Health Effects Associated with Inhalation of Airborne Arsenic Arising from Mining Operations

Abstract

Arsenic in dust and aerosol generated by mining, mineral processing and metallurgical extraction industries, is a serious threat to human populations throughout the world. Major sources of contamination include smelting operations, coal combustion, hard rock mining, as well as their associated waste products, including fly ash, mine wastes and tailings. The number of uncontained arsenic-rich mine waste sites throughout the world is of growing concern, as is the number of people at risk of exposure. Inhalation exposures to arsenic-bearing dusts and aerosol, in both occupational and environmental settings, have been definitively linked to increased systemic uptake, as well as carcinogenic and non-carcinogenic health outcomes. It is therefore becoming increasingly important to identify human populations and sensitive sub-populations at risk of exposure, and to better understand the modes of action for pulmonary arsenic toxicity and carcinogenesis. In this paper we explore the contribution of smelting, coal combustion, hard rock mining and their associated waste products to atmospheric arsenic. We also report on the current understanding of the health effects of inhaled arsenic, citing results from various toxicological, biomedical and epidemiological studies. This review is particularly aimed at OPEN ACCESSGeosciences 2014, 4 129 those researchers engaged in the distinct, but complementary areas of arsenic research within the multidisciplinary field of medical geology.Arsenic is the 20th most abundant element in the earth's crust and may be released into the atmosphere as a result of natural processes and anthropogenic activities [1]. Environmental arsenic is released via chemical and physical weathering processes, biological activity and volcanic emissions, while anthropogenic sources include mining, metal smelting and burning of coal. Annual global arsenic emissions are estimated to be 24,000 t [2], with around 60% originating from copper smelting and coal combustion alone [3]. In some urban and highly industrialized areas, less than 2% of the atmospheric arsenic inputs originate from natural sources [3].Emissions of arsenic-bearing particulate matter (PM) are of particular concern for human populations living in proximity to an emission source. Arsenic and inorganic arsenic compounds are classified as Group 1 carcinogens and are associated with cancers of the lung, bladder, kidney, skin, liver and prostate [2]. It should be noted that within the general population, inhalation is only considered a minor exposure pathway for inorganic arsenic compounds, and ingestion is considered the primary exposure pathway [2]. However, populations living in the vicinity of an arsenic emission source have an increased risk of additional exposure through inhalation of arsenic-contaminated particulates [4][5][6][7][8][9].Despite their substantial contribution to global atmospheric arsenic species, mining operations play an understudied role in the generation of contaminated dust and aerosols [10]. To identify some of the emerging ...

The Human Gut Microbiome’s Influence on Arsenic Toxicity

“…A number of different processes contribute to atmospheric arsenic levels, including volcanic activity, mining and industrial processes, combustion of fossil fuels, use of agricultural pesticides, and volatilization of arsine compounds. Compared with drinking water exposure, inhalation is considered a minor source of arsenic exposure for the general population [3]; however, those living or working in proximity to emission sources may be at substantially higher risk of adverse exposure outcomes [36]. The largest sources of atmospheric arsenic emission are metal smelting, coal combustion, and herbicides, with arsenic laden particulate matter (PM) being the major medium of atmospheric transport [37].…”

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“…In Taiwan in China the average concentrations of TSPbound arsenic species at industrial area (thermal power plant) were 1.06 ng/m 3 and 2.49 ng/m 3 for As(III) and As(V), respectively; while in residential area they were 0.83 ng/m for As(III) and 1.96 ng/m 3 for As(V) [26]. More examples of As species concentration from various mining operations are presented in review paper by Martin et al [12].…”

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“…Coarse PM (particles with aerodynamic diameter ≥2.5 µm) are produced usually by mechanical processes such as crushing and grinding of ore and may be resuspended via wind erosion and mechanical disturbance. Fine PM (particles with aerodynamic diameter ≤2.5 µm) are produced during smelting and combustion through the condensation of high temperature vapors, diffusion and coagulation [12]. It is known that PM generated by anthropogenic sources consists mostly of fine particles, with the domination of particles below 1 µm [13,14].…”