Dag Olav Andersen

• Mansoor, Mohammad Azam & Andersen, Dag Olav (2016). In vivo effect of N-ethylmaleimide (NEM) on the measurement of nitrate in plasma. Clinical Biochemistry. ISSN 0009-9120. 49(18), s. 1361–1363. doi: 10.1016/j.clinbiochem.2016.07.006.
• Andersen, Dag Olav & Christy, Alfred A. (2010). Water Chemistry in the Confluence Zone Downstream a Limestone Treated Lake and an Acid Tributary: Principal Component Analyses Including Warm and Cold Winters and an Episode High in Sea-Salts. International Journal of Arts and Sciences. ISSN 1557-718X. 3(9), s. 23–35. Vis sammendrag

  Extensive limestone treatment of lakes and watercourses has been carried out especially in Norway and Sweden to counteract effects of acidification. Lakes have been the most commonly treated part of the water systems. However, treatment of lakes upstream acid tributaries may introduce downstream toxic mixing zones for fish. To sort this out the outlet of a treated lake, a downstream acid tributary and two sites in the confluence zone were intensely monitored during a period of 28 months. The data accumulated come from a period (from February 1992) where significant climatic variations took place that provide a basis for studying intercorrelations between water chemistry and climatic change. The first two winters were warmer than normal and the catchments were hardly covered with snow and the lake was ice-covered only for a few days. The last winter was colder than normal, nival and the lake was ice-covered from December to April. During the second winter a low pressure over the north Atlantic gave strong south-westerly winds and large amounts of precipitation loaded with sea-salts. The principal component analysis (PCA) separates both the outlet and the tributary data into two groups while the data from the confluence zone are separated into three. Significant different water chemistry was observed in the outlet during the ice-covered period while effects of the sea-salt event splits the data from the tributary into two groups. The water chemistry in the confluence zone reflects both the ice-covered period, the sea-salt event and besides the more general situation. The PCA analysis indicates that the changing weather conditions mainly influenced on the water quality in the tributary. The water quality in the confluence zone was generally a conservative mixture of the outlet and the tributary waters except for alkalinity, H+ and inorganic aluminium (Ali). Generally, hydrolysing Ali in the confluence rendered the water quality highly toxic to fish. The potential toxicity increased during the sea-salt event and during the ice-covered period of the lake due to increased concentrations of Ali both in the outlet and the tributary waters. The results indicate that this may be a general problem in confluence zones downstream limestone treated lakes and acid tributaries.

• Larsen, Tine Lise; Nilsen, Valentina; Andersen, Dag Olav; Francis, George; Rustad, Pål & Mansoor, Mohammad Azam (2009). Reply to: On the importance of the use of proper approaches for comparison of analytical methods for serum nitrate and evaluation of reference concentrations. By Dr. Dimitrios Tsikas and Dr. Jens M Hohlfeld. Clinical Biochemistry. ISSN 0009-9120. 42(10.nov), s. 1197–119.
• Larsen, Tine Lise; Nilsen, Valentina; Andersen, Dag Olav; Francis, George; Rustad, Pål & Mansoor, Mohammad Azam (2008). Comparison of high-pressure liquid chromatography (HPLC) and Griess reagent-spectroscopic methods for the measurement of nitrate in serum from healthy individuals in the Nordic countries. Clinical Biochemistry. ISSN 0009-9120. 41(18), s. 1474–1481. Vis sammendrag

  Objectives Bioavailability of NO can be estimated by measuring the concentration of nitrate (NO3) in serum. However, the methods used for the measurement NO3 in plasma or serum show a great degree of variation. Therefore, we compared two analytical methods for the measurement of NO3 in serum. Design and methods The concentration of NO3 in 600 serum samples collected from healthy individuals was determined by the HPLC and by the Griess reagent-spectroscopic method. Results The concentration of NO3 in the samples was 29.4 ± 16.1 _mmol/L and 26.2 ±4.0 _mmol/L (mean ± SD) measured by HPLC and Griess reagent-spectroscpc method respectively (p < 0.0001). We detected a significant correlation between the two methods (R = 0.81, p < 0.0001). Conclusions A significant correlation between the two methods may suggest that either method can be used for the measurement of NO3 in serum, however the Griess reagent-spectroscopic method measures lower concentrations of NO3 than the HPLC method.

• Larsen, Tine Lise; Nilsen, Valentina; Andersen, Dag Olav; Francis, George W; Rustad, Pål & Mansoor, Mohammad Azam (2008). Comparison of high-pressure liquid chromatography (HPLC) and Griess reagent-spectroscopic methods for the measurement of nitrate in serum from healthy individuals in the Nordic countries. Clinical Biochemistry. ISSN 0009-9120. 41(18), s. 1474–1481. doi: 10.1016/j.clinbiochem.2008.08.083.
• Andersen, Dag Olav (2006). Labile aluminium chemistry downstream a limestone treated lake and an acid tributary: Effects of warm winters and extreme rainstorms. Science of the Total Environment. ISSN 0048-9697. 366, s. 739–748. Vis sammendrag

  The outlet from the limestone treated Lake Terjevann consisted mainly of well-mixed lake water (mean pH 6.1) during the ice-free seasons including the unusually warm winters of 1992 and 1993. However, during the ice-covered period acidic water (mean pH 4.8, mean inorganic aluminium (Al-i) about 160 mu g/l) from the catchment draining under the lake ice dominated. A downstream tributary was generally acid and rich in aluminium (mean pH 4.6, Al-i about 230 mu g/l). After an extreme rainstorm loaded with sea-salts cation exchange in the soil resulted in more than a doubling of the Ali concentration (reaching about 500 mu g/l). It took 3-4 months until the Ali concentration returned to pre-event levels. During the ice-covered period, the acidic outlet and tributary waters resulted in acidic conditions below the confluence (pH < 4.8, Al-i about 150 mu g/l) while during the ice-free periods the more neutral outlet water resulted in higher pH and lower Al-i concentrations (pH > 5.2, Al-i about 95 mu g/l). However, during the latter climatic conditions the water was most probably more harmful to fish due to hydrolysing and polymerizing aluminium. After the sea-salt event, the increased Ali concentration in the tributary made the zone below the confluence potentially more toxic (PH similar to 5, Al-i similar to 250 mu g/l). Expected global warming resulting in winter mean temperatures above 0 degrees C may eliminate the seasonal acidification of the outlet from limestone-treated lakes creating permanent toxic mixing zones in the confluence below acidic aluminium-rich tributaries. Besides, more frequent rainstorms as a consequence of global warming may increase the frequency of sea-salt events and the Ali concentrations in the mixing zones. (c) 2005 Elsevier B.V. All rights reserved.

• Larsen, Jorunn; Paasche, Øyvind; Andersen, Dag Olav; Bjune, Anne Elisabeth & De la Riva Caballero, Argutitxu (2006). Sedimentary diatom assemblages in a small alpine west Norwegian lake: evidence for metal release and precipitation? I Withowski, Andrzej (Red.), Proceedings of the 18th International Diatom Symposium - Miedzyzdroje, Poland, 2nd-7th September, 2004. Andrzej Withowski. ISSN 0-948737-75-1. s. 221–234.
• Debska, Bozena; Drag, Malgorzata & Andersen, Dag Olav (2005). Properties of organic matter and molecular size distribution of humic acids isolated from forest soil. ?. 692, s. 19–28.
• vogelsang, c; Andersen, Dag Olav; hey, a; Håkonsen, Tor; Jantsch, tg & müller, ed [Vis alle 8 forfattere av denne artikkelen] (2004). Removal of humic substances by chitosan. ?. 4(05.jun), s. 121–129.
• Vogt, R.D.; Akkanen, Jarkko & Andersen, Dag Olav (2004). Key site variables governing the functional characteristics of dissolved natural organic matter (DNOM) in Nordic forested catchments. Aquatic Sciences. ISSN 1015-1621. 66, s. 195–210.
• Vogt, Rolf David; Akkanen, Jarkko; Andersen, Dag Olav; Bruggemann, R; Chatterjee, B & Gjessing, Egil [Vis alle 15 forfattere av denne artikkelen] (2004). Key site variables governing the functional characteristics of Dissolved Natural Organic Matter (DNOM) in Nordic forested catchments. Aquatic Sciences. ISSN 1015-1621. 66, s. 195–210. Vis sammendrag

  The objective of this study was to extract and evaluate key catchment characteristics explaining the main variation in the properties of Dissolved Natural Organic Matter (DNOM) in the surface water draining the sites. A number of classical and sophisticated DNOM characterisation methodologies were used for this purpose. The explanatory capability of site characteristics on the variation in descriptors of DNOM, including elemental analysis (EA), DOC fractionation, SEC, CZE, CGE, UV/Vis- and FTIR spectra, FES, TLS, ESR, ESI/MS, 13C-CPMAS-NMR, potentiometric pH titration as well as functional characteristics as biodegradability, response of macrophyte and PAH partitioning coefficient were evaluated. The sampling sites are all natural, coniferous, heathery-forested sites with bogs forming a climatic, anthropogenic deposition and proportional biotope cover gradient. Correlations to the main principal components, as well as a correlation matrix, singled out total S-deposition as the key explanatory site parameters, accounting for most of the variation in the DNOM descriptors. Other significant factors were H+ concentration, length of growing season, biotope coverage (i.e. peatland/ or lake/watershed ratio), site elevation and the TOC concentration. The total S-deposition was strongly negatively correlated to the molecular weight, aromaticity, carboxylic acidity and sorption capacity of PAH. The greater the proportion of lake and histosol biotopes of the sampling sites the greater the aliphatic character of the DNOM. Clustering in PCA of samples from the same site sampled in spring and fall implied a basic site-specific DNOM quality and a weak season effect. The Hasse diagram technique (a method of partial order theory) is used to show, for instance, how the relative histosol coverage may determine NOM quality and, in turn, how this coincides with high macrophyte response.

• Andersen, Dag Olav (2003). Impacts of warm winters and extreme rainstorms on the base consumption in a limed lake, southern Norway. The Science of the Total Envinronment. 313, s. 127–139.
• Andersen, Dag Olav & Gjessing, Egil (2002). Natural organic matter (NOM) in a limed lake and its tributaries. Water Research. ISSN 0043-1354. 36, s. 2372–2382.
• Andersen, Dag Olav; Alberts, JJ & Takacs, Monica (2000). Nature of natural organic matter (NOM) in acidified and limed surface waters. Water Research. ISSN 0043-1354. 34.
• Andersen, Dag Olav (2000). Dissolved oxygen concentration in stream waters draining the catchment of Lake Terjevann, SE Norway. ?. 27, s. 3125–3128.
• Andersen, Dag Olav; Alberts, James J. & Takács, Monika (2000). Nature of natural organic matter (NOM) in acidified and limed surface waters. Water Research. ISSN 0043-1354. 34(1), s. 266–278.
• Andersen, Dag Olav & Seip, Hans Martin (1999). Effects of a rainstorm high in sea-salts on labile inorganic aluminium in drainage from the acidified catchments of Lake Terjevann, southernmost Norway. Journal of Hydrology. ISSN 0022-1694. 224, s. 64–79.
• Andersen, Dag Olav & Pempkowiak, J (1999). Sediment content of metals before and after lake water liming. Science of the Total Environment. ISSN 0048-9697. 243/244.
• Andersen, Dag Olav & Seip, H.M. (1999). Effects of a rainstorm high in sea-salts on labile inorganic aluminium in drainage from the acidified catchments of Lake Terjevann, southernmost Norway. Journal of Hydrology. ISSN 0022-1694. 224.
• Andersen, Dag Olav & Pempkowiak, Janusz (1999). Sediment content of metals before and after lake water liming. The Science of the Total Envinronment. 243-244, s. 107–118.
• Andersen, Dag Olav & Seip, Hans Martin (1999). Effect of a rainstorm high in sea-salts on labile inorganic aluminium in drainage from the acidified catchments of Lake Terjevann, southermost Norway. Journal of Hydrology. ISSN 0022-1694. 224, s. 64–79.
• Alberts, James. J.; Andersen, Dag Olav & Takács, Monika (1998). Effect of lime additions to lake water on natural organic matter (NOM) in Lake Terjevann, SE Norway: FTIR and fluorescence spectral changes, Humic Substances: Structures, properties and uses. The Royal Society of Chemistry. s. 123–132.
• Mulder, Jan; Christophersen, Nils; Hauhs, Michael; Vogt, R.D.; Andersen, Sjur & Andersen, Dag Olav (1990). Water flow paths and hydrochemical controls in the Birkenes catchment as inferred from a rainstorm high in seasalts. Water Resources Research. ISSN 0043-1397. 26, s. 611–622.
• Vogt, Rolf David; Andersen, Dag Olav; Andersen, Sjur; Christophersen, Nils Damm & Mulder, Jan (1990). Streamwater, soil-water chemistry, and water flow paths at Birkenes during a dry-wet hydrological cycle. I Mason, B.J. (Red.), The surface water acidification programme. Cambridge University Press. ISSN 0-521-39533-X. s. 149–154.
• Seip, H.M.; Andersen, Dag Olav; Christophersen, Nils; Sullivan, TJ & Vogt, R.D. (1989). Variations in concentrations of aqueous aluminium and other chemical species during hydrological episodes at Birkenes, southernmost Norway. Journal of Hydrology. ISSN 0022-1694. 108.
• Seip, Hans Martin; Andersen, Dag Olav; Christophersen, Nils; Sullivan, T.J & Vogt, Rolf D. (1989). Variations in concentrations of aqueous aluminium and other chemical species during hydrological episodes at Birkenes, southernmost Norway. Journal of Hydrology. ISSN 0022-1694. 108, s. 387–405.

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• Andersen, Dag Olav (2011). Advances in studies of the interaction between dissolved natural organic matter and hydrophobic organic contaminants.
• Andersen, Dag Olav (2010). Nobelprisen i kjemi 2010 Richard F. Heck, Ei-ichi Negishi og Akira Suzuki.
• Andersen, Dag Olav (2009). Correlation between drainage water colour and hydrologic variability in the catchments of Lake Terjevann, southernmost Norway.
• Larsen, Tine Lise; Nilsen, Valentina; Andersen, Dag Olav; Mansoor, Mohammad Azam; Francis, George W & Rustad, P (2009). Reply to: On the importance of the use of proper approaches for comparison of analytical methods for serum nitrate and evaluation of reference concentrations. By Dr. Dimitrios Tsikas and Dr. Jens M Hohlfeld. Clinical Biochemistry. ISSN 0009-9120. 42(10-11), s. 1197–1199. doi: 10.1016/j.clinbiochem.2009.03.014.
• Larsen, Jorunn; Paasche, Øyvind; Andersen, Dag Olav; Bjune, Anne E. & Caballero, Arguitxu (2004). Sedimentary diatom assemblages in a small alpine west Norwegian lake: evidence for metal release and precipitation.
• Pedersen, Morten André & Andersen, Dag Olav (2003). Seasonal variability in the reactivity of natural organic matter to UV-irradiation.
• Andersen, Dag Olav (2003). Climate change: effects of sea salts on natural organic matter (NOM) in drainage from catchments.
• Vogt, Rolf David; Akkanen, Jussi; Andersen, Dag Olav; Chatterjee, B; Gjessing, Egil & Kukkonen, Jussi [Vis alle 14 forfattere av denne artikkelen] (2003). Key variables governing the functional characteristics of Dissolved NOM.
• Vogt, Rolf David; Andersen, Dag Olav; Blaser, Peter; Luster, Jörg & Gjessing, Egil T. (2002). Empiric Relationships between Key Site Characteristics and the Collective Properties and measured Structural Characteristics of Dissolved Natural Organic Matter. Vis sammendrag

  The physicochemical functional characteristics of a combined data set of 10 + 8 RO isolates from the Nordic countries were correlated with their structural characteristics as well as to key catchment characteristics. These correlations indicate that as the S-deposition is decreasing we should expect relatively more TOC and more Hydrophobic character of the DNOM. Furthermore, lake size or lake/watershed ratio and possibly elevation are key site parameters describing DNOM characteristics. The TOC concentration is a key chemical parameter in describing DNOM characteristics though there may be a concentration artefact on quality parameters.

• Vogt, Rolf David; Andersen, Dag Olav; Bishop, Kevin; Clarke, Nicholas; Gadmar, Tone Charlotte & Gjessing, Egil T. [Vis alle 8 forfattere av denne artikkelen] (2001). Natural organic matter in the Nordic countries: Characterisation of Sampling sites and Reverse osmosis Isolates of DOM. Vis sammendrag

  The main tasks of the NOMiNiC project (Natural Organic Matter in the Nordic countries; see http://www.kjemi.uio.no/envir/nominic/) is to study the physiochemical characteristics of dissolved organic matter (DOM) and provide reverse osmosis (RO) spring and fall isolates of surface water natural organic matter (NOM) from 5 Nordic forested sites that differ mainly in atmospheric S-loading and climate. Hydrophobic and hydrophilic fractions are hypothesized to be more easily defined and have distinct different chemical characteristics than the total sample. A XAD-8 fractionation may then be used as a simple proxy for the physico-chemical properties of NOM. Both XAD-8 fractions and the total DOM sample have been base and metal titrated. Enhanced understanding of the significance of the numerous operationally defined parameters describing NOM will be achieved through a common multi-dimensional characterisation of the same set of isolates, that span a large spectre of the variation found in DOM. 7 institutes are already collaborating in characterizing the RO isolates using a large range of techniques and new participants are invited. In this presentation the 5 sampling sites are described and some results of the characterisation of the RO isolates are presented

• Krogstad, Tore; Andersen, Dag Olav & Becher, Georg (2000). The influence of vegetation types on the C and N content in soil organic matter.
• Riise, Gunnhild; van Hees, Patrick; Lundström, Ulla; Strand, Line Tau; Andersen, Dag Olav & Becher, Georg (2000). Mobility of different size fractions og organic carbon, Al, Fe, Mn and Si in Podzols. Vis sammendrag

  In order to study dynamic processes in soils non-disturbing separation techniques, such as centrifugation and filtration methods, are particularly suitable. To obtain new insight into translocation processes occurring in podzol profiles, soil water from fresh soil samples from three locations have been collected by centrifugation. The soil water was filtered prior to size fractionation by ultramembrane techniques. Emphasis has been placed on the colloidal size fraction, as a major part of the OC occurs in the colloidal fractions and the colloids may represent transitional states between solid and aqueous phases and can also be important transporting agents for metals.. The colloidal fraction comprises a large proportion of dissolved organic carbon (DOC) in the O and the E horizon, while the proportion of low molecular DOC fractions increase with depth. A major part of Fe and Al seems to be associated with the colloidal fraction of DOC in the O horizon. In the mineral soil, however, Fe and Al follow a different size distribution pattern from organic carbon. Maximum concentrations of Si, Al and Fe are found in

• Vogt, Rolf David; Andersen, Dag Olav; Bishop, Kevin; Clarke, Nicholas; Gadmar, Tone Charlotte & Gjessing, Egil T. [Vis alle 9 forfattere av denne artikkelen] (2000). NOM in the Nordic countries. Vis sammendrag

  The project will provide valuable insight into data and method comparison through the "multi-dimensional" NOM characterisation of the same set of material. The results confirm that the selected sites and water sample types (i.e. throughfall, soilwater and surface water) provide the span in chemistry that is required to detect possible correlations between the physicochemical characteristics of the NOM and factors as S-deposition and climate.

• Vogt, Rolf David; Andersen, Dag Olav; Bishop, Kevin; Gadmar, Tone Charlotte; Gjessing, Egil T. & Kitunen, Veikko [Vis alle 11 forfattere av denne artikkelen] (1999). Fractionation and characterisation of NOM in the Nordic countries. Vis sammendrag

  A. Conduct a Nordic intercalibration of dissolved organic carbon (DOC) in natural organic matter (NOM) using high temperature catalytic combustion. B. Study the physiochemical properties of NOM fractions from similar sites that differ in S-loading and climate. (A) There exists to our knowledge no standard operational procedure for the determination of DOC in NOM using high temperature catalytic combustion. This is a problem since different results may emerge depending on how the analysis is conducted on the partly very refractory NOM. Furthermore, there is a lack of documentation of the inter-laboratory analytical merits using the high temperature catalytic combustion method. (B) It is well known that the amount and quality of NOM are strongly influenced by acid rain and seasonal variations in climate. Most conceptually based prediction models for soil/soilwater interactions lack consideration of the organic component. This is mainly due to deficiency of knowledge and understanding of the physiochemical characteristics of NOM as well as its highly inhomogeneous character. Our hypothesis is that the relative fraction of hydrophobic acids (HPO-A) will change due to the decrease in acid rain and change in climate. This is important since HPO-A is a relatively stronger acid and a complex metals more strongly then the other fractions.

• Andersen, Dag Olav (2002). Chemistry of a limed lake and its tributaries - Potential impacts of climate change. Unipub forlag.
• Vogt, Rolf David; Andersen, Dag Olav; Bishop, Kevin; Clarke, Nicholas; Gadmar, Tone Charlotte & Gjessing, Egil T. [Vis alle 8 forfattere av denne artikkelen] (2001). Natural organic matter in the Nordic Countries (NOMiNiC): 1. TOC intercalibration 2. Physico-chemical characteristics of DOM. NordTest. ISSN 0283-7234. Vis sammendrag

  This report consists of to parts: 1. DOM intercalibration. 25 chemical laboratories in the Nordic countries determined the amount of organic and inorganic carbon in a set of 10 samples that included natural and synthetic fresh and isolated sample material. The results have been statistically interpreted by means of e.g. Youlden analysis. 2. Physico-chemical characterisation of Nordic DOM. DOM in spring and fall precipitation, throughfall, soil water and surface water from 5 Nordic sites has been determined for their main physical and chemical characteristics. DOM in surface waters have been reverse osmosis isolated and are being determined for numerous characteristics. The largest variation in the characteristics of DOM is between seasons and between the various water compartments in a site.

• Vogt, Rolf David; Andersen, Dag Olav; Bishop, Kevin; Clarke, Nicholas; Gadmar, Tone Charlotte & Gjessing, Egil T. [Vis alle 15 forfattere av denne artikkelen] (1999). Characterisation of Natural disoolved organic material (NOM) in the Nordic countries. Universitetet i Oslo. Vis sammendrag

  See: http://www.kjemi.uio.no/envir/nominic/mid-term-report/mid-term-report.htm

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