Understanding the Chemical Properties of Macerals and Minerals in Coal and its Potential Application for Occupational Lung Disease Prevention

Abstract

Recent increases in oil price further strengthen the argument that coal and coal products will play an increasingly important role in fulfilling the energy needs of our society. Coal is an aggregate of heterogeneous substances composed of organic (macerals) and inorganic (minerals) materials. The objective of this review was to assess whether some chemical parameters in coal play a role in producing environmental health problems. Basic properties of coal--such as chemical forms of the organic materials, structure, compositions of minerals--vary from one coal mine region to another as well as from coals of different ranks. Most importantly, changes in chemical properties of coals due to exposure to air and humidity after mining--a dynamic process--significantly affect toxicity attributed to coal and environmental fate. Although coal is an extremely complex and heterogeneous material, the fundamental properties of coal responsible for environmental and adverse health problems are probably related to the same inducing components of coal. For instance, oxidation of pyrite (FeS2) in the coal forms iron sulfate and sulfuric acid, which produces occupational lung diseases (e.g., pneumoconiosis) and other environmental problems (e.g., acid mine drainage and acid rain). Calcite (CaCO3) contained in certain coals alters the end products of pyrite oxidation, which may make these coals less toxic to human inhalation and less hazardous to environmental pollution. Finally, knowledge gained on understanding of the chemical properties of coals is illustrated to apply for prediction of toxicity due to coal possibly before large-scale mining and prevention of occupational lung disease during mining.

Leaching of potential hazardous elements of coal cleaning rejects

“…With the noted exceptions, the minerals detected in the coal cleaning residues are those typically found in most coals and CCR (Sakurovs FeSO et al 2007;Huang and Finkelman 2008;López and Ward 2008;Silva and Oliveria 2010). Based on XRD results, major minerals in CCR are quartz, kaolinite, gypsum, microcline, muscovite and pyrite; a similar mineral assemblage was reported by Silva and Oliveria (2010).…”

Iron, Oxidative Stress, and Cell Signaling in the Pathogeneses of Coal Workers' Pneumoconiosis, Silicosis, and Asbestosis

“…Under circumstances when only a small amount of acid is available (e.g., phagolysosomes) or calcite is in large excess, no iron can be released to induce oxidative stress and subsequent biological reactions. Silica has also been considered an important toxicant in the coal (29,67) and surface activity of quartz plays a critical role in catalyzing the formation of oxidants (31,68). In the presence of calcite, there are no acids available to clean the surface of quartz, rendering its surface inactive.…”

“…Coal rank, quartz content, and levels of bioavailable iron in the coal, have been shown to play important roles in the regional differences, which were reviewed in detail (29,55). It is noteworthy that buffering capacity of the coals appears to be the most important chemical component controlling the dissolution of coal particles and, thus, release of bioavailable iron and cleaning of quartz surface for biological activities.…”

“…Iron is one of the best transition metals capable of producing ROS through Fenton, Haber-Weiss, and autoxidation reactions (28). Figure 2 illustrates that the molecular mechanisms of these pathologies are mostly centered on iron, a common constituent in coal (29), asbestos (10, 30), and silica (31). To support this view, asbestos-exposed individuals have altered iron homeostasis in the lungs as manifested by increased levels of bronchoalveolar lavage fluid (BALF) iron, transferrin, transferrin receptor, lactoferrin, and ferritin (32).…”

Turbidity Removal Efficiency of Clay and a Synthetic af-PACl Polymer of Magnesium Hydroxide in AMD Treatment

“…Although the utilization of aluminium in wastewater treatment has been associated with health problems in potable water supplies, the United Kingdom promulgated concentration limits in 1989 to alleviate any inevitable health hazards. The most appropriate utilization of aluminium salt, AlCl3 is in the treatment of AMD, a health and environmental hazardous wastewater which is generated mainly from gold and 89 coal mining and cleaning (Gupta, 2007, Huang et al, 2008, Hower et al, 2008, Cravotta et al, 2008, Silva et al, 2009a, Galatto et al, 2009and Silva et al, 2010a …”