Bioaccumulation of Mercury in the Copepod Pseudodiaptomus marinus: A Comparative Study Between Waterborne and Dietary Pathways

The fate and the accumulation kinetics of mercurychloride (HgCl2) were investigated in the invasive copepod species Pseudodiaptomus marinus, which originates from the North-Western Pacific Ocean and was recently recorded from the Atlantic and Mediterranean coasts. The main objective of this study was to determine lethal concentrations (LC50%) of HgCl2 in P. marinus and to study its bioaccumulation kinetics in the laboratory. Lethality experiments were performed for 24, 48, 72, and 96 h. Experiments in presence and absence of food source using one sub-lethal concentration of HgCl2 (14.15 mu g/L) were carried out to study the uptake, the accumulation and the influence of exposure pathways of HgCl2 in P. marinus. LC50 for 96 h was calculated as 42.4 mu g/L in response to HgCl2. The uptake and bioaccumulation kinetics of HgCl2 in P. marinus are not depending on the exposure pathways, where no significant differences were depicted between the uptake/accumulation of HgCl2 from the micro-algal diet and from the seawater medium. Those results could be helpful in the understanding of mercury uptake, bioaccumulation and bio-amplification processes especially concerning invasive copepod species. Article Highlights LC50 for 96h was calculated as 42.4 mu g/L HgCl2. I. galbana uptaked and accumulated Hg more than starved and fed P. marinus. The uptake and the bioaccumulation kinetics of Hg was slow during the 1st and 4th days in starved and fed P. marinus. The uptake and bioaccumulation kinetics of HgCl2 in P. marinus were not depending on the exposure pathway.