Earth Sciences

Hg distribution and speciation in Antarctic soils of the Fildes and Ardley peninsulas, King George Island

Renato Pereira De Andrade^a1, Roberto Ferreira Machado Michel^a2, Carlos Ernerto Gonçalves Reynaud Schaefer^a3, Felipe Nogueira Bello Simas^a3 and Cláudia Carvalhinho Windmöller^a4 c1

^a1 Minas Gerais Federal Center for Technological Education, 35790-000, MG Brazil

^a2 State Environment Foundation of Minas Gerais, 31630-900, MG Brazil

^a3 Federal University of Viçosa, Soil Science Department, 36570-000, MG Brazil

^a4 Federal University of Minas Gerais, Chemistry Department, 31270-901, MG Brazil

Abstract

Data on the content and speciation of mercury (Hg) in the soils of Antarctica are scarce and vary greatly between the regions studied, but overall Hg concentrations found were generally very low. We investigated the Hg quantity and speciation by solid-phase Hg pyrolysis and chemical fractionation in selected maritime Antarctic soils, comparing ornithogenic and non-ornithogenic areas of the Fildes and Ardley peninsulas of King George Island. The total Hg contents ranged from 4.3–256 ng g^-1, and values for ornithogenic soils were the highest recorded for Antarctic soils. A close correlation between Hg and organic matter was observed in the ornithogenic soils, with levels decreasing with depth. In the non-ornithogenic soils, a correlation between Hg content and soil depth was also observed, but the values were found to increase with depth. Thermograms showed that all Hg was in the 2⁺ oxidation state and was predominantly linked to organic matter, corroborating the chemical fractionation results for the ornithogenic soils. These results show the need for further refined studies about the interactions of Hg with organic matter in order to better understand the biogeochemistry of this metal in the Antarctic environment.

(Received August 31 2011)

(Accepted November 16 2011)

(Online publication March 30 2012)

Key words

• direct mercury analyser;
• Hg contamination;
• ornithogenic soils;
• soil analysis;
• total mercury

Correspondence:

^c1 Corresponding author: claucw@netuno.lcc.ufmg.br