Use of mercury per gram of gold falls to half in northeastern Antioquia

In a 2009 report the United Nations Industrial Development Organization (UNIDO) said that the municipalities of Remedios and Segovia, in the northeastern part of the Province of Antioquia, annually dumped approximately 33 tons or mercury into the water sources and another 17 into the air.

According to a UNal-Medellín research the atmosphere in Segovia had approximately 1,260 nanograms of mercury gas per cubic meter, a very high rate compared to urban areas where the average ranges between 2 and 20 nanograms. In this place miners used 14 grams (0.49 ounces) of mercury to extract 1 gram (0.035 ounces) of gold.

In face of this scenario the Congress of Colombia approved Act 1658 of June 2013 banning use of mercury in industrial and mining projects due to the dangerous effects to the environment and human health. Therefore UNal-Medellín headed a cleaner small mining and artisanal pilot production project to reduce the pollution produced by mercury use.
http://www.agenciadenoticias.unal.edu.co/ndetalle/article/use-of-mercury-per-gram-of-gold-falls-to-half-in-northeastern-antioquia.html