Assessment of tin distribution by a sequential extraction procedure in surface sediments from the Bahía Blanca Estuary (Argentina)

GARRIDO MARIANO; QUINTAS PAMELA; DOMINI CLAUDIA ; ALVAREZ MÓNICA

Alicante

Congreso; XXV Reunión Nacional Espectroscopia - IX Congreso Ibérico Espectroscopia; 2016

Tin inputs on the marine environment are mainly through antifouling paints are generally applied in the hulls of ships to prevent fouling. Once released from an antifouling coating, is rapidly absorbed by organisms such as bacteria and algae or adsorbed onto the surface of particles suspended in the water [1,2]. Due to the different chemical forms in which metals can accumulate, total concentrations are frequently not sufficient to obtain information relevant to environmental studies.Sequential chemical extraction with solutions of increasing dissolving power allows a broad operational classification of the most important binding forms of metals, which can, in principle, be associated with the constituent solid phases in sediments. The need of adequate quality control of the sequential procedures to allow the comparison of results is widely recognized. A fractionation method has been proposed by the European Standards, Measurements and Testing Program (formerly BCR) aiming to improve the comparability while retaining the most significant empirical information generated [3, 5]. Sampling was carried out in seasonal campaigns during 2013, at ten sites along the estuary. Atomic spectrometric techniques were particularly suited for the analysis of the relatively low volumes of the liquid phases resulting from the successive extraction steps. The sum of tin concentrations associated to each fraction obtained by the extraction scheme (acid soluble + reducible + oxidizable + residual) is in good agreement (89 - 106%) with the total metal content obtained by a conventional digestion method. From the environmental point of view, it was observed that those sites with the highest pollution relate not only to human activities, but with tidal currents within the estuary (Figure 1).