Arsenic speciation in marine organisms from Antarctic coastal environments

Antarctic coastal environments offer the unique opportunity to study elemental cycling under pristine conditions. We report arsenic species in various tissues from a range of Antarctic organisms collected from coastal environments, and compare our results with those from similar studies in temperate and tropical waters. The arsenic species were determined in aqueous methanol extracts of tissues (including muscle, liver, gonads and spleen) by HPLC/ICPMS. The major compounds were arsenobetaine and oxo-arsenosugars, with their relative proportions depending on the position of the organism in the food chain and, for some species, on the type of tissue analysed. Several minor compounds, such as dimethylarsinate, trimethylarsine oxide, trimethylarsoniopropionate and arsenocholine were also found; the concentrations of these arsenic species were significantly lower in muscle compared with the other tissues. The transfer of the arsenic through the Antarctic marine food web and the speciation patterns found in the organisms were similar to those reported for comparable organisms from other marine ecosystems. Our study supports the view that the high levels of arsenic occurring in various forms in marine samples is a natural phenomenon, and is little influenced by anthropogenic activities.