An unusual occurrence of arsenic-bearing pyrite in the Upper Freeport coal bed, west-central Pennsylvania

Elemental and mineralogical anomalies in the coal-hosted Ge ore deposit of Lincang, Yunnan, southwestern China: Key role of N2–CO2-mixed hydrothermal solutions

“…18). Arsenic in coal is generally associated with pyrite, commonly as As-rich inclusions in the pyrite lattice (Coleman and Bragg, 1990;Eskenazy, 1995;Hower et al, 1997;Huggins and Huffman, 1996;Minkin et al, 1984;Ruppert et al, 1992;Ward et al, 1999;Yudovich and Ketris, 2005). Occurrences of organically-associated As have also been reported in some other coals (Belkin et al, 1997;Zhao et al, 1998).…”

Arsenic-bearing pyrite and marcasite in the Fire Clay coal bed, Middle Pennsylvanian Breathitt Formation, eastern Kentucky

“…Most of the As in coal is associated with pyrite, most commonly as As-rich inclusions in the pyrite lattice (Minkin et al, 1979;Ruppert et al, 1992;Ward, 2002) and more rarely associated with clays (Huggins, 2002;Yudovich and Ketris, 2005, discuss As forms in coal). Rare occurrences of organically associated As have been reported in coals in Guizhou Province, southwestern China (Belkin et al, 1997;Zhao et al, 1998;Zhang et al, 2002).…”

Arsenic in Natural Environments

“…Although often insignificant when compared with other sources of arsenic, some arsenic in coals originated from water that entered the original peat-forming plants. As in other environments, plants in wetlands often acquire inorganic As(V) along with phosphate and methylate it (Ruppert et al, 1992). The methylarsenic (such as MMA(V) and DMA(V)) may then accumulate in the cell walls of the plants.…”

“…After death and burial under reducing conditions, some microbes convert methylarsenic compounds into volatile (methyl)arsines. If sulfides and Fe(II) are also presence, arsenic may be incorporated into Fe(II) sulfide compounds that eventually transform into arsenian pyrite (Ruppert et al, 1992). In rare cases, arsenian pyrite occurs as replacement materials in cell walls and other parts of fossilized plants (Ruppert et al, 1992).…”