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Abstract:In an attempt to improve the understanding of the natural variability and distribution of trace elements in Antarctic organisms, the concentrations of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, vanadium and zinc in representative benthic species from two pristine coastal environments were measured and compared with literature data for other uncontaminated coastal ecosystems. Correlations between the elements, differences between the species and between the sampling sites were examined by principal component analysis. Metal accumulation was particularly evident in the tissues of the sea star Odontaster validus, the bivalve mollusc Laternula elliptica and in the red alga Phyllophora antarctica. However, metal accumulation was not the same for all the analytes, but, rather, depended on the organism characteristics. In particular, the soft tissues of Odontaster validus were characterized by high concentrations of cadmium, zinc and copper, those of Phyllophora antarctica by high concentrations of manganese and nickel, and the tissues of Laternula elliptica by high concentrations of all measured elements, particularly in its digestive gland. The Antarctic data as well as those reported for other pristine coastal ecosystems showed remarkably high natural variability in metal content, which must be taken into account when interpreting results from biomonitoring programmes.

A procedure for the simultaneous determination of arsenic, selenium and mercury in foodstuffs has been developed. After a two‐step microwave‐assisted wet digestion in closed vessels, using concentrated nitric acid and hydrogen peroxide, the solution was analysed by inductively coupled plasma multichannel‐based emission spectrometry using chemical vapour generation as the sample introduction system. All steps of the procedure, such as solid sample dissolution, pre‐reduction to the suitable oxidation state, vapor generation, transport and atomization have been designed and optimised taking into account the concomitant presence of all the analytes considered. Temporal variation of analytical signals as well as interfering effects due to transition elements were also studied. Under the optimised operating conditions, the achieved detection limits for the simultaneous determination of arsenic, selenium and mercury in foodstuffs were 0.006, 0.023 and 0.018 μg g−1, respectively, allowing their determination in real samples. Precision of the analytical procedure was 6.8% for arsenic, 5.2% for selenium and 7.7% for mercury (n=7). The accuracy and reliability of the method was verified by the analysis of both standard reference materials (rice flour and spinach leaves) and real samples (natural and Se‐enriched rice).

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Environmental context. Although arsenic occurs in marine animals at high concentrations, the pathways by which it is biotransformed and accumulated remain largely unknown. The observation that some species of algae can contain significant concentrations of arsenobetaine, a major marine arsenic species, is relevant to explanations of the source of this compound to marine animals and its transport through the marine food web. Abstract. Significant amounts of arsenobetaine (up to 0.80 μg As g–1 dry mass, representing 17% of the extractable arsenic) were found in the extracts of all four samples of the red alga Phyllophora antarctica collected from two sites in Antarctica (Terra Nova Bay and Cape Evans). The assignment was made with high performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICPMS) based on exact cochromatography with a standard compound with two chromatographic systems (cation-exchange and ion-pairing reversed-phase), each run under two sets of mobile phase conditions. Particular care was taken during sample preparation to ensure that the arsenobetaine was of algal origin and did not result from epiphytes associated with the alga. Another red alga, Iridaea cordata, collected from Terra Nova Bay, did not contain detectable concentrations of arsenobetaine. For both algal species, the majority of the extractable arsenic was present as arsenosugars. Confirmation that marine algae can contain significant amounts of arsenobetaine allows a simpler explanation for the widespread occurrence of this arsenical in marine animals.

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Environmental context. In studies on trace element accumulation and transformation, it is difficult to distinguish the relative contribution of natural and anthropogenic sources. Antarctic ecosystems provide the opportunity to investigate the natural cycles of the elements, because the food webs are relatively simple and trace element contamination from anthropogenic sources is negligible. We report the arsenic species in various tissues from a range of Antarctic organisms, and compare the patterns of arsenicals with those from similar studies in temperate and tropical waters. Abstract. 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.