Rare earth elements (REE) are a set of seventeen elements in the periodic table, specifically the fifteen lanthanides, as well as scandium and yttrium. They are not especially rare, but they tend to occur together in nature and are difficult to separate from one another.

Usage of REE in Modern industries:
REE are known as “vitamins of modern industries” due to their wide use in the variety of industries and their unique magnetic, luminescent and electrochemical properties.

• REE enable many technologies to perform with reduced weight, reduced emissions, energy consumption, greater efficiency, performance, speed, durability, and thermal stability.
• Rare earths are used as catalysts, phosphors, and polishing compounds. These are used for air pollution control, illuminated screens on electronic devices, and the polishing of optical-quality glass.
• The uniqueness of these elements to accept and discharge the electrons enables them to be used in electronic, optical and magnetic applications. They are used in everyday life as rechargeable batteries, cell phones, catalytic converters, fluorescent lighting.
• The military use includes night-vision goggles, precision-guided weapons, communications equipment, GPS equipment, batteries and other defense electronics. Rare earth metals are key ingredients for making the very hard alloys used in armored vehicles and projectiles.

World Distribution and Production of Rare Earth Elements:
Though they are termed as rare earth elements, they are not so rare in occurrence. However, due to their chemical properties, rare earth elements occur together in small quantities, not in concentrated form, dispersed throughout the world. It makes their extraction difficult and economically not viable and also hazardous to extract due to their radioactive nature.

• The global reserves of rare earth mineral resources are contained primarily in bastnasite and monazite. Bastnasite deposits in China and the United States constitute the largest percentage of the world's rare-earth economic resources, while monazite deposits are found in Australia, Brazil, China,
  India, Malaysia, South Africa, Sri Lanka and Thailand.
• India has 3% of world reserves. Primarily these minerals are extracted from monazite which is found in the form of sand on beaches of Kerala. Recently, the Geological Survey of India has found high concentration of the rare earth elements in western Rajasthan.
• Production: China is the world leader and accounts for around 97% of the world production. India, Brazil, Australia, USA, Russia, Thailand and Malaysia comprise the rest.
• Rare earths are also being recycled from e-waste. Vast reserves of rare earth metals on the Pacific seabed may be procured through seabed mining. India’s emergence as a supplier, though a small one, is good news for other countries, as it can reduce their import dependence on China.

Environmental pollution

• Pollution of REEs are mainly caused during the mining process because during the extraction of the ores from rocks, a significant amount of water usage and wastewater production. Also, acidic substances are used during the extraction process, which can leach in to the soil and surrounding environment. In addition, due to the low abundance and varying spatial distribution of REEs, the mining process uses a significant amount of energy, which will have a negative impact on the environment.
• The sources of pollution from REEs consist of; dust and particulates, soil, ground water, rain, radioactivity and bio-accumulation due to high concentrations in terrestrial environments.
• The pollution in the US versus the pollution in China is variable due to the fact that REE mining in the US is subject to regulations, which indicates that there is more pollution mitigation strategies in place. Where as in China there have been numerous studies that show that areas surrounding mines/industrial sites are heavily contaminated with REEs, which may be due to the lack of protocol on REE mining.
• 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.

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.
• 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.

Recycling

• Another recently developed source of rare earths is electronic waste and other wastes that have significant rare-earth components. New advances in recycling technology have made extraction of rare earths from these materials more feasible, and recycling plants are currently operating in Japan, where there is an estimated 300,000 tons of rare earths stored in unused electronics.
• In France, the Rhodia group is setting up two factories, in La Rochelle and Saint-Fons, that will produce 200 tons of rare earths a year from used fluorescent lamps, magnets and batteries. Coal and coal by-products are a potential source of critical elements including rare earth elements (REE) with estimated amounts in the range of 50 million metric tons.