| Abstrakt: |
Two species of arsenic (As) resistant earthworm, Lumbricus rubellusand Dendrodrillus rubidus, their host soils and soil excretions (casts) were collected from 23 locations at a former As mine in Devon, UK. Total As concentrations, measured by ICP-MS, ranged from 255 to 13,080 mg kg−1in soils, 11 to 877 mg kg−1in earthworms and 284 to 4221 mg kg−1in earthworm casts from a sub-sample of 10 of the 23 investigated sites. The samples were also measured for As speciation using HPLC-ICP-MS to investigate potential As biotransformation pathways. Inorganic arsenate (AsV) and arsenite (AsIII) were the only species detected in the soil. AsVand AsIIIwere also the dominant species found in the earthworms and cast material together with lower proportions of the organic species methylarsonate (MAV), dimethylarsinate (DMAV), arsenobetaine (AB) and three arsenosugars. Whilst the inorganic As content of the earthworms increased with increasing As body burden, the concentration of organic species remained relatively constant. These results suggest that the biotransformation of inorganic arsenic to organic species does not contribute to As resistance in the sampled earthworm populations. Quantification of As speciation in the soil, earthworms and cast material allows a more comprehensive pathway for the formation of AB in earthworms to be elucidated. [ABSTRACT FROM AUTHOR] |
