Occurrence of mercury in polychaete species (Annelida) and their associated sediments from an important Southern Atlantic Ocean Bay

In the present study, the Hg levels in freshly collected polychaete species and their associated sediments were evaluated from Todos os Santos Bay, Northeastern Brazil. Additionally, it was also measured the Hg distribution along the annelids' body parts (anterior region, abdomen, and posterior region). Total Hg concentration was as follows: 13.6-144 mu g kg(-1) (Scolelepis chilensis, deposit feeder), 8.2-122 mu g kg(-1) (Laeonereis acuta, deposit feeder), 95-612 mu g kg(-1) (Armandia agilis, deposit feeder); 96.6-206 mu g kg(-1) (Lumbrineris sp., carnivorous), 75.3-112 mu g kg(-1) (Goniada echinulate, carnivorous), and 115-198 mu g kg(-1) (Branchiomma sp., suspension feeder). In turn, Hg levels in sediments ranged from 2.77 & PLUSMN; 0.24 to 6.38 & PLUSMN; 0.15 mu g kg(-1) . Hg concentrations found in polychaete soft tissues were higher than those found in the sediments. Specific habits, feeding behavior, trophic level, and stressful environmental conditions are the main factors affecting the Hg levels in the species studied. The bioaccumulation factor (BAF), contamination factor (CF), and ecological risk assessment (Er) were calculated. The BAF values were higher than 1 for all studied species, indicating Hg bioaccumulation in the annelids, but the low levels of CF e Er showed those Hg levels present low to no significant ecological risk for the biota and benthonic organisms living in the sediments. Finally, no statistically significant difference was observed for Hg concentration levels along the polychaete body parts.

Automated summary

In this study, the levels of mercury (Hg) in polychaete species and sediments from Todos os Santos Bay, Northeastern Brazil were evaluated. The Hg distribution along different body parts of the annelids was also measured. The results showed that Hg levels in the polychaete tissues were higher than those in the sediments. The specific habits, feeding behavior, trophic level, and environmental conditions were found to be the main factors affecting Hg levels in the studied species. The bioaccumulation factor (BAF), contamination factor (CF), and ecological risk assessment (Er) were calculated, indicating low to no significant ecological risk of Hg for the biota and benthonic organisms living in the sediments. Additionally, no statistically significant difference was observed for Hg concentration levels along the polychaete body parts.