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Biotic interactions modify the transfer of cesium‐137 in a soil‐earthworm‐plant‐snail food web
Author(s) -
Fritsch Clémentine,
Scheifler Renaud,
BeaugelinSeiller Karine,
Hubert Philippe,
Cœurdassier Michaël,
de Vaufleury Annette,
Badot PierreMarie
Publication year - 2008
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-416.1
Subject(s) - earthworm , food web , snail , environmental science , soil food web , ecology , food chain , soil biology , environmental chemistry , biology , soil water , chemistry , trophic level
Abstract The present study investigated the possible influence of the earthworm Aporrectodea tuberculata on the transfer of cesium‐137 ( 137 Cs) from a contaminated (130 Bq/kg) deciduous forest soil to the lettuce Lactuca sativa and to the snail Cantareus aspersus (formerly Helix aspersa ) in two laboratory experiments. In the first experiment, the International Organization for Standardization 15952 test was used to expose snails for five weeks to contaminated soil with or without earthworms. In these conditions, the presence of earthworms caused a two‐ to threefold increase in 137 Cs concentrations in snails. Transfer was low in earthworms as well as in snails, with transfer factors (TFs) lower than 3.7 × 10 −2 . Activity concentrations were higher in earthworms (2.8–4.8 Bq/kg dry mass) than in snails (<1.5 Bq/kg). In the second experiment, microcosms were used to determine the contribution of soil and lettuce in the accumulation of 137 Cs in snails. Results suggest that the contribution of lettuce and soil is 80 and 20%, respectively. Microcosms also were used to study the influence of earthworms on 137 Cs accumulation in snail tissues in the most ecologically relevant treatment (soil‐earthworm‐plant‐snail food web). In this case, soil‐to‐plant transfer was high, with a TF of 0.8, and was not significantly modified by earthworms. Conversely, soil‐to‐snail transfer was lower (TF, ˜0.1) but was significantly increased in presence of earthworms. Dose rates were determined in the microcosm study with the EDEN (elementary dose evaluation for natural environment) model. Dose rates were lower than 5.5 × 10 −4 mGy/d, far from values considered to have effects on terrestrial organisms (1 mGy/d).