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  • Dahlén, Johan, et al. (författare)
  • Determination of nitrate and other water quality parameters in groundwater from UV/VIS spectra employing partial least squares
  • 2000
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 40:1, s. 71-77
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of UV/Vis spectroscopy in combination with partial least squares (PLS) regression for the simultaneous prediction of nitrate and non-purgeable organic carbon (NPOC) in groundwaters was evaluated. A model of high quality was obtained using first order derivative spectra in the range 200–300 nm. Inclusion of non-UV-absorbing constituents in the modeling procedure, i.e., chloride, sulfate, fluoride, total carbon (TC), inorganic carbon (IC), alkalinity, pH and conductivity was also evaluated. This model seemed to be useful for prediction of chloride, TC, IC, alkalinity and conductivity, while its ability to predict sulfate, fluoride and pH was poor. In conclusion, application of PLS regression, which requires neither filtration of samples nor addition of chemicals, is a promising alternative for fast interpretation of geochemical patterns of groundwater quality.
  • Dahlén, Johan, et al. (författare)
  • Determination of the molecular weight of fulvic acids by UV/VIS spectroscopy
  • 1999
  • Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 38:4, s. 783-794
  • Tidskriftsartikel (refereegranskat)abstract
    • Partial least squares (PLS) modeling was applied to investigate number-average molecular weights (Mn) and weight-average molecular weights (Mw) of fulvic acids (FAs) in relation to the corresponding UVNIS spectra. The Mn and Mw values were determined by size exclusion chromatography (SEC). The impact of pH control, wavelength range and density as well as smoothing and derivation of spectra were tested. It was found that PLS models based on absorbance spectra can be a fast and powerful complement to existing techniques employed for determination of molecular weights of FAs. Control of pH of the FA solutions is important for the performance of the models. The models were also compared with the best univariate alternatives.
  • Dyke, P. H., et al. (författare)
  • PCB and PAH releases from power stations and waste incineration processes in the UK
  • 2003
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 50:4, s. 469-480
  • Tidskriftsartikel (refereegranskat)abstract
    • This study focused on emissions of polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) from incineration and power generation processes. Increased concern over human exposure to both classes of compounds has meant that environmental regulators need to assess the contribution made by emissions from regulated processes to human exposure. In the first part of an assessment in the UK we reviewed literature data on emissions of PCB, focusing on the dioxin-like PCB assigned toxic equivalency factors by the World Health Organization, and PAR The literature study was supplemented by a series of plant tests to gather initial real plant data. Literature data were limited and the lack of standard protocols for measurement and reporting of both PCB and PAH meant that few data sets were comparable. Levels of dioxin-like PCB reported in the literature and measured in UK plant tests showed that well-controlled modern combustion plants with comprehensive pollution controls gave low emissions, typically about 5-10% of the toxic equivalent of the emissions of polychlorinated dibenzodioxins and dibenzofurans at the same plants and below the widely used standard of 0.1 ng TEQ/N m(3).
  • Engwall, Magnus, 1965-, et al. (författare)
  • Levels of dioxin-like compounds in sewage sludge determined with a bioassay based on EROD induction in chicken embryo liver cultures
  • 1999
  • Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 38:10, s. 2327-2343
  • Tidskriftsartikel (refereegranskat)abstract
    • A bioassay for the detection of dioxin-like compounds was used to estimate levels in sewage sludge from Swedish sewage treatment plants (STPs). The sludge extracts were HPLC-separated into three fractions containing a) monoaromatic/aliphatic, b) diaromatic (e.g. polychlorinated biphenyls [PCBs], polychlorinated dibenzodioxins and polychlorinated dibenzofurans [PCDDs/Fs]), and c) polyaromatic compounds (e.g. polycyclic aromatic hydrocarbons [PAHs]). The bioassay, which is based on EROD (7-ethoxyresorufin O-deethylase) induction in cultured chicken embryo livers detected dioxin-like activity in all unfractionated extracts and in the di- and polyaromatic fractions of all sludge extracts, but not in the monoatomatic/aliphatic fractions. The levels ranged between 6 and 109 pg bio-TEQ/g sludge (d.w.). In sediment samples from rural lakes in Sweden, levels of about 5 pg bio-TEQ/g (d.w.) have been found. The polyaromatic fractions of the sludge samples were potent in the bioassay, probably due to various PAHs and other polyaromatics in the sludge. The levels of six PAHs that are screened for in the sludge at Swedish STPs accounted for only 3-10% of the observed EROD-induction by the polyaromatic fractions. Consequently, many other polyaromatic EROD-inducing compounds were present in the sludge. Inclusion of a biological test like the chicken embryo liver bioassay in the screening of sludge would improve the ability to detect the presence of bioactive dioxin-like compounds. A theoretical estimation of bio-TEQ concentrations in farm-soil following long-term application of sludge with bio-TEQ concentrations similar to those observed in this investigation indicated that the bio-TEQ levels in soil would increase very slowly over time. The chicken embryo liver bioassay proved useful in assessing levels of dioxin-like compounds in sewage sludge and it gives valuable complementary information to chemical analysis data.
  • Engwall, Magnus, 1965-, et al. (författare)
  • Uptake of dioxin-like compounds from sewage sludge into various plant species : assessment of levels using a sensitive bioassay
  • 2000
  • Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 40:9-11, s. 1189-1195
  • Tidskriftsartikel (refereegranskat)abstract
    • A bioassay for the detection of dioxin-like compounds was used to estimate uptake of dioxin-like compounds in carrots, oil seed rape seeds, zucchinis and cucumbers grown in soil amended with sewage sludge from Swedish sewage treatment plants (STP), This sensitive bioassay is based on 7-ethoxyresorufin O-deethylase (EROD)-induction in cultured chicken embryo livers and reflects the combined biological effect of all dioxin-like compounds in a sample, including ones that seldom are analyzed. The bioassay detected low concentrations of dioxin-like compounds in all carrot, zucchini and cucumber samples, but did not detect any dioxin-like compounds in the rape seeds. In carrots the concentrations were increased up to seven times when grown in soil amended with high applications of some of the sludge samples, while others did not increase the concentrations compared to control. More realistic sludge applications only increased the concentrations slightly. The sludge-fertilized carrots contained the highest concentrations of the investigated plants (up to 14 pg bioassay-derived TCDD equivalents (bio-TEQs)/g d.w.). In the carrots, differences in uptake of dioxin-like compounds depended on the sludge origin, which may be due to more easily bioaccumulated dioxin-like compounds in some sludge samples, or other components that facilitated uptake into the carrots. In the cucumbers, a more than two-fold increase (from 0.2 to 0.5 pg bio-TEQs/g d.w.) was observed in specimens grown in sludge-amended soil when compared to controls, suggesting a small uptake from the roots to the shoots. No sludge-dependent increase in uptake was seen in the zucchini fruits. The bio-TEQ levels were generally low in the consumable above ground plant parts of the investigated species. However, the question if repeated sludge application results in a soil accumulation of dioxin-like compounds, thereby increasing the risk of plant uptake, remains to be investigated.
  • Eriksson, M., et al. (författare)
  • Determination of hydrocarbons in old creosote contaminated soil using headspace solid phase microextraction and GC-MS
  • 2001
  • Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 44:7, s. 1641-1648
  • Tidskriftsartikel (refereegranskat)abstract
    • Headspace solid phase microextraction (HS-SPME) has been used together with GC-MS to analyze organic substances directly in a soil, heavily contaminated with PAHs/creosote (similar to 300 mg/kg soil), from an old gaswork site in Stockholm, Sweden. The HS-SPME results, both qualitative and quantitative, were compared with traditional liquid extraction using ethyl acetate/hexane (20:80). It was shown that the concentrations determined with HS-SPME at 60 degreesC correlated well, for compounds containing up to two and three aromatic rings (naphthalenes, acenaphthene, acenaphthylene and fluorenes, while a lower concentration was obtained for phenanthrene, anthracene, fluoranthene and pyrene. The total concentrations for each compound determined with HS-SPME ranged from 2 to 25 mug/g soil. Quantification was done using standard addition of compounds directly to the soil samples. The bioavailable fraction of the compounds in the contaminated soil at 20 degreesC was analyzed using external calibration by spiking sterile uncontaminated sand (same texture and particle size as the contaminated soil but without a heavily sorbed organic fraction) with hydrocarbon standards in different concentrations. Storage of exposed fibers at 20 degreesC showed that analysis should be done within two days to make qualitative measurements and earlier (as soon as possible) for quantitative determinations.
  • Fiedler, Heidelore, 1953-, et al. (författare)
  • Patterns and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans found in soil and sediment samples in southern Mississippi
  • 1996
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 32:3, s. 421-432
  • Tidskriftsartikel (refereegranskat)abstract
    • Using hierarchical cluster analysis and Principal Component Analysis (PCA), sediment and soil samples from the State of Mississippi were compared with the effluents of a pulp mill, a potential point source. Additionally, data of many known sources of PCDD/PCDF from the scientific literature were evaluated. Both methods were able to distinguish between different matrices with known PCDD/PCDF contamination (e.g. PCP, PCB, kraft pulp mill effluents). In some instances, a specific PCDD/PCDF source could be correlated to an environmental sample, e.g. the pattern of a U.S, brand of pentachlorophenate was found in sediment samples. None of the mathematical and statistical techniques could identify the pulp mill as the source of the PCDD/PCDF in the sediments and soils in the floodplain.
  • Fiedler, Heidelore, 1953-, et al. (författare)
  • PCDD, PCDF, and PCB in farm-raised catfish from southeast United States - Concentrations, sources, and CYP1A induction
  • 1998
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 37:9-12, s. 1645-1656
  • Tidskriftsartikel (refereegranskat)abstract
    • Nine catfish fillets, three catfish nuggets, two feed samples, and one pond sediment were analyzed for PCDD, PCDF, and-PCB. Farm-raised catfish from Mississippi, Alabama, and Arkansas contained significant levels of 2,3,7,8-substituted PCDD and PCDF. In addition, a large number of non-2,3,7,8-substituted congeners were present in all samples. The catfish fillets and catfish nuggets also contained high concentrations of dioxin-like PCB, as well as a number of non-dioxin-like PCB. The TEQ based on PCDD and PCDF ranged from 9.5 to 43.0 pg/g lipid and the TEQ based on PCB ranged from 0.45 to 4.9 pg/g lipid for all catfish samples. The dioxin-like PCB contributed 4-16% to the total TEQ (PCDD/PCDF/PCB) for the catfish samples. The major source for the PCDD, PCDF, and PCB appears to be from feed and not from pond sediment. Immunoreactive CYP1A protein was elevated 2.5 fold in the pond-raised catfish compared to the aquarium-raised one. The results of this study suggest that the PCDD/PCDF are more important than the PCB in the CYP1A induction.
  • Fiedler, Heidelore, 1953-, et al. (författare)
  • PCDD/PCDF, chlorinated pesticides and PAH in Chinese teas
  • 2002
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 46:9-10, s. 1429-1433
  • Tidskriftsartikel (refereegranskat)abstract
    • Four samples of Chinese tea (two green teas, and two brick teas) were analyzed for their concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), chlorinated pesticides and PAH. The infusions prepared from these teas were also analyzed for PCDD/PCDF. The levels of DDT and its metabolites in tea leaves were within the safety limit of 0.2 mg/kg. Rather high levels of total PAH were obtained in brick tea (1048-1162 mg/kg), when compared with green tea (497-517 mg/kg). In terms of PCDD/PCDF, the concentrations of green tea and brick tea differed by a factor of 16, while the concentrations of all infusions were within a factor of 2. The dioxin concentrations in green tea leaves can be explained through uptake of atmospheric PCDD/PCDF. The higher concentrations in the brick tea leaves are due the longer exposure time, and to certain extent, the use of old leaves, branches and roots when making the tea, and additional components such as soil particulates through contamination. Certain Chinese populations drinking a large amount of brick tea (>31 per day) indicated that individuals of these populations consume more tea than Europeans or North Americans result in a comparably higher intake of PCDD/PCDF. Tea consumption can attribute to up to 10% of the TDI recommended by WHO (only PCDD/PCDF considered, no PCB analyzed).
  • Fiedler, Heidelore, 1953-, et al. (författare)
  • Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in food samples collected in southern Mississippi, USA
  • 1997
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 34:5-7, s. 1411-1419
  • Tidskriftsartikel (refereegranskat)abstract
    • n 1994, we analyzed 43 foodstuff samples from local supermarkets in southern Mississippi, USA, for PCDD/PCDF. 2,3,7,8-Cl4DD could be quantified in 31 of these samples. On a lipid basis, levels in meat (0.53-1.10 pg I-TEQ/g) and dairy products (0.42-1.10 pg I-TEQ/g) were slightly lower than those reported from other industrialized countries. While levels in dairy samples from the United States and Europe are comparable, there is a difference in the contribution of individual congeners to the I-TEQ: for example, in milk samples from Germany approximately 40% of the I-TEQ is due to the presence of 2,3,4,7,8-Cl5DF while in the Mississippi samples this congener only contributes 16%. The highest concentrations of PCDD/PCDF in our study were detected in the farm-raised catfish (10.2-27.8 pg I-TEQ/g). A unique finding was that in addition to the 2,3,7,8-substituted PCDD/PCDF the catfish samples contained many non-2,3,7,8-substituted congeners. This is unusual because vertebrate animals selectively eliminate or metabolize the non-2,3,7,8-substituted congeners.
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