An assessment of copper,zinc and cadmium contamination and their ecotoxicological effects in O. mediterranea Costa, 1853 (Amphipoda,Talitridae)

This study was conducted to compare metals bioaccumulation in the Talitrid O. mediterranea collected from the banks of Bizerte lagoon. Individuals were exposed to a series of contaminated soil with different concentrations of cadmium, copper, and zinc. Biological and physiological responses were highlighted. Body metals concentrations were measured in the talitrid using flame atomic emission spectrometry. Results showed that after the second week, the mortality increased especially with cadmium exposure, and a mass gain was obtained between weeks for copper and zinc. Furthermore, the concentration factor indicated that O. mediterranea could be considered as a macroconcentrator of copper and zinc. Histopathological analysis showed that the different metals concentrations induced significant changes in the morphology and in the ultrastructural organisation of hepatopancreatic cells. Significant alterations obtained after metals exposure were the increase in the number of the majority cell organelles. Also, heavy metals were present in the form of numerous granules with different size in the cell surface. Furthermore, metals exposure affected the brush border causing the disruption of microvilli filament. Through these results, O. mediterranea could be a good indicator providing measurable responses. It could be an attractive candidate for the biochemical study of heavy metals toxicity in coastal ecosystems.     

The removal of uranium (VI) from aqueous solutions onto activated carbon developed from grinded used tire

In this study, activated carbon was prepared from waste tire by KOH chemical activation. The pore properties including the BET surface area, pore volume, pore size distribution, and average pore diameter were characterized. BET surface area of the activated carbon was determined as 558 m²/g. The adsorption of uranium ions from the aqueous solution using this activated carbon has been investigated. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied by a batch method. The optimum pH for adsorption was found to be 3. The removal efficiency has also been determined for the adsorption system as a function of initial concentration. The experimental results were fitted to Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) isotherm models. A comparison of best-fitting was performed using the coefficient of correlation and the Langmuir isotherm was found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the saturated monolayer sorption capacity of uranium ions onto waste tire activated carbon was 158.73 mg/g. The thermodynamic equilibrium constant and the Gibbs free energy were determined and results indicated the spontaneous nature of the adsorption process. Kinetics data were best described by pseudo-second-order model.     

Ecotoxicological effects of trace element contamination in talitrid amphipod Orchestia montagui Audouin, 1826

Environmental Science and Pollution Research - This study deals with the evaluation of trace element bioaccumulation and histological alterations in the hepatopancreas of the supralittoral amphipod...