Trace metal distribution in pristine permafrost-affected soils of the Lena River delta and its hinterland, northern Siberia, Russia

[摘要] Soils are an important compartment of ecosystems and have the ability tobuffer and immobilize substances of natural and anthropogenic origin toprevent their movement to other environment compartments. Predicted climaticchanges together with other anthropogenic influences on Arctic terrestrialenvironments may affect biogeochemical processes enhancing leaching andmigration of trace elements in permafrost-affected soils. This is especiallyimportant since Arctic ecosystems are considered to be highly sensitive toclimatic changes as well as to chemical contamination. This studycharacterises background levels of trace metals in permafrost-affected soilsof the Lena River delta and its hinterland in northern Siberia(73.5–69.5° N), representing a remote region far from evidentanthropogenic trace metal sources. Investigations on the element content ofiron (Fe), arsenic (As), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu),lead (Pb), cadmium (Cd), cobalt (Co), and mercury (Hg) in different soiltypes developed in different geological parent materials have been carriedout. The highest median concentrations of Fe and Mn were observed in soilsbelonging to ice-rich permafrost sediments formed during the Pleistocene(ice-complex) while the highest median values of Ni, Pb and Zn were found insoils of both the ice-complex and the Holocene estuarine terrace of the LenaRiver delta region, as well as in the southernmost study unit of thehinterland area. Detailed observations of trace metal distribution on themicro scale showed that organic matter content, soil texture and iron-oxidecontents influenced by cryogenic processes, temperature, and hydrologicalregimes are the most important factors determining the metal abundance inpermafrost-affected soils. The observed range of trace element backgroundconcentrations was similar to trace metal levels reported for other pristinenorthern areas.

[学科分类] 地球化学与岩石