The environmental costs of mountaintop mining valley fill operations for aquatic ecosystems of the Central Appalachians

Abstract

Southern Appalachian forests are recognized as a biodiversity hot spot of global significance, particularly for endemic aquatic salamanders and mussels. The dominant driver of land-cover and land-use change in this region is surface mining, with an ever-increasing proportion occurring as mountaintop mining with valley fill operations (MTVF). In MTVF, seams of coal are exposed using explosives, and the resulting noncoal overburden is pushed into adjacent valleys to facilitate coal extraction. To date, MTVF throughout the Appalachians have converted 1.1 million hectares of forest to surface mines and buried more than 2,000 km of stream channel beneath mining overburden. The impacts of these lost forests and buried streams are propagated throughout the river networks of the region as the resulting sediment and chemical pollutants are transmitted downstream. There is, to date, no evidence to suggest that the extensive chemical and hydrologic alterations of streams by MTVF can be offset or reversed by currently required reclamation and mitigation practices.

Isotopic Imprints of Mountaintop Mining Contaminants

“…Leachates were measured for pH, electric conductivity, major ions, Se, and strontium isotope ratios. The variations of δ 13 C DIC and δ 34 S SO4 (Figures 4,5) indicate that DIC and SO 4 were derived from two major sources: (1) diluted tributaries depleted in 13 C DIC (δ 13 C DIC < −6‰) and slightly enriched in 34 S SO4 (δ 34 S SO4 > +5‰) and (2) saline tributaries enriched in 13 C DIC (δ 13 C DIC ∼ +6‰) and slightly depleted in 34 S SO4 (δ 34 S SO4 = −2 to +2‰). The respectively low δ 13 C DIC and high δ 34 S SO4 of the diluted tributaries mimic the natural background conditions (soil processes and meteoric sulfate) and were also observed in the upstream section of the Mud River without any mining influence, prior to the river flow through the MTM affected area.…”

Derivation of a benchmark for freshwater ionic strength

“…The surface runoff and leachate from the crushed rock are neutral to mildly alkaline but contain much higher levels of HCO 3 , and Mg 2þ than occur in undisturbed stream systems [5,6]. This effluent is of particular concern because the amount of dissolved ions entering streams below surface coal-mining operations can be very high and the areal extent of mining may have exceeded the assimilative capacity of streams and entire drainage basins [5,[7][8][9][10]. A protective benchmark is needed to inform decision making because there is currently no regulatory criterion to protect aquatic life from ionic stress.…”

Diversidad de insectos acuáticos en quebradas impactadas por agricultura y minería, Caldas, Colombia

“…Las alteraciones de origen antrópico como la minería y la agricultura alteran directa e indirectamente la diversidad de insectos al interior de los ecosistemas acuáticos (Hepp et al, 2010;Bernhardt & Palmer, 2011;Chará-Serna et al, 2015). En este estudio, la diversidad y composición de la comunidad de insectos acuáticos se ve afectada por la perturbación de tipo agrícola y minera, y el sustrato.…”

“…En las últimas cinco décadas, la agricultura en Colombia ha tenido un crecimiento acelerado, debido a la intensificación de la producción y a la expansión de los cultivos (Etter et al, 2006), y se ha documentado que es una de las actividades antrópicas que más altera las dinámicas de los ecosistemas acuáti-cos (Maloney & Weller, 2011;Piggott, Lange, Townsend, & Matthaei, 2012;Chará-Serna, Chará, Giraldo, Zúñiga, & Allan, 2015). Por otro lado, la minería es una de las actividades que más impacta los ecosistemas lóticos, ya que estos actúan como receptores de los desechos provenientes de la explotación y extracción de minerales (Bernhardt & Palmer, 2011;Brosse et al 2011).…”