Antarctic Science 25(3), 389–396 (2013) & Antarctic Science Ltd 2012 doi:10.1017/S0954102012001071 Lead adsorption in the clay fraction of two soil profiles from Fildes Peninsula, King George Island THIAGO MENDONC ¸A 1 , VANDER F. MELO 1 *, LUI ´ S R.F. ALLEONI 2 , CARLOS E.G.R. SCHAEFER 3 and ROBERTO F.M. MICHEL 4 1 Departamento de Solos e Engenharia Agrı ´cola, Universidade Federal do Parana ´, Rua dos Funciona ´rios 1540, Juveve ˆ, 80.035-070, Curitiba, Parana ´, Brazil 2 Departamento de Cie ˆncia do Solo - Escola Superior de Agricultura Luiz de Queiroz, Universidade de Sa ˜o Paulo, Av. Pa ´dua Dias 11, Agronomia, 13.418-900, Piracicaba, Sa ˜o Paulo, Brazil 3 Departamento de Solos, Universidade Federal de Vic ¸osa, Av. PH Rolfs s/n, 36.570-000, Vic ¸osa, Minas Gerais, Brazil 4 FEAM - Rodovia Prefeito Ame ´rico Gianetti, s/n Bairro Serra Verde, 31.630-900, Belo Horizonte, Minas Gerais, Brazil *corresponding author: vanderfm@ufpr.br Abstract: Antarctica is considered the most isolated continent, but it is not free of pollution, which arrives at specific localities mainly as a result of tourism and research activities. Among environmentally harmful substances, heavy metals are especially important because of their high toxicity to organisms. The aim of this study was to estimate the maximum adsorption of lead (Pb) onto the clay fraction of samples from two soil profiles from the Fildes Peninsula, King George Island, South Shetland Islands. Experimental data were fitted to the Langmuir isotherm, and the adsorption parameters were correlated to mineralogical attributes of this soil fraction characterized by chemical extractions and X-ray diffraction. Values of maximum adsorption of Pb in the clay fraction were extremely high (maximum value: 322 581 mg kg -1 ) when compared to those of soil samples from other regions of the world. Adsorption occurred in two stages: first stage in which a high percentage of Pb was adsorbed, and second stage in which adsorption was lower. From an environmental point of view, soils with high contents of clay and amorphous minerals, ones usually associated with ornithogenic activity in Antarctica, should have greater efficiency in filtering Pb, thus reducing risks of leaching and groundwater contamination. Received 21 December 2011, accepted 4 July 2012, first published online 30 November 2012 Key words: allophone, amorphous minerals, chemisorptions, imogolite, Langmuir isotherm, Maritime Antarctic, ornithogenic activity Introduction Although it is the most isolated continent on Earth, Antarctica is not free of pollution. Fishing, tourism and research activities bring thousands of people, boats and various environmental impacts to specific sites and coastal areas of the continent every year. Antarctica also receives continuous continent-wide deposition of windborne pollutant- containing particles (Sheppard et al. 2000). Among substances harmful to the environment, heavy metals merit special attention because of their high toxicity to organisms. Some researchers have already documented contamination sources related to hydrocarbons (Ferguson et al. 2003) and heavy metals (Sheppard et al. 2000, Santos et al. 2005, Townsend et al. 2009), introduced by human activity. Sheppard et al. (2000) analysed some areas near Scott Base, Antarctica, and at least one sample in each area had Pb levels above the background levels of the site. This was attributed to battery leaks and paint waste containing the metal. Santos et al. (2005) studied soils and coastal sediments of Admiralty Bay, King George Island, and found that house paint and oil were the main sources of heavy metals in sediments. Soils collected near the Commandante Ferraz station on King George Island had low Pb levels (11.5 mg kg -1 ). In the sub-Antarctic, soils from Atlas Cove, Heard Island, showed contamination by heavy metals around the old station but not at levels likely to produce a significant potential toxic impact on local ecosystems (Stark et al. 2003). At Casey Station Cunningham et al. (2005) found a strong relationship between metal concentrations in soil and water and the composition of diatom communities. The Polar Regions are different to other parts of the world, for example, toxicology data using local species, are not available for the Antarctic and setting of triggers and targets are particularly significant in remote regions, where the costs of site clean-up may be orders of magnitude greater than in more populated parts of the world (Snape et al. 2003). No studies to date have examined the relationship between the composition of Antarctic soils and their adsorption of heavy metals. Studies focusing on adsorption of pollutants in different soil constituents can provide information about their interactions with soil colloids and their partition among various soil constituents (Appel et al. 2008). Such data can 389 https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0954102012001071 Downloaded from https://www.cambridge.org/core. Universidade Federal de Vicosa, on 23 Nov 2018 at 11:57:01, subject to the Cambridge Core terms of use, available at