Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone.
In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h(-1). These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H'). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h(-1). This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites. This might result from a selection at the expense of sensitive species after the accident.
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex, France. Electronic address: catherine.lecomte-pradines@irsn.fr.
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Lecomte-Pradines
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Bonzom
Magelis, 6, rue Frederic Mistral, 84160 Cadenet, France.
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Della-Vedova
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LM2E, Building 159, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Beaugelin-Seiller
ELISOL Environment, Building 12, Campus de la Gaillarde, 2 place Viala, 34060 Montpellier cedex 2, France.
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Villenave
Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych, Ukraine.
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Gaschak
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, L2BT, Building 186, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Coppin
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, GARM Building 186, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Dubourg
Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych, Ukraine.
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Maksimenko
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Adam-Guillermin
Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, Building 159, Cadarache 13115 Saint Paul lez Durance cedex, France.
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Garnier-Laplace
D000818:Animals; D047852:Chernobyl Nuclear Accident; D017753:Ecosystem; D009348:Nematoda / Q000737:chemistry*; D011834:Radiation Monitoring / Q000379:methods*; D012987:Soil / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
D012987:Soil; D012990:Soil Pollutants, Radioactive
Chernobyl accident; Chronic radiation exposure; Dose rate prediction; Ecological consequences; Nematode assemblages; Radioactive contamination