Rare-Earth Minerial Harvesting ------------------------------ Due to the importance of REE elements in technological and economic development, REE-containing samples are increasingly investigated. The REE-bearing minerals have attracted the interest of researchers around the world due to their high abundance in nature and the diversity of the corresponding REE-minerals \[[@B28-materials-06-05267],[@B29-materials-06-05267],[@B30-materials-06-05267]\]. REE-bearing minerals were considered as potentially useful industrial minerals until the 1970s, although few studies were reported in scientific literature. The development of modern technologies, such as fluorescent lamps, high-temperature superconductors, catalysts, computers, radar applications, and other applications, led to growing need of REE. Consequently, the REE reserves were exhausted after decades of rapid mining and processing. In the 1980s, China started mineral resources exploration and exploitation in Inner Mongolia. From the 1990s to the 2000s, many REE deposits were explored. As a result, the importance of REE materials became evident, and a large amount of REE was released into the environment, threatening the natural environment of some area. The mining and processing of REE-bearing minerals can induce environmental risks and can have potential or real human health risks. The release of REE to the environment can pollute rivers, lakes, and the soil. For example, REE can be adsorbed by clay and silt, then carried to rivers or lakes, and then be transferred by the wind or hydrographic conditions to the oceans. Some REE are light, but many of them are present in a cationic form in natural soil and water, so REE could move to deeper layers of the ground by leaching and infiltration. Researchers worldwide are concerned about the ecological and economic implications of the large-scale use of REEs. In China, the utilization of REE minerals has been well documented, but there are few reports on health risk assessments and environmental pollution. The environmental contamination of REE mining should be paid more attention. If REE are used excessively in China, their mineral sources may become limited and the price may increase. 1.4. The REE Risk in China -------------------------- China's REE reserves are considered to be large by geologists and most people, but these reserves are relatively poor in quality compared with those of ore deposits. It is estimated that REE reserves and resources are 4% and 13%, respectively, of the world's estimated reserve and resource \[[@B31-materials-06-05267]\]. China holds one-third of the world's REE reserves and is the major producer of REE in the world. Several REE mines, for example, Linfen, Yongping, Xikuangshan, Baotou, are located in Yunnan Province. REE minerals are used in metallurgy, medicine, cosmetics, electronics, nuclear fusion technology, *etc*. The REE production in China was approximately 100,000 tons in 2004, but it was only 11,000 tons in 2001. The total REE consumption in China increased from 30,000 tons in 2000 to 41,000 tons in 2005. In 2004, the main REE products exported to the world were magnetic materials, ferrite-type magnetic materials, and magnets, which were only 3.4%, 3.1% and 1.7%, respectively, of the total REE production. Approximately 7% of the REE production was consumed in China, and the majority of these REE were used for the production of ferrites, semiconductors, nuclear industry, *etc*. Therefore, the release of REE to the environment poses a serious risk to the environment and human health. As of 2010, China had not reported any major pollution problems caused by REE pollution. In China, the following four minerals are important sources of REE: (1) monazite and xenotime (the thorium-bearing mineral); (2) bastnasite; (3) pyrochlore (the rare-earth scandium gadolinium hexaoxide); and (4) the thorium-rare-earth ores \[[@B29-materials-06-05267]\]. REE resources in China are distributed throughout most provinces in China. For example, the Lanthanide (La, Ce, Nd, Sm, *etc*.) resources are mainly distributed in Shaanxi Province, while the HREE (Gd, Tb, Dy, Ho, Yb, Er, Tm, Y, Lu, *etc*.) resources are found in Anhui, Guangxi, and Hubei Provinces \[[@B32-materials-06-05267]\]. [Table 1](#materials-06-05267-t001){ref-type="table"} lists the main REE mines in China and their locations. materials-06-05267-t001_Table 1 ###### The main rare-earth deposits in China. Name of the deposit Localities Depth (km) Ore mineral Reference ------------------------------------ ---------------------------- ------------ ---------------------------------- ----------------------------------------------------- Shuibao deposit Sichuan 14.3 Thyrite-magnesioferite \[[@B30-materials-06-05267]\] Dahei deposit Hubei 70 Thorium-Y bastnaite \[[@B33-materials-06-05267],[@B34-materials-06-05267]\] Laozuoli Hubei 10 Tantalite, Diopside \[[@B34-materials-06-05267]\] Hanzhongtian Hubei 2.3 Thorium-Y bastnaite \[[@B35-materials-06-05267]\] Sanliopanchuan Jiangxi 18.1 Thorium-Y bastnaite \[[@B36-materials-06-05267],[@B37-materials-06-05267]\] Hubei 20.0 Thorium-Y bastnaite \[[@B36-materials-06-05267],[@B38-materials-06-05267]\] Hubei 30.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 40.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Guangxi 25.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Guangxi 45.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Fujian 60.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 40.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 60.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 70.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 70.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 60.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 50.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 40.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 50.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 60.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 70.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 30.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Jiangxi 10.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 60.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 70.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 70.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 10.0 Thorium-Y bastnaite \[[@B36-materials-06-05267]\] Hubei 60.0 Thorium-Y bastnaite \[[@B36-materials