Assessment of toxic trace elements (Cd, Pb, As, and Co) in small, medium, and large individuals of Mytilus galloprovincialis and Perna perna mussel species along the Algerian coast.

This research paper focused on the monitoring of marine sites using mussels, which are highly valuable organisms in assessing environmental health. However, a significant challenge arises when determining the appropriate size of mussels for monitoring purposes. The objective of this study was to examine the levels of Cd, Pb, As, and Co in three different size classes of two mussel species, Mytilus galloprovincialis and Perna perna, collected from three sites along the Algerian coast, each exhibiting varying degrees of pollution.At each of the study sites, a total of thirty individuals from small, medium, and large size classes of mussels were collected during four different time periods. The mussels were then dissected, and the concentrations of Cd, Pb, As, and Co were measured in the entire flesh of the mussels using ICP-MS.Across the various study sites, the concentrations of cadmium, lead, arsenic, and cobalt ranged from 0.06 to 1.32 mg/kg, 0.09 to 12.56 mg/kg, 4.23 to 18.31 mg/kg, and 0.11 to 1.85 mg/kg, respectively. Interestingly, the distribution of these metals in the three different size classes of mussels followed a consistent pattern at all the study sites. Large mussels exhibited higher concentrations, while small and medium-sized mussels displayed lower levels. These findings highlight substantial spatial and temporal variations in metal concentrations within the studied sites.

Baseline levels of integrated biomarker response index (IBR) in Mytilus galloprovincialis (Lamarck, 1819) of BouIsmail bay for monitoring Algerian Bays (Mediterranean Sea).

The Multiple Linear Regression (MLR) technique was used to determine the relationship between the integrated biomarker response index (IBR) with the most important confounding factors (Temperature, pH, Salinity and Dissolved oxygen), in order to define: (1) the baseline assessment criteria (BAC), (2) the environmental assessment criteria (EAC) and (3) the BouIsmail Bay (BIB) -Taxonomy by using Mytilus galloprovincialis sampled from two references sites in BIB (W. Tipaza, Algeria) during one season. Therefore, our results show that, the temperature appeared as a major factor for the explanation of the model. The coefficients of determination and F values for IBR validated the efficiency of model. In addition, the use MLR, BAC and EAC values in BIB-Taxonomy can deference between unpolluted and polluted areas in BouIsmail Bay in particular and Algerian Bays in general. This approach is therefore a valuable tool that could be used for monitoring the coastal sites.

Modeling integrated biomarker response (IBR) index for the mussel Mytilus galloprovincialis (Lamark 1819) exposed to heavy metal mixture using the CCF design.

Marine pollutants such as heavy metals (HMs) are considered among the most copious oxidative stress (OS) inducers in marine organisms which leads to reactive oxygen species (ROS) formation. Complementary to our previous bioassays studies, the present research focuses on Catalase (CAT), Glutathione S-transferase (GST) and Malondialdehyde (MDA) as oxidative stress biomarkers and the integrated biomarker response (IBR) indexes (IBR1 and IBR2) as an ecotoxicological assessment tool in Mytilus galloprovincialis using central composite face centered (CCF) design. The oxidative stress biomarkers were measured in adult mussels (45-55 mm) on 3 days-exposed under different sub-lethal concentrations of cadmium (Cd), zinc (Zn), and copper (Cu). Using multiple regressions, ANOVA analysis revealed that experimental data fitted to second-order (quadratic) polynomial equations. The results showed that types, concentrations and metals combinations has a direct effect in CAT and GST activities, MDA level and IBR indexes. Additionally, metal-metal interactions were found synergistic (supra-additive), antagonistic (infra-additive) or zero interaction in the toxicological effect. As necessary, the optimization of the experimental results was done in order to determine the optimal conditions for the oxidative stress responses and IBR indexes. It was demonstrated that the CCF design combined with the multi-biomarker approach and IBR index can be used as an appropriate tool in ecotoxicological modulation and prediction of oxidative stress and antioxidant status by heavy metals in the mussels Mytilus galloprovincialis.

Electrochemical disinfection of bacterial contamination: Effectiveness and modeling study of E. coli inactivation by electro-Fenton, electro-peroxi-coagulation and electrocoagulation.

The present work undertakes an examination and comparison of electro-Fenton (EF), electro-peroxi-coagulation (EPC) and electrocoagulation (EC) applied to the E. coli inactivation in batch reactor. Indeed, platinum (Pt (anode), EF), stainless steel (SS (cathode), EF, EPC) and ordinary steel (Fe (anode), EPC) and aluminum (Al, EC) were used respectively. The current intensity, nature of electrolytic support, bacterial density and hydrogen peroxide (H2O2) concentration are the most influenced study parameters. The obtained results showed that the high current intensities were significant for better inactivation and destruction of E. coli cells and caused a maximum of energy consumption. Both disinfection and energy consumption were improved by adding NaCl (or Na2SO4) in the three processes. Higher cellular density limited the electrochemical process and has negative effect in E. coli inactivation and the energy consumption. Only in the EPC case, the disinfection was considerably increased in function with H2O2 concentration. The modeling parameters of the inactivation kinetics of E. coli showed a good fitting of the established model (0.9560 < R2 < 0.9979, 0.9267 < R2 adjusted <0.997 and 0.0189 < RMSE <0.4821), faster kinetics of E. coli inactivation (significant values of Kmax and Sl) in the case of high current intensity (0.2442