‘Mercury bomb’ in Arctic

Syllabus: GS3/ Environment

Context

  • Researchers studying sediment in Alaska’s Yukon River discovered that eroding permafrost is contributing mercury-laden sediments to the river. 

About

  • In the Arctic, plants absorb mercury, then die and become part of the soil, which eventually freezes into permafrost.
    • Over thousands of years, mercury concentrations build up in the frozen soil until it thaws, an increasingly common occurrence due to climate change.
  • Mercury amount in permafrost is more than the total of all oceans, soils, atmosphere and biosphere of the earth.
  • Scholars have warned the world of an impressive ‘giant mercury bomb’ that may soon explode.
    • The metal accumulates in the food chain specifically through people’s customary diets of fish and game.

What is Permafrost?

  • Permafrost is essentially any ground that stays frozen — 0 degree Celsius or lower — for at least two years straight. 
  • It is composed of “a combination of soil, rocks, and sand that are held together by ice. The soil and ice in permafrost stay frozen all year long.”
    • Although the ground remains perennially frozen, permafrost regions aren’t always covered with snow.
  • These permanently frozen grounds are often found in Arctic regions such as Greenland, Alaska (the United States), Canada, Russia, and Eastern Europe.
Permafrost

Consequences of Melting of Permafrost

  • Melting permafrost alters the habitat for plants and animals, potentially disrupting local ecosystems and threatening biodiversity.
  • Thawing permafrost causes the ground to become unstable, leading to the sinking or collapse of buildings, roads, pipelines, and other infrastructure. 
  • Permafrost acts as a freezer for ancient bacteria and viruses. Thawing could potentially release these pathogens, posing a risk of new or re-emerging diseases.
  • As permafrost thaws, organic matter trapped in the frozen ground decomposes, releasing carbon dioxide and methane. This process accelerates global warming.
Mercury
– Mercury is a naturally-occurring chemical element found in rock in the earth’s crust.
1. It is a shiny, silver-white metal, historically referred to as quicksilver, and is liquid at room temperature. 
Mercury is released into the atmosphere through natural processes such as weathering of rocks, volcanic eruptions, geothermal activities, forest fires, etc.
Human activities, like burning of coal, oil and wood as fuel are responsible for much of the mercury that is released into the environment. 
Mercury has toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.

Source: TOI