No abstract

A new method has been developed for the extraction and determination of the heavy metals Ni, Cu, Cr, Pb, and Cd in mussels (Mytilus galloprovincialis) and polychaetes (Nereis diversicolor), using biodegradable mixed-micelles (SDS and Triton X-100) as the extractant, and GF-AAS analysis.

A new green method has been developed for the extraction of the pseudo-total content of the heavy metals Ni, Cu, Cr, Pb, and Cd from marine sediments using a mixture of biodegradable micellar media (SDS, Triton X-100) as extractants and graphite furnace atomic absorption spectrometry (GFAAS) for their determination. This work is the first one that uses only surfactants as extractants, without the addition of chelating agents to increase the extraction efficiency of the method, proving to be effective in the extraction of metals from this type of matrices. The proposed method has shown high recovery percentages for all the metals considered (>68%), good linearity and reproducibility (RSD<5.9%), as well as detection limits ranging from 0.06 to 2.78 µg g -1 . The method was applied to the determination of the heavy metals under study in samples with different physicochemical properties. Finally, our results were compared with those obtained using microwave assisted extraction -furnace atomic absorption spectrometry (MAE/GFAAS) described in ISO 11047:1998 obtaining comparable results.Nevertheless, Hübner et al. (5) raise four different options for the use of the term "heavy metal", although they suggest that the term applies to the following elements: arsenic, cadmium, chromium, cobalt, copper, lead, mercury, nickel, tin and zinc. Heavy metals considered in this study (Ni, Cr, Cu, Pb and Cd) are categorized as priority pollutants by the U.S. Environmental Protection Agency (6). They have proved to be important pollutants in the marine environment, with high toxicity, long persistence and rapid accumulation at living organisms (7-9).Due to the hydrophobic behaviour of these metals, their concentration in seawater is very low, and they instead tend to accumulate in marine sediments (8)(9)(10)(11)(12). This trend is due to adsorption, co-precipitation and metal complexation in the surface layers of fine sediment particles. Thus, four types of metal fractions can be distinguished: (a) the exchangeable fraction, which is located in the ion exchange sites and it is freely available to take part in chemical reactions, (b) the reducible fraction, consisting of complex oxides and hydroxides, which is soluble under reducing conditions, (c) the oxidizable fraction, which is formed with the organic matter and sulphides, and