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Differences in the bioaccumulation of selenium by two earthworm species (Pheretima guillemi and Eisenia fetida)
- Xiao, Kongcao, Song, Min, Liu, Jing, Chen, Hao, Li, Dejun, Wang, Kelin
- Chemosphere 2018 v.202 pp. 560-566
- Eisenia fetida, Pheretima, bioaccumulation factor, earthworms, selenium, soil, weight loss
- Information on the bioaccumulation of selenium (Se) in soil invertebrates (e.g. earthworms) is rather scarce. In the present study, bioaccumulation of Se in two eco-physiologically different earthworms, namely anecic Pheretima guillemi and epigeic Eisenia fetida, was determined after 28 days exposure to a successive doses of Se-spiked soil, specifically 0.5, 5, 50, and 200 μg Se g−1 soil. The results showed that Se concentration in earthworms elevated with increasing exposure levels, and maximums were up to 54.6 and 83.0 μg g−1 dry weight in Pheretima guillemi and Eisenia fetida, respectively, after 4 weeks exposure to 200 μg Se g−1 soil. Exposure to Se caused significant inhibition on earthworm growth, with the fresh weight loss ranging from 8.9% to 80.5%. Bioaccumulation factors (BAFs), empirically-derived and non-steady state, ranged from 0.12 to 4.17 and generally declined at higher exposure levels. Moreover, BAFs of Pheretima guillemi were higher than those of Eisenia fetida in low-dose Se-spiked soils, but the opposite was true in high-dose soils, indicating there is a species-specific response to exposure of Se between different earthworms. Further research is thus needed to reveal the accumulation pattern of Se in a wider range of earthworm species other than Eisenia fetida, which allows a better risk assessment of excessive Se to soil invertebrates and higher order organisms.