The contamination was caused by illegal gold extraction in Crucitas, culminating in high levels of Mercury in the water. As a result, four aqueducts and all the artisanal wells from Chamorro, Chorreras, Crucitas, El Roble de Cutris, Llano Verde and El Jocote de Pocosol are slated for closure with over 1,500 people soon to be unemployed.
“In Chorreras, we have frankly very worrying results because all the samples are positive and with levels that are up to eleven times higher than what the international norm dictates. What we have is a very worrying situation,”said Dr. Luis Diego Ugalde, head of the Regional Unit of the Ministry of Health.
The decision came after the Ministry of Health revealed samples collected in November 2022 displayed high grades of mercury in water meant for human consumption. The levels of mercury in the water were 0.00954 milligrams per liter, while the maximum permissible values are 0.001 milligram per liter.
Artisanal miners use mercury to recover small amounts of gold mixed in soil and sediments. Mercury and gold settle and combine to form an amalgam. The mercury is then vaporized leaving gold left over.
Mercury is a powerful neurotoxin that can have direct harmful effects on the human central nervous system, according to the World Health Organization. Exposure effects on the central nervous system are dependent on the size of the dose, duration and route of exposure. In general, mercury can cause a neurological symptoms like tremors, memory problems, cognitive deficits, irritability and depression. At high levels, mercury can cause seizures, coma and death.
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Costa Rica is free of open pit mining but not underground
The effects of mercury exposure are especially disconcerting for developing fetuses and young children. Mercury exposure during these critical periods of brain development can cause irreversible damage.
Due to accidents in the past involving large-scale gold mining, the country reformed its mining code in 2010. It also declared Costa Rica a country free of open pit metals mining in 2010.
The country, however, allows underground mining for subsistence artisanal and small-scale miners.
In 2019, Costa Rica helped develop the Minamata National Action Plan (NAP) to reduce and eliminate mercury use in artisanal and small scale gold mining (ASGM). The NAP is implemented by the United Nations Environmental Programme (UNEP) and funded by the Global Environmental Facility (GEF).
The councillors of the municipality made this decision after a session on Monday, February 20, after the Ministry of Health, the Costa Rican Institute of Aqueducts and Sewers (AyA) and the residents affected by the issue expressed their concerns.
According to Ugalde, the next step is holding a meeting on March 3 to plan to resolve the problem.
Liquid mercury. Image from Marmall4 via wikimedia commons.
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Calibre Mining (TSX: CXB) (OTCQX: CXBMF) is a gold mining company operating in Nicaragua, which does allow open pit mining. It has recently approved a $29 million exploration budget for 2023 for its operations in both Nevada and Nicaragua.
The company will use seven drill rigs in Nicaragua for high-grade expansion opportunities at the Panteon VTEM Corridor, Talavera extension, Veta Azul and Volcan.
Calibre also says its Eastern Borosi Project in the country has the potential for grade increase opportunities and resource expansion.
Calibre Mining is a sponsor of Mugglehead news coverage
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