Topics Covered: Conservation and pollution related issues.
High levels of mercury found in rivers linked to Greenland Ice Sheet:
Mercury level found:
Typical dissolved mercury content in rivers is about 1 – 10 ng L-1 (the equivalent of a salt grain-sized amount of mercury in an Olympic swimming pool of water).
- In the water bodies fed by the Greenland Ice Sheet, scientists found dissolved mercury levels in excess of 150 ng L-1, far higher than an average river.
What are the reasons behind the high concentration of mercury?
It is not the industries or other anthropogenic activities, as is the case with most contaminants. Mercury-rich bedrock is weathered during the slow movement of glaciers down the slope of hills and the ground particles are carried into the streams as the glacier melts.
What are the concerns now?
- So far, efforts were aimed at preventing mercury being released from direct anthropogenic activity, like industry. But mercury coming from climatically sensitive environments like glaciers could be a source that is much more difficult to manage.
- Besides, this will lead to increased water pollution as the Earth continues to heat up and ice-sheets and glaciers melt faster than ever before.
Significance of the latest discovery:
- We now understand that even glaciers carry potential toxins. This will force researchers to study how these toxins influence water quality and downstream communities, which may alter in a warming world.
- Also, it shall help us understand it’s influence on the Earth’s geochemical and biological processes.
Basics- about Mercury(Hg, Atomic No 80):
Sources: Mercury is a naturally occurring element that is found in air, water and soil. Released into the atmosphere through natural processes such as weathering of rocks, volcanic eruptions, geothermal activities, forest fires, etc. Mercury is also released through human activities.
Mercury may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.
Chemical of major public health concern- Mercury is considered by the World Health Organisation (WHO) as one of the top ten chemicals or groups of chemicals of major public health concern.
Minamata Disease: A disorder caused by methylmercury poisoning that was first described in the inhabitants of Minamata Bay, Japan and resulted from their eating fish contaminated with mercury industrial waste.
About the Minamata Convention:
- The Minamata Convention on Mercury is a global treaty to protect human health and the environment from the adverse effects of mercury and its compounds.
- It was agreed at the fifth session of the Intergovernmental Negotiating Committee in Geneva, Switzerland 2013. It entered into force in 2017.
- Controlling the anthropogenic releases of mercury throughout its lifecycle is one of the key obligations under the Convention.
- It is a UN treaty.
- The Convention also addresses interim storage of mercury and its disposal once it becomes waste, sites contaminated by mercury as well as health issues.
- India has ratified the Convention.
- The Arctic region is adversely affected by pollution of many sorts. There can be a Mains question on this. Note down a few important points from here.
- About Mercury- Source, contamination and effects on health.
- About Minamata disease.
- What is Minamata convention?
- What is WHO ten chemicals or groups of chemicals of major public health concern?
- Meaning of Ratification of a convention.
Write a note on mercury contamination and discuss international efforts to address the issue.
Sources: Down to Earth.