| 1. |
- Lundstedt, Staffan, et al.
(författare)
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Pressurised liquid extraction of polycyclic aromatic hydrocarbons from contaminated soils
- 2000
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Ingår i: Journal of Chromatography A. ; 883:1-2, s. 151-62
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Tidskriftsartikel (refereegranskat)abstract
- The reliability and efficiency of the pressurised liquid extraction technique (PLE) for extracting polycyclic aromatic hydrocarbons (PAHs) from contaminated soil has been investigated. Experimental design was used to study the influence of seven extraction variables (sample load, solvents used, solvent ratios, pressure, temperature, extraction time, and rinse volume). The results show that large sample loads in combination with small solvent volumes may result in low extraction efficiency. They also indicate that the recovery of low-molecular-mass PAHs is reduced by low extraction temperatures. The exact settings of the other variables are, however, less significant for the extraction efficiency. Repeated extractions at optimised settings of the tested variables show that PLE is an exhaustive extraction technique that generally results in high yields. In addition, extraction of a certified reference material (CRM 103-100) revealed that the method is both accurate and precise. Another finding was that adding the internal standard on top of the soil in the extraction cell causes considerable over-estimation of the concentrations when large samples are extracted with small solvent volumes. This is because the PLE-cell resembles a chromatographic column, so compounds added to the top of the soil layer have a longer distance to travel through the soil compared to the average distance of the native compounds, which are distributed evenly throughout the column. We therefore recommend that the internal standard should be added to the extract immediately after the extraction or, alternatively, carefully mixed with the sample prior to extraction.
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| 2. |
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| 3. |
- Strandberg, B, et al.
(författare)
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Organochlorine compounds in the Gulf of Bothnia : sediment and benthic species
- 2000
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Ingår i: Chemosphere. ; 40:9-11, s. 1205-1211
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Tidskriftsartikel (refereegranskat)abstract
- Surface sediment, amphipods (Monoporeia affinis), isopods (Saduria entomon) and fourhorn sculpins (Oncocottus quadricornis) were collected at two coastal stations in the Gulf of Bothnia, one in the Bothnian Bay and the other in the Bothnian Sea. The objective was to study the concentrations, composition profiles, bioaccumulation features and spatial differences of organochlorine compounds such as hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz), chlordanes (CHLs), dieldrin, Mirex and polychlorinated biphenyls (PCBs). All groups of compounds were found in every sample investigated, with the exception of Mirex that was not detected in the sediment samples. The concentrations for e.g. PCBs and CHLs ranged from 700 to 2400 and 70 to 400 ng/g lipid in the specimens. For the corresponding sediments the results were 9.0-9.3 ng/g dw for PCBs and 0.54-0.57 ng/g dw for CHLs, respectively. Bioaccumulation differences between the species with regard to both degree of and type of compound were observed. The highest accumulation potential was found for the cyclodiene compounds including CHLs and Mirex in isopod. Finally, there were only small concentration and bioaccumulation differences between the two stations.
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| 4. |
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| 5. |
- Wingfors, Håkan, et al.
(författare)
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Multivariate data evaluation of PCB and dioxin profiles in the general population in Sweden and Spain
- 2000
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 40:9-11, s. 1083-1088
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-three polychlorinated biphenyls and 20 dioxin-like congeners were determined by GC–MS in blood and adipose tissue samples from two general population groups, one in Spain (n=35) and one in Sweden (n=28). The results were evaluated by multivariate projection (Simca), after normalisation to the most abundant and stable congener in each data set, in order to reveal differences in the “national” congener profiles. The mean values of each population group did not differ significantly. The sum of PCBs in the Spanish was 1450 ng/g and in the Swedish 1310 ng/g. The sum of the dioxin-like compounds in Spain was 1180 pg/g and in Sweden 804 pg/g. The congener profiles differed between the countries. Mainly the higher chlorinated congeners for both the dioxin-like compounds and the PCBs are more dominant in the Spanish group compared to the Swedish.
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