Why in the News?

A recent study published in journal IEEE Transactions on Geoscience and Remote Sensing has found that Chile’s Atacama salt flat (Salar de Atacama) is sinking at a rate of 1 to 2 centimetres per year due to lithium brine extraction.
- Lithium brine extraction involves pumping salt-rich water to the surface and letting it evaporate in ponds to collect lithium.

About Salar de Atacama

The Salar de Atacama in Chile boasts the highest lithium concentration (0.15% by weight) among all brine sources worldwide.
Argentina boasts more than half of the world’s total lithium resources.
It holds the distinction of having the 2nd-largest lithium resources, the 3rd-largest lithium reserves, and the 4th-largest lithium production in the world.
It is a part of the Lithium Triangle comprising of Uyuni (Bolivia) and Hombre Muerto (Argentina).

Researchers analyzed satellite data from 2020 to 2023 to observe deformations in the Earth’s crust in the salt flat.
The area experiencing subsidence measures approximately 8 km north to south and 5 km east to west.
The study indicates that subsidence occurs because the rate of lithium brine pumping is faster than the recharge rate of aquifers, leading to the ground sinking.

Lithium is an alkali metal, often referred to as ‘white gold’ due to its value and color.
It is a soft, silvery-white metal, and notably, it is the lightest metal on the periodic table.
It is typically found in various minerals like spodumene, petalite, and lepidolite, from which it is extracted and refined.
The leading producers of lithium are Australia, Chile, China, and Argentina.

Water Use: Lithium mining, especially from salt flats and brine pools, requires substantial water usage, which can deplete local water resources in arid areas.
Ecological Disruption: The extraction process can alter the chemical balance of the natural environment, affecting local flora and fauna.
Pollution: Mining and processing lithium can release harmful chemicals into the environment, impacting air and water quality.

[2008] Which one of the following pairs of metals constitutes the lightest metal and the heaviest metal, respectively?

(a) Lithium and mercury

(b) Lithium and osmium

(d) Aluminium and mercury