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

Abstract

In order to identify other hotspot areas and trace sources, comprehensive analysis of PCDD/Fs in surface sediments is needed in all areas of the Baltic Sea that have not been previously investigated. The high levels of PCDD/Fs observed in surface sediments also indicate a need to elucidate whether they are due mainly to current emissions or a combination of recent pollution and re-distribution of historically deposited pollutants. To do so, better understanding of sediment dynamics and present-day inputs, such as riverine inputs, industrial effluents, and leakage from contaminated soil is required. There are indications that contaminated sediments have a regional impact on fish contamination levels. However, as yet there is no statistically robust evidence linking contaminated sediments with elevated levels in Baltic biota. It should also be noted that the Baltic Sea is being massively invaded by the deep-burrowing polychaete Marenzielleria ssp., whose presence in sediments has been shown to increase water concentrations of hydrophobic pollutants. In awareness of this, it is clear that high levels in sediments cannot be ignored in risk assessments. In order to investigate the emission trends more thoroughly, analysis of PCDD/Fs in offshore sediment cores throughout the Baltic Sea is also recommended.

Concentrations, distribution and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in coastal sediments from Xiamen, China

“…A strong positive Pearson correlation was obtained between LOI and ∑ PCDF with a correlation coefficient of 0.908 (p b 0.01) (Table 4), which implied that PCDFs tended to bind with organic matter as previous studies reported (Gouin and Harner, 2003;Persson et al, 2002). However, there was no obvious correlation between LOI and ∑PCDD or ∑DL-PCB, since local emissions most likely affect the relationship between levels of organic carbon and PCDD/Fs (Sundqvist et al, 2009a). Grain size plays an important role in the content and distribution of organic carbon, since fine sediments show high capacity of sorption and carry more organic carbons due to the high surface to volume ration (Bergamaschi et al, 1997;Lee et al, 2006), which could be explained by the strong correlation among LOI, silt and gray.…”

“…The extraction, clean up and instrumental analysis were carried out at Umeå University, Sweden, and details of the methods used were described elsewhere (Sundqvist et al, 2009a). Briefly, homogenized sediment samples (15-20 g) were Soxhlet extracted in cellulose thimbles using toluene for 24 h after being spiked with 13 C-labelled PCDD/Fs and DL-PCBs as recovery standards.…”

“…Based on a previous study in the Baltic Sea that implies a significant relationship between the sediment organic content and Loss of Ignition (LOI) (Sundqvist et al, 2009a), LOI is used in this study to explore the relationship of organic content with PCDD/Fs and DL-PCBs. Dried sediments were heated at 550°C for 4 h and the LOI were calculated as the difference of the weight before and after heating.…”

Factors determining the accumulation of pentachlorophenol — a precursor of dioxins in bottom sediments of the Gulf of Gdańsk (Baltic Sea)

“…Additionally, the test revealed a statistically significant correlation between the toxicity of sediments and pH of bottom water, and confirmed no significant correlation between the toxicity and the concentration of PCP. The observed relation between toxicity and pH of bottom water may be associated with the presence of hydrogen sulfide formed when sulfur compounds become an electron acceptor as a results of oxygen deficit (Stephenson 1992). This phenomenon may be further enhanced by the exceptional sensitivity of Vibrio fisherii to sulfur compounds (Ricking et al 2002, Calace et al 2005.…”

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

“…Sediment samples were prepared according to Sundqvist et al (2009) with minor modifications. Briefly, the freezedried samples were Soxhlet-extracted with toluene.…”