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Why has mercury amalgamation created health and environmental concerns?

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A diagram showing the periodic table entry for gold, with the symbol Au, atomic number 79, atomic weight 196.96657, electron configuration, and labels for its properties as a solid transition metal with a face-centered cubic crystal structure. — gold The precious metal gold is a chemical element with the symbol Au. Its square on the periodic table details some of its properties, including its atomic weight, atomic number, and crystal structure.

Mercury amalgamation creates significant health and environmental risks primarily due to the inherent toxicity of mercury. When used to recover gold, mercury can enter the environment or affect human health through the inhalation of vapours, ingestion of soluble compounds, or absorption through the skin.12

The process involves mixing gold ore with mercury to form an amalgam, which is later heated in a retort to distill off the mercury for reuse. If this process is not managed with carefully designed equipment, mercury can escape into the surrounding environment, leading to mercury poisoning among operators and contamination of the local ecosystem.134

Because of these severe risks, the application of amalgamation in gold recovery is increasingly limited, and there is a strong ethical imperative to utilize specialized, secure technology to prevent toxic exposure and environmental degradation.12