Impact of gold mining associated with mercury contamination in soil, biota sediments and tailings in Kenya

Odumo, Benjamin Okang’; Carbonell, Gregoria; Angeyo, H. K.; Patel, J. P.; Torrijos, Manuel; Martín, José Antonio Rodríguez

doi:10.1007/s11356-014-3190-3

Cited by 91 publications

(52 citation statements)

References 54 publications

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“…Gold production in Kenya is a major driver of the country's economic growth and development and contributes $10.3 million per year to the nation's economy. In the Migori and Transmara districts (SW Kenya), gold‐mining started in the 1930s (Odumo et al, ), whereas industrial mining has recently become a relevant activity (in 2008) as newly explored gold‐bearing reefs were discovered in the Lolgorien region. As several companies have been licensed for gold prospecting, it is quite likely that industrialised gold‐mining will spread to other areas.…”

Section: Introductionmentioning

confidence: 99%

“…As several companies have been licensed for gold prospecting, it is quite likely that industrialised gold‐mining will spread to other areas. Additionally, artisanal gold‐mining (AGM) undertaken by local populations (Figure S1) has become one of the most important sources of income in this area (Odumo et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, artisanal gold-mining (AGM) undertaken by local populations ( Figure S1) has become one of the most important sources of income in this area (Odumo et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Artisanal gold‐mining in a rural environment: Land degradation in Kenya

Odumo

Nanos²,

Carbonell³

et al. 2018

Land Degrad Dev

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Artisanal gold‐mining (AGM) is one of the most important activities in the districts of Migori and Transmara (Kenya). Gold‐mining, however, is known to release vast quantities of arsenic and metals (some of which are very toxic like As, Hg, Cd, or Pb), which poses a serious threat to not only miners but also to the ecosystem and local populations. We, herein, determine the concentrations of arsenic and some heavy metals in several sample types (i.e., ore, soil, river sediment, and mine tailing) collected from the districts of Migori and Transmara. We also employ lichens and mosses as pollution bioindicators. Geostatistical tools and canonical correlation analysis were used to identify the relevant factors that affected arsenic and metal concentrations in the analysed samples. The following concentration ranges were reported in topsoil: As (1–17,250 mg kg−1), Cd (0.01–15.10 mg kg−1), Cu (7–9,238 mg kg−1), Cr (1–214 mg kg−1), Ni (5–766 mg kg−1), Pb (3–1,149 mg kg−1), and Zn (22–1,271 mg kg−1). It was concluded that the ecosystem in both districts was highly polluted by heavy metals whereas the arsenic concentrations in topsoil were among the highest reported worldwide. The results of this study provide new evidence on the impact of AGM on the environment and may further contribute to the design of policy measures with the aim of reducing environmental and human health risks associated to AGM activities.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Artisanal gold‐mining in a rural environment: Land degradation in Kenya

Odumo

Nanos²,

Carbonell³

et al. 2018

Land Degrad Dev

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“…En suelos contaminados con Hg, su contenido depende en gran medida de las fuentes contaminantes como la minería de cinabrio, la metalúrgica (Llanos et al 2011), la extracción de oro (Kpan et al 2014) y la industria química (Miller et al 2013), entre otras. Varios estudios a nivel mundial han reportado concentraciones de Hg en suelos, principalmente proveniente de minería aurífera, entre otros en Kenia (Odumo et al 2014), China (Chen et al 2016) y Venezuela (Santos-Francés et al 2011).…”

Section: Introductionunclassified

Impacto De La Minería Del Oro Asociado Con La Contaminación Por Mercurio en Suelo Superficial De San Martín De Loba, Sur De Bolívar (Colombia)

Rocha-Román

Olívero-Verbel

Caballero-Gallardo

2018

Rev. Int. Contam. Ambie.

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Palabras clave: toxicidad, ambiente, actividades antrópicas, salud humana RESUMEN Las actividades humanas han aumentado la contaminación por mercurio (Hg) en los ambientes terrestres, especialmente en áreas de minería de oro. El objetivo de este estudio fue evaluar las concentraciones de mercurio total (Hg-t) en muestras de suelo superficial de San Martin de Loba, sur de Bolívar (Colombia), así como determinar el nivel de contaminación en el suelo. Un total de 202 muestras de suelo superficial fueron colectadas en San Martín de Loba. Los niveles de Hg-t fueron medidos por atomización electrotérmica y espectroscopia de absorción atómica. Las concentraciones de Hg-t variaron de 0.002 a 23.83 μg/g, con un valor medio de 3.40 ± 0.36 μg/g, el cual es ligeramente más alto que para el Hg en suelo a nivel mundial. El índice de geo-acumulación (Igeo) para suelo alcanzó valores superiores a 5, indicando una contaminación extrema (Clase 6) en el 17 % de las muestras, mientras que el 70 % fueron Clase 5 (fuertemente a extremadamente contaminado). Este estudio también ofrece un mapa de riesgos para evaluar las posibles repercusiones negativas. En conclusión, el municipio de San Martín de Loba puede considerarse una zona fuertemente contaminada con alto contenido de Hg. La tecnología utilizada para extraer oro a lo largo de los procesos de amalgamación provoca un alto grado de contaminación por Hg en torno a esta área de minería de oro. Por lo tanto, deben considerarse métodos alternativos de extracción para reducir los niveles de Hg que pueden liberarse al ambiente y afectar la salud humana.Key words: toxicity, environment, anthropogenic activities, human health ABSTRACT Human activities have increased mercury (Hg) contamination of terrestrial environments, especially gold mining areas. The aim of this study was to evaluate total Hg concentrations (T-Hg) in surface soil samples of San Martín de Loba, south of Bolívar (Colombia), to determine their Hg contamination level. For that purpose, 202 surface soil samples were collected. T-Hg levels were measured by electrothermal atomization and atomic absorption spectroscopy. The T-Hg surface soil concentrations ranged between 0.002 and 23.83 μg/g, with a median value of 3.40 ± 0.36 μg/g, which is

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“…A relatively recent contributor to MeHg exposure and subsequent toxicity, is the use of mercury amalgam for extracting gold in artisanal gold mining (Schmidt, 2012). This may represent the most frequent contemporary route of exposure to MeHg, especially in South America (Ashe, 2012; Fraser, 2016) and Africa (Odumo et al, 2014, Rajaee et al, 2015). …”

Section: Introductionmentioning

confidence: 99%

Effects of methylmercury on spinal cord afferents and efferents—A review

2017

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Methylmercury (MeHg) is an environmental neurotoxicant of public health concern. It readily accumulates in exposed humans, primarily in neuronal tissue. Exposure to MeHg, either acutely or chronically, causes severe neuronal dysfunction in the central nervous system and spinal neurons; dysfunction of susceptible neuronal populations results in neurodegeneration, at least in part through Ca2+-mediated pathways. Biochemical and morphologic changes in peripheral neurons precede those in central brain regions, despite the fact that MeHg readily crosses the blood-brain barrier. Consequently, it is suggested that unique characteristics of spinal cord afferents and efferents could heighten their susceptibility to MeHg toxicity. Transient receptor potential (TRP) ion channels are a class of Ca2+-permeable cation channels that are highly expressed in spinal afferents, among other sensory and visceral organs. These channels can be activated in numerous ways, including directly via chemical irritants or indirectly via Ca2+ release from intracellular storage organelles. Early studies demonstrated that MeHg interacts with heterologous TRPs, though definitive mechanisms of MeHg toxicity on sensory neurons may involve more complex interaction with, and among, differentially-expressed TRP populations. In spinal efferents, glutamate receptors of the N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and possibly kainic acid (KA) classes are thought to play a major role in MeHg-induced neurotoxicity. Specifically, the Ca2+-permeable AMPA receptors, which are abundant in motor neurons, have been identified as being involved in MeHg-induced neurotoxicity. In this review, we will describe the mechanisms that could contribute to MeHg-induced spinal cord afferent and efferent neuronal degeneration, including the possible mediators, such as uniquely expressed Ca2+-permeable ion channels.

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Impact of gold mining associated with mercury contamination in soil, biota sediments and tailings in Kenya

Cited by 91 publications

References 54 publications

Artisanal gold‐mining in a rural environment: Land degradation in Kenya

Artisanal gold‐mining in a rural environment: Land degradation in Kenya

Impacto De La Minería Del Oro Asociado Con La Contaminación Por Mercurio en Suelo Superficial De San Martín De Loba, Sur De Bolívar (Colombia)

Effects of methylmercury on spinal cord afferents and efferents—A review

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