Anthropogenic and naturally-produced organobrominated compounds in marine mammals from Brazil

Liver samples from 51 cetaceans, comprising 10 species, stranded between 1994 and 2006 in a highly industrialized and urbanized region in Southeast Brazil, were analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated-PBDEs (MeO-PBDEs). A concentration range of PBDEs (3-5960 ng/g lw) similar to that observed in Northern Hemisphere dolphins was found. MeO-PBDE concentrations in continental shelf (CS) dolphins from Brazil are among the highest detected to date in cetaceans (up to 250 µg/g lw). Higher [Sigma]MeO-PBDE concentrations were measured in CS and oceanic dolphins than in estuarine dolphins. The [Sigma]PBDE/[Sigma]MeO-PBDE ratio varied significantly ranging from a mean value of 7.12 to 0.08 and 0.01 for estuarine, CS and oceanic species, respectively. A positive correlation was observed between [Sigma]PBDE and year of stranding of male estuarine dolphins (Sotalia guianensis), which suggests temporal variation in the exposure. Placental transfer of organobrominated compounds was also evidenced in S. guianensis