User:Zitong Lin1996/Rare-earth element

Editing assignment:

Environmental pollution[ edit]
Literature published in 2004 suggests that along with previously established pollution mitigation, a more circular supply chain would help mitigate some of the pollution that the extraction point. This means recycling and reusing REEs that are already in use or reaching the end of their life cycle. A research done in 2014 suggest a method to recycle rare earth elements from waste nickel-metal hydride batteries, the recovery rate is found to be 95.16%.

Under pollution section

A research done in 2014 suggest a method to recycle rare earth elements from waste nickel-metal hydride batteries, the recovery rate is found to be 95.16%.

Impact on human health

REEs are a large group with many different properties and levels in the environment, because of this, and limited research, it has been difficult to determine safe levels of exposure for humans. A number of studies have focused on risk assessment based on routes of exposure and divergence from back ground levels related to nearby agriculture, mining, and industry. It has been demonstrated that numerous REEs have toxic properties and are present in the environment or in work places. Exposure to these can lead to a wide range of negative health outcomes such as cancer, respiratory issues, dental loss including death. However these elements are numerous and present in many different forms and at different levels of toxicity, as such it has been difficult to give blanket warnings on cancer risk and toxicity as some of these are harmless while others pose a risk.

What toxicity is shown appears to be at very high levels of exposure through ingestion of contaminated food and water, through inhalation of dust/smoke particles either as an occupational hazard or due to proximity to contaminated sites such as mines and cities. Therefore, the main issues that these residents would face is bioaccumulation of REEs and the impact on their respiratory system but overall, there can be other possible short term and long term health effects. It was found that people living near mines in China had many times the levels of REEs in their blood, urine, bone and hair compared to controls far from mining sites. This higher level was related to the high levels of REEs present in the vegetables they cultivated, the soil, and the water from the wells indicating that the high levels were caused by the nearby mine. While REE levels varied between men and women the group most at risk were children because REEs can impacted the neurological development of children. Hence, it can impact their IQ and can cause memory loss.

'''The rare earth mining and smelting process can release airborne fluoride which will associated with total suspended particles (TSP) to form aerosols that can enter human's respiratory systems and cause damage and respiratory diseases. a research down in Baotou, China shows than the fluoride concentration in air near REE mines is found to be higher than the limit value from WHO which can affect the surrounding environments and become a risk to the people that live or work nearby that area'''.

Residents blamed a rare-earth refinery at Bukit Merah for birth defects and eight leukemia cases within five years in a community of 11,000 — after many years with no leukemia cases. Seven of the leukemia victims died. Osamu Shimizu, a director of Asian Rare Earth, said "the company might have sold a few bags of calcium phosphate fertilizer on a trial basis as it sought to market byproducts; calcium phosphate is not radioactive or dangerous" in reply to a former resident of Bukit Merah who said that "The cows that ate the grass [grown with the fertilizer] all died." Malaysia's Supreme Court ruled on 23 December 1993 that there was no evidence that the local chemical joint venture Asian Rare Earth was contaminating the local environment.