Probabilistic meta-analysis of risk from the exposure to Hg in artisanal gold mining communities in Colombia

Abstract

HIGHLIGHTSo Data of Hg in air and in fish across Colombia are evaluated in terms of risk. o Probability distribution functions are fitted to exposure and concentration data. o lnhalation of Hg contributes more to the overall risk than ingestion of fish. o The risk for the residents of mining communities greatly exceeds the threshold of 1. o The risk for miner-smelters is 200 times higher than what is deemed acceptable. A B S T R A C TColombia is one of the largest per capita mercury polluters in the world as a consequence of its artisanal gold mining activities. The severity of this problem in terms of potential health effects was evaluated by means of a probabilistic risk assessment carried out in the twelve departments (or provinces) in Colombia with the largest gold production. The two exposure pathways included in the risk assessment were inhalation of elemental Hg vapors and ingestion of fish contaminated with methyl mercury. Exposure parameters for the adult population (especially rates of fish consumption) were obtained from nation-wide surveys and concentrations of Hg in air and of methyl-mercury in fish were gathered from previous scientific studies. Fish consumption varied between departments and ranged from O to 0.3 kg d 1. Average concentrations oftotal mercury in fish (70 data) ranged from 0.026 to 3.3 I-lg g 1. A total of 550 individual measurements of Hg in workshop air (ranging from <DL to 1 mg m 3) and 261 measurements of Hg in outdoor air (ranging from <DL to 0.652 mg m 3) were used to generate the probability distributions used as concentration terms in the calculation of risk. All but two of the distributions of Hazard Quotients (HQ) associated with ingestion of Hg-contaminated fish for the twelve regions evaluated presented median values higher than the threshold value of 1 and the 95th percentiles ranged from 4 to 90. In the case of exposure to Hg vapors, minimum values of HQ for the general population exceeded 1 in all the towns included in this study, and the HQs for miner-smelters burning the amalgam is two orders of magnitude higher, reaching values of 200 for the 95th percentile. Even acknowledging the conservative assumptions included in the risk assessment and the uncertainties associated with it, its results clearly reveal the exorbitant levels of risk endured not only by miner-smelters but also by the general population of artisanal gold mining communities in Colombia.

Large‐scale degradation of Amazonian freshwater ecosystems

“…2; Nevado et al, 2010;Swenson et al, 2011;Asner et al, 2013;De Miguel et al, 2014;Marinho et al, 2014). Although gold mining activities have existed in the Amazon for decades, they have recently surged following a 360% increase in gold prices after 2000 ( Fig.…”

“…Although gold mining activities have existed in the Amazon for decades, they have recently surged following a 360% increase in gold prices after 2000 (Fig. 2;Nevado et al, 2010;Swenson et al, 2011;Asner et al, 2013;De Miguel et al, 2014;Marinho et al, 2014). Artisanal miners extract gold by dredging sediments from the river bottom and using mercury (Hg) to amalgamate fine gold particles, thereby altering stream and river morphology, increasing suspended sediment loads, and polluting waters via the release of Hg.…”

A DPSIR-analysis of water uses and related water quality issues in the Colombian Alto and Medio Dagua Community Council

“…A recent work by Alvarez (2013a) estimated a mean concentration of 1.36 mg/kg for mercury in bivalves from the Dagua river, which is a value almost three times higher than the standard legal limits of 0.5 mg/kg for fish products (Resolution 776/2008). Likewise, De Miguel et al (2014) indicated that mercury concentration in fish ranged from 0.026 to 3.3 mg/kg arising from artisanal gold mining in Colombia. The same authors further state that the mercury concentration in fish of Valle del Cauca ranged from 0.16 to 0.5 mg/kg.…”

Review of improving the water management for the informal gold mining in Colombia

“…Mercury vapour impacts public health most directly, causing problems with the respiratory tract in short-term exposure to high levels of mercury vapour. Symptoms include chest pains, dyspnoea, cough, haemoptysis, impairment of pulmonary function and interstitial pneumonitis [11,18,19]. The mercury contamination in Colombia by artisanal gold mining has been recognized by a number of researchers and local authorities for over a decade.…”

“…During this operation, a large amount of Hg is accidentally or intentionally discharged to the environment and eventually reaches nearby fresh water bodies where, together with the significant amounts of mercury supplied by wet atmospheric deposition, it is subjected to methylation and subsequently bioaccumulation in aquatic fauna [16]. In order to recover the gold, the amalgam is heated in open charcoal furnaces either on site, or in small workshops (or even in the home of the miner) and the emitted Hg vapors are inhaled by the unprotected artisanal minersmelters, but also outdoors and at home by residents of the mining communities [17,18]. Mercury vapour impacts public health most directly, causing problems with the respiratory tract in short-term exposure to high levels of mercury vapour.…”