Toxic Mercury Dumping Declines in Antioquia: USAID ‘Legal Gold’ Analysis

The U.S. Agency for International Development (USAID) “Oro Legal” (legal gold) project management announced July 17 that toxic mercury dumping and processing has declined “significantly” among artisanal gold-mining operations in Bajo Cauca as well as Northeast Antioquia.

The agency noted that Colombia officially banned all further use of mercury in gold-mining activities as of July 15, 2018, following a five-year “transitional period” that started in 2013.

Socially responsible national and international gold miners in Colombia abolished mercury usage years ago. But some informal and criminal gold-mining operators here continue to dump toxic mercury, poisoning the environment, gold-processing workers and nearby populations.

Following the Colombian government’s mercury-phase-out transitional period, “some concerns arise regarding [the mercury-ban law’s] effectiveness,” according to USAID.

However, recent studies indicate a “significant reduction in the use of [mercury] in the Bajo Cauca Antioqueño and Northeast Antioquia mines, and there is also evidence of a decrease in [mercury vapor] emissions in the air in populated areas, as demonstrated by the comparative measurements made by USAID during the years 2016 and 2017,” according to the agency.

USAID’s “Legal Gold” study examined use of mercury in local gold mines, analyzed commercial movement of mercury, and measured mercury vapors in certain towns via a novel sampling protocol.

Samples were taken in 63 small mining production units located in Bajo Cauca and Northeast Antioquia, according to the agency.

“The mining units that received or receive accompaniment from the USAID Legal Gold program’s formalization process in the last two years have registered an approximate elimination of 7.8 tons of mercury in the department of Antioquia,” the agency reported.

“This is due to the technical assistance provided in the field and to the [artisanal miner] formalization contracts or subcontracts established between owners and small-scale miners, which obliges the latter to process their material in zero-mercury [gold-processing] plants.

“However, due to cultural and economic situations of the small miner, mercury use still persists. Comparative studies indicate that, on average, in the three types of [artisanal] mining [open-pit, alluvial and mini-dredge] in 2016, for each gram of gold produced, 14 grams of mercury were used, while in 2017 the figure dropped to 6.15 grams to process one gram of gold.,” according to USAID.

“In December 2016, in order to establish a control on the importation and commercialization of mercury and all products that contain it, the national government issued Decree 2133 of 2016, which establishes the process and allowed quota for the importation of mercury.

“Likewise, the government determined that the import quota of mercury to the country for the period from September 16, 2017 to September 15, 2020 was stipulated at two tons per year, and this should be used for activities other than mining.

“This reduction in the import quota of mercury hindered the acquisition of this metal in the different municipalities and multiplied its real price. Before the controls, a kilogram of mercury was quoted at COP$220,000 [US$76], but today this figure amounts to COP$750,000 [US$260 ],” the agency added.

As for mercury-vapor air-pollution studies, the agency took air samples in gold-trading and processing centers in six municipalities of Antioquia and three of Chocó: Segovia, Remedios, El Bagre, Caucasia, Zaragoza, Santafé de Antioquia, Quibdó, Condoto and Istmina.

Over time, the investigators discovered the emergence of new mercury-vapor hot-spots “in the perimeter areas of the town, away from shopping areas and gold purchases,” according to the agency.

“The conclusion of this monitoring is that [mercury vapor pollution] declined in urban areas, which indicates less impact on public health, but a greater dispersion was detected in peripheral areas, a situation that makes [mercury pollution] control difficult,” added Peter Doyle, USAID’s legal-gold program director.

While government controls on the importation and commercialization of mercury along with prohibition of the burning of gold-processing amalgams in residential, commercial institutional areas has helped cut such pollution, more remains to be done.

“The progress in reducing mercury has been impressive and little recognized, but it is going to reach a point where some miners do not have the culture, technology and funding sources for [mercury] elimination [and these miners] will need more support to achieve elimination,” Doyle concluded.