Comparative study on the bioaccumulation and biotransformation of arsenic by some northeastern Atlantic and northwestern Mediterranean sponges

Abstract The bioaccumulation and biotransformation of arsenic (As) were studied in six representative marine spongesfrom the French Mediterranean and Irish Atlantic coasts. Methodologies were carefully optimized in one of the species on Haliclonafulva spongesfor two critical steps: the sample mineralization for total As analysis by ICP-MS and the extraction of As species for HPLC-ICP-MS analysis. During the optimization, extractions performed with 0.6 mol L −1 H 3 PO 4 were shown to be the most efficient. Extraction recovery of 81% was obtained which represents the best results obtained until now in spongesamples. Total As analyses and As speciation were performed on certified reference materialsand allow confirming the measurement quality both during the sample preparation and analysis. Additionally, this study represents an environmental surveydemonstrating a high variability of total As concentrations among the different species, probably related to different physiological or microbial features. As speciation results showed the predominance of arsenobetaine(AsB) regardless of the spongespecies, as well as the occurrence of low amounts of dimethylarsinic acid (DMA), arsenate (As(+V)), and unknown As species in some samples. The process responsible for As transformation in spongesis most likely related to spongesmetabolism itself or the action of symbiont organisms. AsB is supposed to be implied in the protection against osmolyticstress. This study demonstrates the ability of spongesto accumulate and bio-transform As, proving that spongesare relevant bio-monitors for As contamination in the marine environment, and potential tools in environmental bio-remediation.