Consider the following statements regarding mercury pollution:
1. Gold mining activity is a source of mercury pollution in the world.
2. Coal-based thermal power plants cause mercury pollution.
3. There is no known safe level of exposure to mercury.
How many of the above statements are correct?
Explanation
Statement 1 — Correct: Artisanal and small-scale gold mining (ASGM) is the single largest global source of anthropogenic mercury pollution, resulting from miners using elemental mercury to form amalgams with fine gold particles before vaporizing the mercury.
Statement 2 — Correct: Coal combustion in coal-based thermal power plants releases trace mercury present in raw coal, discharging it into the atmosphere via flue gas and into aquatic ecosystems through fly-ash slurries.
Statement 3 — Incorrect: Regulatory and public health agencies (including the World Health Organization and national occupational bodies) establish specific threshold limit values and reference exposure levels (e.g., tolerable weekly intakes and maximum permissible airborne concentrations of 0.01 mg/m^3) below which adverse systemic effects are not expected.
Therefore, only two statements are correct.