However, there is knowledge about a standardised extraction method for sediments: EPA 3200 (EPA, 2005). This method uses HNO3 4 mol L1 as extractant agent. It has also been taken into account that, in almost half the studies summarised in Table 1, hydrochloric acid was used as the extractant agent. Therefore, the extractants tested were HNO3 4 mol L1, such as EPA 3200 employs, and HCl 4 mol L1, as an adaptation of this method