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Automated method for determination of dissolved organic carbon–water distribution constants of structurally diverse pollutants using pre-equilibrium solid-phase microextraction
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2015 (English)In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 34, no 2, 266-274 p.Article in journal (Refereed) Published
Abstract [en]

Dissolved organic carbon (DOC) plays a key role in determining the environmental fate of semivolatile organic environmental contaminants. The goal of the present study was to develop a method using commercially available hardware to rapidly characterize the sorption properties of DOC in water samples. The resulting method uses negligible-depletion direct immersion solid-phase microextraction (SPME) and gas chromatography–mass spectrometry. Its performance was evaluated using Nordic reference fulvic acid and 40 priority environmental contaminants that cover a wide range of physicochemical properties. Two SPME fibers had to be used to cope with the span of properties, 1 coated with polydimethylsiloxane and 1 coated with polystyrene divinylbenzene polydimethylsiloxane, for nonpolar and semipolar contaminants, respectively. The measured DOC–water distribution constants showed reasonably good reproducibility (standard deviation ≤ 0.32) and good correlation (R2 = 0.80) with log octanol–water partition coefficients for nonpolar persistent organic pollutants. The sample pretreatment is limited to filtration, and the method is easy to adjust to different DOC concentrations. These experiments also utilized the latest SPME automation that largely decreases total cycle time (to 20 min or shorter) and increases sample throughput, which is advantageous in cases when many samples of DOC must be characterized or when the determinations must be performed quickly, for example, to avoid precipitation, aggregation, and other changes of DOC structure and properties. The data generated by this method are valuable as a basis for transport and fate modeling studies.

Place, publisher, year, edition, pages
2015. Vol. 34, no 2, 266-274 p.
Keyword [en]
pre-equilibrium solid-phase microextraction, dissolved organic carbon–water distribution constant, organic contaminant
National Category
Organic Chemistry
URN: urn:nbn:se:umu:diva-98927DOI: 10.1002/etc.2805ISI: 000348994200007PubMedID: 25393710OAI: diva2:784186
Available from: 2015-01-28 Created: 2015-01-28 Last updated: 2015-04-26Bibliographically approved
In thesis
1. Bioavailability of organic contaminants in a changing climate
Open this publication in new window or tab >>Bioavailability of organic contaminants in a changing climate
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The effects of predicted future climate change was investigated with special emphasis on the association of organic contaminants with dissolved organic carbon (DOC) in the Baltic Sea.

An automated method was developed for the measurements of DOC - water distribution constants at realistic DOC concentrations in brackish water. The method proved to be valid for 30 organic contaminants with different structural elements in the 5 – 100 mg car bon/L DOC concentration range. There were limitations of this method. Firstly, its applicability is limited towards contaminants with lower affinity to DOC. Secondly, at higher (>100 mg carbon/L) DOC concentrations the sorption of contaminants was underest imated.

Afterwards, water samples were collected from 15 points within the Baltic Sea in a north - south gradient t o examine the spatial differences in DOC characteristics and sorption properties . The DOC samples were analyzed using proton nuclear magnetic resonance and ultraviolet spectroscopy. Results from both techniques indicated that the aromatic nature of the DOC pool increased towards the northern Baltic Sea. This was expected as the freshwater inflow has high significance in controlling the hydrograp hic conditions in the Bothnian Bay. Sorption of organic contaminants was subsequently measured in the same samples. The results showed decreased sorption from north to south for hydrophobic contaminants such as chlorinated benzenes but for contaminants lik e tributyl - phosphate no spatial tendencies were observed. The data generated was used to determine molecular descriptors of DOC using linear free energy relationships. The results indicated a higher significance of hy drogen bond donor/acceptor functional g roups of the DOC in the south.

Changes in contaminant distribution were simulated in model pelagic ecosystems at possible endpoints predicted by future climate change scenarios. Separate and combined effects of temperature a nd DOC were studied in mesocosms. The results indicated interesting tendencies. Increased temperature resulted in increased losses in the amounts of organic contaminants. Increased DOC levels promoted sedimentation and sorption of contaminants to particulate matter and biota. Hi gher amounts of contaminants were retained. The combined effects of the two factors led to and overall decrease in dissolved amounts. Higher losses or increased sedimentation and sorption to particles were also observed depending on contaminant properties.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2015. 82 p.
climate change, organic contaminants, sorption, dissolved organic carbon, bioavailability
National Category
Analytical Chemistry Environmental Sciences
urn:nbn:se:umu:diva-98828 (URN)978-91-7601-220-8 (ISBN)
Public defence
2015-02-20, Södra Hörsalen, KBC Huset, Umeå, 10:00 (English)
Available from: 2015-01-30 Created: 2015-01-27 Last updated: 2015-02-02Bibliographically approved

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Ripszam, MatyasHaglund, Peter
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