Sorption of radioiodide in an acidic nutrient-poor boreal bog

Insights into the microbial impact

M. Lusa (Corresponding Author), M. Bomberg, H. Aromaa, J. Knuutinen, J. Lehto

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ~4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20°C, and with the bacterial cell counts obtained from plate count agar at +4°C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.
Original languageEnglish
Pages (from-to)110-122
JournalJournal of Environmental Radioactivity
Volume143
DOIs
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

Fingerprint

Wetlands
Iodides
bog
iodide
Nutrients
Sorption
sorption
gyttja
Sphagnopsida
Food
moss
Peat
nutrient
Biological materials
peat
Bryophyta
organic matter
Clay
clay
Weights and Measures

Keywords

  • sorption
  • radioiodides
  • peat
  • microbes
  • bacteria
  • radionuclides

Cite this

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title = "Sorption of radioiodide in an acidic nutrient-poor boreal bog: Insights into the microbial impact",
abstract = "Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97{\%}), maximum sorption was observed at a pH between ~4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20°C, and with the bacterial cell counts obtained from plate count agar at +4°C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.",
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journal = "Journal of Environmental Radioactivity",
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Sorption of radioiodide in an acidic nutrient-poor boreal bog : Insights into the microbial impact. / Lusa, M. (Corresponding Author); Bomberg, M.; Aromaa, H.; Knuutinen, J.; Lehto, J.

In: Journal of Environmental Radioactivity, Vol. 143, 2015, p. 110-122.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Sorption of radioiodide in an acidic nutrient-poor boreal bog

T2 - Insights into the microbial impact

AU - Lusa, M.

AU - Bomberg, M.

AU - Aromaa, H.

AU - Knuutinen, J.

AU - Lehto, J.

PY - 2015

Y1 - 2015

N2 - Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ~4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20°C, and with the bacterial cell counts obtained from plate count agar at +4°C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.

AB - Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ~4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20°C, and with the bacterial cell counts obtained from plate count agar at +4°C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.

KW - sorption

KW - radioiodides

KW - peat

KW - microbes

KW - bacteria

KW - radionuclides

U2 - 10.1016/j.jenvrad.2015.02.022

DO - 10.1016/j.jenvrad.2015.02.022

M3 - Article

VL - 143

SP - 110

EP - 122

JO - Journal of Environmental Radioactivity

JF - Journal of Environmental Radioactivity

SN - 0265-931X

ER -