|Abstract Title:||Mercury pollution from the artisanal gold mining in the La Paz department, Bolivia|
|Presenter Name:||Karla Villegas|
|Company/Institution:||Universitat Politcnica de Catalunya|
|Session:||Mercury in Artisanal Gold Mining|
Abstract Information :
Bolivia is the only country in the Andean region that still allows the use and import of mercury, which is being used in artisanal and small-scale gold mining. In the department of La Paz there is a large gold mining activity, which is mainly developed as artisanal mining through cooperatives. Gold is exploited from primary orogeneic-type deposits, and from placer-type deposits, where gold is free. In both cases, miners still use mercury to gold recovering. In this study, an assessment of gold pollution and the efficiency of gold processing by amalgamation was carried out to demonstrate the need to abandon these practices. A significant part of the mercury still used in South America is obtained through Bolivia. Eradication in this country would therefore have important consequences for the elimination of mercury use on a continent-wide scale. A sampling of water and hair from the Apolobamba, Sorata and Cotapata areas was performed. Also, the gold content was determined in the ores and mine tailings. The obtained results indicate the THg concentration in water is usually below the tolerable limits indicated by the World Health Organization. However, mercury concentration in hair from habitants of the areas close to the primary gold processing indicated a high level of pollution. On the other hand, gold deposits in this area often exceed 30 g/tone Au. After gold recovering, tailings still contain high amounts of gold, being recovered less than 50% of the total gold from the ore. This economic aspect is important to convince miners that amalgamation is an undesirable method, both because of the pollution it causes and because of its low economic efficiency. Acknowledgements: This research was financed by the project AECID: A3/042750/11 and CCD 2019-B005, 2020-B006 and 20212-G007.