Advisory Assistance on Avoidance of Mercury Pollution from Artisanal Gold Mining Operations in Bolivar State, Venezuela
This report brings an impartial viewpoint about the informal mining practices and the use of mercury in gold extraction in the Guayana Region.
Mercury has been misused by artisanal miners all over the State of Bolivar. A gold production in Venezuela of around 18 tonnes annually likely results mercury emission in the same magnitude. Symptoms of mercurialism in miners and gold dealers were already detected by various researchers. The high content of organic acids in sediments and waters of the Caroni River and other darkwater streams favours oxidation of metallic mercury dumped by mining activities or precipitated from the atmosphere. Soluble Hg-organic complexes can be transformed into methylmercury and quickly taken up by aquatic biota. Bioaccumulation occurs predominantly by food intake rather than via fish respiration. In some mining areas the process is occurring at slow rates but more information is needed.
Other sources of mercury emission have not been previously considered in the Guayana Region. The hazardous effect of artificial impoundment to increase methylmercury levels in biota is a worldwide phenomenon and has been recently detected in a hydroelectric dam in Venezuela (Guri). Fish are being contaminated by methylmercury generated by methylation of atmospheric mercury deposited over the years in the sediments of Guri. Submerged vegetation, the amount of organic matter in sediments and bacterial activity are contributing to biomethylation in Guri. Carnivorous fish show a biomagnification of Hg stronger than other fish species.
The creation of Amalgamation Centers in the lower part of the Caroni River is emphasized as a concrete solution to reduce Hg emission to "tolerable" levels. Other methods to minimize Hg emissions, such as special Hg-plates and the use of home-made retorts were demonstrated to artisanal miners in Guayana. Meetings and talks with miners from El Callao to Ikabaru stressed the danger of Hg misuse and the possibilities of biomethylation. Education is a long term solution for Hg problem.
Legislation, technology and educational measures are key steps to transform artisanal miners into small miners. Fantasies, panic and political interests are results of a poor role played by part of the Venezuelan press. Affected communities (miners and fish-eating people) have been ignored. A massive campaign to inform fish-eating pregnant women in Guri region about Hg-poisoning of carnivorous fish is strongly suggested.
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Additional Info
- Author(s)
- M Veiga
- Publication Year
- 1996
- Language
- English
- Publishing Institution Webpage
- https://www.unido.org/
- Data Source Classification
- Program Report
- Research Type
- Primary
- Research Methodology
- Primary - OBSERVATION
- Thematic Tags
- Environmental, Mercury
- Minerals
- Gold
- Region
- Latin America & Caribbean
- Country
- Brazil, Venezuela
- Last Updated
- September 4, 2019