Under aerobic conditions, microorganisms break down less chlorinated

biphenyl rings to yield chlorinated benzoates and pentanoic acid derivatives (Rodrigues et al. 2006). The spatial distribution pattern of POPs in surface sediments has been widely investigated in the Arctic (e.g. Valette-Silver et al. 1999, Savinov et al. 2000, 2003, Gustaffsson et al. 2001, Strachan et al. 2001, Kuzyk et al. 2005), providing insight into linkages between sources and contamination patterns. The Barents Sea has been a focal point of investigation in the European Arctic both offshore (Yunker et al. 1996, Boitsov et al. 2009a, Dahle et al. Mitomycin C 2009) and in adjacent coastal areas (Næs et al. 1995, Sericano et al. 2001, Dahle et al. 2003, Carroll et al. 2008a). However, with the notable exception of Yunker et al. (1996) and Boitsov et al. (2009a,b), the majority of studies are limited to the investigation of surface sediments (down to ~1–2 cm). In the present study, we examine the contaminant record (~150 years) from four locations along a south- north latitudinal transect of the western Barents Sea using sediment cores dated by 210Pb geochronology.

We identify potential contaminant sources based on interpretation of the congener proportions and overall sediment concentrations of the studied compounds. For PCBs and HCB we assess whether sediment contaminant levels reflect the decline in production associated with the regulatory ban on the usage of products containing these compounds. Finally, the study provides an opportunity to discuss the influence of burial and post-depositional sediment reworking processes AZD2281 nmr on the interpretation of persistent organic contaminants detected in marine sediments. Sediment cores were collected from four stations in the central and northern regions of the western Barents Sea using a 4-core multi-corer (Figure 1). At each station, two of the four retrieved sediment cores were sliced at 1 cm intervals, and 1 cm of the outside edge of each interval was discarded

to eliminate down-core contamination. Sediments from similar depth intervals in each of the two cores were combined to obtain sufficient sample material for contaminant analyses. Sediment subsamples were stored in covered glass jars previously heated to 450°C. Sample jars were frozen at –20°C until further Interleukin-3 receptor processing in the laboratory. The remaining two sediment cores collected during each multi-corer cast were stored for the analysis of sediment properties and of radionuclide concentration measurements: 234Th, 210Pb, 137Cs, 239,240Pu. Sediments at all stations were composed mainly of fine material (45–98% pelite) with organic carbon contents ranging from 1.0–2.4% Corg (Carroll et al. 2008b). Profiles of both 210Pb and 234Th were used to determine sediment mixing rates (Carroll et al. 2008b), while sedimentation velocities were determined by 210Pb and validated with 137Cs (Zaborska et al. 2008).