ABSTRACT
Figure 1. Seasonal variation of total As levels in tissues of S. spallanzanii from a reference site (mean ± s.d., n = 5).
the presence of DMA in tissues of S. spallanzanii might also derive from the methylation of inorganic As usually present in abiotic matrices, such as seawater and sediments. To obtain further insights on the As metabolism in S. spallanzanii, bioaccumulation and biotransformation were investigated in this Mediterranean fan worm in laboratory conditions. Polychaetes were exposed to various chemical species of As including arsenate (AsV) (20 μg/L), DMA (60 μg/L), trimethylarsine (TMA) (60 μg/L) and AsB (60 μg/L). After 20 days total As content and chemical speciation were measured in both branchial crowns and body portion. The highest increases of As content were observed in branchial crowns of organisms treated with arsenate, which can enter the cell through the phosphate carrier system; still significant but lower variations were measured after exposures with DMA and TMA, while no accumulation was observed with AsB (Fig. 2). In body tissues, exposure to As(V), DMA, TMA confirmed a progressively lower accumulation of total As, while a marked increase was caused by AsB.
