| Summary: | Progress Code: completed Statement: The dates provided in temporal coverage are approximate only. Years are correct. See the referenced paper for full details on steps taken to ensure quality of data. To assess extraction efficiency for a range of sediment types, four marine sediments were analysed in detail. Two international certified reference materials (CRMs) and two well-characterised Antarctic sediments were chosen to compare and contrast moderately to strongly contaminated samples (based on total metal digest), with clean samples of similar matrices. One CRM was an uncontaminated continental shelf mud (MESS-2), and the other a contaminated harbour mud (PACS-2) (NRCC, 2002). The two Antarctic sediments were collected as part of a regional hierarchical survey (Stark et al., 2003). One Antarctic sample was from an area of known metal pollution in Brown Bay (BB), which is adjacent to the 'Old' Casey Station waste disposal site (Snape et al., 2001; Stark et al., 2003). The second Antarctic sample was from a non-impacted control site from O'Brien Bay (OBB), 3 km south of Casey Station and the disposal site (Fig. 1). The Antarctic samples, OBB and BB, have similar matrices, proportions of mud (less than 63 microns; 19% and 22% respectively) and total organic carbon contents (1.9% and 2.3% respectively). Both MESS and PACS are sieved, homogenised and dried CRMs that have been ground to ~50 microns (NRCC, 2002). In contrast, OBB and BB were only sieved to less than 2 mm, thereby removing only the very largest particles (less than or equal to 3%). The Antarctic samples were collected using acid-washed PVC coring tubes. The samples were kept frozen at -20 degrees C until wet-sieved with a small amount of clean filtered (0.45 microns cellulose nitrate) O'Brien Bay seawater through 2 mm nylon mesh held in a plastic sieve unit. The sediments were then oven-dried to constant weight at 103 degrees C (Loring and Rantala 1992), and stored in Nalgene HDPE bottles until analysis. These results are for the 4 hour ...
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