Change search
ReferencesLink to record
Permanent link

Direct link
Fate and transport of POPs in the aquatic environment: with focus on contaminated sediments
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Persistent organic pollutants (POPs) are hydrophobic substances that readily sorb to organic matter in particles and colloids instead of being freely dissolved in the water phase. This sorption affects the bio­availability and environmental transport of the POPs. The major part of this thesis concerns the role of sediments as secondary sources of POPs. As the primary emissions decrease, contaminated sediments where POPs have accumulated can become the main source of contamination. If the contaminated sediment by time becomes covered with cleaner layers, the POPs are buried and no longer in contact with the aquatic environment. Experiments in this thesis showed, however, that new invading species can alter the sediment-water dynamics as a result of their bioturbation, i.e. mixing of sediment particles and pore-water. Marenzelleria spp., invading species in the Baltic Sea that burrow deeper than native species, were found to increase the remobilization of buried contaminants. The sediment-to-water flux was inversely related to the burial depth (2-10 cm) of the POP congeners (polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers) and also inversely related to the hydrophobicity of the congener. The flux was therefore most pronounced for less hydrophobic contaminants, which was linked to the bioirrigating behaviour of these species. Marenzelleria spp. also accumulated the buried POPs and increased concentrations in surface sedi­ment. Contaminants previously considered buried at a ’safe’ depth can thus be remobilized as a result of the invasion of Marenzelleria spp. in the Baltic Sea.

One method to decrease the remobilization of contaminants from sediments is ’capping’, i.e. a layer of clean material is placed as a cap on the sediment. By amending the cap with active materials, which sequester the POPs and decrease their availability, thinner layers can be used (’active capping’ or ’thin-layer capping’). Results from an experiment with thin-layer capping using different active materials (activated carbon (AC) and kraft lignin) showed that both the sediment-to-water flux and the bioaccumulation by benthic species of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), hexachlorobenzene (HCB) and octachlorostyrene (OCS) decreased with increased thick­ness of the cap layer (0.5-5 cm). Amendments with active materials further increased the cap efficiency. AC was more efficient than kraft lignin, and a 3 cm cap with 3.3% AC reduced the flux and bioaccumulation with ~90%. The reduction of the sediment-to-water flux was inversely related to the hydrophobicity of the POP, and reductions in the flux had similar magnitudes as reductions in the concentration in deep-burrowing polychaetes, demonstrating the importance of bioturbation for sediment-to-water transport.

In a one-year study on the levels of PCDD/Fs, PCBs, and HCB in a coastal area of the Baltic Sea, the correlations between the POP levels and the levels of particles and organic carbon in the water were found to differ for POPs of different structure and hydrophobicity. The levels of PCDD/Fs decreased to one third in May, which could be related to the increased sedimentation, i.e. water-to-sediment transport, during spring bloom.

Place, publisher, year, edition, pages
Umeå: Kemiska institutionen , 2011. , 65 p.
Keyword [en]
bioturbation, bioirrigation, bioaccumulation, secondary sources, buried contaminants, sediment remediation, active capping, thin-layer capping, Marenzelleria spp., Baltic Sea, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, hexachlorobenzene, octachloro¬styrene, polybrominated diphenyl ethers, PCDD/Fs, PCBs, HCB, OCS, PBDEs, water sampling, passive sampling, particulate fraction, freely dissolved, apparently dissolved, colloid, organic carbon, activated carbon, lignin, sediment-to-water flux, spring bloom
National Category
Chemical Sciences
Research subject
biology, Environmental Science
Identifiers
URN: urn:nbn:se:umu:diva-42107ISBN: 978-91-7459-179-8OAI: oai:DiVA.org:umu-42107DiVA: diva2:408617
Public defence
2011-05-06, KB3B1, KBC-huset, Linnaeus väg 6, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2011-04-15 Created: 2011-04-05 Last updated: 2011-09-30Bibliographically approved
List of papers
1. Structure-related distribution of PCDD/Fs, PCBs and HCB in a river-sea system
Open this publication in new window or tab >>Structure-related distribution of PCDD/Fs, PCBs and HCB in a river-sea system
Show others...
2011 (English)In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 83, no 2, 85-94 p.Article in journal (Refereed) Published
Abstract [en]

Water concentrations of PCDD/Fs, HCB, and non-ortho, mono-ortho, and non-dioxin-like PCBs were measured four times during 1year in a coastal area of the Baltic Sea, to investigate background levels and distribution behaviour. Sampling sites included two rivers, an estuary, and the sea. Particulate and apparently dissolved concentrations were determined using active sampling (filters+PUFs), while freely dissolved concentrations were determined using passive sampling (POM-samplers). The distribution between particulate+colloidal and freely dissolved phases, in the form of TOC-normalized distribution ratios (K(TOC)), was found to be near or at equilibrium. The observed K(TOC) were not significantly different between sampling sites or seasons. For PCDD/Fs, the concentrations were significantly correlated to suspended particulate matter (SPM), while no correlation to organic carbon (TOC) was observed. In the estuary and the sea, PCB concentrations were correlated to TOC. The sorption of various congeners to SPM and TOC appeared to be related to both hydrophobicity and 3D-structure. The PCDD/F concentration in the sea decreased to one third in May, likely connected to the increased vertical flux of particles during the spring bloom.

Place, publisher, year, edition, pages
Elsevier Ltd, 2011
Keyword
Organic carbon, Particulate matter, HOC, Spring bloom, Baltic Sea
Identifiers
urn:nbn:se:umu:diva-39986 (URN)10.1016/j.chemosphere.2011.01.019 (DOI)21296376 (PubMedID)
Available from: 2011-03-03 Created: 2011-02-14 Last updated: 2011-04-15Bibliographically approved
2. Bioturbation-driven release of buried PCBs and PBDEs from different depths in contaminated sediments
Open this publication in new window or tab >>Bioturbation-driven release of buried PCBs and PBDEs from different depths in contaminated sediments
2010 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 44, no 19, 7456-64 p.Article in journal (Refereed) Published
Abstract [en]

Bioturbation can remobilize previously buried contaminants, leading to an increased exposure of aquatic biota. The remobilization of buried polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) from three different sediment depth layers (2.0-2.5 cm, 5.0-5.5 cm, and 10.0-10.5 cm) was studied in a laboratory experiment with two benthic macrofauna species, the amphipod Monoporeia affinis and the polychaete Marenzelleria spp. Remobilization of PCBs and PBDEs was significantly higher in the presence of Marenzelleria spp. than in M. affinis treatments and controls (without macrofauna). The highest remobilization occurred from the most shallow layers (2.0-2.5 cm > 5.0-5.5 cm > 10.0-10.5 cm), but contaminants were remobilized due to bioturbation from layers down to at least 10 cm. Congeners with lower hydrophobicity were remobilized to a higher extent than more hydrophobic congeners. The contaminant distribution between the particulate and the dissolved phase in the water column depended on hydrophobicity and burial depth of the contaminant, with congeners from deeper layers displaying an increased distribution to the particulate phase. Release fluxes and sediment-to-water mass transfer coefficients (MTCs) show that bioturbation by the polychaete Marenzelleria spp. can lead to a significant remobilization of buried contaminants from Baltic Sea sediments.

Place, publisher, year, edition, pages
American Chemical Society, 2010
Keyword
Marenzelleria-Viridis Polychaeta, Water Partition-Coefficients, Baltic Sea Sediments, Monoporeia-Affinis, Marine-Sediments, Organic-Matter, Polychlorinated Biphenyl, Congener Distributions
Identifiers
urn:nbn:se:umu:diva-37433 (URN)10.1021/es100615g (DOI)000282209700046 ()20831254 (PubMedID)
Available from: 2010-11-03 Created: 2010-11-03 Last updated: 2011-04-15Bibliographically approved
3. Influence of contaminant burial depth on the bioaccumulation of PCBs and PBDEs by two benthic invertebrates (Monoporeia affinis and Marenzelleria spp.)
Open this publication in new window or tab >>Influence of contaminant burial depth on the bioaccumulation of PCBs and PBDEs by two benthic invertebrates (Monoporeia affinis and Marenzelleria spp.)
2011 (English)In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 85, no 9, 1444-1451 p.Article in journal (Refereed) Published
Abstract [en]

The bioaccumulation of buried polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) added to specific depths in sediment (2.0-2.5, 5.0-5.5 and 10.0-10.5cm) was studied in two infaunal species with similar feeding habits (surface deposit-feeders) but different bioturbation modes. The deep-burrowing polychaetes Marenzelleria spp. (Mz) displayed up to 36 times higher tissue concentrations of buried (spiked) contaminants than the surface-dwelling biodiffusing amphipod Monoporeia affinis. The differences in bioaccumulation were most pronounced for less hydrophobic contaminants due to the bioirrigating activity of Mz. Contaminants buried at shallow depths displayed higher accumulation than more deeply buried contaminants. In contrast, the bioaccumulation of unspiked (native) contaminants with a uniform vertical distribution in the sediment was similar between the species. For Mz, the BSAFs increased with increased K(OW) for the uniformly distributed contaminants, but decreased for the buried contaminants, which indicates that the dominant uptake routes of the buried contaminants can differ from the uniformly distributed contaminants. The surface sediment concentration of buried contaminants increased in Mz treatments, showing that Mz bioturbation can remobilize historically buried contaminants to the biologically active surface layer and increase the exposure for surface-dwelling species.

Place, publisher, year, edition, pages
Elsevier, 2011
Keyword
Bioturbation, BSAFs, sediment pollution, Baltic Sea, invasive species
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-47526 (URN)10.1016/j.chemosphere.2011.08.024 (DOI)21924758 (PubMedID)
Available from: 2011-09-22 Created: 2011-09-22 Last updated: 2011-12-19Bibliographically approved
4. Capping efficiency of various carbonaceous and mineral materials for in situ remediation of marine sediments contaminated with PCDD/Fs, OCS and HCB
Open this publication in new window or tab >>Capping efficiency of various carbonaceous and mineral materials for in situ remediation of marine sediments contaminated with PCDD/Fs, OCS and HCB
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The efficiency of various thin-layer capping materials in reducing the sediment-to-water flux and benthic organism bioaccumulation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), hexachlorobenzene (HCB) and octachlorostyrene (OCS) was investigated in a boxcosm experiment. The influence of cap layer thickness (0.5-5 cm) and different cap materials were tested using a three-factor experimental design. The capping materials consisted of a passive carrier (coarse or fine limestone material, or a marine clay sediment), and an active material (activated carbon (AC) or kraft lignin) to sequester the contaminants and decrease their bioavailability. Macrofauna was added to the boxes to get a semi-natural bioturbation. The sediment-to-water flux was measured using passive (SPMD) samplers, and the bioaccumulation by the surface-dwelling gastropod Hinia reticulata and the deep-burrowing polychaetes Nereis spp. was determined. Results showed substantial decreases in both flux and bioaccumulation as a result of thin-layer capping. The thickness of the capping layer and the choice of active material were important factors, while the use of different types of passive materials was not statistically significant for any of the observed endpoints. Flux and bioaccumulation decreased with increased cap thickness, and could be further decreased with addition of active material. Activated carbon was more efficient than lignin, and a ~90% reduction of the flux and bioaccumulation, compared to uncapped control sediment, could be achieved with 3 cm caps with 3.3% AC (g C/g ww clay). The reduction was generally larger in the surface-dwelling H. reticulata than in Nereis spp., and the magnitude of the reduction was frequently similar between Nereis spp. and sediment-to-water fluxes. The latter was interpreted to indicate a link between Nereis spp. bioirrigation and sediment-to-water fluxes. Furthermore, the reduction in sediment-to-water flux was dependent on the hydrophobicity of the congeners, with less hydrophobic congeners achieving a larger reduction than more hydrophobic congeners.      

Keyword
sediment-to-water fluxes, benthic bioaccumulation, thin-layer capping, cap thickness
National Category
Environmental Sciences Environmental Sciences Other Environmental Engineering
Research subject
biology, Environmental Science
Identifiers
urn:nbn:se:umu:diva-42104 (URN)
Available from: 2011-04-05 Created: 2011-04-05 Last updated: 2011-04-15Bibliographically approved

Open Access in DiVA

fulltext(920 kB)978 downloads
File information
File name FULLTEXT01.pdfFile size 920 kBChecksum SHA-512
68a507847147b9c58851fc479d482b6773410e41cd7597a53fc55785b15c1880517c455af4dfd59c034fc5e8d95c4da598590b8237b99c7b80d4c096500b7b23
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Josefsson, Sarah
By organisation
Department of Chemistry
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 978 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1806 hits
ReferencesLink to record
Permanent link

Direct link