Elemental analysis of soils and Salix polaris in the town of Pyramiden and its surroundings (Svalbard)

Abstract

The contents of elements in the top soil (upper 5 cm) and deeper soil (5 to 10 cm) layers and in Salix polaris (leaves and stem) from the former Soviet mining town of Pyramiden and its close vicinity on the Svalbard archipelago were determined. The analyses covered major and trace elements, including heavy metals, in order to describe anthropogenic impacts related to the management of the mining town. Soil samples and plant tissues were analysed from 13 localities across and close to town vicinity. The plant ground cover of all sampling points was determined, and plant tissues (leaves and stem) were collected. Higher contents of Cd (3-11 mg kg(-1)) and Mo (11-33 mg kg(-1)) were detected in the soils. With relation to the world average concentration of metals in soils, the geo-accumulation indexes (Igeo) and the level of pollution of the analysed soils were classified into seven pollution grades. The soils of the studied localities were usually unpolluted (grade 1) when analysed for metals, with the soil pollution grades 4-6 identified only for Cd and Mo (moderately to strongly polluted). In Salix polaris, excessive amounts of Fe (60-1520 mg kg(-1)), Zn (80-1050 mg kg(-1)), Cd (0.2-5.5 mg kg(-1)) and Cr (0-3.6 mg kg(-1)) were observed. The Igeo of these elements, compared with values considered sufficient for plants, showed pollution grades from 2 to 6. The pollution load index (PLI) ranged between 0.49 and 1.01. Only one locality could be considered polluted having a PLI higher than 1. Plant/soil transfer factors (TF) for trace metals decreased in the following order: Zn > Cu > Cd > Mn > Ni > As > Mo > Pb > Co > Al > Cr > Fe. The principal contribution of this study consists in the assessment of the contamination of soils and plants by toxic heavy metals in an otherwise pristine environment of the Svalbard archipelago related to urban/industrial activities.

Keywords: Geo-accumulation index; Major and trace elements; Metals; Pollution; Pollution load index; Pyramiden; Salix polaris; Soil; Svalbard; Transfer factor.