Arctic vegetation damage by winter-generated coal mining pollution released upon thawing.
Acid mine drainage (known as AMD) is a well-known environmental problem resulting from the oxidation of sulfidic mine waste. In cold regions, AMD is often considered limited by low temperatures most of the year and observed environmental impact is related to pollution generated during the warm summer period. Here we show that heat generation within an oxidizing, sulfidic, coal-mining waste-rock pile in Svalbard (78 degrees N) is high enough to keep the pile warm (roughly 5 degrees C throughout the year) despite mean annual air temperatures below -5 degrees C. Consequently, weathering processes continue year-round within the waste-rock pile. During the winter, weathering products accumulate within the pile because of a frozen outer layer on the pile and are released as a flush within 2 weeks of soil thawing in the spring. Consequently, spring runoff water contains elevated concentrations of metals. Several of these metals are taken up and accumulated in plants where they reach phytotoxic levels, including aluminum and manganese. Laboratory experiments document that uptake of Al and Mn in native plant species is highly correlated with dissolved concentrations. Therefore, future remedial actions to control the adverse environmental impacts of cold region coal-mining need to pay more attention to winter processes including AMD generation and accumulation of weathering products.
Elberling
Bo
B
Institute of Geography and Geology, University of Copenhagen, Copenhagen, Denmark. be@geogr.ku.dk
Søndergaard
Jens
J
Jensen
Louise A
LA
Schmidt
Lea B
LB
Hansen
Birger U
BU
Asmund
Gert
G
Zunić
Tonci Balić
TB
Hollesen
Jørgen
J
Hanson
Susanne
S
Jansson
Per-Erik
PE
Friborg
Thomas
T
D000704:Analysis of Variance; D001110:Arctic Regions; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity; D008906:Mining; D008956:Models, Chemical; D010944:Plants / Q000187:drug effects* / Q000378:metabolism; D012621:Seasons; D012987:Soil / Q000032:analysis; D013696:Temperature; D014866:Waste Products / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity
D019216:Metals, Heavy; D012987:Soil; D014866:Waste Products; D014874:Water Pollutants, Chemical