Q. Birds are called the “canary in the gold mine” because the condition of birds in an ecosystem serves as an indicator of the health of the environment which can be impacted by gold mining. Which of the following is/are the reason(s) associated with the gold mining that impact birds?
1.Bioleaching
2.Exposure to Mercury
3.In-situ leaching
4.Solvent extraction
Select the correct answer using the codes given below:
Answer: B
Notes:
Explanation – Bioleaching, In-situ leaching and Solvent extraction are the different types of methods used in mining gold. However, all these three processes are considered safer for the environment or birds.
Whereas, mercury is commonly used in small-scale gold mining to separate gold from other minerals due to its ability to bind to gold and form amalgam.
Due to this, small-scale gold mining releases large amounts of mercury to the environment and is estimated to contribute approximately 37% of mercury emissions on a global scale. This becomes harmful for the birds.
According to the study:
- Mercury may be playing a role in the declining biodiversity of tropical birds like kingfishers, wrens, warblers among others.
- Birds living within 7 km (4 miles) of such gold mining activity were found to have mercury concentrations over four times higher than those living at other sites across the tropics of Central and South America.
Source: ForumIAS
