provide safety protective work clothes and take corresponding protective measures. Residents living in relevant factories and mines should try to stay away from rare earth areas or have regular physical examinations. And try to avoid long-term exposure to rare earth environment.
Influence of mining rare earth minerals on the environment
If the rare earth is not well developed, even if it is dug and mined indiscriminately, it will not only cause huge losses to the national economy, but also cause great damage to the entire ecological environment, especially after mining, refining and rare earth recovery. If the environment is not properly managed, the impact on the environment will be very serious. Among them, the most serious harm is the light radioactive slurry tailings from rare earth elements thorium and uranium. In addition, toxic acid is a necessary auxiliary material in the refining process of rare earth elements, and improper treatment will lead to large-scale environmental damage. A series of environmental problems, including soil erosion, landslides, ground cracks and subsidence, the destruction of fertile land, eutrophication of water sources in mining areas, heavy metal pollution and other problems will follow.
The specific hazards are as follows:
Thorium and uranium associated with rare earths are highly radioactive and are the main raw materials for nuclear weapons. Although bastnaesite is considered to be low in radioactivity, there is still the possibility of radioactive pollution in the process of mining and refining only compared with monazite. Radioactive pollution is one of the biggest critical factors for rare earth production by many national and international environmentalists.
The extraction and separation of rare earth minerals need to consume a lot of sulfuric acid or liquid alkali, which will cause serious pollution to the environment after extraction.
A large amount of wastewater and waste residue produced in the process of ion adsorption refining of rare earth minerals have seriously damaged the local soil and water sources.
In the suburb of Baotou City, Inner Mongolia Autonomous Region, the rare earth waste residue formed by Baotou Steel's rare earth was transported to the tailings dam with the waste liquid, which accumulated over time to form a "rare earth lake" with the current capacity of 65.438+0.7 billion tons, causing serious environmental pollution.
Reference: /metal/re/health.shtml