Baltic Sea sediment records: unlikely near-future declines in PCBs and HCB.

Unlabelled: We present a comprehensive study on PCBs and HCB in dated sediment cores from the Baltic Sea covering the 20th century, and compare their spatiotemporal trends with those of PCDD/Fs from the same areas. PCB concentrations in coastal impacted sediment followed the temporal trend of estimated global emissions of PCBs and thus responded quickly to changes in global industrial use, whereas concentrations in offshore sediment needed 10-20 years longer to respond. Differences in spatiotemporal trends of PCDD/Fs and PCBs were smaller than expected based on documented differences in key sources and source areas.

Assessment of PCDD/F source contributions in Baltic Sea sediment core records.

Spatial and temporal trends of sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea were evaluated by positive matrix factorization (PMF) and principal component analysis (PCA). Sediment cores were sampled at eight coastal, one coastal reference, and six offshore sites covering the northern to the southern Baltic Sea. The cores, which covered the period 1919-2010, were sliced into 2-3 cm disks among which 8-11 disks per core (in total 141 disks) were analyzed for all tetra- through octa-CDD/Fs.

Temporal trends of PCDD/Fs in Baltic Sea sediment cores covering the 20th century.

The pollution trend of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea region was studied based on depth profiles of PCDD/Fs in sediment cores collected from six offshore areas, eight coastal sites impacted by industrial/urban emissions, and one coastal reference site. A general trend was observed for the offshore and coastal reference sites with substantial increase in PCDD/F concentrations in the mid-late 1970s and peak levels during 1985-2002. The overall peak year for PCDD/Fs in Baltic Sea offshore areas was estimated (using spline-fit modeling) to 1994 ± 5 years, and a half-life in sediments was estimated at 29 ± 11 years.

Quantifying the total and bioavailable polycyclic aromatic hydrocarbons and dioxins in biochars.

Biochar soil amendment is advocated to mitigate climate change and improve soil fertility. A concern though, is that during biochar preparation PAHs and dioxins are likely formed. These contaminants can possibly be present in the biochar matrix and even bioavailable to exposed organisms.

Characterization of dioxin-like contamination in soil and sediments from the "hot spot" area of petrochemical plant in Pancevo (Serbia).

Purpose: Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions.

Materials And Methods: Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS).

Congener fingerprints of tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans in Baltic surface sediments and their relations to potential sources.

Comprehensive congener fingerprints of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), including non-2,3,7,8-substituted congeners, in 142 surface sediment samples from the Baltic Sea were characterized by Principal Component Analysis (PCA). The pattern analysis revealed source specific indicators of chlorophenol use, high temperature processes, chlorine bleach/chloralkali production and a source signature suggested to originate from pulp/paper or related production. Congener patterns in sediments from offshore and pristine coastal areas showed strong resemblance to patterns of atmospheric deposition and flue gases, indicating that these sources have high impact in areas that are not affected by point sources.

Levels and homologue profiles of PCDD/Fs in sediments along the Swedish coast of the Baltic Sea.

Background, Aim, And Scope: The primary aim of this study was to explore the variations in PCDD/F levels and homologue profiles of Baltic surface sediments by comprehensively analyzing polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in samples from a large number of sites, encompassing not only previously known hotspot areas, but also sites near other potential PCDD/F sources, in pristine reference areas (in which there was no industrial activity) and offshore sites.

Materials And Methods: Surface sediment samples (146 in total) were collected at various points along the Swedish coast and offshore areas. In addition, bulk deposition was sampled, monthly, at a single site in northern Sweden during 1 year.

Spatial variation in concentrations and patterns of the PCDD/F and dioxin-like-PCB content in herring from the northern Baltic Sea.

The purpose of the current study was to investigate spatial and seasonal variation of dioxin and dioxin-like PCB (dl-PCB) content in herring sampled along the northern Baltic Sea coast and map out risk zones for dioxins and dl-PCBs. We further aimed to investigate relationships between congener distribution (pattern) and sampling location and season. The results showed that there were distinct geographical differences in concentrations of dioxins, dibenzofurans and dl-PCBs along the Swedish coast, from the Bothnian Bay to north Baltic Proper, with the highest levels detected in the southern Bothnian Sea.

Air-sea gas exchange of HCHs and PCBs and enantiomers of alpha-HCH in the Kattegat Sea region.

Concentrations and air-water gas exchange of polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) were determined in nine paired air and water samples. The samples were collected monthly in the Kattegat Sea between December 1998 and November 1999. Average fugacity and flux values indicated that PCBs were oversaturated in the water, while HCHs were net deposited.