Metal contamination of soils at Scott Base, Antarctica

Soil samples taken from excavated pits on traverses across New Zealand's Sc ott Base, Antarctica,were leached with water and 0.01 M HNO3 and the leacha tes analysed for Ag, Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The soils h ad high conductivity and pH values generally increasing with depth and in t he range 8.3-10.1. The water leachate generally contained most of the extra ctable metals except Mn and Cd, and As. Linear relationships were observed between some metals leached into alkaline solution and the Fe in those solu tions. The ratios to Fe were comparable to those of the host basanite, and this observation is interpreted as showing that these metals are incorporat ed in fine mineral particulates derived directly from the rock mass. Outlie rs in leachable metal concentrations in the soils indicated appreciable con tamination of the soil from anthropogenic sources with Ag, Cd, Cu, Pb and Z n as well as As. In some locations high concentrations of Ag and Cd corresp ond to specific sources and drainage channels. High concentrations of Pb we re widely spread and in the top soil layers whereas the elevated concentrat ions of Zn were distributed throughout the soil profiles indicating atmosph eric sources and different mobilities within the soils. Transport within th e soils is evident for some metals, as is lateral movement over and through the soils. (C) 2000 Elsevier Science Ltd. All rights reserved.