Study of heavy metal bioaccumulation in Mytilus galloprovincialis (Lamark 1819) from heavy metal mixture using the CCF design

Marine pollutants such as heavy metals are well-known due to their bioaccumulative nature, toxicity and persistence in the marine environment. The present research aims to evaluate the bioaccumulation of three metals (Cd, Zn and Cu), individual mean (multimetal) bioaccumulation index (IMBI) and metal pollution index (MPI) as an assessment tool in Mediterranean mussel (Mytilus galloprovincis), based on the full factorial central composite face centered (CCF) design. Mussels were exposed to different sub-lethal concentrations (0-10%-72h-LC50 -72h-mg.L-1) of studied heavy metals for three days. At the end of exposure cycle, the bioaccumulations of heavy metals content in mussels were determined. Multiple regressions were used to fit experimental data to a second-order polynomial equation, which was then examined using variance analysis (ANOVA). The results revealed that the indexes IMBI and MPI depend on the type and concentration of metals and also on the metals combination. Accordingly, the toxicological metal-metal interactions were found not linear meaning supra-additive (synergistic), infra-additive (antagonistic) or no/zero interaction. The optimization of experimental data was used to determine the optimal conditions for the heavy metal bioaccumulation. It was demonstrated that the CCF design combined with the concept of quantitative bioindicators can be used as appropriate tool in ecotoxicological evaluation and prediction of metals bioaccumulation. (C) 2021 The Author(s). Published by Elsevier B.V.