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| Titel |
Halogens in pore water of peat bogs – the role of peat decomposition and dissolved organic matter |
| VerfasserIn |
H. Biester, D. Selimović, S. Hemmerich, M. Petri |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 3, no. 1 ; Nr. 3, no. 1 (2006-01-27), S.53-64 |
| Datensatznummer |
250000730
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| Publikation (Nr.) |
 copernicus.org/bg-3-53-2006.pdf |
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| Zusammenfassung |
| Halogens are strongly enriched in peat and peatlands and such they are one
of their largest active terrestrial reservoir. The enrichment of halogens in
peat is mainly attributed to the formation of organohalogens and
climatically controlled humification processes. However, little is known
about release of halogens from the peat substrate and the distribution of
halogens in the peat pore water. In this study we have investigated the
distribution of chlorine, bromine and iodine in pore water of three pristine
peat bogs located in the Magellanic Moorlands, southern Chile. Peat pore
waters were collected using a sipping technique, which allows in situ sampling down
to a depth greater than 6m. Halogens and halogen species in pore water were
determined by ion-chromatography (IC) (chlorine) and IC-ICP-MS (bromine and
iodine). Results show that halogen concentrations in pore water are 15–30
times higher than in rainwater. Mean concentrations of chlorine, bromine and
iodine in pore water were 7–15 mg l−1, 56–123 μg l−1, and
10–20 μg l−1, which correspond to mean proportions of 10–15%,
1–2.3% and 0.5–2.2% of total concentrations in peat,
respectively. Organobromine and organoiodine were the predominant species in
pore waters, whereas chlorine in pore water was mostly chloride. Advection
and diffusion of halogens were found to be generally low and halogen
concentrations appear to reflect release from the peat substrate. Release of
bromine and iodine from peat depend on the degree of peat degradation,
whereas this relationship is weak for chlorine. Relatively higher release of
bromine and iodine was observed in less degraded peat sections, where the
release of dissolved organic carbon (DOC) was also the most intensive. It
has been concluded that the release of halogenated dissolved organic matter
(DOM) is the predominant mechanism of iodine and bromine release from peat. |
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