Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 110-122 |
| Journal | Journal of Environmental Radioactivity |
| Volume | 143 |
| DOIs | |
| Publication status | Published - 2015 |
| MoE publication type | A1 Journal article-refereed |
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Keywords
- sorption
- radioiodides
- peat
- microbes
- bacteria
- radionuclides
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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 journal › Article › Scientific › peer-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 -