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| 2. |
- Hollert, Henner, et al.
(författare)
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Biological and Chemical Determination of Dioxin-like Compounds in Sediments by Means of a Sediment Triad Approach in the Catchment Area of the River Neckar
- 2002
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Ingår i: Ecotoxicology. - 0963-9292 .- 1573-3017. ; 11:5, s. 323-36
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the sediment quality of selected sites in the catchment area of the River Neckar, an integrative assessment approach was used to assess the ecological hazard potential of dioxin-like sediment compounds. The approach is based on 7-ethoxyresorufin-O -deethylase (EROD) induction in embryonic chicken liver culture and comprehensive chemical analyses of polycyclic aromatic hydrocarbons (priority PAHs according to the US Environmental Protection Agency). The majority of the sediment extracts exhibited high potencies as EROD-inducers. In one sediment sample, which was influenced by a sewage treatment plant, a very high concentration of 930 ng bioassay 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) equivalents (bio-TEQs )/g organic carbon could be determined. However, in none of the samples, more than 6% of the EROD-inducing potency could be explained by the PAHs analyzed chemically. Thus, non-analyzed compounds with EROD-inducing potency were present in the extracts. A fractionation of sediment samples according to pH allowed to localize the major part of EROD-inducing compounds in the neutral fractions. However, a significant portion of the EROD induction could also be explained by the acidic fractions. Following the concept of the Sediment Quality Triad according to Chapman, in situ alterations of macrozoobenthos were examined. A comparison of the results predicted by the EROD assay and chemical analyses with alterations in situ , as measured by means of the saprobic index and the ecotoxicological index according to Carmargo, revealed a high ecological relevance of the results of bioassays and chemical analyses for major sites.
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| 3. |
- Kitti, Anna, et al.
(författare)
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Multivariate characterization of polycyclic aromatic hydrocarbons using semi-empirical molecule orbital calculations and physical data
- 2003
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Ingår i: Chemosphere. ; 50:5, s. 627-37
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Tidskriftsartikel (refereegranskat)abstract
- Multivariate characterization of 60 polycyclic aromatic hydrocarbons (PAHs) was performed using data from literature and semi-empirical molecular orbital calculations. This dataset was analyzed by principal component analysis and projections to latent structures by means of partial least square. The PAHs were found to distribute in the chemical domain in several groups mainly governed by the number of aromatic rings and the number of five-membered rings. The multivariate model and training set was used to predict GC retention times on a non-polar column (DB-5). Using a 24 experimental design on the principal components of the chemical characterization model, a test set of PAHs was selected dependent on the distribution in the chemical domain of the PAHs. Such a test set is expected to improve selection of PAHs for future testing and modeling of both biological and chemical responses. Although the model of GC retention times was good, the precision was however not good enough for practical use.
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| 4. |
- Lundgren, Kjell, et al.
(författare)
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Development of a high-performance liquid chromatography carbon column based method for the fractionation of dioxin-like polychlorinated biphenyls
- 2002
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Ingår i: Journal of Chromatography A. ; 962:1-2, s. 79-93
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Tidskriftsartikel (refereegranskat)abstract
- A method to separate polychlorinated biphenyls (PCBs) by using high-performance liquid chromatography (HPLC) was developed. The HPLC column was packed with Amoco PX-21 activated carbon dispersed on octadecylsilane (ODS). The separation was carried out by gradient elution with n-hexane–dichloromethane and toluene in the forward direction followed by reversed elution with toluene. The results show that this HPLC method is useful for the separation of PCBs according to the number of substituted ortho chlorine atoms attached to the biphenyl structure. Average recoveries for a number of individual di-ortho PCBs, mono-ortho PCBs, and non-ortho PCBs in three selected elution windows were 97, 92, and 96%, respectively. Clophen A50, a herring sample, and a cod liver oil sample were fractionated on the column and the analytical results are compared with data from the literature. The method presented here is useful for quantitative separations of mono-ortho PCBs as well as non-ortho PCBs which have been assigned toxic equivalency factors by the World Health Organisation.
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| 5. |
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| 6. |
- Lundgren, Kjell, et al.
(författare)
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Flux estimates and sedimentation of polychlorinated naphthalenes in the northern part of the Baltic sea
- 2003
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Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 126:1, s. 93-105
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations and fluxes of polychlorinated naphthalenes (PCNs) were measured in surface sediments, and settling particulate matter collected in sediment traps, at two coastal and two offshore sampling stations in the Gulf of Bothnia, northern Baltic Sea, Sweden. The PCN concentrations (of tetra- to hepta-chloro congeners) in the surface sediments ranged from 0.27 to 2.8 ng/g dry weight and were of the same order of magnitude as background concentrations reported previously in Europe. The PCN fluxes in the southern basin (0.93 and 0.86 μg/m2/year) of the Gulf of Bothnia were higher than those in the northern basin (0.58 and 0.49 μg/m2/year); they were also higher near the coast than in the open sea. These PCN fluxes are similar to the pre-industrial levels determined from lake sediments in northwest England. The PCN homologue distribution changed from a relatively even distribution in samples collected near the coast, to TeCNs dominating in the samples from the open sea. This indicates that higher chlorinated PCNs are deposited and retained in sediments to a higher degree near the coast. The total annual deposition of PCNs in sediments in the Gulf of Bothnia was estimated to be 91 kg/year. Background concentrations in sediments, fluxes and annual sedimentation rates of polychlorinated naphthalenes were measured and estimated at two coastal and two offshore remote sampling stations in the Gulf of Bothnia, northern Baltic Sea.
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| 7. |
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| 8. |
- Lundgren, Kjell, et al.
(författare)
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Polychlorinated Naphthalene Levels, Distribution, and Biomagnification in a Benthic Food Chain in the Baltic Sea
- 2002
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 36:23, s. 5005-13
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Tidskriftsartikel (refereegranskat)abstract
- The scientific literature contains little information regarding bioaccumulation and biomagnification of polychlorinated naphthalenes (PCNs) in food webs. Here we present new information on the food chain transfer of PCNs within a food chain in a subarctic environment. PCNs (tetra- to hepta-chloro congeners) were measured in surface sediments and in a marine benthic food chain, comprising amphipods, isopods, and fourhorned sculpins. Samples were collected from five locations in the Gulf of Bothnia, northern Baltic Sea. PCN concentrations in the sediments were similar to background levels determined previously in sediments from the northern hemisphere. Measurement of the carbon content of the sediments allowed the calculation of biota to sediment accumulation factors (BSAFs). Tetra- and penta-CNs exhibited BSAF values greater than one, while BSAFs for the more chlorinated PCNs were less than one. This suggests more efficient assimilation, by amphipods, of the less chlorinated PCNs. A decrease in PCN concentrations from the lowest to the highest trophic level was demonstrated (amphipods: 10-69 ng/g lw; isopods: 3.9-16 ng/g lw; fourhorned sculpins: 0.54-1.5 ng/g lw). Biomagnification factors (BMFs) were calculated based on the concentrations of the congeners. These indicated that a few congeners biomagnified significantly: the highest BMFs (0.09-1.4) were found for 2,3,6,7-substituted congeners and those lacking adjacent hydrogen-substituted carbon atoms.
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| 9. |
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| 10. |
- 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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